Pervasive developmental disorders
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 .
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 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, 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 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.
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.
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.
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 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.
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.
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.
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.
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.
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.
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.
Asperger Syndrome Education Network. Web site: http://www.aspennj.org/.
Developmental Delay Resources. Web site: http://www.devdelay.org/.
National Alliance for Autism Research. 99 Wall Street, Research Park, Princeton, NJ 08540. Web site: http://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: http://www.nichd.nih.gov/default.htm.
"NINDS Pervasive Developmental Disorders Information Page." National Institute of Neurological Disorders and Stroke , July 2003. Available online at http://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