A category of childhood disorders characterized by delay or abnormality in the development of functions such as speaking, reading, arithmetic ability, motor skills, and social and communication skills.
A handicap or impairment originating before the age of 18 which may be expected to continue indefinitely and which constitutes a substantial impairment. The disability may be attributable to mental retardation, cerebral palsy, epilepsy, or other neurological conditions and may include autism.
Childhood disorders characterized by unusually slow progress in attaining developmental milestones or the prolonged demonstration of a behavioral deviance.