Causes and associations of severe and persistent specific speech and language disorders in children.

Eighty-two school-age children with severe and persistent specific speech and language disorders were studied. 71 had specific developmental language disorders, three had structural malformations (cleft palate) and eight had disorders acquired after a period of normal language development, including five with Landau-Kleffner syndrome. The sex ratio was 3.8 boys to one girl. Nearly half had a family history of speech-language disorder, with one in 5.2 affected siblings. Aetiological factors were found in 26 per cent: 11 per cent prenatal, 3 per cent perinatal and 12 per cent postnatal. 21 per cent had had a seizure and 7 per cent had had seizures after the age of eight. 29 per cent were left-handed, 90 per cent were clumsy and 22 per cent first walked after 18 months. The complex origins of specific speech and language disorders are discussed.