Pervasive Developmental Disor... Health Article

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 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 and 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'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.