Intellectual disability is the main disabling condition in 11,800 of the estimated 355,500 people who have a disability in Western Australia;

• 39% of people (4,600) who have an intellectual disability have a severe or profound handicap; See DEFINITIONS
• Many people with an intellectual disability also have physical disabilities;
• The number of people registered with an intellectual disability has fallen over the past 30 years from 10-14 per 1,000 births to just less than nine per 1,000 births.

(Information provided by the Disability Services Commission.)

People with an intellectual disability have difficulties with thought processes, learning, communicating, remembering information and using it appropriately, making judgements, and problem-solving.

An intellectual disability is present if the level of intellectual functioning is significantly lower than average and there are limitations in two or more adaptive skills, in the areas of communication, self-care, home living, social skills, self-direction, health and safety, leisure and work.

The identification of intellectual functioning is based largely upon the intelligence quotient (IQ) test. Using this test, scores of 90-109 are classified as average. People who score less than 70 may be considered to be handicapped by an intellectual disability depending on how well they function in key areas of everyday life.

An intellectual disability may become apparent early in life or in the case of people with a mild intellectual disability, not be diagnosed until school age or later.

Many people with an intellectual disability also have physical disabilities.

Source: Alessandri, L.M., Leonard, H., Blum, L.M., Bower, C. Disability Counts: a profile of disability in Western Australia. West Perth: Disability Services Commission, 1996.