About Intellectual Disabilities

There are a variety of definitions of intellectual disabilities. What follows are definitions used in legislation and/or for eligibility for services and programs referred to on this web site.

The Individuals with Disabilities Education Act (IDEA)

Definition of Intellectual Disabilities

An intellectual disability is a disability that involves significant limitations both in intellectual functioning and in adaptive behavior, which covers many everyday social and practical skills. This disability originates before the age of 18 and encompasses a wide range of conditions, types, and levels. Intellectual disability is caused by factors that can be physical, genetic, and/or social.

Definition of the Lanterman Developmental Disabilities Service Act

According to this California law, a developmental disability is defined as occurring before the age of 18 and includes specific categories of eligible conditions: mental retardation, epilepsy, cerebral palsy, autism, and "conditions requiring services similar to those required for persons with mental retardation." The developmental disability shall likely continue indefinitely and constitutes a substantial disability. A substantial disability is a significant functional limitation in three or more of the following life activities: receptive/expressive language, learning, self care, mobility, self direction, capacity of independent living and economic self sufficiency.

Statistics:

The California Department of Education, Special Education Division reported that in December of 2011 that there were a total of 38,534 students ages 14-22 that were classified with intellectual disabilities (20,059), autism (17,544) and  traumatic brain injury (931). (CASEMIS, 2011).

The Chancellor’s Office for the Community Colleges distributes funding on the basis of 9 disability categories. For the year 2010-2011 California Community Colleges reported serving 11,005 Developmentally Delayed Learners. (Data Mart) DDL is characterized both by a significantly below-average score on a test of mental ability or intelligence and by limitations in the ability to function in areas of daily life, such as communication, self-care, and getting along in social situations and school activities.