Pervasive Developmental Disorders

Definition

Pervasive developmental disorders include five different conditions: Asperger's syndrome, autistic disorder, childhood disintegrative disorder (CDD), pervasive developmental disorder not otherwise specified (PDDNOS), and Rett's syndrome. They are grouped together because of the similarities between them. The three most common shared problems involve communication skills, motor skills, and social skills. Since there are no clear diagnostic boundaries separating these conditions it is sometimes difficult to distinguish one from the other for diagnostic purposes.

Asperger's syndrome, autistic disorder, and childhood disintegrative disorder are four to five times more common in boys, and Rett's syndrome has been diagnosed primarily in girls. All of these disorders are rare.

Description

Asperger's syndrome

Children afflicted with Asperger's syndrome exhibit difficulties in social relationships and communication. They are reluctant to make eye contact, do not respond to social or emotional contacts, do not initiate play activities with peers, and do not give or receive attention or affection. To receive this diagnosis the individual must demonstrate normal development of language, thinking and coping skills. Due to an impaired coordination of muscle movements, they appear to be clumsy. They usually become deeply involved in very few interests, which tend to occupy most of their time and attention.

Autistic disorder

Autistic disorder is frequently evident within the first year of life, and must be diagnosed before age three. It is associated with moderate mental retardation in three out of four cases. These children do not want to be held, rocked, cuddled or played with. They are unresponsive to affection, show no interest in peers or adults and have few interests. Other traits include avoidance of eye contact, an expressionless face and the use of gestures to express needs. Their actions are repetitive, routine and restricted. Rocking, hand and arm flapping, unusual hand and finger movements, and attachment to objects rather than pets and people are common. Speech, play, and other behaviors are repetitive and without imagination. They tend to be overactive, aggressive, and self-injurious. They are often highly sensitive to touch, noise, and smells and do not like changes in routine. Autism and several disorders classified with it have increased significantly in recent years so that they now are diagnosed more often in children than spina bifida, cancer, or Down syndrome. This may be due partly to improved recognition and diagnosis.

Childhood disintegrative disorder

Childhood disintegrative disorder is also called Heller's disease and most often develops between two and ten years of age. Children with CDD develop normally until two to three years of age and then begin to disintegrate rapidly. Signs and symptoms include deterioration of the ability to use and understand language to the point where they are unable to carry on a conversation. This is accompanied by loss of control of the bladder and bowels. Any interest or ability to play and engage in social activities is lost. The behaviors are nearly identical with those that are characteristic of autistic disorder. However, childhood disintegrative disorder becomes evident later in life and results in developmental regression, or loss of previously attained skills, whereas autistic disorder can be detected as early as the first month of life and results in a failure to progress.

Pervasive developmental disorder not otherwise specified

The term pervasive developmental disorder not otherwise specified (PDDNOS) is also referred to as atypical personality development, atypical PDD, or atypical autism. Individuals with this disorder share some of the same signs and symptoms of autism or other conditions under the category of pervasive developmental disorders, but do not meet all of the criteria for diagnosis for any of the four syndromes included in this group of diseases. Because the children diagnosed with PDDNOS do not all exhibit the same combination of characteristics, it is difficult to do research on this disorder, but the limited evidence available suggests that patients are seen by medical professionals later in life than is the case for autistic children, and they are less likely to have intellectual deficits.

Rett's syndrome

Rett's syndrome was first described in 1966 and is found almost exclusively in girls. It is a disease in which cells in the brain experience difficulty in communicating with each other. At the same time the growth of the head falls behind the growth of the body so that these children are usually mentally retarded. These conditions are accompanied by deficits in movement (motor) skills and a loss of interest in social activities.

The course of the illness has been divided into four stages. In stage one the child develops normally for six to 18 months. In stage two, development slows down and stops. Stage three is characterized by a loss of the speech and motor skills already acquired. Typically this happens between nine months and three years of age. Stage four begins with a return to learning that will continue across the lifespan, but at a very slow rate. Problems with coordination and walking are likely to continue and even worsen. Other conditions that can occur with Rett's syndrome are convulsions, constipation, breathing problems, impaired circulation in the feet and legs, and difficulty chewing or swallowing.

Causes and symptoms

The causes of these disorders are unknown although brain structure abnormalities, genetic mutation, and alterations in brain function are believed to play a role. Still, no single brain abnormality or location has been connected to a cause. In 2004, scientists reported finding the gene mutation (on gene MECP2) that is present in 80% of people affected with Rett's syndrome. In 2004, comprehensive review of research on twins revealed that interactions between multiple genes may play a role in the cause of autism. A number of neurological conditions, such as convulsions, are commonly found to accompany these disorders.

Diagnosis

The diagnosis of pervasive developmental disorder is made by medical specialists based on a thorough examination of the patient, including observing behavior and gathering information from parents and caregivers. Because many symptoms are common to more than one condition, distinctions between conditions must be carefully made. The following summary describes the distinction between three common disorders.

PDDNOS:

• impairment of two-way social interaction
• Repetitive and predictable behavior patterns and activities

Autism:

• all listed for PDDNOS
• severe impairment in communication
• abnormal social interaction and use of language for social communication or imaginative play before age of three
• not better accounted for by another psychiatric order

Asperger's disorder:

• all listed for PDDNOS
• clinically significant impairment in social, occupational, or other areas of functioning
• no general delay in language
• no delay in cognitive development, self-help skills, or adaptive behavior
• not better accounted for by another pervasive developmental disorder or schizophrenia

Rett's syndrome:

• a period of normal development between 6-18 months
• normal head circumference at birth, followed by a slowing of head growth
• retardation
• repetitive hand movements

CDD:

• normal development for at least two years
• loss of skills in at least two of the following areas: language, social skills, bowel or bladder control, play, movement skills
• abnormal functioning in at least two of the following areas: social interaction, communication, behavior patterns
• not better accounted for by another PDD or mental illness

Treatment

Treatment for children with pervasive developmental disorders is limited. Those who can be enrolled in educational programs will need a highly structured learning environment, a teacher-student ratio of not more than 1:2, and a high level of parental involvement that provides consistent care at home. Psychotherapy and social skills training can prove helpful to some. There is no specific medication available for treating the core symptoms of any of these disorders, though research is promising. Some psychiatric medications may be helpful in controlling particular behavior difficulties, such as agitation, mood instability, and self-injury. Music, massage, and hydrotherapy may exert a calming effect on behavior. Treatment may also include physical and occupational therapy.

Prognosis

In general, the prognosis in all of these conditions is tied to the severity of the illness.

The prognosis for Asperger's syndrome is more hopeful than that for other diseases in this cluster. These children are likely to grow up to be functional independent adults, but will always have problems with social relationships. They are also at greater risk for developing serious mental illness than the general population.

The prognosis for autistic disorder is not as good, although great strides have been made in recent years in its treatment. The higher the patient's IQ (intelligence quotient) and ability to communicate, the better the prognosis. However, many patients will always need some level of custodial care. In the past, most of these individuals were confined to institutions, but many are now able to live in group homes or supervised apartments. The prognosis for childhood disintegrative disorder is even less favorable. These children will require intensive and long-term care. Children diagnosed with PDDNOS have a better prognosis because their initial symptoms are usually milder, IQ scores are higher, and language development is stronger.

Prevention

The causes of pervasive developmental disorders are not understood, although research efforts are getting closer to understanding the problem. Until the causes are discovered, it will remain impossible to prevent these conditions.

Resources

PERIODICALS

"MECP2 Open Reading Framd Defines Protein Linked to Rett Syndrome." Biotech Week June 9, 2004: 300.

Muhle, Rebecca, Stephanie V. Trentacoste, and Isabelle Rapin. "The Genetics of Autism." Pediatrics May 2004: 1389-1391.

ORGANIZATIONS

Autism Society of America. 7910 Woodmont Avenue, Suite 300, Bethesda, Maryland 20814-3067. (800) 328-8476. 〈http://www.autism-society.org〉.

International Rett Syndrome Association. 9121 Piscataway Road, Suite 2B, Clinton, MD 20735. (800) 818-7388. 〈http://www.rettsyndrome.org〉.

Learning Disabilities Association of America. 4156 Library Road, Pittsburg, PA 15234. (412) 341-1515. 〈http://www.ldanatl.org〉.

National Organization for Rare Disorders. P.O. Box 8923, New Fairfield, CT 06812-8923. (800) 999-6673. 〈http://www.rarediseases.org〉.

OTHER

Boyle, Thomas D. "Diagnosing Autism and Other Pervasive Personality Disorders." INJersye.com Page. 〈http://www.injersey.com〉.

"Childhood Disintegrative Disorder." HealthAnswers.com. 〈http://www.healthanswers.com/database/ami/converted/001535.html〉.

"Information on Childhood Disintegrative Disorder." Yale-New Haven Medical Center Page. 〈http://info.med.yale.edu〉.

The International Rett Syndrome Association. 9121 Piscataway Road, Suite 2B, Clinton, MD 20735. (800) 818-7388 〈http://www.rettsyndrome.org〉.

Koenig, Kathy. "Frequently Asked Questions." Yale-New Haven Medical Center Page. 〈http://info.med.yale.edu〉.

KEY TERMS

Hydrotherapy— This term literally means "water treatment" and involves the use of water in physical therapy as well as treatment of physical and emotional illness.

Mutation— A mutation is a change in a gene. Since genes determine how a body is structured and functions, any change in a gene will produce some change in these areas.

Neurological conditions— A condition that has its origin in some part of the patient's nervous system.

Pervasive developmental disorders

Definition

The pervasive developmental disorders, or PDDs, are a group of childhood disorders that manifest during the first years of the child's life. They are marked by severe weaknesses in several areas of development: social interaction, communication, or the appearance of stereotyped behavior patterns and interests. The PDDs are also known as autistic spectrum disorders. As the phrase spectrum disorder suggests, persons with these disorders fall at different points along a fairly wide continuum of disabilities and associated disorders. As defined by DSM-IV, the pervasive developmental disorders include:

• autistic disorder
• Rett syndrome
• childhood disintegrative disorder (CDD)
• Asperger syndrome
• pervasive developmental disorder not otherwise specified (PDD-NOS)

Description

The PDDs form a diagnostic category intended to identify children with delays in or deviant forms of social, linguistic, cognitive, and motor (muscular movement) development. The category covers children with a wide variety of developmental delays of differing severity in these four broad areas. The precise cause(s) of the PDDs are still obscure, but are assumed to be abnormalities of the central nervous system.

Autistic disorder

Autistic disorder, or autism , was first described in 1943. Autistic children are characterized by severe impairment in their interactions with others and delayed or abnormal patterns of communication; about 50% of autistic children do not speak at all. These abnormalities begin in the first weeks of life; it is not unusual for the parents of an autistic child to say that they "knew something was wrong" quite early in the child's development. Another characteristic symptom has been termed "insistence on sameness;" that is, these children may become extremely upset by trivial changes in their environment or daily routine—such as a new picture on the wall or taking a different route to the grocery store. Autistic children often make repetitive or stereotyped gestures or movements with their hands or bodies. Their behavioral symptoms may also include impulsivity, aggressiveness, temper tantrums, and self-biting or other forms of self-injury.

About 75% of children diagnosed with autism are also diagnosed with moderate mental retardation (IQ between 35 and 50). Their cognitive skills frequently develop unevenly, regardless of their general intelligence level. A minority of autistic children have IQs above 70; their condition is sometimes called high-functioning autism, or HFA. In addition to mental retardation, autism is frequently associated with other neurological or medical conditions, including encephalitis, phenylketonuria , tuberous sclerosis, fragile X syndrome , and underdeveloped reflexes. About 25% of autistic children develop seizure disorders, most often in adolescence.

Rett syndrome

Unlike autism, Rett syndrome has a very distinctive onset and course. The child develops normally during the first five months of life; after the fifth month, head growth slows down and the child loses whatever purposeful hand movements she had developed during the first five months. After 30 months, the child frequently develops repetitive hand-washing or hand-wringing gestures; over 50% of children with the disorder will develop seizure disorders. Rett syndrome is also associated with severe or profound mental retardation. As of 2001, this disorder has been diagnosed only in females.

Childhood disintegrative disorder (Heller's syndrome)

Childhood disintegrative disorder, or CDD, was first described by an educator named Theodore Heller in 1908. He referred to it as dementia infantilis. Children with CDD have apparently normal development during the first two years of life. Between two and ten years of age, the child loses two or more previously acquired skills, including language skills, social skills, toileting, self-help skills, or motor skills. The child may also lose interest in his or her surroundings, and often comes to "look autistic." The data available as of 2001 indicate that CDD has several different patterns of onset and development; it may develop rapidly (within weeks) or more slowly (over a period of months).

CDD is frequently associated with severe mental retardation. In addition, children with CDD have a higher risk of seizures. CDD is occasionally associated with general medical conditions (metachromatic leukodystrophy or Schilder's disease) that could account for the developmental losses, but in most cases there is no known medical cause of the child's symptoms.

Asperger syndrome

Asperger syndrome (AS) was first identified in 1944 by a Viennese psychiatrist. It is sometimes called autistic psychopathy. AS is distinguished from autism by later onset of symptoms; these children usually develop normally for the first few years of life and retain relatively strong verbal and self-help skills. They are often physically clumsy or awkward, however, and this symptom may be noticed before the child starts school. AS is diagnosed most frequently when the child is between five and nine years of age. One of the distinctive features of Asperger syndrome is an abnormal degree of fascination or preoccupation with a limited or restricted subject of interest, such as railroad timetables, the weather, astronomical data, French verb forms, etc. In addition, the child's knowledge of the topic reflects rote memorization of facts rather than deep understanding.

Unlike autism, AS does not appear to be associated with a higher risk of seizure disorders or such general conditions as fragile X syndrome.

Pervasive developmental disorder not otherwise specified

PDD-NOS is regarded as a "sub-threshold" category, which means that it covers cases in which the child has some impairment of social interaction and communication, or has some stereotyped patterns of behavior, but does not meet the full criteria for another PDD. PDDNOS is sometimes referred to as atypical personality development, atypical autism, or atypical PDD. No diagnostic criteria specific to this category are provided in DSM-IV. Little research has been done on children diagnosed with PDD-NOS because the condition has no clear definition. The available data indicate that children placed in this category are diagnosed at later ages than children with autism, and are less likely to have mental impairment.

Genetic profile

Of the PDDs, autism has the best-documented genetic component, although more research is required. It is known that the degree of similarity in a pair of twins with respect to autism is significantly higher in identical than in fraternal twins. The likelihood of the biological parents of an autistic child having another child with the disorder is thought to be about 1:20. It is possible that the actual rate is higher, since many parents of one autistic child decide against having more children.

The genetic profile of Asperger syndrome is less well known, although the disorder appears to run in families—most commonly families with histories of depression or bipolar disorder . Rett syndrome is known only from case studies, so data about its genetic profile is not available as of 2001. The same lack of information is true also of CDD—partly because the disorder was first reported in 1966 and has only been officially recognized since 1994, and partly because the condition has been frequently misdiagnosed.

Demographics

Autism is thought to affect between two and five children out of every 10,000. Childhood disintegrative disorder is much less frequent, perhaps only a tenth as common as autism. Rett syndrome is also very rare, and is known only from case series reported in the medical literature. The incidence of Asperger syndrome is not definitely known as of 2001, but is thought to lie somewhere between 0.024% and 0.36% of the general population.

Some of the PDDs are considerably more common in boys than in girls. The male to female sex ratio in autism is variously given as 4:1 or 5:1. Less is known about the incidence of Asperger syndrome, but one study reported a male/female ratio of 4:1. Initial studies of CDD suggested an equal sex ratio, but more recent data indicate that the disorder is more common among males. Rett syndrome, on the other hand, has been reported only in females.

Signs and symptoms

The signs and symptoms of each PDD are included in its description.

Diagnosis

The differential diagnosis of autistic spectrum disorders is complicated by several factors. One is the wide variation in normal rates of children's development. In addition, because some of the symptoms of autism are present in mental retardation, it can be difficult to determine which condition is present in a specific child, or whether both conditions are present. A definitive diagnosis of autism is rarely given to children below the age of three years. Delays or abnormal patterns in cognitive and social development can be more accurately assessed in children age three or four; children with AS or PDDNOS may not be diagnosed until age five or later. A third factor is the tangled history of differential diagnosis of childhood disorders. Autism was first described by a physician named Leo Kanner in 1943. For several decades after Kanner's initial observations, researchers assumed that there was an association or continuity between autism in children and schizophrenia in adults. In fact, the term autism was first used to describe the self-focused thinking that characterizes schizophrenia; it was only later that the word was applied to the severe impairment of social behaviors that is a major symptom of autistic disorder. It took years of further research to establish clear diagnostic distinctions between autism and schizophrenia. Furthermore, the early assumption of a connection between autism and schizophrenia led to the hypothesis that autism was caused by painful experiences in early childhood. It is now known that autism and the other PDDs are essentially neurological disturbances.

Medical or laboratory testing

There are no brain imaging studies or laboratory tests that can be performed to diagnose a pervasive developmental disorder. The examiner may, however, recommend a hearing test to rule out deafness as a possible cause of a child's failure to respond to the environment, or a brain scan to rule out other physical conditions.

Diagnostic interviews

A PDD may be diagnosed by a pediatrician, pediatric neurologist, psychologist, or specialist in child psychiatry. The diagnosis is usually based on a combination of the child's medical and developmental history and clinical interviews or observations of the child. Children who cannot talk can be evaluated for their patterns of nonverbal communication with familiar as well as unfamiliar people. The parents may be asked to describe the child's use of eye contact, gestures, facial expressions, and body language. A clinical psychologist can administer special tests designed to evaluate the child's problem-solving abilities without the use of language.

Diagnostic questionnaires and other tools

The examiner may use a diagnostic checklist or screener such as the Childhood Autism Rating Scale, or CARS, which was developed in 1993. In addition, the Autism Research Institute (ARI) distributes a Form E-2 questionnaire that can be completed by the parents of a child with a PDD and returned to ARI. Form E-2 is not a diagnostic instrument as such but a checklist that assists ARI in the compilation of a database of symptoms and behaviors associated with autistic spectrum disorders. Parents who complete the form will receive a brief report about their child. Researchers expect that the database will help to improve the accuracy of differential diagnosis as well as contribute to more effective treatments for children with PDDs.

Treatment and management

The treatment and management of children with PDDs will vary considerably according to the severity of the child's impairment and the specific areas of impairment.

Medications

As of 2001, there are no medications that can cure any of the PDDs, and no single medication that is recommended for the symptoms of all children with PDDs. In addition, there are few comparative medication studies of children with autistic spectrum disorders. The five sites (UCLA, University of Indiana, Ohio State, Yale, and the Kennedy-Krieger Institute) involved in the Research Units in Pediatric Psychopharmacology (RUPP) Program are currently conducting a study of respiridone in PDD children with behavioral problems. The RUPP sites are also testing medications approved for use in adults with self-injuring behaviors, anxiety, aggressive behavior, and obsessive-compulsive disorder on children with PDDs. This research is expected to improve the available treatments for children with these disorders.

Psychotherapy

The only PDD patients who benefit from individual psychotherapy are persons with AS or with HFA who are intelligent enough to have some insight into their condition. Typically they become depressed in adolescence or adult life when they recognize the nature and extent of their social disabiliities.

Educational considerations

Most children with AS and some children with high-functioning autism are educable. Many people with AS, in fact, successfully complete graduate or professional school. Only a small percentage of autistic children, however, complete enough schooling to be able to live independently as adults. Children with CDD must be placed in schools for the severely disabled.

Employment

Most children with AS can finish school and enter the job market. They do best, however, in occupations that have regular routines or allow them to work in isolation. Only a few high-functioning autistic children are potentially employable.

Prognosis

The PDDs as a group are lifelong disorders, but the prognoses vary according to the child's degree of impairment. As a general rule, language skills and the child's overall IQ are the most important factors in the prognosis. Children with AS have the most favorable educational prognosis but usually retain some degree of social impairment even as adults. Of autistic children, only about one-third achieve partial or complete independence in adult life. The prognoses for Rett syndrome and CDD are worse than that for autism, as the skill levels of these children often continue to deteriorate. Some, however, make very modest developmental gains in adolescence. Lastly, current information about the prognoses of children with PDDs is derived from treatments given to patients in the 1970s or 1980s. As knowledge of effective treatments for PDDs continues to accumulate, children with these disorders receive treatment earlier than they did two decades ago. It is likely that future prognoses for the PDDs will reflect these improvements.

Resources

BOOKS

American Psychiatric Association Staff. Diagnostic and Statistical Manual of Mental Disorders. 4th ed, revised. Washington, DC: American Psychiatric Association, 2000.

"Psychiatric Conditions in Childhood and Adolescence." In The Merck Manual of Diagnosis and Therapy. Edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.

Thoene, Jess G., ed. Physicians' Guide to Rare Diseases. Montvale, NJ: Dowden Publishing Company, 1995.

Waltz, Mitzi. Pervasive Developmental Disorders: Finding a Diagnosis and Getting Help. New York: O'Reilly & Associates, Inc., 1999.

PERIODICALS

Autism Research Institute. Autism Research Review International. San Diego, CA: 1987.

ORGANIZATIONS

Autism Research Institute. 4182 Adams Ave., San Diego, 92116. Fax: (619) 563-6840.

National Organization for Rare Disorders (NORD). PO Box 8923, New Fairfield, CT 06812-8923. (203) 746-6518 or (800) 999-6673. Fax: (203) 746-6481. <http://www.rarediseases.org>.

Yale-LDA Social Learning Disabilities Project. Yale Child Study Center, 230 South Frontage Road, New Haven, CT 06520-7900. (203) 785-3488. <http://info.med.Yale.edu/chldstdy/autism>.

WEBSITES

Center for the Study of Autism Home Page, maintained by Stephen Edelson, PhD. <http://www.autism.org>.

Yale Child Study Center. <http://info.med.Yale.edu/chldstdy/autism>.

Rebecca J. Frey, PhD

Pervasive developmental disorders

Definition

Pervasive developmental disorders are a group of neurological disorders that include autistic disorder (autism ), Asperger's syndrome, childhood disintegrative disorder, Rett's syndrome, and pervasive developmental disorder not otherwise specified (PDDNOS). These disorders are characterized by delayed development in functional, socialization, and communication skills .

Description

The term pervasive developmental disorders was first used in the 1980s to describe a class of neurological disorders that involved impaired social and communication skills and repetitive behaviors.

Due to difficulties in accurately describing these disorders using the term pervasive developmental disorders, some neurological and psychiatric specialists have proposed new terminology to describe this class of disorders, including autistic spectrum disorders and multi-system neurological disorders.

Asperger's syndrome

Asperger's syndrome is characterized by difficulties with social relationships and skills and with poor coordination and restricted range of interests. Children with Asperger's syndrome generally have a normal to above average intelligence level and adequate knowledge of vocabulary and grammar but poor concentration and ability to understand language subtleties, such as humor. Asperger's syndrome is often incorrectly referred to as "high-functioning autism."

Autistic disorder

Autistic disorder, also referred to as autism, is characterized by moderate to severe communication, socialization, and behavioral problems, and in some children, mental retardation .

Childhood disintegrative disorder

Childhood disintegrative disorder is extremely rare, relative to the other pervasive developmental disorders. Children with this disorder develop normally until at least two years of age, after which an obvious regression in multiple functional skills occurs, including bladder and bowel control, ability to move, and language skills.

Pervasive developmental disorder not otherwise specified (PDDNOS)

Children are diagnosed with PDDNOS if their symptoms do not fit any of the other four types and/or they do not have the degree of impairment of the other four types. PDDNOS involves developmental impairments, such as communication and social skills, and repetitive behaviors that cannot be attributed to a specific developmental disorder or personality disorder. Usually, children with PDDNOS do not exhibit symptoms until age three or four.

Rett's syndrome

Rett's syndrome occurs primarily in female children and is characterized by normal development for the first six to 18 months, followed by a noticeable change in behavior and loss of some abilities, especially motor skills. As the child ages, significant loss of speech, hand movement, and reasoning develops. Children with Rett's syndrome usually repeat certain movements and gestures, in particular, hand wringing or hand washing. Rett's syndrome is the rarest of the pervasive developmental disorders.

Demographics

About one in 1,000 children born in the United States is diagnosed with autistic disorder, and it is four to five times more common in boys. Rett's syndrome has been diagnosed primarily in girls. Although autism is the most well-known of these disorders, PDDNOS is at least twice as common in children.

Causes and symptoms

As of 2004, the causes of these disorders were unknown. While genetics is believed to play a primary role, some children in families with a history of pervasive developmental disorders do not have a disorder. Medical researchers believe that genetic susceptibility plus additional factors contribute to the development of one of these disorders. Factors under investigation as a cause of these disorders include immune system problems, allergies , drugs, environmental pollution, and infections. Autopsy studies of individuals with pervasive developmental disorders have shown that brain cell structure is different, particularly in the brain stem area. In addition, because many individuals with pervasive developmental disorders are also affected by seizures, "electrical miswiring" of the brain may also contribute to these disorders. Researchers have used magnetic resonance imaging (MRI) and positron emission tomography (PET) to find subtle differences in the brain structure and function of children with these disorders.

Symptoms of pervasive developmental disorders may be visible as early as infancy; however, the typical age of onset is age three. Although each of the five types has some distinctive symptoms, in general, early symptoms of a pervasive developmental disorder include the following:

• impaired language skills
• difficulties relating to people, objects, or activities
• unusual play
• repetitive body movements or behavior patterns
• difficulties handling changes in routine or surroundings
• unusual responses to sensory stimuli, like loud noises and lights

When to call the doctor

Parents should see a physician as soon as they notice developmental problems or delays in their infant or child.

Diagnosis

Pervasive developmental disorders are diagnosed using the Diagnostic and Statistical Manual of Mental Disorders (DSM), which provides criteria for physicians to diagnose the specific type. Diagnosis of a pervasive developmental disorder is difficult because there is no specific medical test, like a blood test or imaging test that can confirm the diagnosis. Some physicians may hesitate to diagnose very young children with a specific type of pervasive developmental disorder.

Diagnosis of these disorders usually requires consultation and assessment by a specialist in childhood developmental disorders, such as a child psychiatrist, pediatric neurologist, neuropsychologist, or developmental child psychologist. These specialists evaluate laboratory medical tests, neurological tests, and psychological tests ; interview parents and children; and observe and assess behaviors. Educational skill testing, communication assessment, and motor skill assessment may also be conducted. Medical tests that may be performed to rule out other medical conditions include electroencephalography, MRI, and blood tests.

Once a pervasive developmental disorder is diagnosed, the diagnosis must be narrowed to one of the five types, which is achieved by using pre-established DSM criteria that outline the key differences among the types. For example, for childhood disintegrative disorder to be diagnosed, symptoms must be preceded by at least two years of normal development and onset of decline and regression must occur prior to age 10 years.

Treatment

As of 2004, no cure existed for these disorders, and no specific therapy works for all individuals. Treatment depends on the severity of the disorder and consists of specialized therapy, special education , and medication to address specific behavioral problems. Medications that may be prescribed to treat specific symptoms include anti-depressants, anti-anxiety medications, anti-spasmodic and anti-seizure medications, and stimulants. Therapeutic interventions include applied behavior analysis (the Lovaas method), auditory integration training, behavior modification programs, play therapy, occupational and physical therapy, animal-assisted therapy, art/music/dance therapy, sensory integration, and speech therapy.

Alternative treatment

Alternative treatments for pervasive developmental disorders focus on nutrition . Some evidence has shown that vitamin therapy with vitamin B6 and magnesium supplementation can help children with autism and PDDNOS. Because some children with pervasive developmental disorders have food sensitivities or food allergies , allergy testing and subsequent dietary modification may help. In food-allergic children, certain foods have been shown to increase hyperactivity and autistic behavior. Anti-yeast therapy has also been proposed because children with autism and PDDNOS sometimes have higher yeast levels in their bodies. Administering anti-yeast medications has decreased negative behaviors in some children. Before parents turn to alternative therapy, they should consult a physician to make sure it does not interfere or interact with any other medications.

Prognosis

Pervasive developmental disorders are not life-threatening and do not affect normal life expectancy. Prognosis depends on the severity and type of disorder and the effectiveness of early interventions. Early intervention with specialized educational and behavioral support programs improves the quality of life and level of functioning of children with these disorders. However, because of their impaired communication and social skills, about 70 percent of individuals with a pervasive developmental disorder are never able to live on their own.

Prevention

Pervasive developmental disorders are caused by a complex interaction of genetics, neurological factors, and environmental factors. As of 2004, there was no genetic test to detect these disorders, and there is no way to prevent their development.

Parental concerns

The majority of children with a pervasive developmental disorder will require special education services. By law, public schools must evaluate children at no cost and provide special education services to eligible children with disabilities. Some private or alternative schools may be dedicated to serving children with such disorders and offer more comprehensive education and therapeutic options, but at an additional cost to parents.

Parenting children with pervasive developmental disorders is difficult and emotionally demanding. Parents and families can benefit from joining a support group. Benefits of parent support groups include information sharing, emotional support, and educational assistance.

KEY TERMS

Electroencephalography —The recording of electrical impulses produced by the brain's activity via electrodes attached to a patient's scalp.

Magnetic resonance imaging (MRI) —An imaging technique that uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct detailed images of internal body structures and organs, including the brain.

Positron emission tomography (PET) —A computerized diagnostic technique that uses radioactive substances to examine structures of the body. When used to assess the brain, it produces a three-dimensional image that shows anatomy and function, including such information as blood flow, oxygen consumption, glucose metabolism, and concentrations of various molecules in brain tissue.

Resources

BOOKS

Bashe, P. R., and B. L. Kirby. The Oasis Guide to Asperger Syndrome. Oakland, CA: PAR Bookworks, 2001.

Myles, B. S., and D. Adreon. Asperger Syndrome and Adolescence: Practical Solutions for School Success. Shawnee Mission, KS: Autism Asperger Publishing Company, 2001.

Stockman, Ida J. Movement and Action in Learning and Development: Clinical Implications for Pervasive Developmental Disorders. Kent, UK: Elsevier Science and Technology Books, 2004.

Volkmar, Fred R., et al. Handbook of Autism and Pervasive Developmental Disorders. New York: John Wiley & Sons, 2005.

PERIODICALS

Muhle, R., et al. "The Genetics of Autism." Pediatrics 113 (May 2004): 472–86.

Szatmari, P., et al. "Two-Year Outcome of Preschool Children with Autism or Asperger's Syndrome." American Journal of Psychiatry 157 (December 2000): 1980–87.

ORGANIZATIONS

Asperger Syndrome Education Network. Web site: <www.aspennj.org/>.

Developmental Delay Resources. Web site: <www.devdelay.org/>.

National Alliance for Autism Research. 99 Wall Street, Research Park, Princeton, NJ 08540. Web site: <www.naar.org/naar.asp>.

National Institute of Child Health and Human Development. Bldg 31, Room 2A32, MSC 2425, 31 Center Drive, Bethesda, MD 20892–2425. Web site: <www.nichd.nih.gov/default.htm>.

WEB SITES

"NINDS Pervasive Developmental Disorders Information Page." National Institute of Neurological Disorders and Stroke, July 2003. Available online at <www.ninds.nih.gov/health_and_medical/disorders/pdd.htm> (accessed October 27, 2004).

Sanders, Lisamarie. "Pervasive Developmental Disorders: What Parents Need to Know", 2004. Available online at <http://toddlerstoday.com/resources/articles/pdd.htm> (accessed October 27, 2004).

Jennifer E. Sisk, MA

Pervasive Developmental Disorders

What are Pervasive Developmental Disorders?

What Are the Types of Pervasive Developmental Disorders?

What Causes Pervasive Developmental Disorders?

How Are Pervasive Developmental Disorders Diagnosed and Treated?

Resources

Pervasive (per-VAY-siv) developmental disorders are a group of conditions in which the brain fails to develop normally, resulting in serious problems with communication, social interaction, and behavioral development.

KEYWORDS

for searching the Internet and other reference sources

Asperger disorder

Rett disorder

Autism

Childhood disintegrative disorder

What are Pervasive Developmental Disorders?

Pervasive developmental disorders are conditions that prevent children from developing normal communication and normal social abilities. Signs of these conditions begin to appear in the very early years of childhood. Some forms of pervasive developmental disorder (PDD) are milder and other forms are more severe. Most children with these conditions have very limited interests and activities, and some engage in unusual behavior, such as rocking, flapping their hands, or even behavior that causes self-injury.

PDDs include autism (AW-tizm), Asperger (AS-per-ger) disorder, Rett disorder, and childhood disintegrative disorder. The term “pervasive developmental disorder” refers to the whole group of conditions, but it sometimes is used to refer to milder forms of autism. The word “pervasive” means affecting all aspects of something. It is used for these conditions because they can affect all aspects of a person’s life.

What Are the Types of Pervasive Developmental Disorders?

Autism is a brain disorder that affects children within the first 3 years of life. Sometimes these children may appear to develop normally for a time in early infancy. The word “autism” comes from the Greek word meaning “self.” It was chosen for the disorder because of the characteristic self-absorption of people who have it. Indeed, children with autism appear to live in a world of their own, often seeming not even to notice members of their own family around them. They seldom make eye contact with other people or share their interests.

Children with autism are socially isolated. Their social problems are made worse by the fact that their language skills usually do not develop normally. Some children may never learn to talk. Others may talk, but they use language inappropriately, perhaps simply repeating the words of others or reversing the meanings of “I” and “you.” They may repeat certain behavior, such as hand-flapping or body-rocking, over and over for no apparent purpose.

Asperger disorder is generally thought to be a milder form of pervasive developmental disorder, and it shares with autism the features of social isolation and lack of responsiveness to other people. The difference between Asperger disorder and what is called “classic” autism is that a child with Asperger disorder has the intellectual function and language skills of a normal child of the same age. In fact, children with this disorder often have excellent vocabularies, but do not use their language skills for appropriate conversation. Socially, they often lack good give-and-take interactions. They may memorize and then recite timetables or lists (for example, facts from almanacs) or have intense and very focused interests (for example, mechanical devices). A child with Asperger disorder may know the names and numbers of every Amtrak engine or be an expert on their town’s fire stations. Also, their social interactions often revolve around their overly focused interests (“Which fire station is near your house?” may be a way to say “Hello”).

Rett disorder is a severe genetic* developmental condition that affects only girls. At first, the child develops normally, usually for about 1 to 2 years after birth. She may even begin to walk and talk. Then she starts to lose these skills and may show signs of a stiff-legged walk. Losing the ability to use words to communicate, she also may lose interest in making friends. A typical physical sign of Rett disorder is that the child’s head stops growing at the normal rate.

* genetic

(je-NE-tik) pertains to the genes, which are contained in the chromosomes found in the cells of the body. Genes help determine a person’s characteristics, such as hair or eye color, and they also are involved in the cause of some medical conditions. They are inherited from a person’s parents.

Childhood disintegrative disorder has signs that are in many ways similar to those of autism. An important difference is that in childhood disintegrative disorder a child may develop normally for 2 to 10 years. Then the child may begin to lose some combination of social or communicative skills, bowel or bladder control, or motor skills (physical coordination).

What Causes Pervasive Developmental Disorders?

Rett disorder is now understood to be caused primarily by a faulty gene. The causes of most cases of autism, Asperger disorder, and childhood disintegrative disorder are not yet known. Because autism and Asperger disorder tend to run in families, it is believed that they are at least partly caused by faulty genes. Some authorities believe that childhood disintegrative disorder may be the result of damage to the developing brain, but it is not known how this damage occurs.

How Are Pervasive Developmental Disorders Diagnosed and Treated?

In order to diagnose a developmental disorder, a doctor or psychologist first asks the child’s parents questions about the child’s early development and then carefully observes the child to identify possible signs of impairment in social activities, behavior, and communication.

There are no cures for pervasive developmental disorders, but many children do improve over time. Early intervention is key to developing social and language skills. Therefore, prompt and proper diagnosis is important, so that well-planned special training and education can begin. Children are taught how to overcome the effects of certain impairments and to build on the skills they have. Medication may be used to treat special problems, such as seizures* or hyperactivity*. One key to treatment is the development of a communication system that can help children with their social skills. One communication system that has proven to be effective uses “picture exchanges.” For example, if a child wants a drink, he hands the teacher a picture (symbol) of a drink. Pictures are gradually added together (picture of orange + picture of drink) and paired with words. Often, words then begin to replace the picture exchange system.

* seizures

(SEE-zhurs) are sudden attacks of involuntary (uncontrollable) body movements, changes in behavior, or loss of consciousness that result from bursts of abnormal electrical energy within the brain.

* hyperactivity

(hy-per-ak-TI-vitee) is overly active behavior, which makes it hard for a person to sit still.

Often, children with these disorders can learn to attend to their basic needs such as self-feeding, dressing, and personal care. Many individuals with milder developmental problems learn to use language effectively and learn to relate well enough to gain some degree of independence (have a job; live in a group home) as adults. Some people with autism and Asperger disorder make rapid developmental progress in school and eventually may live by themselves.

Many individuals with PDDs, however, never lean to relate socially, develop a communication system to express their needs, or rid themselves of unusual behaviors such as rocking or hand-flapping.

See also

Autism

Asperger Disorder

Rett Disorder

Resources

Books

Attwood, Tony. Asperger’s Syndrome: A Guide for Parents and Professionals. Philadelphia: Jessica Kingsley Publishers, 1997.

Lewis, Jackie, and Debbie Wilson. Pathways to Learning in Rett Syndrome. London: David Fulton, 1998. Written for parents.

Seroussi, Karyn. Unraveling the Mystery of Autism and Pervasive Developmental Disorder: A Mother’s Story of Research and Recovery. New York: Simon and Schuster, 2000. Written for parents.

Organization

Kidshealth.org, A. I. duPont Hospital for Children, 1600 Rockland Road, Wilmington, DE 19803. This organization is dedicated to issues of children’s health. Their website has much valuable information for children, teens, and parents. For specific information on autism, go to http://KidsHealth.org.

Pervasive Developmental Disorders

Definition

Description

Prognosis

Resources

Definition

Pervasive developmental disorders are a group of conditions originating in childhood that involve serious impairment in several areas, including physical, behavioral, cognitive, social, and language development.

Description

Pervasive developmental disorders (PDDs) are thought to be genetically based, with no evidence linking them to environmental factors; their incidence in the general population is estimated at 1%. The most serious PDD is autism , a condition characterized by severely impaired social interaction, communication, and abstract thought, and often manifested by stereotyped and repetitive behavior patterns. Many children who are diagnosed with PDDs today would have been labeled psychotic or schizophrenic in the past.

The handbook used by mental health professionals to diagnose mental disorders such as PDDs is the Diagnostic and Statistical Manual of Mental Disorders. The 2000 edition of this manual (fourth edition, text revised) is known as the DSM-IV-TR. Published by the American Psychiatric Association, the DSM contains diagnostic criteria, research findings, and treatment information for mental disorders. It is the primary reference for mental health professionals in the United States.

The DSM lists several other conditions as PDDs:

Rett’s disorder

Characterized by physical, mental, and social impairment, this syndrome appears between the ages of five months and four years in children whose development has been normal up to that point. Occurring only in girls, it involves impairment of coordination, repetitive movements, a slowing of head growth, and severe or profound mental retardation , as well as impaired social and communication skills .

Childhood disintegrative disorder

This disorder is marked by the deterioration of previously acquired physical, social, and communication skills after at least two years of normal development. More common in males than females, it first appears between the ages of two and 10 (usually at three or four years of age), and many of its symptoms resemble those of autism. Other names for this disorder are Heller’s syndrome, dementia infantilis, and disintegrative psychosis . It sometimes appears in conjunction with a medical condition such as Schilder’s disease, but usually no organic cause can be found.

Asperger’s disorder

Children with this disorder have many of the same social and behavioral impairments as autism, except for difficulties with language. They lack normal tools of social interaction, such as the ability to meet someone else’s gaze, use appropriate body language and gestures, or react to another person’s thoughts and feelings. Behavioral impairments include the repetitive, stereotyped motions and rigid adherence to routines that are characteristic of autism. Like childhood disintegrative disorder , Asperger’s disorder is more common in males than females.

Prognosis

In general, the prognosis in each of these conditions is tied to the severity of the illness.

The prognosis for Asperger’s syndrome is more hopeful than the others in this cluster. These children are likely to become functional, independent adults, but will always have problems with social relationships. They are also at greater risk for developing serious mental illness than the general population.

The prognosis for autistic disorder is not as good, although great strides have been made in recent years in its treatment. The higher the patient’s intelligence quotient (IQ) and ability to communicate, the better the prognosis. However, many patients will always need some level of custodial care. In the past, most of these individuals were confined to institutions, but many are now able to live in group homes or supervised apartments. The prognosis for childhood disintegrative disorder is the least favorable. These children will require intensive and long-term care.

Resources

BOOKS

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fourth edition, text revised. Washington DC: American Psychiatric Association, 2000.

Volkmar, Fred R., ed. Autism and Pervasive Developmental Disorders. New York: Cambridge University Press, 1998.

Waltz, Mitzi, and Linda Lamb. Pervasive Developmental Disorders: Finding a Diagnosis & Getting Help. Cambridge: O’Reilly & Associates, Incorporated, 1999.

ORGANIZATIONS

Autism National Committee (AUTCOM). P.O. Box 6175, North Plymouth, MA 02362-6175. Web site: http://www.autcom.org/

Autism Research Institute. 4182 Adams Avenue, San Diego, CA 92116. Telephone: (619) 281-7165. Web site: http://www.autism.com/ari

New Jersey Center for Outreach and Services for the Autism Community (COSAC). 1450 Parkside Avenue Suite 22, Ewing, NJ 08638. Telephone: (609) 883-8100 or (800) 4-AUTISM (428-8476). Web site: http://www.njcosac.org