Intellectual disability is a general term to describe a deficit in intelligence; either a general deficit or a general learning deficit. It is currently defined as a combination of an intellectual quotient (IQ) of less than 70 (with 100 being average) combined with a deficiency of at least two adaptive behaviors that affect everyday living.
Intellectual disabilities are further sub-categorized by two types:
- Syndromic - Where the deficits are the result of a diagnosed syndrome, such as Trisomy-21
- Non-syndromic - Where the deficits appear to be unrelated to a pathological condition
Somewhere between 2 and 3 percent of the general population suffers from an intellectual disability. In over 75% of cases, the impairment is mild. Somewhere between 30-50% of cases are non-syndromic. About 25% of those affected have a genetic condition.
Intellectual disabilities are usually identified in early childhood. Typical signs are delay in developing motor skills (such as walking), difficulties with speech and language, difficulty with self-help skills (such as dressing), problems socializing, and poor school performance.
Although many cases are not identified until the child starts school, care must be taken to rule out specific learning disabilities.
Treatment of intellectually disabled persons generally addresses their skill set. Although intellectually disabled persons often take a great deal of time to learn a basic skill, they can generally remember it once they have mastered it.