Subnormal intellectual functioning which originates during the developmental period. This has multiple potential etiologies, including genetic defects and perinatal insults. Intelligence quotient (IQ) scores are commonly used to determine whether an individual has an intellectual disability. IQ scores between 70 and 79 are in the borderline range. Scores below 67 are in the disabled range. (from Joynt, Clinical Neurology, 1992, Ch55, p28)
    

concept

Feeble-mindedness, its causes and consequences / by Henry Herbert Goddard.

John Donaldson, a simpleton. Etching.

Mendelism and the problem of mental defect.

A cerebral atlas : illustrating the difference between the brains of mentally defective and normal individuals, with a social, mental and neurological record of 120 defectives during life / by Richard J.A. Berry.

Intellectual Disability

Images

Catalogue

Twelfth annual report of the New York Asylum for Idiots : transmitted to the Legislature February 4th, 1863 / New York State Asylum for Idiots.

On the education of the imbecile / by Dora Greenwell.

Rehabilitation : report of a Sub-Committee of the Standing Medical Advisory Committee.

Report of the Mental Deficiency Committee : being a joint committee of the Board of Education and Board of Contro.

Walter / by David Cook.