Table 1.
Domains of impairment in autistic spectrum disorder (ASD)a
| Domain | Autism | Asperger | PDD-NOS | ASD |
|---|---|---|---|---|
| social communication | required | required | required | |
| language | required | – | variable | |
| repetitive, restrictive behaviors | required | required | variable | |
| sensory abnormalities | >90% | 80% | variable | 94% |
| developmental regressionb | 15%–40% | ? | ? | 15%–40% |
| motor signsc | 60%–80% | 60% | 60% | 60%–80% |
| gross motor delay | 10% | ? | ? | 5%–10% |
| sleep disturbance | 55% | 5%–10% | 40% | 50% |
| gastrointestinal disturbanced | 45% | 4% | 50% | 4%–50% |
| epilepsye | 10%–60% | 0%–5% | 5–40% | 6%–60% |
| comorbid psychiatric diagnosisf | 70% | 60% | >25% | 25–70% |
Diagnostic features are denoted as “required”; those that are not observed are denoted by a dashed line. There have been few large-scale, epidemiologic studies of features associated with ASD, so the frequencies of allied symptoms or disorders given here are conservative estimates based on the author’s amalgamation from References 82–92. The ASD column at far right provides an estimate for the combined broad category of ASD, which includes autism, Asperger syndrome, and PDD-NOS.
Loss of function in either or both the language or social skills domain.
Motor signs include hyptonia, gait problems, toe walking, and apraxia.
Six months or more of diarrhea, constipation, reflux, or bloating.
The range of epilepsy estimates reflects the presence of other comorbid features, such as concurrent intellectual disability or intellectual disability and cerebral palsy, which significantly increase epilepsy risk (25%–30% and 60%, respectively).
Mood disorders, conduct disorders, aggression, and attention deficit/hyperactivity disorder (ADHD). ADHD symptoms are observed in ~25% of children with ASD.