Pervasive Developmental Disorders (PDD)

The term “pervasive development disorders” (PDDs) refers to a group of conditions that involve delays in the development of many basic skills, most notably the ability to socialize with others, to communicate and to use imagination. Children with these conditions often are confused in their thinking and generally have problems understanding the world around them.

Because these conditions typically are identified in children around 3 years of age — a critical period in a child’s development — they are called development disorders. Although the condition begins far earlier than 3 years of age, parents often do not notice a problem until the child is a toddler who is not walking, talking or developing as well as other children of the same age.

What Conditions Are Considered Pervasive Development Disorders?

There are five types of PDDs:

• Autism: Children with autism have problems with social interaction, pretend play and communication. They also have a limited range of activities and interests. Many (nearly 75%) of children with autism also have some degree of mental retardation.
• Asperger’s syndrome : Like children with autism, children with Asperger’s syndrome have difficulty with social interaction and communication, and have a narrow range of interests. However, children with Asperger’s have average or above average intelligence, and develop normally in the areas of language and cognition (the mental processes related to thinking and learning). Children with Asperger’s often also have difficulty concentrating and may have poor coordination.
• Childhood disintegrative disorder: Children with this rare condition begin their development normally in all areas, physical and mental. At some point, usually between 2 and 10 years of age, a child with this illness loses many of the skills he or she has developed. In addition to the loss of social and language skills, a child with disintegrative disorder may lose control of other functions, including bowel and bladder control.
• Rett’s syndrome: Children with this very rare disorder have the symptoms associated with a PDD and also suffer problems with physical development. They generally suffer the loss of many motor, or movement, skills — such as walking and use of their hands — and develop poor coordination. This condition has been linked to a defect on the X chromosome, so it almost always affects girls.
• Pervasive development disorder not otherwise specified (PDDNOS): This category is used to refer to children who have significant problems with communication and play, and some difficulty interacting with others, but are too social to be considered autistic.

What Are the Symptoms of Pervasive Development Disorders?

The use of the word “pervasive” to describe these illnesses is somewhat misleading. The definition of pervasive is “to be present throughout,” but children with PDDs generally do not have problems in all areas of functioning. Rather, most children with PDDs have specific problem areas and often function very well in other areas.

Children with PDDs, such as autism, can display a wide range of symptoms, and the symptoms can range in severity from mild to disabling. They also vary widely in their individual abilities, intelligence and behavior.

General symptoms that may be present to some degree in a child with a PDD include:

• Difficulty with verbal communication, including problems using and understanding language
• Difficulty with non-verbal communication, such as gestures and facial expressions
• Difficulty with social interaction, including relating to people and to his or her surroundings
• Unusual ways of playing with toys and other objects
• Difficulty adjusting to changes in routine or familiar surroundings
• Repetitive body movements or patterns of behavior, such as hand flapping, spinning and head banging
• Changing response to sound (The child may be very sensitive to some noises and seem to not hear others.)
• Temper tantrums
• Difficulty sleeping
• Aggressive behavior
• Fearfulness or anxiety (nervousness)

What Causes Pervasive Development Disorders?

The cause of these illnesses is not known, but researchers are looking for answers. Some studies suggest that PDDs are caused by a problem with the nervous system (brain and spinal cord). Studies currently in progress are examining the structure and function of the brain in people with autism for clues that may help us better understand these conditions, as well as how to treat and/or prevent them.

How Common Are Pervasive Development Disorders?

It is estimated that PDDs occur in about 5 to 15 children per 10,000 births. In general, PDDs are more common in boys than in girls, with the exception of Rett’s syndrome, which occurs almost always in girls.

How Are Pervasive Development Disorders Diagnosed?

If symptoms are present, the doctor will begin an evaluation by performing a complete medical history and physical examination. Although there are no laboratory tests to diagnose a PDD, the doctor may use various tests — such as X-rays and blood tests — to determine if there is a physical disorder causing the symptoms.

If no physical disorder is found, the child may be referred to a specialist in childhood development disorders, such as a child and adolescent psychiatrist or psychologist, pediatric neurologist, developmental pediatrician, or other health professionals who are specially trained to diagnose and treat PDDs. The doctor bases his or her diagnosis on the child’s level of development, and the doctor’s observation of the child’s speech and behavior, including his or her play and ability to socialize with others. The doctor often seeks input from the child’s parents, teachers and other adults who are familiar with the child’s symptoms.

How Are Pervasive Development Disorders Treated?

Because children with PDDs have a range of symptoms and abilities, a plan of therapy must be developed with the child’s specific needs in mind. The treatment plan — or more appropriately, a program of intervention — will address the child’s needs at home and at school. For that reason, intervention planning is a cooperative effort of the parents, healthcare providers, teachers and others who may be needed to provide services, such as counselors, social workers and occupational, physical or speech therapists. The plan aims to promote better socializing and communication, and reduce behaviors that can interfere with learning and functioning.

A plan of care for a child with a PDD may include:

• Special education: Education is structured to meet the child’s unique educational needs.
• Behavior modification: This may include strategies for supporting positive behavior by the child.
• Speech, physical or occupational therapy: These therapies are designed to increase the child’s functional abilities.
• Medication : There are no drugs to treat the PDDs themselves. Medications may be used, however, to treat specific symptoms such as anxiety (nervousness), hyperactivity and behavior that may result in injury.

What Is the Outlook for People With Pervasive Development Disorders?

The outlook varies depending on the type and severity of the condition, the age at which treatment is started, and the availability of supportive resources for the child. Most children with PDDs will continue to have some problems with communication and socialization, but many can experience a significant increase in function.