Cerebral Palsy

Definition

Cerebral palsy (CP) is the term used for a group of nonprogressive disorders of movement and posture caused by abnormal development of, or damage to, motor control centers of the brain. CP is caused by events before, during, or after birth. The abnormalities of muscle control that define CP are often accompanied by other neurological and physical abnormalities.

Description

Voluntary movement (walking, grasping, chewing, etc.) is primarily accomplished using muscles that are attached to bones, known as the skeletal muscles. Control of the skeletal muscles originates in the cerebral cortex, the largest portion of the brain. Palsy means paralysis, but may also be used to describe uncontrolled muscle movement. Therefore, cerebral palsy encompasses any disorder of abnormal movement and paralysis caused by abnormal function of the cerebral cortex. In truth, however, CP does not include conditions due to progressive disease or degeneration of the brain. For this reason, CP is also referred to as static (nonprogressive) encephalopathy (disease of the brain). Also excluded from CP are any disorders of muscle control that arise in the muscles themselves and/or in the peripheral nervous system (nerves outside the brain and spinal cord).

CP is not a specific diagnosis, but is more accurately considered a description of a broad but defined group of neurological and physical problems.

The symptoms of CP and their severity are quite variable. Those with CP may have only minor difficulty with fine motor skills, such as grasping and manipulating items with their hands. A severe form of CP could involve significant muscle problems in all four limbs, mental retardation, seizures, and difficulties with vision, speech, and hearing.

Muscles that receive defective messages from the brain may be constantly contracted and tight (spastic), exhibit involuntary writhing movements (athetosis), or have difficulty with voluntary movement (dyskinesia). There can also be a lack of balance and coordination with unsteady movements (ataxia). A combination of any of these problems may also occur. Spastic CP and mixed CP constitute the majority of cases. Effects on the muscles can range from mild weakness or partial paralysis (paresis), to complete loss of voluntary control of a muscle or group of muscles (plegia). CP is also designated by the number of limbs affected. For instance, affected muscles in one limb is monoplegia, both arms or both legs is diplegia, both limbs on one side of the body is hemiplegia, and in all four limbs is quadriplegia. Muscles of the trunk, neck, and head may be affected as well.

CP can be caused by a number of different mechanisms at various times—from several weeks after conception, through birth, to early childhood. For many years, it was accepted that most cases of CP were due to brain injuries received during a traumatic birth, known as birth asphyxia. However, extensive research in the 1980s showed that only 5-10% of CP can be attributed to birth trauma. Other possible causes include abnormal development of the brain, prenatal factors that directly or indirectly damage neurons in the developing brain, premature birth, and brain injuries that occur in the first few years of life.

Advances in the medical care of premature infants in the last 20 years have dramatically increased the rate of survival of these fragile newborns. However, as gestational age at delivery and birth weight of a baby decrease, the risk for CP dramatically increases. A term pregnancy is delivered at 37-41 weeks gestation. The risk for CP in a preterm infant (32-37 weeks) is increased about five-fold over the risk for an infant born at term. Survivors of extremely preterm births (less than 28 weeks) face as much as a 50-fold increase in risk. About 50% of all cases of CP now being diagnosed are in children who were born prematurely.

Two factors are involved in the risk for CP associated with prematurity. First, premature babies are at higher risk for various CP-associated medical complications, such as intracerebral hemorrhage, infection, and difficulty in breathing, to name a few. Second, the onset of premature labor may be induced, in part, by complications that have already caused neurologic damage in the fetus. A combination of both factors almost certainly plays a role in some cases of CP. The tendency toward premature delivery runs in families, but the genetic mechanisms are far from clear.

An increase in multiple pregnancies in recent years, especially in the United States, is blamed on the increased use of fertility drugs. As the number of fetuses in a pregnancy increases, the risks for abnormal development and premature delivery also increase. Children from twin pregnancies have four times the risk of developing CP as children from singleton pregnancies, owing to the fact that more twin pregnancies are delivered prematurely. The risk for CP in a child of triplets is up to 18 times greater. Furthermore, recent evidence suggests that a baby from a pregnancy in which its twin died before birth is at increased risk for CP.

Approximately 500,000 children and adults in the United States have CP, and it is newly diagnosed in about 6,000 infants and young children each year. The incidence of CP has not changed much in the last 20-30 years. Ironically, while advances in medicine have decreased the incidence from some causes—Rh disease for example—they have increased it from others, notably, prematurity and multiple pregnancies. No particular ethnic groups seem to be at higher risk for CP. However, people of disadvantaged back-ground are at higher risk due to poorer access to proper prenatal care and advanced medical services.

Causes and symptoms

As noted, CP has many causes, making a discussion of the genetics of CP complicated. A number of hereditary/genetic syndromes have signs and symptoms similar to CP, but usually also have problems not typical of CP. Put another way, some hereditary conditions "mimic" CP. Isolated CP, meaning CP that is not a part of some other syndrome or disorder, is usually not inherited.

It might be possible to group the causes of CP into those that are genetic and those that are non-genetic, but most would fall somewhere in between. Grouping causes into those that occur during pregnancy (prenatal), those that happen around the time of birth (perinatal), and those that occur after birth (postnatal), is preferable. CP related to premature birth and multiple pregnancies (twins, triplets, etc., not "many pregnancies") is somewhat different and considered separately.

Prenatal causes

Although much has been learned about human embryology in the last few decades, a great deal remains unknown. Studying prenatal human development is difficult because the embryo and fetus develop in a closed environment—the mother's womb. However, the relatively recent development of a number of prenatal tests has opened a window on the process. Add to that more accurate and complete evaluations of newborns, especially those with problems, and a clearer picture of what can go wrong before birth is possible.

The complicated process of brain development before birth is susceptible to many chance errors that can result in abnormalities of varying degrees. Some of these errors will result in structural anomalies of the brain, while others may cause undetectable, but significant, abnormalities in how the cerebral cortex is "wired." An abnormality in structure or wiring is sometimes hereditary, but is most often due to chance, or a cause unknown at this time. Whether and how much genetics played a role in a particular brain abnormality depends to some degree on the type of anomaly and the form of CP it causes.

Several maternal-fetal infections are known to increase the risk for CP, including rubella (German measles, now rare in the United States), cytomegalovirus (CMV), and toxoplasmosis. Each of these infections is considered a risk to the fetus only if the mother contracts it for the first time during that pregnancy. Even in those cases, though, most babies will be born normal. Most women are immune to all three infections by the time they reach childbearing age, but a woman's immune status can be determined using the so-called TORCH (for Toxoplasmosis, Rubella, Cytomegalovirus, and Herpes) test before or during pregnancy.

Reserchers continue to study the role of perinatal infection in development of cerebral palsy. New evidence in 2004 linked inflammatory cytokines to possible cerebral injury that could lead to CP. Scientists suggested new research with intravenous immunoglobulin to limit inflammatory damage.

Just as a stroke can cause neurologic damage in an adult, so too can this type of event occur in the fetus. A burst blood vessel in the brain followed by uncontrolled bleeding (coagulopathy), known as intracerebral hemorrhage, could cause a fetal stroke, or a cerebral blood vessel could be obstructed by a clot (embolism ). Infants who later develop CP, along with their mothers, are more likely than other mother-infant pairs to test positive for factors that put them at increased risk for bleeding episodes or blood clots. Some coagulation disorders are strictly hereditary, but most have a more complicated basis.

A teratogen is any substance to which a woman is exposed that has the potential to harm the embryo or fetus. Links between a drug or other chemical exposure during pregnancy and a risk for CP are difficult to prove. However, any substance that might affect fetal brain development, directly or indirectly, could increase the risk for CP. Furthermore, any substance that increases the risk for premature delivery and low birth weight, such as alcohol, tobacco, or cocaine, among others, might indirectly increase the risk for CP.

The fetus receives all nutrients and oxygen from blood that circulates through the placenta. Therefore, anything that interferes with normal placental function might adversely affect development of the fetus, including the brain, or might increase the risk for premature delivery. Structural abnormalities of the placenta, premature detachment of the placenta from the uterine wall (abruption), and placental infections (chorioamnionitis) are thought to pose some risk for CP.

Certain conditions in the mother during pregnancy might pose a risk to fetal development leading to CP. Women with autoimmune anti-thyroid or anti-phospholipid (APA) antibodies are at slightly increased risk for CP in their children. A potentially important clue uncovered recently points toward high levels of cytokines in the maternal and fetal circulation as a possible risk for CP. Cytokines are proteins associated with inflammation, such as from infection or autoimmune disorders, and they may be toxic to neurons in the fetal brain. More research is needed to determine the exact relationship, if any, between high levels of cytokines in pregnancy and CP. A woman has some risk of developing the same complications in more than one pregnancy, slightly increasing the risk for more than one child with CP.

Serious physical trauma to the mother during pregnancy could result in direct trauma to the fetus as well, or injuries to the mother could compromise the availability of nutrients and oxygen to the developing fetal brain.

Perinatal causes

Birth asphyxia significant enough to result in CP is now uncommon in developed countries. Tight nuchal cord (umbilical cord around the baby's neck) and prolapsed cord (cord delivered before the baby) are possible causes of birth asphyxia, as are bleeding and other complications associated with placental abruption and placenta previa (placenta lying over the cervix).

Infection in the mother is sometimes not passed to the fetus through the placenta, but is transmitted to the baby during delivery. Any such infection that results in serious illness in the newborn has the potential to produce some neurological damage.

Postnatal causes

The remaining 15% of CP is due to neurologic injury sustained after birth. CP that has a postnatal cause is sometimes referred to as acquired CP, but this is only accurate for those cases caused by infection or trauma.

Incompatibility between the Rh blood types of mother and child (mother Rh negative, baby Rh positive) can result in severe anemia in the baby (erythroblastosis fetalis ). This may lead to other complications, including severe jaundice, which can cause CP. Rh disease in the newborn is now rare in developed countries due to routine screening of maternal blood type and treatment of pregnancies at risk. The routine, effective treatment of jaundice due to other causes has also made it an infrequent cause of CP in developed countries. Rh blood type poses a risk for recurrence of Rh disease if treatment is not provided.

Serious infections that affect the brain directly, such as meningitis and encephalitis, may cause irreversible damage to the brain, leading to CP. A seizure disorder early in life may cause CP, or may be the product of a hidden problem that causes CP in addition to seizures. Unexplained (idiopathic) seizures are hereditary in only a small percentage of cases. Although rare in infants born healthy at or near term, intracerebral hemorrhage and brain embolism, like fetal stroke, are sometimes genetic.

Physical trauma to an infant or child resulting in brain injury, such as from abuse, accidents, or near drowning/suffocation, might cause CP. Likewise, ingestion of a toxic substance such as lead, mercury, poisons, or certain chemicals could cause neurological damage. Accidental overdose of certain medications might also cause similar damage to the central nervous system.

By definition, the defect in cerebral function causing CP is nonprogressive. However, the symptoms of CP often change over time. Most of the symptoms of CP relate in some way to the abnormal control of muscles. To review, CP is categorized first by the type of movement/postural disturbance(s) present, then by a description of which limbs are affected, and finally by the severity of motor impairment. For example, spastic diplegia refers to continuously tight muscles that have no voluntary control in both legs, while athetoid quadraparesis describes uncontrolled writhing movements and muscle weakness in all four limbs. These three-part descriptions are helpful in providing a general picture, but cannot give a complete description of any one person with CP. In addition, the various "forms" of CP do not occur with equal frequency—spastic diplegia is seen in more individuals than is athetoid quadraparesis. CP can also be loosely categorized as mild, moderate, or severe, but these are very subjective terms with no firm boundaries between them.

A muscle that is tensed and contracted is hypertonic, while excessively loose muscles are hypotonic. Spastic, hypertonic muscles can cause serious orthopedic problems, including scoliosis (spine curvature), hip dislocation, or contractures. A contracture is shortening of a muscle, aided sometimes by a weak-opposing force from a neighboring muscle. Contractures may become permanent, or "fixed," without some sort of intervention. Fixed contractures may cause postural abnormalities in the affected limbs. Clenched fists and contracted feet (equinus or equinovarus) are common in people with CP. Spasticity in the thighs causes them to turn in and cross at the knees, resulting in an unusual method of walking known as a "scissors gait." Any of the joints in the limbs may be stiff (immobilized) due to spasticity of the attached muscles.

Athetosis and dyskinesia often occur with spasticity, but do not often occur alone. The same is true of ataxia. It is important to remember that "mild CP" or "severe CP" refers not only to the number of symptoms present, but also to the level of involvement of any particular class of symptoms.

Mechanisms that can cause CP are not always restricted to motor-control areas of the brain. Other neurologically based symptoms may include:

• mental retardation/learning disabilities
• behavioral disorders
• seizure disorders
• visual impairment
• hearing loss
• speech impairment (dysarthria)
• abnormal sensation and perception

These problems may have a greater impact on a child's life than the physical impairments of CP, although not all children with CP are affected by other problems. Many infants and children with CP have growth impairment. About one-third of individuals with CP have moderate-to-severe mental retardation, one-third have mild mental retardation, and one-third have normal intelligence.

Diagnosis

The signs of CP are not usually noticeable at birth. Children normally progress through a predictable set of developmental milestones through the first 18 months of life. Children with CP, however, tend to develop these skills more slowly because of their motor impairments, and delays in reaching milestones are usually the first symptoms of CP. Babies with more severe cases of CP are usually diagnosed earlier than others.

Selected developmental milestones, and the ages for normally acquiring them, are given below. If a child does not acquire the skill by the age shown in parentheses, there is some cause for concern.

• sits well unsupported—6 months (8-10 months)
• babbles—six months (eight months)
• crawls—nine months (12 months)
• finger feeds, holds bottle—nine months (12 months)
• walks alone—12 months (15-18 months)
• uses one or two words other than dada/mama—12 months (15 months)
• walks up and down steps—24 months (24-36 months)
• turns pages in books; removes shoes and socks—24 months (30 months)

Children do not consistently favor one hand over the other before 12-18 months, and doing so may be a sign that the child has difficulty using the other hand. This same preference for one side of the body may show up as asymmetric crawling or, later on, favoring one leg while climbing stairs.

It must be remembered that children normally progress at somewhat different rates, and slow beginning accomplishment is often followed by normal development. Other causes for developmental delay—some benign, some serious—should be excluded before considering CP as the answer. CP is nonprogressive, so continued loss of previously acquired milestones indicates that CP is not the cause of the problem.

No one test is diagnostic for CP, but certain factors increase suspicion. The Apgar score measures a baby's condition immediately after birth. Babies that have low Apgar scores are at increased risk for CP. Presence of abnormal muscle tone or movements may indicate CP, as may the persistence of infantile reflexes. Imaging of the brain using ultrasound, x rays, MRI, and/or CT scans may reveal a structural anomaly. Some brain lesions associated with CP include scarring, cysts, expansion of the cerebral ventricles (hydrocephalus ), periventricular leukomalacia (an abnormality of the area surrounding the ventricles), areas of dead tissue (necrosis), and evidence of an intracerebral hemorrhage or blood clot. Blood and urine biochemical tests, as well as genetic tests, may be used to rule out other possible causes, including muscle and peripheral nerve diseases, mitochondrial and metabolic diseases, and other inherited disorders. Evaluations by a pediatric developmental specialist and a geneticist may be of benefit.

Treatment

Cerebral palsy cannot be cured, but many of the disabilities it causes can be managed through planning and timely care. Treatment for a child with CP depends on the severity, nature, and location of the primary muscular symptoms, as well as any associated problems that might be present. Optimal care of a child with mild CP may involve regular interaction with only a physical therapist and occupational therapist, whereas care for a more severely affected child may include visits to multiple medical specialists throughout life. With proper treatment and an effective plan, most people with CP can lead productive, happy lives.

Therapy

Spasticity, muscle weakness, coordination, ataxia, and scoliosis are all significant impairments that affect the posture and mobility of a person with CP. Physical and occupational therapists work with the patient, and the family, to maximize the ability to move affected limbs, develop normal motor patterns, and maintain posture. "Assistive technology," things such as wheelchairs, walkers, shoe inserts, crutches, and braces, are often required. A speech therapist, and high-tech aids such as computer-controlled communication devices, can make a tremendous difference in the life of those who have speech impairments. A new experimental physical therapy treatment was tested on children in 2004 that often is used on adults who have had strokes. Called constraint-induced movement therapy, it consists of placing the child's stronger arm in a case for three weeks and giving him or her 21 straight days to retrain the weaker arm.

Medications

Before fixed contractures develop, muscle-relaxant drugs such as diazepam (Valium), dantrolene (Dantrium), and baclofen (Lioresal) may be prescribed. Botulinum toxin (Botox), a newer and highly effective treatment, is injected directly into the affected muscles. Alcohol or phenol injections into the nerve controlling the muscle are another option. Multiple medications are available to control seizures, and athetosis can be treated using medications such as trihexyphenidyl HCl (Artane) and benztropine (Cogentin).

Surgery

Fixed contractures are usually treated with either serial casting or surgery. The most commonly used surgical procedures are tenotomy, tendon transfer, and dorsal rhizotomy. In tenotomy, tendons of the affected muscle are cut and the limb is cast in a more normal position while the tendon regrows. Alternatively, tendon transfer involves cutting and reattaching a tendon at a different point on the bone to enhance the length and function of the muscle. A neurosurgeon performing dorsal rhizotomy carefully cuts selected nerve roots in the spinal cord to prevent them from stimulating the spastic muscles. Neurosurgical techniques in the brain such as implanting tiny electrodes directly into the cerebellum, or cutting a portion of the hypothalamus, have very specific uses and have had mixed results.

Education

Parents of a child newly diagnosed with CP are not likely to have the necessary expertise to coordinate the full range of care their child will need. Although knowledgeable and caring medical professionals are indispensable for developing a care plan, a potentially more important source of information and advice is other parents who have dealt with the same set of difficulties. Support groups for parents of children with CP can be significant sources of both practical advice and emotional support. Many cities have support groups that can be located through the United Cerebral Palsy Association, and most large medical centers have special multidisciplinary clinics for children with developmental disorders.

Prognosis

Cerebral palsy can affect every stage of maturation, from childhood through adolescence to adulthood. At each stage, those with CP, along with their caregivers, must strive to achieve and maintain the fullest range of experiences and education consistent with their abilities. The advice and intervention of various professionals remains crucial for many people with CP. Although CP itself is not considered a terminal disorder, it can affect a person's lifespan by increasing the risk for certain medical problems. People with mild cerebral palsy may have near-normal lifespans, but the lifespan of those with more severe forms may be shortened. However, more than 90% of infants with CP survive into adulthood.

The cause of most cases of CP remains unknown, but it has become clear in recent years that birth difficulties are not to blame in most cases. Rather, developmental problems before birth, usually unknown and generally undiagnosable, are responsible for most cases. The rate of survival for preterm infants has leveled off in recent years, and methods to improve the long-term health of these at-risk babies are now being sought. Current research is also focusing on the possible benefits of recognizing and treating coagulopathies and inflammatory disorders in the prenatal and perinatal periods. The use of magnesium sulfate in pregnant women with preeclampsia or threatened preterm delivery may reduce the risk of CP in very preterm infants. Finally, the risk of CP can be decreased through good maternal nutrition, avoidance of drugs and alcohol during pregnancy, and prevention or prompt treatment of infections.

KEY TERMS

Asphyxia— Lack of oxygen. In the case of cerebral palsy, lack of oxygen to the brain.

Ataxia— A deficiency of muscular coordination, especially when voluntary movements are attempted, such as grasping or walking.

Athetosis— A condition marked by slow, writhing, involuntary muscle movements.

Coagulopathy— A disorder in which blood is either too slow or too quick to coagulate (clot).

Contracture— A tightening of muscles that prevents normal movement of the associated limb or other body part.

Cytokine— A protein associated with inflammation that, at high levels, may be toxic to nerve cells in the developing brain.

Diplegia— Paralysis affecting like parts on both sides the body, such as both arms or both legs.

Dorsal rhizotomy— A surgical procedure that cuts nerve roots to reduce spasticity in affected muscles.

Dyskinesia— Impaired ability to make voluntary movements.

Hemiplegia— Paralysis of one side of the body.

Hypotonia— Reduced or diminished muscle tone.

Quadriplegia— Paralysis of all four limbs.

Serial casting— A series of casts designed to gradually move a limb into a more functional position.

Spastic— A condition in which the muscles are rigid, posture may be abnormal, and fine motor control is impaired.

Spasticity— Increased mucle tone, or stiffness, which leads to uncontrolled, awkward movements.

Static encephalopathy— A disease of the brain that does not get better or worse.

Tenotomy— A surgical procedure that cuts the tendon of a contracted muscle to allow lengthening.

Resources

BOOKS

Peacock, Judith. Cerebral Palsy. Mankato, MN: Capstone Press, 2000.

Pimm, Paul. Living With Cerebral Palsy. Austin, TX: Raintree Steck-Vaughn Publishers, 2000.

Pincus, Dion. Everything You Need to Know About Cerebral Palsy. New York: Rosen Publishing Group, Inc., 2000.

PERIODICALS

Chambers, Henry G. "Research in Cerebral Palsy." The Exceptional Parent 29 (July 1999): 50.

"Experimental Treatment Yields New Hope for Children Battling Cerebral Palsy." Drug Week February 27, 2004: 82.

Mohan, P.V., et al. "Can Polyclonal Intravenous Immunoglobulin Limit Cytokine Mediated Cerebral Damage and Chronic Lung Disease in Preterm Infants?" Archives of Disease in Childhood January 2004: pF5-pF9.

Myers, Scott M., and Bruce K. Shapiro. "Origins and Causes of Cerebral Palsy: Symptoms and Diagnosis." The Exceptional Parent 29 (April 1999): 28.

ORGANIZATIONS

Epilepsy Foundation of America. 4351 Garden City Dr., Suite 406, Landover, MD 20785-2267. (301) 459-3700 or (800) 332-1000. 〈http://www.epilepsyfoundation.org〉.

March of Dimes Birth Defects Foundation. 1275 Mamaroneck Ave., White Plains, NY 10605. (888) 663-4637. [email protected]. 〈http://www.modimes.org〉.

National Easter Seal Society. 230 W. Monroe St., Suite 1800, Chicago, IL 60606-4802. (312) 726-6200 or (800) 221-6827. 〈http://www.easter-seals.org〉.

National Institute of Neurological Disorders and Stroke. 31 Center Drive, MSC 2540, Bldg. 31, Room 8806, Bethesda, MD 20814. (301) 496-5751 or (800) 352-9424. 〈http://www.ninds.nih.gov〉.

National Society of Genetic Counselors. 233 Canterbury Dr., Wallingford, PA 19086-6617. (610) 872-1192. 〈http://www.nsgc.org/GeneticCounselingYou.asp〉.

United Cerebral Palsy Association, Inc. (UCP). 1660 L St. NW, Suite 700, Washington, DC 20036-5602. (202) 776-0406 or (800) 872-5827. 〈http://www.ucpa.org〉.

OTHER

"Cerebral Palsy: Hope Through Research." National Institute of Neurological Disorders and Stroke. 〈http://www.ninds.nih.gov/health_and_medical/pubs/cerebral_palsyhtr.htm〉.

"Cerebral Palsy Information Page." National Institute of Neurological Disorders and Stroke. 〈http://www.ninds.nih.gov/health_and_medical/pubs/cerebral_palsy.htm〉.

Cerebral Palsy

Definition

Cerebral palsy (CP) is the term used for a group of nonprogressive disorders of movement and posture caused by abnormal development of, or damage to, motor control centers of the brain or, in some cases, hypoxemia (insufficient oxygen in the blood ) during the birth process. CP is caused by events before, during, or after birth. The abnormalities of muscle control that define CP are often accompanied by other neurological and physical abnormalities.

Description

Voluntary movement (walking, grasping, chewing, etc.) is primarily accomplished using muscles that are attached to bones, known as the skeletal muscles. Control of the skeletal muscles originates in the cerebral cortex, the largest portion of the brain. Palsy means paralysis, but may also be used to describe uncontrolled muscle movement. Therefore, cerebral palsy encompasses any disorder of abnormal movement and paralysis caused by abnormal function of the cerebral cortex. However, CP does not include conditions due to progressive disease or degeneration of the brain. For this reason, CP is also referred to as static (nonprogressive) encephalopathy (disease of the brain). Also excluded from the definition of CP are any disorders of muscle control that arise in the muscles themselves or in the peripheral nervous system (nerves outside the brain and spinal cord ).

CP is not a specific diagnosis but is more accurately considered a description of a broad but defined group of neurological and physical problems.

The symptoms of CP and their severity are quite variable. Persons with CP may have only minor difficulty with fine motor skills, such as grasping and manipulating items with their hands. A severe form of CP could involve significant muscle problems in all four limbs, mental retardation, seizures, and difficulties with vision, speech, and hearing.

Muscles that receive defective messages from the brain may be constantly contracted and tight (spastic), and the person with CP may exhibit involuntary writhing movements (athetosis) or have difficulty with voluntary movement (dyskinesia). There can also be a lack of balance and coordination with unsteady movements (ataxia). A combination of any of these problems may also occur. Spastic CP and mixed CP constitute the majority of cases. Effects on the muscles can range from mild weakness or partial paralysis (paresis), to complete loss of voluntary control of a muscle or group of muscles (plegia). CP is also designated by the number of limbs affected. For instance, affected muscles in one limb is called monoplegia, affected muscles in both arms or both legs is called diplegia, affected muscles in both limbs on one side of the body is called hemiplegia, and affected muscles in all four limbs is called quadriplegia. Muscles of the trunk, neck, and head may be affected as well.

Approximately 500,000 children and adults in the United States have CP, and it is newly diagnosed in about 6,000 infants and young children each year. The incidence of CP has changed little since the 1960s and 1970s. Ironically, advances in medicine have decreased the incidence from some causes—Rh disease, for example—but have increased its incidence from other causes, notably, prematurity and multiple pregnancies. (Medical advances have made it possible for more babies born prematurely or in multiple but underweight births to survive, thus allowing more time for CP to be recognized when it does occur.) No particular ethnic groups seem to be at higher risk for CP. However, people of disadvantaged background are at higher risk due to poorer access to adequate prenatal care and advanced medical services.

Causes and symptoms

CP can be caused by a number of different mechanisms at various times—from several weeks after conception, through birth, and into early childhood. For many years it was accepted that most cases of CP were due to brain injuries received during a traumatic birth, known as birth asphyxia. However, extensive research in 1980s showed that only 5-10% of CP could be attributed to birth trauma. Other possible causes include abnormal development of the brain, prenatal factors that directly or indirectly damage neurons in the developing brain, premature birth, and brain injuries that occur in the first few years of life.

Because CP has many causes, a discussion of the genetics of CP is complicated. A number of hereditary or genetic syndromes have signs and symptoms similar to CP, but usually also have problems not typical of CP. Put another way, some hereditary conditions mimic CP. Isolated CP, meaning CP that is not a part of some other syndrome or disorder, is usually not inherited.

It might be possible to group the causes of CP into those that are genetic and those that are nongenetic, but most would fall somewhere in between. Grouping causes into those that occur during pregnancy (prenatal), those that happen around the time of birth (perinatal), and those that occur after birth (postnatal), is preferable. CP related to premature birth and multiple pregnancies (twins, triplets, etc.) is somewhat different and considered separately.

Prenatal causes

Although much has been learned about human embryology in the latter part of the twentieth century, a great deal remains unknown. Studying prenatal human development is difficult because the embryo and fetus develop in a closed environment, namely the mother's uterus. However, the relatively recent development of a number of prenatal tests provides a window on the process. Add to that more accurate and complete evaluations of newborns, especially those with problems, and a clearer picture of what can go wrong before birth is now possible.

The complicated process of brain development before birth is susceptible to many chance errors that can result in abnormalities of varying degrees. Some of these errors will result in structural anomalies of the brain, while others may cause undetectable, but significant, abnormalities among connections (sometimes referred to as wiring) in the cerebral cortex. An abnormality in structure or wiring is sometimes hereditary, but is most often due to chance, or a cause unknown at this time. Whether and how much genetics played a role in a particular brain abnormality depends to some degree on the type of anomaly and the form of CP it causes.

Just as a stroke can cause neurologic damage in an adult, so too can this type of event occur in the fetus. A burst blood vessel in the brain followed by uncontrolled bleeding (coagulopathy), known as intracerebral hemorrhage, could cause a fetal stroke. Alternatively, a cerebral blood vessel could be obstructed by a clot (embolism). Infants who later develop CP, along with their mothers, are more likely than other mother-infant pairs to test positive for factors that put them at increased risk for bleeding episodes or blood clots. Some coagulation disorders are strictly hereditary, but most have a more complicated basis.

A teratogen is any substance to which a pregnant woman is exposed that has the potential to harm an embryo or fetus. Links between a drug or other chemical exposure during pregnancy and a risk for CP are difficult to prove. However, any substance used by the pregnant woman that might affect fetal brain development, directly or indirectly, could increase the risk for CP. Furthermore, any substance used by the mother that increases the risk for premature delivery and low birth weight—such as alcohol, tobacco, or cocaine, among others—might indirectly increase the risk for CP.

The fetus receives all nutrients and oxygen from blood that circulates through the placenta. Therefore, anything that interferes with normal placental function might adversely affect development of the fetus, including the brain, or might increase the risk for premature delivery. Structural abnormalities of the placenta, premature detachment of the placenta from the uterine wall (abruption), and placental infections (chorioamnionitis), are thought to pose some risk for CP.

Certain conditions in the mother during pregnancy might pose a risk to fetal development leading to CP. Women with autoimmune antithyroid or antiphospholipid (APA) antibodies are at slightly increased risk for CP in their children. A potentially important clue points toward high levels of cytokines in the maternal and fetal circulation as a possible risk for CP. Cytokines are proteins associated with inflammation, such as from infection or autoimmune disorders, and they may be toxic to neurons in the fetal brain. More research is needed to determine the exact relationship, if any, between high levels of cytokines during pregnancy and CP. A woman with high cytokine levels has some risk of developing the same complications in more than one pregnancy, slightly increasing the risk for more than one child with CP.

Serious physical trauma to the mother during pregnancy could result in direct trauma to the fetus as well. Injuries to the mother can compromise the availability of nutrients and oxygen to the developing fetal brain.

Perinatal causes

Birth asphyxia significant enough to result in CP is now uncommon in developed countries. Tight nuchal cord (umbilical cord around the baby's neck) and prolapsed cord (the cord presents through the birth canal before the baby and becomes kinked or buckled) are possible causes of birth asphyxia, as are bleeding and other complications associated with placental abruption and placenta previa (placenta lying over the cervix exit).

Infection in a mother is sometimes not passed to her fetus through the placenta but, rather, transmitted to the baby during delivery. Many of these infections are sexually transmitted diseases, such as gonorrhea, syphilis, and even AIDS. Any such infection that results in serious illness in the newborn has the potential to produce some neurological damage.

Postnatal causes

The remaining 15% of CP is due to neurologic injury sustained after birth. CP with a postnatal cause is sometimes referred to as acquired CP, but this is only accurate for those cases caused by infection or trauma.

Incompatibility between the Rh blood types of mother and child (mother Rh negative, baby Rh positive) can result in severe anemia in the baby (erythroblastosis fetalis). This occurs because the mother's blood develops antibodies to the infant's blood and attempts to destroy what it perceives as the "foreign" blood. This may lead to other complications, including severe jaundice, which can cause CP. Rh disease in the newborn is now rare in developed countries due to routine screening of maternal blood type and treatment of pregnancies at risk. The routine, effective treatment of jaundice due to other causes has also made it an infrequent cause of CP in developed countries. Rh blood type incompatibility poses a risk for recurrence of Rh disease with each pregnancy if treatment is not provided.

Serious infections that affect the brain directly, such as meningitis and encephalitis, may cause irreversible damage to the brain, leading to CP. A seizure disorder early in life may cause CP, or may be the product of a hidden problem that causes CP in addition to seizures. Unexplained (idiopathic) seizures are hereditary in only a small percentage of cases. Although rare in infants born healthy at or near term, intracerebral hemorrhage and brain embolism, like fetal stroke, are sometimes genetic.

Physical trauma resulting in brain injury to an infant or child, such as physical abuse, accidents causing impact to the head, or near drowning/suffocation, might cause CP. Likewise, ingestion of a toxic substance such as lead, mercury, poisons, or certain chemicals could cause neurological damage. Accidental overdose of certain medications might also cause similar damage to the central nervous system.

Prematurity and multiple pregnancy

Advances since the 1980s in the medical care of premature infants have dramatically increased the rate of survival of these fragile newborns. However, as gestational age at delivery and birth weight of a baby decrease, the risk for CP dramatically increases. A term pregnancy is delivered between 37 and 41 weeks of gestation. The risk for CP in a preterm infant (32-37 weeks) is increased about five-fold over the risk for an infant born at term. Survivors of extremely preterm births (less than 28 weeks) face as much as a 50-fold increase in risk. About 50% of all cases of CP being diagnosed are in children who were born prematurely.

Two factors are involved in the risk for CP associated with prematurity. First, premature babies are at higher risk for various CP-associated medical complications, such as intracerebral hemorrhage, infection, and difficulty in breathing, to name a few. Second, the onset of premature labor may be induced, in part, by complications that have already caused neurologic damage in the fetus. A combination of both factors almost certainly plays a role in some cases of CP. The tendency toward premature delivery tends to run in families, but the genetic mechanisms are far from clearly understood.

An increase in multiple pregnancies, especially in the United States, is attributed to the increased use of fertility drugs. As the number of fetuses in a pregnancy increases, the risks for abnormal development and premature delivery also increase. Children from twin pregnancies have four times the risk of developing CP as children from single pregnancies. This is because more twin pregnancies are delivered prematurely or, in some cases, overcrowding occurs in the uterus causing pressure on one infant from contact with the other. The risk for CP in a child of triplets is up to 18 times greater. Furthermore, evidence suggests that a baby from a pregnancy in which its twin died before birth is at increased risk for CP.

By definition, the defect in cerebral function causing CP is nonprogressive. However, the symptoms of CP often change over time. Most of the symptoms of CP relate in some way to the aberrant control of muscles. To review, CP is categorized first by the type of movement or postural disturbance(s) that are present, then by a description of which limbs are affected, and finally by the severity of motor impairment. For example, spastic diplegia refers to continuously tight muscles that have no voluntary control in both legs, while athetoid quadraparesis describes uncontrolled writhing movements and muscle weakness in all four limbs. These three-part descriptions are helpful in providing a general picture, but cannot give a complete description of any one person with CP. In addition, the various presentations of CP do not occur with equal frequency. For example, spastic diplegia is seen in more individuals than is athetoid quadraparesis. CP can also be loosely categorized as mild, moderate, or severe, but these are very subjective terms with no firm boundaries between them.

A muscle that is tensed and contracted is hypertonic, while excessively loose muscles are hypotonic. Spastic, hypertonic muscles can cause serious orthopedic problems, including scoliosis (spine curvature), hip dislocation, or contractures. A contracture is shortening of a muscle, usually affecting muscles involved in flexion or extension of a joint, and are aided sometimes by a weak opposing force from a neighboring muscle. Contractures may become permanent or they may resolve without some sort of intervention. Fixed contractures may cause postural abnormalities in the affected limbs. Clenched fists and contracted feet (equinus or equinovarus) are common in people with CP. Spasticity in the thighs causes them to turn in and cross at the knees, resulting in an unusual method of walking known as a scissors gait. Any of the joints in the limbs may be stiff (immobilized) due to spasticity of the attached muscles.

Athetosis and dyskinesia often occur with spasticity, but do not often occur alone. The same is true of ataxia. It is important to remember that the terms mild CP or severe CP refer not only to the number of symptoms present, but also to the level of involvement of any particular class of symptoms.

Mechanisms that can cause CP are not always restricted to motor-control areas of the brain. Other neurologically based symptoms may include:

• mental retardation or learning disabilities
• behavioral disorders
• seizure disorders
• visual impairment
• hearing loss
• speech impairment (dysarthria)
• abnormal sensation and perception

These problems may have a greater impact on a child's life than the primary physical impairments of CP, although not all children with CP are affected by other problems. Many infants and children with CP have growth impairment. About one-third of individuals with CP have moderate-to-severe mental retardation, one-third have mild mental retardation, and one-third have normal intelligence.

Diagnosis

The signs of CP are not usually noticeable at birth. Children normally progress through a predictable set of developmental milestones through the first 18 months of life. Children with CP, however, tend to develop these skills more slowly because of their motor impairments, and delays in reaching milestones are usually the first symptoms of CP. Babies with more severe involvement with of CP are usually diagnosed earlier than others.

Selected developmental milestones, and the ages for normally acquiring them, are given below. If a child does not acquire the skill by the age shown in parentheses, there is some cause for concern:

• sits well unsupported (6-10 months)
• babbles (6-8 months)
• crawls (9-12 months)
• finger feeds, holds bottle (9-12 months)
• walks alone (12-18 months)
• uses one or two words other than "dada" or "mama" (12-15 months)
• walks up and down steps (24-36 months)
• turns pages in books; removes shoes and socks (24-30 months)

Children do not consistently favor one hand over the other before 12-18 months of age, and doing so may be a sign that the child has difficulty using the other hand. This same preference for one side of the body may show up as asymmetric crawling or, later on, favoring one leg while climbing stairs.

It must be remembered that children normally progress at somewhat different rates, and slow beginning accomplishment is often followed by normal development. Other causes for developmental delay, both benign and serious should be ruled out before considering CP as an explanation. CP is nonprogressive, so continued loss of previously acquired milestones indicates that CP is not the cause of the problem.

No single test is diagnostic for CP, but certain factors increase suspicion. The Apgar score measures a baby's condition immediately after birth. Babies that have low Apgar scores are at increased risk for CP. Presence of abnormal muscle tone or movements may indicate CP, as may the persistence of infantile reflexes. Imaging of the brain using ultrasound, x rays, MRI, and/or CT scans, may reveal structural anomalies. Some brain lesions associated with CP include scarring, cysts, expansion of the cerebral ventricles (hydrocephalus), periventricular leukomalacia (an abnormality of the area surrounding the ventricles), areas of dead tissue (necrosis), and evidence of an intracerebral hemorrhage or blood clot. Blood and urine biochemical tests, as well as genetic tests, may be used to rule out other possible causes, including muscle and peripheral nerve diseases, mitochondrial and metabolic diseases, and other inherited disorders. Evaluations by a pediatric developmental specialist and a geneticist may be of benefit.

Treatment

Therapy

Spasticity, muscle weakness, lack of coordination, ataxia, and scoliosis are all significant impairments that affect the posture and mobility of a person with CP. Physical and occupational therapists work with affected persons and their families to maximize ability to move affected limbs, develop normal motor patterns, and maintain posture. So-called assistive technology, items such as wheelchairs, walkers, shoe inserts, crutches, and braces, are often required. A speech therapist and high-technology aids, such as computer-controlled communication devices, may make a tremendous difference in the life of those who have speech impairments with CP.

Medications

Before fixed contractures develop, muscle-relaxant drugs such, as diazepam (Valium), dantrolene (Dantrium), and baclofen (Lioresal) may be prescribed. Botulinum toxin (Botox), a newer and highly effective treatment, is injected directly into the affected muscles. Alcohol or phenol injections into the nerves controlling specific muscles are another option. Multiple medications are available to control seizures, and athetosis can be treated using medications such as trihexyphenidine (Artane) and benztropine (Cogentin).

Surgery

Fixed contractures are usually treated with either serial casting or surgery. The most commonly used surgical procedures are tenotomy (tendon transfer) and dorsal rhizotomy. In tenotomy, tendons of an affected muscle are cut and either repositioned or reattached in a different position, and the limb is then immobilized in a cast in a more normal position while the tendons regrow. A neurosurgeon performing dorsal rhizotomy carefully cuts selected nerve roots in the spinal cord to prevent them from stimulating the spastic muscles. Neurosurgical techniques in the brain, such as implanting tiny electrodes directly into the cerebellum or cutting a portion of the hypothalamus, have very specific applications and have had mixed results.

Education

Parents of a child newly diagnosed with CP are not likely to have the necessary expertise to coordinate the full range of care their child will need. Although knowledgeable and caring medical professionals are indispensable for developing a care plan, a potentially more important source of information and advice is other parents who have dealt with the same set of difficulties. Support groups for parents of children with CP can be significant sources of both practical advice and emotional support. Many cities have support groups that can be located through the United Cerebral Palsy Association, and most large medical centers have special multidisciplinary clinics for children with developmental disorders.

Prognosis

Cerebral palsy can affect every stage of maturation—from childhood through adolescence to adulthood. At each stage, those with CP, along with their caregivers, must strive to achieve and maintain the fullest range of experiences and education consistent with their abilities. The advice and intervention of various professionals remains crucial for many people with CP. Although CP itself is not considered a terminal disorder, it can affect a person's lifespan by increasing the risk for certain medical problems. People with mild cerebral palsy may have near-normal life spans, but the lifespan of those with more severe forms may be shortened. However, more than 90% of infants with CP survive into adulthood.

The cause of most cases of CP remains unknown, but it has become clear that birth difficulties are not to blame in most cases. Rather, developmental problems before birth, usually unknown and generally undiagnosable, are responsible for most cases. The rate of survival for preterm infants has leveled off, and methods to improve the long-term health of at-risk babies are being sought. Current research is also focusing on the possible benefits of recognizing and treating coagulopathies and inflammatory disorders in the prenatal and perinatal periods. The use of magnesium sulfate in pregnant women with preeclampsia or threatened preterm delivery may reduce the risk of CP in very preterm infants. The risk of CP can be decreased through good maternal nutrition, avoidance of drugs and alcohol during pregnancy, and prevention or prompt treatment of infections.

Health care team roles

The number of health care professionals who provide care for persons with CP is extensive. Pediatricians or family physicians may make the initial diagnosis. However, in the growing environment of primary care, the pediatric nurse practitioner may be the first to describe symptoms or developmental delays associated with CP. Care and treatment is then provided by many health professionals, including general or orthopedic surgeons and neurosurgeons. Radiologists assist in diagnosis and monitoring; speech and language specialists and physical and occupational therapists provide rehabilitative therapy. Psychologists, pastoral counselors, and social workers may provide emotional support to patients and their families, while social workers will help families access resources for care and equipment. Manufacturers of prostheses and assistive devices may also provide services. For most persons with CP, assistive care is a life-long need. In an outpatient environment, nurses play a continuing role as educators for such needs as medication administration and side-effect recognition, in-home adaptations for physical therapy necessary between visits to physical therapists, and as a conduit for connecting parents with support groups. Should the child require surgery, the nurse has a perioperative role in caring for the patient.

Prevention

Several maternal-to-fetal cross infections are known to increase the risk for CP, including rubella (German measles, now rare in the United States), cytomegalovirus (CMV), and toxoplasmosis. Each of these infections is considered a risk to the fetus only if the mother contracts it for the first time during that pregnancy. Even in those cases, though, most babies will be born normal. Most women are immune to all three infections by the time they reach childbearing age, but a woman's immune status can be determined using the so-called TORCH (for TOxoplasmosis, Rubella, Cytomegalovirus, and Herpes) test before or during pregnancy.

Cerebral palsy cannot be cured, but many of the disabilities it causes may be managed through planning and timely care. Treatment for a child with CP depends upon the severity, nature, and location of the primary muscular symptoms, as well as any associated problems that might be present. Optimal care of a child with mild CP may involve regular interaction with only a physical therapist and occupational therapist, whereas care for a more severely affected child may include visits to multiple medical specialists throughout life. With proper treatment and an effective care plan coverage, most people with CP can lead productive, happy lives.

Adequate prenatal monitoring by competent health care professionals is needed to prevent CP. Risk factors should be identified and appropriate tests conducted. Pregnant women who discontinue the use of substances that are potentially harmful to their fetuses significantly reduce the risk of CP in their children.

KEY TERMS

Asphyxia— Lack of oxygen. In the case of CP, lack of oxygen to the brain.

Ataxia— Impaired balance and coordination.

Athetosis— A condition marked by slow, writhing, involuntary muscle movements.

Coagulopathy— A disorder in which blood does not coagulate normally; it can coagulate (clot) either abnormally slowly or abnormally quickly.

Contracture— A shortening of a muscle causing a joint to become stiff or immovable.

Cytokine— A protein associated with inflammation that, at high levels, may be toxic to nerve cells in the developing brain.

Diplegia— Paralysis of corresponding parts on both sides of the body.

Dorsal rhizotomy— A surgical procedure that cuts nerve roots to reduce spasticity in affected muscles.

Dyskinesia— Difficulty with voluntary movement of a muscle.

Hemiplegia— Paralysis of the limbs on one side of a body.

Hypotonia— Reduced tone, referring to a muscle that is loose or flaccid.

Quadriparesis— Partial or incomplete paralysis of all four limbs.

Quadriplegia— Paralysis of all four limbs.

Serial casting— A series of casts designed to gradually move a limb into a more functional position.

Spastic— A condition in which the muscles are rigid, posture may be abnormal, and fine motor control is impaired.

Static encephalopathy— A disease of the brain that does not get better or worse.

Tenotomy— A surgical procedure that cuts the tendon of a contracted muscle to allow lengthening.

Resources

BOOKS

Adams, Raymond D., Maurice Victor, and Allan H. Ropper. Adams & Victor's Principles of Neurology. 6th ed. New York: McGraw Hill, 1997.

Brazis, Paul. Localization in Clinical Neurology. Philadelphia: Lippincott Williams & Wilkins Publishers, 2001.

Carter, Alden R., and Carol Carter. Stretching Ourselves: Kids With Cerebral Palsy. Morton Grove: Albert Whitman & Co., 2000.

Haslem, Robert H.A. "Cerebral Palsy." In Nelson Textbook of Pediatrics. 16th ed. Eds. Richard E. Behrman, et al. Philadelphia: Saunders, 2000, 1843-1845.

Perlot, Velickovic, and B.G.R. Neville. Cerebral Palsy. New York: Elsevier Science, 2001.

Stamer, Marcia H. Posture and Movement of the Child With Cerebral Palsy. San Antonio: Communication Skill Builders, 2000.

Stanley, Fiona, and Eve Blair. Cerebral Palsies: Epidemiology and Causal Pathways. Cambridge: MacKeith Press, 2000.

PERIODICALS

Byrne J.M., J.F. Connolly, S.E. MacLean, T.L. Beattie, J.M. Dooley, and K.E. Gordon. "Brain Activity and Cognitive Status in Pediatric Patients: Development of a Clinical Assessment Protocol." Journal of Child Neurology 16, no. 5 (2001): 325-332.

Greenfield A.L., F. Miller, and G.W. Gross. "Diagnosis and Management of Orthopedic Problems in Children with Cerebral Palsy." Seminars in Musculoskeletal Radiology 3, no.4 (1999): 317-334.

Hargreaves D.G., D.J. Warwick, M.A. Tonkin. "Changes in Hand Function Following Wrist Arthrodesis in Cerebal Palsy." Journal of Hand Surgery [Britain] 25, no. 2 (2000): 193-194.

Moster D. R.T. Lie, L.M. Irgens, T. Bjerkedal, and T. Markestad. "The Association of Apgar Score with Subsequent Death and Cerebral Palsy: A Population-Based Study in Term Infants." Journal of Pediatrics 138, no.6 (2001): 798-803.

Paneth, N. "Cerebral Palsy In Term Infants—Birth or Before Birth?" Journal of Pediatrics 138, no. 6 (2001): 791-792.

Philp, I., and M. Law. "Web Sites Related to Cerebral Palsy." Physical Occupational Therapy in Pediatrics 20, no. 4 (2001): 79-88.

ORGANIZATIONS

American Academy of Family Physicians. 11400 Tomahawk Creek Pkwy., Leawood, KS 66211-2672. (913) 906-6000. 〈http://www.aafp.org〉.

American Academy of Neurology. 1080 Montreal Ave., St. Paul, MN 55116. (651) 695-1940. 〈http://www.aan.com〉.

American Academy of Pediatrics. 141 Northwest Point Blvd., Elk Grove Village, IL 60007-1098. (847) 434-4000. 〈http://www.aap.org/default.htm〉.

American Academy of Physical Medicine and Rehabilitation. One IBM Plaza, Ste. 2500, Chicago, IL 60611-3604. (312) 464-9700. 〈http://www.aapmr.org/consumers/public/amputations.htm〉.

American College of Foot and Ankle Surgeons, 515 Busse Hwy., Park Ridge, IL 60068-3150. (888) 843-3338. 〈http://www.acfas.org/index.html〉.

American College of Physicians, 190 N. Independence Mall West, Philadelphia, PA 19106-1572. (800) 523-1546 x2600 or (215) 351-2600. 〈http://www.acponline.org〉.

American College of Surgeons. 633 North St. Clair St., Chicago, IL 60611-32311. (312) 202-5000. 〈http://www.facs.org〉.

American Medical Association. 515 N. State St., Chicago, IL 60610. (312) 464-5000. 〈http://www.ama-assn.org〉.

National Association of Pediatric Nurse Associates and Practitioners. 1101 Kings Highway N., Ste. 206, Cherry Hill, NJ 08034-1912. (856) 667-1773, or (877) 662-7627. 〈http://www.napnap.org〉.

United States Cerebral Palsy Athletic Association. SCPAA National Center, 25 W. Independence Way, Kingston, RI 02881. (401) 792-7130. 〈http://www.uscpaa.org/main.htm〉.

OTHER

American Cerebral Palsy Information Center. 〈http://www.cerebralpalsy.org〉.

Cerebral Palsy and Deaf Organization. 〈http://www.cpado.org〉.

Internet Resources for Special Children. 〈http://www.irsc.org/cerebral.htm〉.

National Institute of Neurological Disorders and Stroke. 〈http://www.ninds.nih.gov/health_and_medical/pubs/cerebral_palsyhtr.htm〉.

National Library of Medicine. 〈http://www.nlm.nih.gov/medlineplus/cerebralpalsy.html〉.

Nemours Foundation. 〈http://kidshealth.org/parent/medical/brain/cerebral_palsy.html〉.

UCP National. 〈http://www.ucpa.org〉.

University of Virginia Medical Center. 〈http://hsc.virginia.edu/cmc/tutorials/cp/cp.htm〉.

Cerebral palsy

Definition

Cerebral palsy (CP), or static encephalopathy, is the name for a collection of movement disorders caused by brain damage that occurs before, during, or shortly after birth. A person with CP is often also affected by other conditions caused by brain damage.

Description

The affected muscles of a person with CP may become rigid or excessively loose. The person may lose control of muscles, or have problems with balance and coordination. A combination of these is also possible. Those with CP may be primarily affected in the legs (paraplegia or diplegia), or in the arm and leg of one side of the body (hemiplegia), or all four limbs may be involved (quadriplegia).

A person with CP may also be affected by a number of other problems, including a seizure disorder, visual deficits, hearing problems, mental retardation, learning disabilities, and attention-deficit hyperactivity disorder . None of these is necessarily part of CP, however, they may accompany the disorder.

CP affects approximately 500,000 children and adults in the United States, and is diagnosed in more than 6,000 newborns and young children each year. It is not an inherited disorder, and as of yet there is no way to predict with certainty which children will develop CP. It is not a disease, and is not communicable. CP is a nonprogressive disorder, which means that symptoms neither worsen nor improve over time. However manifestation of the symptoms may become more severe over time. For example, rigidity of muscles can lead to contractures and deformities that require a variety of interventions.

Causes & symptoms

Causes

Cerebral palsy is caused by damage to the motor control centers of the brain. When the nerve cells (neurons) in these regions die, the appropriate signals can no longer be sent to the muscles under their control. The resulting poor control of these muscles causes the symptoms of CP.

The brain damage leading to CP may be caused by lack of oxygen (asphyxia), infection, trauma, malnutrition, drugs or other chemicals, or hemorrhage. In most cases it is impossible to determine the actual cause, although premature birth is recognized as a significant risk factor. It was once thought that difficult or prolonged delivery was responsible for many cases of CP, but most researchers now believe that the great majority of cases result from brain damage occurring before birth. The same injury that damages the motor areas can harm other areas as well, leading to problems commonly associated with CP.

If brain cells do not get enough oxygen because of poor circulation, they may die. Defects in circulation in the developing brain may cause CP in some cases. Asphyxia during birth is also possible, and about half of newborns known to have suffered asphyxia during birth (perinatal asphyxia) develop CP. However, asphyxia during birth is usually considered a symptom of an underlying neurological problem in a newborn, rather than its cause, and the resulting CP may be another sign of that problem. Asphyxia after birth can be caused by choking, poisoning (such as from carbon monoxide or barbiturates), or near-drowning.

The fetal brain may be damaged by an infection contracted by the mother. Infections correlated with CP include rubella (German measles ), toxoplasmosis (often contracted from cat feces), cytomegalovirus (a herpes virus), and HIV (the virus that causes AIDS ). Encephalitis and meningitis , infections of the brain and its coverings, can also cause CP when contracted by infants.

Physical trauma to the pregnant mother or infant may cause brain damage. Blows to the infant's head, as from a motor vehicle accident, violent shaking, or other physical abuse can damage the infant's brain. Maternal malnutrition may cause brain damage, as can the use of drugs, including cocaine or alcohol. Although these factors may cause CP, they may be more likely to cause mental retardation or other impairments.

Incompatibility between the Rh blood types of mother and child was once a major cause of athetoid CP, one type of movement impairment seen in cerebral palsy. In some cases, this incompatibility can cause the mother's defense (immune) system to attack and destroy the child's blood cells during pregnancy , a condition called erythroblastosis fetalis. High levels of a blood cell breakdown product called bilirubin in a child's circulation, leading to yellowish pigmentation of the skin caused by bile (jaundice ) can result in brain damage. This condition is now rare because of testing procedures that identify potential Rh incompatibility, and treatment that prevents the mother's immune system from attacking the child's blood cells. Jaundice that does occur can be treated with special lights that help the breakdown of bilirubin. Blood transfusions for the child are also possible in extreme cases. Despite the virtual elimination of this cause of CP in the last few decades, CP rates have not declined, largely because of the increase of survival of premature babies.

Prematurity is one of the most significant risk factors for CP. About 7% of babies weighing less than three pounds at birth develop CP, and the risk increases dramatically as weight falls. Prematurity may increase the risk of CP because of the increased likelihood of hemorrhaging in the brain associated with low birth weight. Brain hemorrhage is most common in babies weighing less than four pounds at birth, and the risk increases as weight decreases. The hemorrhage may destroy brain tissue, either through asphyxia or release of toxic breakdown products.

Researchers in Sweden reported in 2002 that babies conceived through in vitro fertilization (IVF) were 3.7 times more likely to have CP than babies conceived naturally. Some of the reason can be attributed to a higher rate of twins, low birthweight, and premature births associated with IVF babies, but some single births also have higher rates of CP.

Symptoms

The symptoms of CP are usually not noticeable at birth. As children develop in the first 18 months of life, however, they progress through a predictable set of developmental milestones. Children with CP will develop these skills more slowly because of their motor impairments, and delay in reaching milestones is usually the first symptom of CP. The more severe the CP, the earlier the diagnosis is usually made.

Selected developmental milestones, and the ages at which a child will normally acquire them, are given below. There is some cause for concern if the child does not acquire the skill by the age shown in parentheses:

• sits well unsupported, 6 months (8-10 months)
• babbles, 6 months (8 months)
• crawls, 9 months (12 months)
• finger feeds, holds bottle, 9 months (12 months)
• walks alone, 12 months (15-18 months)
• uses one or two words other than dada/mama, 12 months (15 months)
• walks up and down steps, 24 months (24-36 months)
• turns pages in books, removes shoes and socks, 24 months (30 months)

Children do not consistently favor one hand over the other before 18 months, and doing so may be a sign that the child has difficulty using the other hand. This same preference for one side of the body may show up as an asymmetric crawling effort, or continuing to use only one leg for the work of stair climbing after age three.

It must be remembered that children normally progress at somewhat different rates, and slow initial accomplishment is often followed by normal development. There are also other causes for delay in reaching some milestones, including problems with vision or hearing. Because CP is a non-progressive disease, loss of previously acquired milestones indicates that CP is not the cause of the problem.

The impairments of CP become recognizable in early childhood. The type of motor impairment and its location are used as the basis for classification. There are five generally recognized types of impairment:

• Spastic. Muscles are rigid, posture may be abnormal, and fine motor control is impaired.
• Athetoid. It is marked by slow, writhing, involuntary movements.
• Hypotonic. Muscles are floppy, without tone.
• Ataxic. Balance and coordination are impaired.
• Dystonic. Impairment is mixed.

The location of the impairment usually falls into one of three broad categories:

• Hemiplegia. One arm and one leg on the same side of the body are involved
• Diplegia. Both legs; arms may be partially involved.
• Quadriplegia. All four extremities are involved.

A person with CP may be said to have spastic diplegia, or ataxic hemiplegia, for instance. CP is also termed mild, moderate, or severe, although these are subjective categories with no firm boundaries.

Loss of muscle control, especially of the spastic type, can cause serious orthopedic problems, including scoliosis (spine curvature), hip dislocation, or contractures. Contracture is shortening of a muscle, caused by an imbalance of opposing force from a neighboring muscle. Contractures begin as prolonged contractions, but can become fixed or irreversible without regular range of motion exercises. A fixed contracture occurs when the contracted muscle adapts by reducing its overall length. Fixed contractures may cause postural abnormalities in the affected limbs, including clenched fists, tightly pressed or crossed thighs, or equinus. In equinus, the most common postural deformity, the foot is extended by the strong pull of the rear calf muscles, causing the toes to point. The foot is commonly pulled inward as well, a condition called equinovarus. Contractures of all kinds may be painful, and may interfere with normal activities of daily living, including hygiene and mobility.

As noted, the brain damage that causes CP may also cause a large number of other disorders. These may include:

• mental retardation
• learning disabilities
• attention-deficit hyperactivity disorder
• seizure disorder
• visual impairment, especially strabismus ("cross-eye")
• hearing loss
• speech impairment

These problems may have an even greater impact on the child's life than the physical impairment of CP, although not all children with CP are affected by other problems. About one-third of children with CP have moderate to severe mental retardation, one-third have mild mental retardation, and one-third have normal to above average intelligence.

Diagnosis

The tracking of developmental progress is the most important test the physician has in determining whether a child has cerebral palsy. Most children with CP can be confidently diagnosed by 18 months. However, diagnosing CP is not always easy, since variations in child development may account for delays in achieving milestones, and since even children who are obviously delayed may continue to progress through the various developmental stages, attaining a normal range of skills later on. Serious or prolonged childhood illness may cause delays that are eventually caught up.

Evidence of other risk factors may aid the diagnosis. The Apgar score, evaluated immediately after birth, measures a newborn's heart rate, cry, color, muscle tone, and motor reactions. Apgar scores of less than three out of a possible 10 are associated with a highly increased indication of CP. Presence of abnormal muscle tone or movements may signal CP, as may the persistence of infantile reflexes. A child with seizures or congenital organ malformation has an increased likelihood of CP. Ultra-sound examination, a diagnostic technique that creates a two-dimensional image of internal body structures, may help to identify brain abnormalities, such as enlarged ventricles (chambers containing fluid) or periventricular leukomalacia (an abnormality of the area surrounding the ventricles), which may be associated with CP.

X rays, magnetic resonance imaging (MRI) studies, and computed tomography (CT) scans are often used to look for scarring, cysts, expansion of the cerebral ventricles (hydrocephalus), or other brain abnormalities that may indicate the cause of symptoms. Blood tests and genetic tests may be used to rule out other possible causes, including muscular dystrophy (a disease characterized by the progressive wasting of muscles), mitochondrial (cellular) disease, and other inherited disorders or infections.

Treatment

A number of people with cerebral palsy, both children and adults, have found systematic relief and enhanced quality of life from a combination of alternative and complementary treatments, including nutritional therapy, craniosacral therapy , bodywork, herbal therapy, homeopathy , and acupuncture .

General recommendations

Pregnant women should avoid cleaning cat litter, which may contain toxoplasma parasite. This organism causes severe brain damage or death in the unborn fetus. Unprotected sex increases risk of contracting sexually transmitted diseases such as genital herpes , which can infect the unborn child. Women should also vaccinate before getting pregnant to prevent measles and rubella, which can cause severe brain damage to the fetus. They should avoid taking certain drugs, smoking , or drinking alcohol. Cocaine, heroine, nicotine and alcohol are toxic to the developing brain of the fetus.

Nutritional therapy

The following dietary adjustments have been recommended to alleviate some symptoms in patients with cerebral palsy:

• Those with CP should avoid potential allergenic foods. Allergic foods are believed to worsen symptoms in many CP patients.
• CP patients should also avoid preservatives and food additives such as MSG (which are potentially toxic to the brain) by eating fresh and unprocessed foods such as whole grains, vegetables, beans, fruits, nuts, and seeds.
• To improve muscle tone, CP patients should supplement their diets with magnesium, thiamine, pyridoxine, vitamin C , and bioflavonoids . Alternatively, they can take daily multivitamin/mineral supplements that can provide all these helpful nutrients and make sure they are getting adequate protein in diet or supplements.

Osteopathy

Craniosacral therapy, a special form of osteopathic treatment, may be successful in preventing cerebral palsy if performed right after a difficult labor or delivery by forceps. This manipulation of bones of the newborn's skull may prevent stress and distortion of the child's head occurring during traumatic delivery. Craniosacral therapy is less successful, however, in established cerebral palsy in an older child.

Bodywork

Bodywork such as massage, reflexology, Feldenkrais , or rolfing can help improve blood circulation and muscle tone and reduce muscle spasms in patients with cerebral palsy.

Other therapies

Other potentially helpful treatments include acupuncture, homeopathy and herbal therapy, and dance and music therapy . Although still not proven in clinical trials, hyperbaric oxygen therapy (HBOT) has been used to alleviate many symptoms of CP. It provides pure oxygen at higher-tha-normal pressure in an enclosed chamber and is more commonly known for treating divers with compression sickness. A Cornell University study in 1999–2000 studied the effects of 40 one-hour sessions on 23 children with moderate to severe CP. They noted improvements in motor skills, attention, language, and play.

Allopathic treatment

Cerebral palsy cannot be cured, but many of the disabilities it causes can be managed through planning and timely care. Treatment for a child with CP depends on the severity, nature, and location of the impairment, as well a child's associated problems. Optimal care of a child with mild CP may involve regular interaction with only physical and occupational therapists, whereas care for a more severely affected child may include a speech-language therapist, special education teacher, adaptive sports therapist, nutritionist, orthopedic surgeon, and neurosurgeon.

Parents of a child newly diagnosed with CP are not likely to have the necessary expertise to coordinate the full range of care their child will need. Support groups for parents of physically or mentally impaired children can be significant sources of both practical advice and emotional support. Many cities have support groups that can be located through the United Cerebral Palsy Association or a local hospital or social service agency. Children with CP are also eligible for special education services. The diagnosing doctor should refer parents to the local school district for these services. Even children aged birth to three years are eligible through early intervention programs.

Influence of CP on development

Cerebral palsy may restrict a child's ability to reach for and grasp objects, to move about, to explore the properties of toys, and to communicate with others, which are all central activities in the child's growth and development. Therefore, the disease inhibits acquisition of motor skills, knowledge of the world, and social competence. The family can do much to overcome these restrictions by adapting the child's environment to meet his or her needs and providing challenges within the child's abilities to accomplish. The advice and direction of an occupational therapist can be critical to promoting normal development of the child with CP.

Posture and mobility

Spasticity, muscle coordination, ataxia, and scoliosis are all significant impairments that affect the posture and mobility of a person with cerebral palsy. Physical therapists work with the family to maximize the child's ability to move affected limbs, to develop normal motor patterns, and to maintain posture. Adaptive equipment may be needed, including wheelchairs, walkers, shoe inserts, crutches, or braces. The need for adaptive equipment may change as the person develops, or as new treatments are introduced.

SPASTICITY. Spasticity causes muscles to shorten, joints to tighten, and postures to change. Spasticity can affect the ability to walk, use a wheelchair, and sit unaided; and it can prevent independent feeding, dressing, hygiene, or other activities of daily living. Contracture and dislocations are common consequences of spasticity.

Mild spasticity may be treated by regular stretching of the affected muscles through their full range of motion. This usually is done at least daily. Moderate spasticity may require bracing to keep a limb out of the abnormal position, or serial casting to return it to its normal position. Ankle-foot braces (orthoses) made of lightweight plastic are often used to increase a child's stability and to promote proper joint alignment.

Spasticity may also be treated with muscle relaxing drugs, including diazepam (Valium), dantrolene (Dantrium), and baclofen (Lioresal). A variety of experimental surgeries have been tried for people with cerebral palsy to control spasticity. Most of these have not proven effective.

ATAXIA AND COORDINATION Ataxia, or lack of balance control, is another factor affecting mobility. Physical therapy is an important tool to help the child with CP maximize balance. Coordination can be worsened if one member of a muscle pair is overly strong; bracing or surgical transfer of the muscle to a less over-powering position may help.

SCOLIOSIS. Scoliosis, or spine curvature, can develop when the muscles that hold the spine in place become either weak or spastic. This can cause pain , as well as interfere with normal posture and internal organ function. Scoliosis may be treated with a trunk brace. If this proves unsuccessful, spinal fusion surgery may be needed to join the vertebrae together, which keeps the spine straight.

Seizures

Seizures occur in 30-50% of children with CP. Seizures may be treated with drugs, most commonly carbamazepine (Tegretol) or ethosuximide (Zarontin). A combination of a ketogenic diet and fasting may also be used to control seizures. Although the need for anti-seizure medication is temporary in some children, it may be required throughout life for others.

Strabismus

Strabismus, or squinting and lack of parallelism in the eyes, occurs in nearly half of all people with spastic CP. Strabismus may be treated with patching and corrective lenses. When these do not work, it may be treated with either surgery on the eye muscles causing the problem or by injection of botulinum toxin.

Nutrition

Due to poor muscle coordination, CP children may not take in adequate nutrition for full growth and development, worsening the results of the disorder. Careful attention to nutritional needs and nutritional supplements is required. Poor swallowing coordination may lead to aspiration, or inhaling of food or saliva. A speech-language therapist may be able to teach the person more effective movement patterns to avoid aspiration. In severe cases, a gastrostomy tube may be required to provide adequate nutrition directly into the digestive system while preventing aspiration.

Other common medical problems

Drooling, dental caries (cavities), and gum disease are more common in people with CP than in the general population, partly because of lowered coordination and increased muscle tightness in the mouth and jaw. Each of these can be prevented to some degree, either through behavioral changes alone or in combination with drug therapy. Constipation is more common as well, and may be treated through dietary changes, or with enemas or suppositories when necessary.

Communication

Poor coordination of the tongue and mouth muscles can also affect speech. Children may benefit from picture boards or other communication devices that allow them to point to make their desires known. For school-age children or older persons with CP, there are a large number of augmentative communication devices, including shorthand typing programs and computer-assisted speech devices. A speech-language therapist can offer valuable advice on the types of equipment available.

Education

The best choice of school for the child with CP depends on the presence and degree of mental impairment and physical impairment, as well as the facilities available in the area. "Inclusion," or mainstreaming the child in a regular public school classroom, may work well for the child with mild physical impairment. Separate classrooms or special schools may be needed for more severely involved children. Schooling for disabled students is governed by the Individuals with Disabilities Education Act (IDEA) at the federal level and state special education rules at the local level. An educational specialist within the school system or from a community social services agency may be able to help the family navigate the various bureaucratic pathways that will ensure the best schooling available.

The process of developing an educational plan for a child with CP begins with an assessment of the child's needs. The assessment is carried out under state guidelines by a team of medical professionals. After the assessment, the school district works with the parents and others involved in the child's education and treatment to develop an Individualized Educational Plan (IEP). The IEP states the child's specific needs for special instruction and indicates what services will be provided. The special services may be as simple as allowing extra time to travel between classes or as extensive as individualized instruction, adapted classroom equipment, and special testing procedures. More information about assessments and IEPs is available through the National Information Center for Children and Youth with Disabilities. The United Cerebral Palsy Assocation is another resource for advocacy, information, and legal rights.

Behavioral and mental health services

The child with CP may have behavioral problems or emotional issues that affect psychological development and social interactions. These may require special intervention or treatment, including behavior modification programs or individual and family counseling. Attention-deficit hyperactivity disorder is common in children with CP, and may require behavioral, educational, and medical intervention.

Expected results

Cerebral palsy can affect every stage of maturation, from childhood through adolescence to adulthood. At each stage, the person with CP and his or her caregivers must strive to achieve and maintain the fullest range of experiences and education consistent with the person's abilities. The advice and intervention of professionals remains crucial for many people with CP.

Although CP is not a terminal disorder, it can affect a person's lifespan by increasing the risk of infection, especially lung infections. Poor nutrition can contribute to the likelihood of infection. People with mild cerebral palsy may have near-normal lifespans. The lifespan of those with more severe forms, especially spastic quadriplegia, is often considerably shortened. However, over 90% of infants with CP survive into adulthood.

In 2002, a radical new method for repairing the damage caused by lack of oxygen at delivery of babies with CP was being funded for study. The possible treatment involved transplanting mature stem cells into babies' circulations, which will then migrate to the site of injury caused by oxygen deprivation, hopefully promoting natural repair of the brain damage. However, this treatment was in very early stages of testing in animals only as of late 2002.

Prevention

The cause of most cases of CP is unknown, but it has become clear in recent years that birth difficulties are not to blame in most cases. Developmental problems before birth, usually unknown and generally undiagnosable, are responsible for most cases. Although the incidence of CP caused by Rh factor incompatibility has declined markedly, the incidence of CP as a consequence of prematurity has increased, because of the increasing success of medical intervention in keeping premature babies alive.

The risk of CP can be decreased through good maternal nutrition, avoidance of drugs or alcohol during pregnancy, and prevention or prompt treatment of infections. Recent preliminary research suggests that magnesium sulfate may reduce the risk of CP in mothers taking it for the medical treatment of preeclampsia and preterm labor

Resources

BOOKS

The Burton Goldberg Group. "Cerebral Palsy." Alternative Medicine: The Definitive Guide. Tiburon, CA: Future Medicine Publishing, Inc., 1999.

"Cerebral Palsy." Reader's Digest Guide to Medical Cures and Treatments. Canada: The Reader's Digest Association, Inc., 1996.

Kramer, Laura. Uncommon Voyage: Parenting a Special Needs Child in the World of Alternative Medicine. Faber & Faber, 1996.

Miller, Freema, and Steven J. Bachrach. Cerebral Palsy: A Complete Guide for Caregiving. Johns Hopkins University Press, 1995.

Vickers, Andrew. Health Options: Complementary Therapies for Cerebral Palsy and Related Conditions. Element Publications, 1994.

PERIODICALS

Exceptional Parent Magazine. 555 Kinderkamack Road, Oradell, NJ 07649-1517; 800-EPARENT, or 201-634-6550.

"Hyperbaric Oxygen Therapy." The Exceptional Parent (July 2002): 52.

"IVF Babies at Increased Risk of Cerebral Palsy." Contemporary OB/GYN (July 2002): 41.

Kuban, KCK, and A. Leviton. "Cerebral Palsy." New England Journal of Medicine (1994): 188-95.

"Mature Stem Cell Transplants Linked to Treatment." Pain & Central Nervous System Week (July 22, 2002): 11.

ORGANIZATION

Cranial Academy. 3500 Depaw Boulevard. Indianapolis, IN 46268. (317) 879-0713.

National Information Center for Children and Youth with Disabilities. PO Box 1492, Washington DC 20013-1492. (800) 695-0285.

United Cerebral Palsy Association. 1660 L Street, NW Washington, DC 20036-5602. (800) USA-5-UCP,(202) 776-0406, (202) 973-7197 (TTY). Fax: (202) 776-0414. [email protected]. http://www.ucpa.org.

OTHER

Electronic forum for cerebral palsy. http://neuro-www.mgh.harvard.edu/forum/CerebralPalsyMenu.html.

Mai Tran

Teresa G. Odle

Cerebral palsy

Definition

Cerebral palsy (CP) is the term used for a group of nonprogressive disorders of movement and posture caused by abnormal development of, or damage to, motor control centers of the brain. CP is caused by events before, during, or after birth. The abnormalities of muscle control that define CP are often accompanied by other neurological and physical abnormalities.

Description

Voluntary movement (for example, walking, grasping, chewing) is primarily accomplished using skeletal muscles (muscles attached to bones). Control of the skeletal muscles originates in the cerebral cortex, the largest portion of the brain. Palsy means paralysis but may also be used to describe uncontrolled muscle movement. Therefore, cerebral palsy encompasses any disorder of abnormal movement and paralysis caused by abnormal function of the cerebral cortex. CP does not include conditions due to progressive disease or degeneration of the brain. For this reason, CP is also referred to as static (nonprogressive) encephalopathy (disease of the brain). Also excluded from CP are any disorders of muscle control that arise in the muscles themselves and/or in the peripheral nervous system (nerves outside the brain and spinal cord). CP is not a specific diagnosis but is more accurately considered a description of a broad but defined group of neurological and physical problems.v

Because CP is not one disorder, it is difficult to classify. It has been divided into four general types: spastic, athetoid, ataxic, and mixed. Another general categorization describes spastic, dyskinetic, and ataxic CP as follows:

• Spastic refers to diplegic impairment of either legs or arms, quadriplegic involving all four extremities, hemiplegic or one-sided involvement of arms and legs, or double hemiplegic impairment of both sides, arms and legs. Spasticity means having an increased stretch reflex.
• Dyskinetic refers to abnormal movements caused by inadequate regulation of muscle tone and coordination. The category includes athetoid or choreoathetoid CP; both are hyperkinetic forms of the disease.
• Ataxic refers to disturbances in coordination of voluntary movements; it includes mixed forms of CP, with mixed characteristics and symptoms.

Muscles that receive defective messages from the brain may be constantly contracted and tight (spastic), exhibit involuntary writhing movements (athetosis), or have difficulty with voluntary movement (dyskinesia). A lack of balance and coordination with unsteady movements (ataxia) may also be present. Spastic CP and mixed CP constitute the majority of cases. Effects on the muscles can range from mild weakness or partial paralysis (paresis) to complete loss of voluntary control of a muscle or group of muscles (plegia). CP is also designated by the number of limbs affected. For instance, affected muscles in one limb is monoplegia, both arms or both legs is diplegia, both limbs on one side of the body is hemiplegia, and in all four limbs is quadriplegia. Muscles of the trunk, neck, and head may be affected.

About 50 percent of all cases of CP diagnosed are in children who are born prematurely. Advances in the medical care of premature infants since the 1980s have dramatically increased the rate of survival of these fragile newborns. However, as gestational age at delivery and birth weight of a baby decrease, the risk for CP dramatically increases. A term pregnancy is delivered at 37–41 weeks gestation. The risk for CP in a preterm infant (32–37 weeks) is increased about five-fold over the risk for an infant born at term. Survivors of extremely preterm births (less than 28 weeks) face as much as a 50-fold increase in risk.

Two factors are involved in the risk for CP associated with prematurity . First, premature babies are at higher risk for various CP-associated medical complications, such as intracerebral hemorrhage, infection, and difficulty in breathing, to name a few. Second, the onset of premature labor may be induced, in part, by complications that have already caused neurologic damage in the fetus. A combination of both factors may play a role in some cases of CP. The tendency toward premature delivery runs in families, but genetic mechanisms are not fully clear.

An increase in multiple births in the early 2000s, especially in the United States, is associated with the increased use of fertility drugs. As the number of fetuses in a pregnancy increases, the risks for abnormal development and premature delivery also increase. Twins , for example, have four times the risk of developing CP as children from singleton pregnancies, owing to the fact that more twin pregnancies are delivered prematurely. The risk for CP in one of triplets is up to 18 times greater. Furthermore, evidence suggests that a baby from a pregnancy in which its twin died before birth is at increased risk for CP.

Although CP is the leading cause of disability in children, its incidence in the United States did not changed much between the 1980s and the early 2000s. Advances in medicine have decreased the incidence from some causes. Rh disease, for example, has been controlled by the advent of anti-Rh globulin; its administration to Rh-negative mothers has reduced one risk factor for CP. The risk has still increased from other causes, however, notably prematurity and multiple-birth pregnancies. The cause of most cases of CP remains unknown, but it has become clear in the early 2000s that birth difficulties are not to blame in most cases. Rather, developmental problems before birth, usually unknown and generally undiagnosable, are largely responsible. The rate of survival for preterm infants has leveled off in the early 2000s, and methods to improve the long-term health of these at-risk babies are being sought.

Demographics

Approximately 500,000 children and adults in the United States have CP, and it is newly diagnosed in about 6,000 infants and young children each year, representing about two to three children in 1,000 live births. No particular ethnic group seems to be at higher risk for CP. However, some low income families may be at higher risk due to poorer access to proper prenatal care and advanced medical services.

Causes and symptoms

CP can be caused by a number of different mechanisms at various times of life, ranging from several weeks after conception, through birth, to early childhood. In the twentieth century, it was accepted that most cases of CP were due to brain injuries received during a traumatic birth, a condition known as birth asphyxia. However, extensive research in the 1980s showed that only 5 to 10 percent of CP can be attributed to birth trauma. Other possible causes include abnormal development of the brain, prenatal factors that directly or indirectly damage neurons in the developing brain, premature birth, and brain injuries that occur in the first few years of life.

The causes of CP could be grouped into those that are genetic and those that are non-genetic, although most would fall somewhere in between. Grouping causes into those that occur during pregnancy (prenatal), those that happen around the time of birth (perinatal), and those that occur after birth (postnatal), is preferable. CP related to premature birth and multiple births is somewhat different and considered separately.

Prenatal causes

Although much was learned about human embryology in the last couple of decades of the twentieth century, a great deal remains unknown in the early 2000s. Studying prenatal human development is difficult because the embryo and fetus develop in a closed environment—the mother's womb. However, the development of a number of prenatal tests has opened a window on the process. Add to that more accurate and complete evaluations of newborns, especially those with problems, and a clearer picture of what can go wrong before birth is possible.

The complicated process of brain development before birth is susceptible to many chance errors that can result in abnormalities of varying degrees. Some of these errors will result in structural anomalies of the brain, while others may cause undetectable, but significant, abnormalities in how the cerebral cortex is wired. An abnormality in structure or wiring is sometimes hereditary but is most often due to chance or some unknown cause. The possible role genetics plays in a particular brain abnormality depends to some degree on the type of anomaly and the form of CP it causes.

Several maternal-fetal infections are known to increase the risk for CP, including rubella (German measles , now rare in the United States), cytomegalovirus (CMV), and toxoplasmosis . Each of these infections is considered a risk to the fetus only if the mother contracts it for the first time during that pregnancy. Even in those cases, most babies are born normal. Most women are immune to all three infections by the time they reach childbearing age, but a woman's immune status can be determined using the so-called TORCH (for toxoplasmosis, rubella, cytomegalovirus, and herpes) test before or during pregnancy.

Just as a stroke can occur in an adult and cause neurologic damage in an adult, so too can this type of event occur in the fetus. A burst blood vessel in the brain followed by uncontrolled bleeding (intracerebral hemorrhage) can cause a fetal stroke, or a clot (embolism) can obstruct a cerebral blood vessel. Infants who later develop CP, along with their mothers, are more likely than other mother-infant pairs to have coagulation disorders (coagulopathies) that put them at increased risk for bleeding episodes or blood clots. Certain coagulation disorders are inherited while others may be deficiencies in essential clotting factors or defects in the coagulation process.

Any substance that might affect fetal brain development, directly or indirectly, can increase the risk for CP. Likewise, any substance that increases the risk for premature delivery and low birth weight, such as alcohol, tobacco, or cocaine, among others, might indirectly increase the risk for CP. Links between a drug or other chemical exposure during pregnancy and a risk for CP are difficult to prove.

Because the fetus receives all nutrients and oxygen from blood that circulates through the placenta, anything that interferes with normal placental function might adversely affect development of the fetus, including the brain, or might increase the risk for premature delivery. Structural abnormalities of the placenta, premature detachment of the placenta from the uterine wall (abruption), and placental infections (chorioamnionitis) are thought to pose some risk for CP.

Certain conditions in the mother during pregnancy might pose a risk to fetal development leading to CP. Women with autoimmune anti-thyroid or anti-phospholipid (APA) antibodies are at slightly increased risk for CP in their children. A potentially important clue points toward high levels of cytokines in the maternal and fetal circulation as a possible risk for CP. Cytokines are proteins associated with inflammation, such as from infection or autoimmune disorders, and they may be toxic to neurons in the fetal brain.

Serious physical trauma to the mother during pregnancy could result in direct trauma to the fetus as well, or injuries to the mother could compromise the availability of nutrients and oxygen to the developing fetal brain.

Perinatal causes

Birth asphyxia that is significant enough to result in CP is uncommon in developed countries. An umbilical cord around the baby's neck (tight nuchal cord) and the cord delivered before the baby (prolapsed cord) are possible causes of birth asphyxia, as are bleeding and other complications associated with placental abruption and placenta previa (placenta lying over the cervix).

Infection in the mother is sometimes not passed to the fetus through the placenta but is transmitted to the baby during delivery. Any such infection, such as herpes, that results in serious illness in the newborn has the potential to produce some neurological damage.

Postnatal causes

The remaining 15 percent of CP cases are due to neurologic injury sustained after birth. CP that has a postnatal cause is sometimes referred to as acquired CP, but this is only accurate for those cases caused by infection or trauma.

Incompatibility between the Rh blood types of mother and child (mother Rh negative, baby Rh positive) can result in severe anemia in the baby (erythroblastosis fetalis ). This may lead to other complications, including severe jaundice , which can cause CP. Rh disease in the newborn is rare in developed countries due to routine screening of maternal blood type and routine prevention of anti-Rh antibodies in Rh negative women after each birth of an Rh positive infant. The routine, effective treatment of jaundice due to other causes has also made it an infrequent cause of CP in developed countries.

Serious infections that affect the brain directly, such as meningitis and encephalitis , may cause irreversible damage to the brain, leading to CP. A seizure disorder early in life may cause CP or may be the product of a hidden problem that causes CP in addition to seizures. Unexplained (idiopathic) seizures are hereditary in only a small percentage of cases. Although rare in healthy infants born at or near term, intracerebral hemorrhage and brain embolism, like fetal stroke, are sometimes genetic.

Physical trauma to an infant or child resulting in brain injury, such as from abuse, accidents, or near drowning/suffocation, might cause CP. Likewise, ingestion of a toxic substance such as lead, mercury, other poisons, or certain chemicals could cause neurological damage. Accidental overdose of certain medications might also cause similar damage to the central nervous system.

Symptoms

The symptoms of CP and their severity are variable. Those who have CP may have only minor difficulty with fine motor skills , such as grasping and manipulating items with their hands. A severe form of CP could involve significant muscle problems in all four limbs, mental retardation , seizures, and difficulties with vision, speech, and hearing.

Although the defect in cerebral function that causes CP is not progressive, the symptoms of CP often change over time. Most of the symptoms relate in some way to the aberrant control of muscles. CP is categorized first by the type of movement/postural disturbance(s) present, rather than by a description of which limbs are affected. The severity of motor impairment is also a factor. Spastic diplegia, for example, refers to continuously tight muscles that have no voluntary control in both legs, while athetoid quadraparesis describes uncontrolled writhing movements and muscle weakness in all four limbs. These may describe CP symptoms generally but do not describe all people with CP. Spastic diplegia is seen in more individuals than is athetoid quadraparesis. CP can also be loosely categorized as mild, moderate, or severe, but these are subjective terms.

A muscle that is tensed and contracted is hypertonic, while excessively loose muscles are hypotonic. Spastic, hypertonic muscles can cause serious orthopedic problems, including curvature of the spine (scoliosis ), hip dislocation, or contractures. A contracture is shortening of a muscle, aided sometimes by a weak-opposing force from a neighboring muscle. Contractures may become permanent, i.e., fixed, without some sort of intervention. Fixed contractures may cause postural abnormalities in the affected limbs. Clenched fists and contracted feet (equinus or equinovarus) are common in people with CP. Spasticity in the thighs causes them to turn in and cross at the knees, resulting in an unusual method of walking known as scissors gait. Any of the joints in the limbs may be stiff (immobilized) due to spasticity of the attached muscles.

Athetosis and dyskinesia often occur with spasticity but do not often occur alone. The same is true of ataxia. It is important to remember that mild CP or severe CP refers not only to the number of symptoms present but also to the level of involvement of any particular class of symptoms.

Other neurologically based symptoms may include the following:

• mental retardation/learning disabilities
• behavioral disorders
• seizure disorders
• visual impairment
• hearing loss
• speech impairment (dysarthria)
• abnormal sensation and perception

These problems may have a greater impact on a child's life than the physical impairments of CP, although not all children with CP are affected by other problems. Many infants and children with CP have growth impairment. About one third of individuals with CP have moderate-to-severe mental retardation, one third have mild mental retardation, and one third have normal intelligence .

When to call the doctor

Parents should seek medical advice when they notice what seems to be slow development in movement, speech, or cognitive ability in their young child. If a child does not acquire certain skills within a normal time frame, there may be some cause for concern. However, it is known that children progress at somewhat different rates, and a slow beginning is often followed by normal development.

Normal developmental milestones with typical ages for acquiring them, include the following:

• sits well unsupported at about six months (eight to ten months)
• babbles at about six months (up to eight months)
• crawls at about nine months (up to 12 months)
• finger feeds, holds bottle at about nine months (up to 12 months)
• walks alone at about 12 months (up to 15–18 months)
• uses one or two words other than dada/mama at about 12 months (up to 15 months)
• walks up and down steps at about 24 months (24 to 36 months)
• turns pages in books and removes shoes and socks at about 24 months (to 30 months)

Children do not consistently favor one hand over the other before 12 to 18 months of age, and doing so may be a sign that the child has difficulty using the other hand. This same preference for one side of the body may show up as asymmetric crawling or, later on, favoring one leg while climbing stairs. Because CP is nonprogressive, continued loss of previously acquired milestones may indicate that CP is not the cause of the problem; medical evaluation is needed to determine the cause.

Diagnosis

The signs of CP are not usually noticeable at birth. Children normally progress through a predictable set of developmental milestones through the first 18 months of life. Children with CP, however, tend to develop these skills more slowly because of their motor impairments, and delays in reaching milestones are usually the first symptoms of CP. Babies with more severe cases of CP are usually diagnosed earlier than others.

No one test is diagnostic for CP, but certain factors increase suspicion. The Apgar score measures a baby's condition immediately after birth. Babies who have low Apgar scores are at increased risk for CP. Presence of abnormal muscle tone or movements may indicate CP, as may the persistence of infantile reflexes. Imaging of the brain using ultrasound, x rays , MRI, and/or CT scans may reveal a structural anomaly. Some brain lesions associated with CP include scarring, cysts, expansion of the cerebral ventricles (hydrocephalus ), abnormality of the area surrounding the ventricles (periventricular leukomalacia), areas of dead tissue (necrosis), and evidence of an intracerebral hemorrhage or blood clot. Blood and urine biochemical tests, as well as genetic tests, may be used to rule out other possible causes, including muscle and peripheral nerve diseases, mitochondrial and metabolic diseases, and other inherited disorders. Evaluations by a pediatric developmental specialist and a geneticist may be of benefit.

Treatment

Cerebral palsy cannot be cured, but many of the disabilities it causes can be managed through planning and timely care. Treatment for a child with CP depends on the severity, nature, and location of the primary muscular symptoms, as well as any associated problems that might be present. Optimal care of a child with mild CP may involve regular interaction with only a physical therapist and occupational therapist, whereas care for a more severely affected child may include visits to multiple medical specialists throughout life. With proper treatment and an effective plan, most people with CP can lead productive, happy lives.

Physical, occupational, and speech therapy

Spasticity, muscle weakness, coordination, ataxia, and scoliosis are all significant impairments that affect the posture and mobility of children and adults with CP. Physical and occupational therapists work with the patient and the family to maximize the patient's ability to move affected limbs, develop normal motor patterns, and maintain posture. Assistive technology, including wheelchairs, walkers, shoe inserts, crutches, and braces, are often required. A speech therapist and high-tech aids such as computer-controlled communication devices can make a tremendous difference in the life of those who have speech impairments.

Drug therapy

Before fixed contractures develop, muscle-relaxant drugs such as diazepam (Valium), dantrolene (Dantrium), and baclofen (Lioresal) may be prescribed. Botulinum toxin (Botox), a highly effective treatment, is injected directly into the affected muscles. Alcohol or phenol injections into the nerve controlling the muscle are another option. Multiple medications are available to control seizures, and athetosis can be treated using medications such as trihexyphenidyl HCl (Artane) and benztropine (Cogentin).

Surgery

Fixed contractures are usually treated with either serial casting or surgery. The most commonly used surgical procedures are tenotomy, tendon transfer, and dorsal rhizotomy. In tenotomy, tendons of the affected muscle are cut, and the limb is cast in a more normal position while the tendon regrows. Alternatively, tendon transfer involves cutting and reattaching a tendon at a different point on the bone to enhance the length and function of the muscle. A neurosurgeon performing dorsal rhizotomy carefully cuts selected nerve roots in the spinal cord to prevent them from stimulating the spastic muscles. Neurosurgical techniques in the brain such as implanting tiny electrodes directly into the cerebellum or cutting a portion of the hypothalamus have very specific uses and have had mixed results.

KEY TERMS

Asphyxia —Lack of oxygen.

Ataxia —A condition marked by impaired muscular coordination, most frequently resulting from disorders in the brain or spinal cord.

Athetosis —A condition marked by slow, writhing, involuntary muscle movements.

Cerebral palsy —A nonprogressive movement disability caused by abnormal development of or damage to motor control centers of the brain.

Coagulopathy —A disorder in which blood is either too slow or too quick to coagulate (clot).

Contracture —A tightening or shortening of muscles that prevents normal movement of the associated limb or other body part.

Cytokines —Chemicals made by the cells that act on other cells to stimulate or inhibit their function. They are important controllers of immune functions.

Diplegia —Paralysis affecting like parts on both sides the body, such as both arms or both legs.

Dorsal rhizotomy —A surgical procedure that cuts nerve roots to reduce spasticity in affected muscles.

Dyskinesia —Impaired ability to make voluntary movements.

Hemiplegia —Paralysis of one side of the body.

Hypotonia —Having reduced or diminished muscle tone or strength.

Quadriplegia —Paralysis of all four limbs and the trunk below the level of an associated injury to the spinal cord. Also called tetraplegia.

Serial casting —A series of casts designed to gradually move a limb into a more functional position.

Spastic —Refers to a condition in which the muscles are rigid, posture may be abnormal, and fine motor control is impaired.

Spasticity —Increased mucle tone, or stiffness, which leads to uncontrolled, awkward movements.

Static encephalopathy —A disease or disorder of the brain that does not get better or worse.

Tenotomy —A surgical procedure that cuts the tendon of a contracted muscle to allow lengthening.

Prognosis

Cerebral palsy can affect every stage of maturation, from childhood through adolescence to adulthood. At each stage, those with CP, along with their caregivers, must strive to achieve and maintain the fullest range of experience and education consistent with their abilities. The advice and intervention of various professionals are crucial for many people with CP. Although CP itself is not considered a terminal disorder, it can affect a person's lifespan by increasing the risk for certain medical problems. People with mild cerebral palsy may have near-normal lifespan, but the lifespan of those with more severe forms may be shortened. However, over 90 percent of infants with CP survive into adulthood.

Prevention

Research in the early 2000s is focused on the possible benefits of recognizing and treating coagulopathies and inflammatory disorders in the prenatal and perinatal periods in order to reduce the incidence of CP and other congenital diseases. The use of magnesium sulfate in pregnant women with preeclampsia or threatened preterm delivery may reduce the risk of CP in very preterm infants. Finally, the risk of CP can be decreased through good maternal nutrition , avoidance of drugs and alcohol during pregnancy, and prevention or prompt treatment of infections.

Parental concerns

Parents of a child diagnosed with CP may not feel that they have the necessary expertise to coordinate the full range of care their child needs. Although knowledgeable and caring medical professionals are indispensable for developing a care plan, a potentially more important source of information and advice can be gained from other parents who have dealt with the same set of difficulties. Support groups for parents of children with CP can be significant sources of both practical advice and emotional support. Many cities have support groups that can be located through the United Cerebral Palsy Association, and most large medical centers have special multidisciplinary clinics for children with developmental disorders.

See also Febrile seizures; TORCH test; Seizure disorder.

Resources

BOOKS

Peacock, Judith. Cerebral Palsy. Mankato, MN: Capstone Press, 2000.

Pimm, Paul. Living with Cerebral Palsy. Austin, TX: Raintree Steck-Vaughn Publishers, 2000.

Pincus, Dion. Everything You Need to Know about Cerebral Palsy. New York: Rosen Publishing Group Inc., 2000.

ORGANIZATIONS

National Institute of Neurological Disorders and Stroke. 31 Center Drive, MSC 2540, Bldg. 31, Room 8806, Bethesda, MD 20814. Web site: <www.ninds.nih.gov>.

National Society of Genetic Counselors. 233 Canterbury Dr., Wallingford, PA 19086–6617. (610) 872–1192. http://www.nsgc.org/GeneticCounselingYou.asp.

United Cerebral Palsy Association Inc. (UCP). 1660 L St. NW, Suite 700, Washington, DC 20036–5602. Web site: <www.ucpa.org>.

WEB SITES

"Cerebral Palsy: Hope Through Research." National Institute of Neurological Disorders and Stroke, 2004. Available online at <www.ninds.nih.gov/health_and_medical/pubs/cerebral_palsyhtr.htm> (accessed November 29, 2004).

"NINDS Cerebral Palsy Information Page." National Institute of Neurological Disorders and Stroke, October 2004. Available online at <www.ninds.nih.gov/disorders/cerebral_palsy/cerebral_palsy.htm> (accessed November 29, 2004).

L. Lee Culvert Scott J. Polzin, MS

Cerebral palsy

Definition

Cerebral palsy (CP) is the term used for a group of nonprogressive disorders of movement and posture caused by abnormal development of, or damage to, motor control centers of the brain. CP is caused by events before, during, or after birth. The abnormalities of muscle control that define CP are often accompanied by other neurological and physical abnormalities.

Description

Voluntary movement (walking, grasping, chewing, etc.) is primarily accomplished using muscles that are attached to bones, known as the skeletal muscles. Control of the skeletal muscles originates in the cerebral cortex, the largest portion of the brain. Palsy means paralysis, but may also be used to describe uncontrolled muscle movement. Therefore, cerebral palsy encompasses any disorder of abnormal movement and paralysis caused by abnormal function of the cerebral cortex. In truth, however, CP does not include conditions due to progressive disease or degeneration of the brain. For this reason, CP is also referred to as static (nonprogressive) encephalopathy (disease of the brain). Also excluded from CP are any disorders of muscle control that arise in the muscles themselves and/or in the peripheral nervous system (nerves outside the brain and spinal cord).

CP is not a specific diagnosis, but is more accurately considered a description of a broad but defined group of neurological and physical problems.

The symptoms of CP and their severity are quite variable. Those with CP may have only minor difficulty with fine motor skills, such as grasping and manipulating items with their hands. A severe form of CP could involve significant muscle problems in all four limbs, mental retardation, seizures, and difficulties with vision, speech, and hearing.

Muscles that receive abnormal messages from the brain may be constantly contracted and tight (spastic), exhibit involuntary writhing movements (athetosis), or have difficulty with voluntary movement (dyskinesia). There can also be a lack of balance and coordination with unsteady movements (ataxia). A combination of any of these problems may also occur. Spastic CP and mixed CP constitute the majority of cases. Effects on the muscles can range from mild weakness or partial paralysis (paresis), to complete loss of voluntary control of a muscle or group of muscles (plegia). CP is also designated by the number of limbs affected. For instance, affected muscles in one limb is monoplegia, both arms or both legs is diplegia, both limbs on one side of the body is hemiplegia, and in all four limbs is quadriplegia. Muscles of the trunk, neck, and head may be affected as well.

CP can be caused by a number of different mechanisms at various times—from several weeks after conception, through birth, to early childhood. For many years, it was accepted that most cases of CP were due to brain injuries received during a traumatic birth, known as birth asphyxia. However, extensive research in the 1980s showed that only 5–10% of CP can be attributed to birth trauma. Other possible causes include abnormal development of the brain, prenatal factors that directly or indirectly damage neurons in the developing brain, premature birth, and brain injuries that occurin the first few yearsof life.

Genetic profile

As noted, CP has many causes, making a discussion of the genetics of CP complicated. A number of hereditary/genetic syndromes have signs and symptoms similar to CP, but usually also have problems not typical of CP. Put another way, some hereditary conditions "mimic" CP. Isolated CP, meaning CP that is not a part of some other syndrome or disorder, is usually not inherited.

It might be possible to group the causes of CP into those that are genetic and those that are non-genetic, but most would fall somewhere in between. Grouping causes into those that occur during pregnancy (prenatal), those that happen around the time of birth (perinatal), and those that occur after birth (postnatal), is preferable. CP related to premature birth and multiple birth pregnancies (twins, triplets, etc.) is somewhat different and considered separately.

Prenatal causes

Although much has been learned about human embryology in the last couple of decades, a great deal remains unknown. Studying prenatal human development is difficult because the embryo and fetus develop in a closed environment—the mother's womb. However, the relatively recent development of a number of prenatal tests has opened a window on the process. Add to that more accurate and complete evaluations of newborns, especially those with problems, and a clearer picture of what can go wrong before birth is possible.

The complicated process of brain development before birth is susceptible to many chance errors that can result in abnormalities of varying degrees. Some of these errors will result in structural anomalies of the brain, while others may cause undetectable, but significant, abnormalities in how the cerebral cortex is "wired." An abnormality in structure or wiring is sometimes hereditary, but is most often due to chance, or a cause unknown at this time. Whether and how much genetics played a role in a particular brain abnormality depends to some degree on the type of anomaly and the form of CP it causes.

Several maternal-fetal infections are known to increase the risk for CP, including rubella (German measles, now rare in the United States), cytomegalovirus (CMV), and toxoplasmosis. Each of these infections is considered a risk to the fetus only if the mother contracts it for the first time during that pregnancy. Even in those cases, though, most babies will be born normal. Most women are immune to all three infections by the time they reach childbearing age, but a woman's immune status can be determined using the TORCH (Toxoplasmosis, Rubella, Cytomegalovirus, and Herpes) test before or during pregnancy.

Just as a stroke can cause neurologic damage in an adult, so too can this type of event occur in the fetus. A burst blood vessel in the brain followed by uncontrolled bleeding (coagulopathy), known as intracerebral hemorrhage, could cause a fetal stroke, or a cerebral blood vessel could be obstructed by a clot (embolism). Infants who later develop CP, along with their mothers, are more likely than other mother-infant pairs to test positive for factors that put them at increased risk for bleeding episodes or blood clots. Some coagulation disorders are strictly hereditary, but most have a more complicated basis.

A teratogen is any substance to which a woman is exposed that has the potential to harm the embryo or fetus. Links between a drug or other chemical exposure during pregnancy and a risk for CP are difficult to prove. However, any substance that might affect fetal brain development, directly or indirectly, could increase the risk for CP. Furthermore, any substance that increases the risk for premature delivery and low birth weight, such as alcohol, tobacco, or cocaine, among others, might indirectly increase the risk for CP.

The fetus receives all nutrients and oxygen from blood that circulates through the placenta. Therefore, anything that interferes with normal placental function might adversely affect development of the fetus, including the brain, or might increase the risk for premature delivery. Structural abnormalities of the placenta, premature detachment of the placenta from the uterine wall (abruption), and placental infections (chorioamnionitis) are thought to pose some risk for CP.

Certain conditions in the mother during pregnancy might pose a risk to fetal development leading to CP. Women with autoimmune anti-thyroid or anti-phospholipid (APA) antibodies are at slightly increased risk for CP in their children. A potentially important clue uncovered recently points toward high levels of cytokines in the maternal and fetal circulation as a possible risk for CP. Cytokines are proteins associated with inflammation, such as from infection or autoimmune disorders, and they may be toxic to neurons in the fetal brain. More research is needed to determine the exact relationship, if any, between high levels of cytokines in pregnancy and CP. A woman has some risk of developing the same complications in more than one pregnancy, slightly increasing the risk for more than one child with CP.

Serious physical trauma to the mother during pregnancy could result in direct trauma to the fetus as well, or injuries to the mother could compromise the availability of nutrients and oxygen to the developing fetal brain.

Perinatal causes

Birth asphyxia significant enough to result in CP is now uncommon in developed countries. Tight nuchal cord (umbilical cord around the baby's neck) and prolapsed cord (cord delivered before the baby) are possible causes of birth asphyxia, as are bleeding and other complications associated with placental abruption and placenta previa (placenta lying over the cervix).

Infection in the mother is sometimes not passed to the fetus through the placenta, but is transmitted to the baby during delivery. Any such infection that results in serious illness in the newborn has the potential to produce some neurological damage.

Postnatal causes

The remaining 15% of CP is due to neurological injury sustained after birth. CP that has a postnatal cause is sometimes referred to as acquired CP, but this is only accurate for those cases caused by infection or trauma.

Incompatibility between the Rh blood types of mother and child (mother Rh negative, baby Rh positive) can result in severe anemia in the baby (erythroblastosis fetalis). This may lead to other complications, including severe jaundice, which can cause CP. Rh disease in the newborn is now rare in developed countries due to routine screening of maternal blood type and treatment of pregnancies at risk. The routine, effective treatment of jaundice due to other causes has also made it an infrequent cause of CP in developed countries. Rh blood type poses a risk for recurrence of Rh disease if treatment is not provided.

Serious infections that affect the brain directly, such as meningitis and encephalitis, may cause irreversible damage to the brain, leading to CP. A seizure disorder early in life may cause CP, or may be the product of a hidden problem that causes CP in addition to seizures. Unexplained (idiopathic) seizures are hereditary in only a small percentage of cases. Although rare in infants born healthy at or near term, intracerebral hemorrhage and brain embolism, like fetal stroke, are sometimes genetic.

Physical trauma to an infant or child resulting in brain injury, such as from abuse, accidents, or near drowning/suffocation, might cause CP. Likewise, ingestion of a toxic substance such as lead, mercury, poisons, or certain chemicals could cause neurological damage. Accidental overdose of certain medications might also cause similar damage to the central nervous system.

Prematurity and multiple birth pregnancy

Advances in the medical care of premature infants in the last 20 years have dramatically increased the rate of survival of these fragile newborns. However, as gestational age at delivery and birth weight of a baby decrease, the risk for CP dramatically increases. A term pregnancy is delivered at 37–41 weeks gestation. The risk for CP in a preterm infant (32–37 weeks) is increased about five-fold over the risk for an infant born at term. Survivors of extremely preterm births (less than 28 weeks) face as much as a fifty-fold increase in risk. About 50% of all cases of CP now being diagnosed are in children who were born prematurely.

Two factors are involved in the risk for CP associated with prematurity. First, premature babies are at higher risk for various CP-associated medical complications, such as intracerebral hemorrhage, infection, and difficulty in breathing, to name a few. Second, the onset of premature labor may be induced, in part, by complications that have already caused neurologic damage in the fetus. A combination of both factors almost certainly plays a role in some cases of CP. The tendency toward premature delivery tends to run in families, but the genetic mechanisms are far from clear.

An increase in multiple birth pregnancies in recent years, especially in the United States, is blamed on the increased use of fertility drugs. As the number of fetuses in a pregnancy increases, the risks for abnormal development and premature delivery also increase. Children from twin pregnancies have four times the risk of developing CP as children from singleton pregnancies, owing to the fact that more twin pregnancies are delivered prematurely. The risk for CP in a child of triplets is up to 18 times greater. Furthermore, recent evidence suggests that a baby from a pregnancy in which its twin died before birth is at increased risk for CP.

Demographics

Approximately 500,000 children and adults in the United States have CP, and it is newly diagnosed in about 6,000 infants and young children each year. The incidence of CP has not changed much in the last 20–30 years. Ironically, advances in medicine have decreased the incidence from some causes, Rh disease for example, but increased it from others, notably, prematurity and multiple birth pregnancies. No particular ethnic groups seem to be at higher risk for CP. However, people of disadvantaged background are at higher risk due to poorer access to proper prenatal care and advanced medical services.

Signs and symptoms

By definition, the defect in cerebral function causing CP is nonprogressive. However, the symptoms of CP often change over time. Most of the symptoms of CP relate in some way to the aberrant control of muscles. To review, CP is categorized first by the type of movement/postural disturbance(s) present, then by a description of which limbs are affected, and finally by the severity of motor impairment. For example, spastic diplegia refers to continuously tight muscles that have no voluntary control in both legs, while athetoid quadraparesis describes uncontrolled writhing movements and muscle weakness in all four limbs. These three-part descriptions are helpful in providing a general picture, but cannot give a complete description of any one person with CP. In addition, the various "forms" of CP do not occur with equal frequency—spastic diplegia is seen in more individuals than is athetoid quadraparesis. CP can also be loosely categorized as mild, moderate, or severe, but these are very subjective terms with no firm boundaries between them.

A muscle that is tensed and contracted is hypertonic, while excessively loose muscles are hypotonic. Spastic, hypertonic muscles can cause serious orthopedic problems, including scoliosis (spine curvature), hip dislocation, or contractures. A contracture is shortening of a muscle, aided sometimes by a weak-opposing force from a neighboring muscle. Contractures may become permanent, or "fixed," without some sort of intervention. Fixed contractures may cause postural abnormalities in the affected limbs. Clenched fists and contracted feet (equinus or equinovarus) are common in people with CP. Spasticity in the thighs causes them to turn in and cross at the knees, resulting in an unusual method of walking known as a "scissors gait." Any of the joints in the limbs may be stiff (immobilized) due to spasticity of the attached muscles.

Athetosis and dyskinesia often occur with spasticity, but do not often occur alone. The same is true of ataxia. It is important to remember that "mild CP" or "severe CP" refers not only to the number of symptoms present, but also to the level of involvement of any particular class of symptoms.

Mechanisms that can cause CP are not always restricted to motor-control areas of the brain. Other neurologically based symptoms may include:

• mental retardation/learning disabilities
• behavioral disorders
• seizure disorders
• visual impairment
• hearing loss
• speech impairment (dysarthria)
• abnormal sensation and perception

These problems may have a greater impact on a child's life than the physical impairments of CP, although not all children with CP are affected by other problems. Many infants and children with CP have growth impairment. About one-third of individuals with CP have moderate-to-severe mental retardation, one-third have mild mental retardation, and one-third have normal intelligence.

Diagnosis

The signs of CP are not usually noticeable at birth. Children normally progress through a predictable set of developmental milestones through the first 18 months of life. Children with CP, however, tend to develop these skills more slowly because of their motor impairments, and delays in reaching milestones are usually the first symptoms of CP. Babies with more severe cases of CP are normally diagnosed earlier than others.

Selected developmental milestones, and the ages for normally acquiring them, are given below. If a child does not acquire the skill by the age shown in parentheses, there is some cause for concern.

• Sits well unsupported—6 months (8–10 months)
• Babbles—6 months (8 months)
• Crawls—9 months (12 months)
• Finger feeds, holds bottle—9 months (12 months)
• Walks alone—12 months (15–18 months)
• Uses one or two words other than dada/mama—12 months (15 months)
• Walks up and down steps—24 months (24–36 months)
• Turns pages in books; removes shoes and socks—24 months (30 months)

Children do not consistently favor one hand over the other before 12–18 months, and doing so may be a sign that the child has difficulty using the other hand. This same preference for one side of the body may show up as asymmetric crawling or, later on, favoring one leg while climbing stairs.

It must be remembered that children normally progress at somewhat different rates, and slow beginning accomplishment is often followed by normal development. Other causes for developmental delay—some benign, some serious—should be excluded before considering CP as the answer. CP is nonprogressive, so continued loss of previously acquired milestones indicates that CP is not the cause of the problem.

No one test is diagnostic for CP, but certain factors increase suspicion. The Apgar score measures a baby's condition immediately after birth. Babies that have low Apgar scores are at increased risk for CP. Presence of abnormal muscle tone or movements may indicate CP, as may the persistence of infantile reflexes. Imaging of the brain using ultrasound, x rays, MRI, and/or CT scans may reveal a structural anomaly. Some brain lesions associated with CP include scarring, cysts, expansion of the cerebral

ventricles (hydrocephalus ), periventricular leukomalacia (an abnormality of the area surrounding the ventricles), areas of dead tissue (necrosis), and evidence of an intra-cerebral hemorrhage or blood clot. Blood and urine biochemical tests, as well as genetic tests, may be used to rule out other possible causes, including muscle and peripheral nerve diseases, mitochondrial and metabolic diseases, and other inherited disorders. Evaluations by a pediatric developmental specialist and a geneticist may be of benefit.

Cerebral palsy cannot be cured, but many of the disabilities it causes can be managed through planning and timely care. Treatment for a child with CP depends on the severity, nature, and location of the primary muscular symptoms, as well as any associated problems that might be present. Optimal care of a child with mild CP may involve regular interaction with only a physical therapist and occupational therapist, whereas care for a more severely affected child may include visits to multiple medical specialists throughout life. With proper treatment and an effective plan, most people with CP can lead productive, happy lives.

Therapy

Spasticity, muscle weakness, coordination, ataxia, and scoliosis are all significant impairments that affect the posture and mobility of a person with CP. Physical and occupational therapists work with the patient and the family to maximize the ability to move affected limbs, develop normal motor patterns, and maintain posture. Assistive technology such as wheelchairs, walkers, shoe inserts, crutches, and braces are often required. A speech therapist and high-tech aids, such as computer-controlled communication devices, can make a tremendous difference in the life of those who have speech impairments.

Medications

Before fixed contractures develop, muscle-relaxant drugs such as diazepam (Valium), dantrolene (Dantrium), and baclofen (Lioresal) may be prescribed. Botulinum toxin (Botox), a newer and highly effective treatment, is injected directly into the affected muscles. Alcohol or phenol injections into the nerve controlling the muscle are another option. Multiple medications are available to control seizures, and athetosis can be treated using medications such as trihexyphenidyl HCl (Artane) and benztropine (Cogentin).

Surgery

Fixed contractures are usually treated with either serial casting or surgery. The most commonly used surgical procedures are tenotomy, tendon transfer, and dorsal rhizotomy. In tenotomy, tendons of the affected muscle are cut and the limb is cast in a more normal position while the tendon regrows. Alternatively, tendon transfer involves cutting and reattaching a tendon at a different point on the bone to enhance the length and function of the muscle. A neurosurgeon performing dorsal rhizotomy carefully cuts selected nerve roots in the spinal cord to prevent them from stimulating the spastic muscles. Neurosurgical techniques in the brain such as implanting tiny electrodes directly into the cerebellum, or cutting a portion of the hypothalamus, have very specific uses and have had mixed results.

Education

Parents of a child newly diagnosed with CP are not likely to have the necessary expertise to coordinate the full range of care their child will need. Although knowledgeable and caring medical professionals are indispensable for developing a care plan, a potentially more important source of information and advice is other parents who have dealt with the same set of difficulties. Support groups for parents of children with CP can be significant sources of both practical advice and emotional support. Many cities have support groups that can be located through the United Cerebral Palsy Association, and most large medical centers have special multidisciplinary clinics for children with developmental disorders.

Prognosis

Cerebral palsy can affect every stage of maturation, from childhood through adolescence to adulthood. At each stage, those with CP, along with their caregivers, must strive to achieve and maintain the fullest range of experiences and education consistent with their abilities. The advice and intervention of various professionals remains crucial for many people with CP. Although CP itself is not considered a terminal disorder, it can affect a person's lifespan by increasing the risk for certain medical problems. People with mild cerebral palsy may have near-normal life spans, but the lifespan of those with more severe forms may be shortened. However, over 90% of infants with CP survive into adulthood.

The cause of most cases of CP remains unknown, but it has become clear in recent years that birth difficulties are not to blame in most cases. Rather, developmental problems before birth, usually unknown and generally undiagnosable, are responsible for most cases. The rate of survival for preterm infants has leveled off in recent years, and methods to improve the long-term health of these at-risk babies are now being sought. Current research is also focusing on the possible benefits of recognizing and treating coagulopathies and inflammatory disorders in the prenatal and perinatal periods. The use of magnesium sulfate in pregnant women with preeclampsia or threatened preterm delivery may reduce the risk of CP in very preterm infants. Finally, the risk of CP can be decreased through good maternal nutrition, avoidance of drugs and alcohol during pregnancy, and prevention or prompt treatment of infections.

Resources

BOOKS

Miller, Freema, and Steven J. Bachrach. Cerebral Palsy: A Complete Guide for Caregiving. Baltimore: Johns Hopkins University Press, 1995.

Peacock, Judith. Cerebral Palsy. Mankato, MN: Capstone Press, 2000.

Pimm, Paul. Living With Cerebral Palsy. Austin, TX: Raintree Steck-Vaughn Publishers, 2000.

Pincus, Dion. Everything You Need to Know About Cerebral Palsy. New York: Rosen Publishing Group, Inc., 2000

PERIODICALS

Chambers, Henry G. "Research in Cerebral Palsy." The Exceptional Parent 29 (July 1999): 50.

Myers, Scott M., and Bruce K. Shapiro. "Origins and Causes of Cerebral Palsy: Symptoms and Diagnosis." The Exceptional Parent 29 (April 1999): 28.

Seppa, Nathan. "Infections may underlie cerebral palsy." Science News 154 (October 17, 1998): 244.

Stephenson, Joan. "Cerebral Palsy Clues." The Journal of the American Medical Association 280 (21 October 1998): 1298.

ORGANIZATIONS

Epilepsy Foundation of America. 4351 Garden City Dr., Suite 406, Landover, MD 20785-2267. (301) 459-3700 or (800) 332-1000. <http://www.epilepsyfoundation.org>.

March of Dimes Birth Defects Foundation. 1275 Mamaroneck Ave., White Plains, NY 10605. (888) 663-4637. [email protected]. <http://www.modimes.org>.

National Easter Seal Society. 230 W. Monroe St., Suite 1800, Chicago, IL 60606-4802. (312) 726-6200 or (800) 221-6827. <http://www.easter-seals.org>.

National Institute of Neurological Disorders and Stroke. 31 Center Drive, MSC 2540, Bldg. 31, Room 8806, Bethesda, MD 20814. (301) 496-5751 or (800) 352-9424. <http://www.ninds.nih.gov>.

National Society of Genetic Counselors. 233 Canterbury Dr., Wallingford, PA 19086-6617. (610) 872-1192. <http://www.nsgc.org/GeneticCounselingYou.asp>.

United Cerebral Palsy Association, Inc. (UCP). 1660 L St. NW, Suite 700, Washington, DC 20036-5602. (202)776-0406 or (800)872-5827. <http://www.ucpa.org>.

WEBSITES

"Cerebral Palsy: Hope Through Research." National Institute of Neurological Disorders and Stroke. <http://www.ninds.nih.gov/health_and_medical/pubs/cerebral_palsyhtr.htm>

"Cerebral Palsy Information Page." National Institute of Neurological Disorders and Stroke. <http://www.ninds.nih.gov/health_and_medical/pubs/cerebral_palsy.htm>

Scott J. Polzin, MS, CGC