Pervasive Developmental Disorders
(2-19-15)
Characterized by severe and pervasive impairment in several areas of development: social interaction, communication, age normal interests and activities.
The terminology "pervasive developmental disorder" is controversial, because the grouping has been restricted (in DSM) to autistic like disorders: "social communicative disorders", "autistic spectrum disorder", "autism and autistic-like conditions", and "disorder of social interaction, communication, and imagination) have been suggested as alternatives (Harris, 1998).
Autistic Disorder (Autism): impairments in social relationships, and communication, and markedly restricted repertoire of activities and interests.
Onset prior to 36 months (by definition)
Course usually continuous and life long
Asperger's Disorder: severe and sustained impairment in social interaction and development of restricted, repetitive patterns of behavior, interests, and activities.
Language development is unremarkable
Cognitive development and age-appropriate adaptive behavior essentially normal
Appears to be more common in males
Course usually continuous and life long
Rett's Disorder: development of multiple deficits following a period of normal development after birth. No longer viewed as a PDD (because etiology better understood)
Characteristics:
Apparently normal prenatal and perinatal development
Onset between 5 and 48 months
Loss of purposeful movement, loss of social engagement, severely impaired language development
Head growth decelerates
Clinical population almost entirely female (genotype usually fatal in males)
This position may need to be revised in light of reports that Rett's syndrome like patterns have been observed in mildly impaired females and severely impaired males (Shevell et al., 2003)
Usually associated with Severe or Profound Mental Retardation
Course usually continuous and life long
Second only to Down Syndrome as known cause of global developmental delay in females (Shevell et al., 2003)
Conceptualization/Etiology:
Approximately 80% of cases have MECP2 mutation: mutation in the X-linked gene encoding methyl-CpG-binding protein 2 (MECP2 mutation)
Increasing viewed, along with Childhood Disintegrative Disorder, as a neurological/neurodegenerative rather than mental disorder and may have limited relationship to autism spectrum disorders (Autistic Disorder, Asperger's Disorder, atypical autism). (See discussions in Brock, Jimerson, & Hansen, 2006; Harris, 1998)
An excellent discussion of Rett's Syndrome is Barbro Lindberg (2006) revised edition of her earlier (1991) report of a study of 39 women between 2 and 39 years of age conducted between 1985 and 1986.
Childhood Disintegrative Disorder: marked regression in multiple areas of functioning after at least two years of apparently normal development.
Conceptualization:
Very rare, much less prevalent than Autistic Disorder
More common in males
Course usually continuous and life long
Usually associated with Severe Mental Retardation
Increasing viewed, along with Rett's Syndrome, as a neurological/neurodegenerative rather than mental disorder and may have limited relationship to autism spectrum disorders (Autistic Disorder, Asperger's Disorder, atypical autism). (See discussions in Brock, Jimerson, & Hansen, 2006; Harris, 1998)
Pervasive Developmental Disorder Not Otherwise Specified
meet essential characteristics of PDD but not specific diagnoses of AD, AspD, RD, or CDD: heterogenious "left-overs", borderline/mild severity cases, and so called "atypical autism" (unusally an autistic disorder pattern of symptoms with onset after the 36 month criterion)
Other pervasive developmental disorders, not included in DSM-IV
ICD-10
Atypical Autism
Overactive Disorder Associated With Mental Retardation
possibly related topics
Nonverbal Learning Disabilities (NVLD)
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