Rett syndrome

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 4-5 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 a 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.

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 the 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 availabe 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 devided into four stages. In stage one the child develops normally for some 6-18 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 which 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 & symptoms

The causes of these disorders is unknown although brain structure abnormalities, genetic mutation, and alterations in brain function are believed to all play a role. Still, no single brain abnormality or location has been connected to a cause. Rett's syndrome demonstrates the strongest evidence that it is caused by the mutation of a gene. Research with twins has indicated that genetics may also 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'sdisorder:

• 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'ssyndrome:

• 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 are 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.

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.

Psychotherapy

Psychotherapy, which literally means mind treatment, is one method that mental healthcare specialists use to help patients overcome mental and emotional illness.

Further Reading

For Your Information

Books

• Boyd, Mary Ann, and Mary Ann Nihart. Psychiatric Nursing: Contemporary Practice. Philadelphia, PA: Lippincott, 1998.
• Mauk, Joyce E. "Autism and Pervasive Developmental Disorders." In Pediatric Clinics of North America, edited by Mark L. Batshaw. Philadelphia, PA: W.B. Saunders Co.: June, 1993.

  Organizations

• Autism Society of America. 7910 Woodmont Avenue, Suite 650, Bethesda, MD 20814. (800) 328-8476.
• The International Rett Syndrome Association. 9121 Piscataway Road, Suite 2B, Clinton, MD 20735. (800) 818-7388. http://www2.paltech.com/irsa/irsa.htm.
• Learning Disabilities Association of America, 4156 Library Road, Pittsburg, PA 15234. (412) 341-1515. http://www.mhsource.com/hy/asperger.html.
• National Association for Rare Disorders, Inc., PO Box 8923, New Fairfield, CT 06812-8923. (800) 999-6673. http://www.nord-rdb.com//worphan.

  Other

• Applied Medical Informatics Inc. Childhood Disintegrative Disorder. http://www.healthanswers.com/database/ami/converted/001535.html.(1998.)
• Center for Outreach & Services for the Autism Community. Thomas D. Boyle, Ph.D. Diagnosing Autism and Other Pervasive Personality Disorders. http://www.injersey.com/Living/Health/Autism/page3.html. (1998.)
• The International Rett Syndrome Association. http://www2.paltech.com/irsa/whatis.htm.
• Koenig, Kathy. Frequently Asked Questions. http://info.med.yale.edu/chldstdy/autism/faq.html. (1998.)
• Learning Disabilities Association of America. Asperger's Syndrome. http://www.mhsource.com/hy/asperger.html. (1998).
• National Association for Rare Diseases in Wesport, CT. Information on Childhood Disintegrative Disorder. http://info.med.yale.edu/chldstdy/autism/cdd-info.html.(1998).

Gale Encyclopedia of Medicine. Gale Research, 1999.