More threads by David Baxter PhD

David Baxter PhD

Late Founder
Pervasive Developmental Disorders
June 15, 2004

Sometimes it's hard to know at first if a child has what's called a pervasive developmental disorder (PDD). PDDs can encompass a wide spectrum of social and communication disorders, including autism, and they can be complicated to diagnose. Typically, they should be recognizable before a child is 3 years old, but a toddler can be difficult to diagnose, and although some behaviors might fit the criteria, they also might just be part of a youngster's developing personality.

Today, though, there are acknowledged criteria for determining if a child has a PDD, and there are ways to help children at an early age.

What Are PDDs?
Say a 3-year-old likes to play with the same toy over and over. And maybe he doesn't look at people when they talk with him. At preschool, he's just not mixing in with the others.

If the behavior seems to interfere with his establishing relationships and communicating with others, the child should be evaluated for a language disorder or for possible features of a PDD.

PDDs, also known as autistic spectrum disorders, refer to a group of neurobiological conditions that are characterized by delayed development of communication and social skills.

Perhaps the most noticeable feature of a PDD is a problem with communication, including using and understanding language. Children with these disorders can also have trouble relating to others. They may also exhibit unusual play with toys and other objects, including flicking or shaking of toys in nontraditional manners, repetitively spinning toys or parts of toys (these repetitive motions are called stereotypes), and needing to line up toys instead of play with them. Children with a PDD tend to lack curiosity about their environments and have difficulty with changes in routines.

It's important to note that all children can exhibit unusual behaviors occasionally, or they can seem shy around others sometimes - without having a PDD. What sets children with PDD's apart is the consistency of their unusual behaviors.

"It [a PDD] is notable in all facets in the children's lives, not just at home or at school," says Rhonda Walter, MD, a developmental pediatrician. "It has to be present in all settings and over considerable periods of time. There is a lack of social interaction, an impairment in nonverbal behaviors, and maybe the child ignores facial expressions or doesn't look at you. There's a failure to develop peer relations."

Autism is the most well-known PDD. First identified about 50 years ago, autism is estimated to occur in one or two out of every 1,000 people. Approximately 400,000 people in the United States have autism. Because autism affects communication as well as cognitive and behavioral skills, it's considered a PDD. Although normal in appearance, children with autism are withdrawn into their own worlds and are unable to relate normally to others. And although kids with PDD can usually be drawn out enough to be communicative, children with autism often cannot.

Other PDDs include Asperger's Syndrome, which is a high-functioning autism in children who generally have high IQs, and Childhood Disintegrative Disorder, in which a child may develop fairly normally until 18 to 36 months and then begin to regress, especially in speech and social interaction. Other PDDs include Rett Syndrome and a disorder called PDD-Not Otherwise Specified, or PDD- NOS. All of these conditions, to varying degrees, inhibit normal communication skills and can affect a child's cognitive skills and behavior.

What Causes PDDs?
It's not known what causes PDDs. Many scientists believe they stem from biological and neurological problems in the brain. They may also have a genetic basis.

Some studies have shown that PDDs may stem from a wide-ranging and seemingly unrelated host of causes, including food allergies, excessive amounts of yeast in the digestive tract, and exposure to environmental toxins.

What is known is that PDDs are not caused by what used to be known as "the cold mother" in psychological studies. According to Dr. Walter, earlier notions that these disorders developed because of the emotional detachment of a child's parents have been debunked.

Diagnosing PDDs
More recent research suggests that a PDD's onset can be recognized in a child before the age of 3 years. If a child has difficulty with social interaction and communication and exhibits repetitive behavior, often a doctor or specialist will refer to the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders - Fourth Edition (DSM-IV), which contains criteria for diagnosing PDDs.

Treating PDDs
Early intervention is the key to treating a PDD. Although there's no cure, there is hope for children with these disorders.

"The key is to get kids early," Dr. Walter says.

The main goal is to maximize communication with kids with a PDD. Through behavior modification, parents and teachers work to lessen the child's atypical behaviors and to improve speech and communication.

And although the main treatments are education and intervention, medication may have a role in some cases. For some children, medication may help with problems of inattention, obsessive-compulsive behaviors, and mood swings.

Therapy for children with PDD should be specialized because each child's disorder is often distinct and presents specific needs. Some children with these disorders do well in small classes with lots of one-on-one attention. Others do well in standard classrooms with support.

And although the main treatments are educational and behavior modification interventions, medication may have a role in some cases. For some children, medication may help with problems of inattention, obsessive-compulsive behaviors, and mood swings.

The goal of treatment is to get children with PDDs to a point where they can be mainstreamed into a regular classroom. They may also require special programs and support services, including speech and language therapy.

Many other treatments - some considered controversial - have been used. Facilitated communication (FC) uses another person, a facilitator, to support the hand, arm, or shoulder of the person with the disorder, assisting him or her in pressing the keys of a computer keyboard or communication board. Athough the Autism Society of America neither condones nor dismisses FC, most research does not support the procedure as a valid treatment.

The hormone secretin has been tried as a treatment for autism. Normally used to diagnose gastrointestinal problems, the hormone was linked in preliminary studies to improved communication and social interaction in children with autism. Further studies have not shown this effect.

The use of gluten-free and casein-free diets has shown some positive results in treating PDDs, although more research has to be done. Other vitamin and herbal remedies have not been scientifically proven, although they may have merit for an individual child.

Helping Your Child
Once you learn your child has a PDD, it's important to get help. Children with disabilities are entitled to free preschool services at 3 years of age under the Individuals with Disabilities Education Act (IDEA). Check out the services offered by your local Easter Seals, United Cerebral Palsy Association, Intermediate Units, and school districts.

Because the needs of children with these disorders vary, you may want to set up an individualized education plan (IEP) for your child. You'll want to incorporate social skills and communication into the program, and most experts agree it should be highly structured. Maximized speech and language intervention is important, as is the use of behavior modification and rewards to try to stop problem behaviors and to encourage all types of communication.

Encourage your child with hugs and verbal praise, as well as rewards that stimulate social interaction (like a trip to the playground). If your child is in school, talk with your child's teacher and try using some of the same rewards and behavior modification techniques at home. That way, your child will get a consistent message at home and at school.
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