Wellesley D, Hockey A, Stanley F
Authority for Intellectually Handicapped Persons, West Perth, WA.
Dev Med Child Neurol. 1991 Nov;33(11):963-73. doi: 10.1111/j.1469-8749.1991.tb14812.x.
A register of intellectual disability is being established to assess the level and aetiology of intellectual disability in all children born and/or living in Western Australia. 1602 children aged between six and 16 years were identified who had IQs less than 70. 40 per cent had a definite genetic basis, 20 per cent an environmental cause and 40 per cent were of unknown aetiology. The insult was prenatal in 61 per cent, 10 per cent had a possible perinatal cause, 8 per cent were postnatal and for 21 per cent the timing could not be assessed. Approximately 20 per cent had concomitant cerebral palsy and 13 per cent were epileptic. A disparity was found between rural and urban areas, the prevalence being 9.9 and 6.5 per 1000 live births.