Pervasive developmental disorders (PDD) refers to a group of disorders characterized by delays in the development of multiple basic functions including socialization and communication. Parents may note symptoms as early as infancy and typically onset is prior to 3 years of age. Symptoms may include communication problems such as using and understanding language; difficulty relating to people, objects, and events; unusual play with toys and other objects; difficulty with changes in routine or familiar surroundings, and repetitive body movements or behavior patterns.

The most common types of PDD are:

• Autism - a developmental brain disorder characterized by impaired social interaction and communication skills, and limited range of activities and interests
• Asperger's Syndrome/Disorder - characterized by impairments in social interactions and the presence of restricted interests and activities, with no clinically significant general delay in language, and testing in the range of average to above average intelligence.
• Childhood Disintegrative Disorder - characterized by normal development for at least the first 2 years, significant loss of previously acquired skills.
• Rett's Syndrome/Disorder - a progressive disorder which, to date, has occurred only in girls. Period of normal development and then loss of previously acquired skills, loss of purposeful use of the hands replaced with repetitive hand movements beginning at the age of 1-4 years.

Autism:
Autism is a complex developmental disability that typically appears during the first three years of life. The result of a neurological disorder that affects the functioning of the brain, autism and its associated behaviors have been estimated to occur in as many as 1 in 500 individuals (Centers for Disease Control and Prevention 1997). Autism is four times more prevalent in boys than girls and knows no racial, ethnic, or social boundaries. Family income, lifestyle, and educational levels do not affect the chance of autism's occurrence.

Autism impacts the normal development of the brain in the areas of social interaction and communication skills. Children and adults with autism typically have difficulties in verbal and non-verbal communication, social interactions, and leisure or play activities. The disorder makes it hard for them to communicate with others and relate to the outside world. In some cases, aggressive and/or self-injurious behavior may be present. Persons with autism may exhibit repeated body movements (hand flapping, rocking), unusual responses to people or attachments to objects and resistance to changes in routines. Individuals may also experience sensitivities in the five senses of sight, hearing, touch, smell, and taste.

Causes: Although a single specific cause of autism is not known, current research links autism to biological or neurological differences in the brain. In many families there appears to be a pattern of autism or related disabilities — which suggests there is a genetic basis to the disorder — although at this time no gene has been directly linked to autism. The genetic basis is believed by researchers to be highly complex, probably involving several genes in combination. Autism is not a mental illness. Children with autism are not unruly kids who choose not to behave. Autism is not caused by bad parenting. Furthermore, no known psychological factors in the development of the child have been shown to cause autism.

Symptoms of autism include:

• Difficulty in mixing with other children
• Insistence on sameness; resists changes in routine
• Inappropriate laughing and giggling
• No real fear of dangers
• Little or no eye contact
• Sustained odd play
• Apparent insensitivity to pain
• Echolalia (repeating words or phrases in place of normal language)
• Prefers to be alone; aloof manner
• May not want cuddling or act cuddly
• Spins objects
• Not responsive to verbal cues; acts as deaf
• Inappropriate attachment to objects
• Difficulty in expressing needs; uses gestures or pointing instead of words
• Noticeable physical overactivity or extreme underactivity
• Tantrums - displays extreme distress for no apparent reason
• Unresponsive to normal teaching methods
• Uneven gross/fine motor skills. (May not want to kick ball but can stack blocks.)

Asperger's Syndrome / Disorder:
Asperger's Syndrome, also known as Asperger's Disorder or Autistic Psychopathy, is characterized by severe and sustained impairment in social interaction, development of restricted and repetitive patterns of behavior, interests, and activities. These characteristics result in clinically significant impairment in social, occupational, or other important areas of functioning.

In contrast to Autistic disorder (Autism), there are no clinically significant delays in language or cognition or self help skills or in adaptive behavior, other than social interaction. Prevalence is limited but it appears to be more common in males. Onset is later than what is seen in Autism, or at least recognized later. A large number of children are diagnosed between the ages of 5 and 9. Motor delays, clumsiness, social interaction problems, and idiosyncratic behaviors are reported. Adults with Asperger's have trouble with empathy and modulation of social interaction - the disorder follows a continuous course and is usually lifelong.

Asperger's is not easily recognizable - in fact, many children are misdiagnosed with other neurological disorders such as Tourette's Syndrome or Autism. More frequently, children are misdiagnosed with Attention Deficit (and Hyperactivity) Disorders (ADD & ADHD), Oppositional Defiant Disorder (ODD), or Obsessive-Compulsive Disorder (OCD).

Remedies used today to treat Asperger's range from St. John's Wort tea to drugs such as Haldol and Ritalin. Treatments vary to a great degree with the individual patient - no single medication or remedy works for everyone - and Asperger's Syndrome cannot be completely cured.

Symptoms of Asperger's Syndrome include:

• Qualitative impairment in social interaction, as manifested by at least two of the following:
  • marked impairment in the use of multiple nonverbal behaviors such as eye-to-eye gaze, facial expression, body postures, and gestures to regulate social interaction
  • failure to develop peer relationships appropriate to developmental level
  • a lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., by a lack of showing, bringing, or pointing out objects of interest to other people)
  • lack of social or emotional reciprocity
• Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:
  • encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus
  • apparently inflexible adherence to specific, nonfunctional routines or rituals
  • stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole-body movements)
  • persistent preoccupation with parts of objects

Childhood Disintegrative Disorder:
Children with this pervasive developmental disorder appear to develop normally for the first two years of life, but then lose skills in areas such as language, play, and bowel control and manifest impaired social interaction and communication associated with "restrictive, repetitive, stereotyped" behaviors.

Diagnostic criteria for CDD include:

• Apparently normal development for at least the first 2 years after birth as manifested by the presence of age-appropriate verbal and nonverbal communication, social relationships, play, and adaptive behavior.
• Clinically significant loss of previously acquired skills (before age 10 years) in at least two of the following areas:
  • expressive or receptive language
  • social skills or adaptive behavior
  • bowel or bladder control
  • play
  • motor skills
• Abnormalities of functioning in at least two of the following areas:
  • qualitative impairment in social interaction (e.g., impairment in nonverbal behaviors, failure to develop peer relationships, lack of social or emotional reciprocity)
  • qualitative impairments in communication (e.g., delay or lack of spoken language, inability to initiate or sustain a conversation, stereotyped and repetitive use of language, lack of varied make-believe play)
  • restricted, repetitive, and stereotyped patterns of behavior, interests, and activities, including motor stereotypies and mannerisms
• The disturbance is not better accounted for by another specific Pervasive Developmental Disorder or by Schizophrenia.

Rett's Syndrome / Disorder:
Rett's Syndrome is a complex genetic condition which is found almost exclusively in girls. In some ways the early stages of Rett's can look like autism, but the progression of the condition is different. Girls with Rett Syndrome have normal early development followed by degeneration in motor and communication skills. After a few years, the condition stabilizes and some skills may be regained.

Rett's disorder is inherited as an X-linked trait. It affects only females. The exact cause of the trait is unknown, but it has been linked with a metabolic disorder. The prevalence of Rett's disorder is 6 to 7 cases per 100,000 females. During the first five months the child is developmentally on track. From six months to two years the child's condition deteriorates.

Symptoms:

• the child's head growth becomes slowed (deceleration in head circumference)
• loss of previously acquired hand skills
• loss of social engagement (the child no longer wants to interact with others)
• poorly coordinated gait and trunk movements
• difficulty expressing and understanding language (severely impaired expressive and receptive language development)
• severe psychomotor retardation