Abstract
The study was carried out in children born during the four year period 1981–1984 in the Greater Manchester County. The children were investigated for possible congenital infections. Perinatal assessment was carried out for adverse aetiological factors. Family histories were obtained and parents and siblings were examined for any hearing impairment. A total of 164 cases were investigated. Various aetiological groups were formed which showed the following distribution: cause unknown 36.5 per cent; genetic group 20.1 per cent; adverse perinatal factors 14.6 per cent; congenital infections 9.8 per cent; meningitis 6.1 per cent; chromosomal abnormalities 3.7 per cent; syndromal group 3.7 per cent; and miscellaneous 5.5 per cent. The findings are discussed in the light of previous studies.