little girl sitting in front of blue doorMost everyone has heard the term autism. You may have also heard of Asperger’s Disorder, Rett’s Syndrome, and/or PDD. What do these terms mean? How do they differ? Does your child fit one of these diagnoses? Here’s some basic information that can help you decide if you should consult with a professional.

Simply speaking, Pervasive Development Disorder (PDD), sometimes called Autism Spectrum Disorder, is the broad umbrella term covering the following:

  • Autism
  • Asperger’s Disorder
  • Rett’s Syndrome
  • Childhood Disintegrative Disorder
  • PDD–NOS (Pervasive Developmental Disorder–Not Otherwise Specified).

While all of these fall into the PDD category, there are important differences.

The Autism profile

Children diagnosed with autism have difficulties in three areas: social relationships, communication, and behavior.

  1. Social relationships
    They have difficulty making and maintaining eye contact, and understanding facial expressions and gestures people use to start and stop a social interaction. They’re typically not interested in interacting with peers and are often unable to share an experience with others.
  2. Communication
    They’re slow to, or never develop, speech. Often a child with autism may show echolalia (repetitive language or sounds).
  3. Behavior
    There are often repetitive patterns of behavior in which a child has one or two particular interests, such as trains. He pursues these interests with intensity, and can become preoccupied with specific parts of objects, such as the wheels of a train. Children with autism also have a strong preference for routines, becoming upset when there are changes in routine. They sometimes flap their hands or fingers and tend to repeat actions over and over again (stereotyped behaviors).
Later this year, the American Psychiatric Association may propose a change to the definition of autism. Read about it here.

Asperger’s Disorder

People sometimes refer to Asperger’s Disorder (AD) as mild autism. While it’s true that children with AD can have any or all of the symptoms of autism, with AD there’s no delay in language. A child with Asperger’s can use words by age 1 and phrases by age 3. Also, children with AD can adapt to different environments, and can handle changes in routines without significant distress. They remain curious about their surrounding environment. 

Rett’s Syndrome

Rett’s Syndrome is unique in that it affects mainly girls. A child with Rett’s Syndrome appears normal until 18 months of age, at which time there’s a surprising, notable loss of skills (often motor skills such as walking, speech, and hand use). A red flag is repetition of movements, such as hand-wringing or hand-washing.

Childhood Disintegrative Disorder

Childhood Disintegrative Disorder (CDD) is rare and comes with specific signs of regression of motor skills and potty training. CDD is diagnosed when a child has had two years of typical development, then sudden regression between 2 and 10 years. Similar to most PDD disorders, the loss of skills adversely affects the ability to communicate and play with others.

Pervasive Developmental Disorder–Not Otherwise Specified (PDD–NOS)

Some children have many of the symptoms of PDD, particularly challenges with social interaction and communication, but don’t meet the full “formal” criteria for any disorder. These children are often diagnosed with PDD-NOS. 

Early Warnings of Developmental Disorders 

Given that PDD disorders aren’t always evident at birth, it can be confusing for parents to know when to seek professional help. If you’re concerned about your child’s development, answer the following questions. These skills typically develop during the first year.

  •  Is your child is able to respond to his name when called by mommy, daddy, or siblings?
  •  Is your child able to tune into something or someone else, usually through pointing?
  •  Is your child able to imitate?
  •  Is your child able to react and respond to another emotionally?
  •  Does your child engage in pretend play?
  •  Does your child babble or use gestures (e.g., pointing) by age 1?

If you answered “No” to more than three of these questions, talk to your pediatrician and get referrals to specialists so your child receives the help she needs. 

Dr. Liz Matheis is a licensed clinical psychologist and school psychologist in Parsippany who provides psychotherapy, consulting, and advocacy for children and families managing autism spectrum disorders. Learn more here.

To find our list of organizations that help families manage autism spectrum disorder and other special needs, search for Special Needs Resources on