Hearing loss in an institutionalized mentally retarded population. Identification by auditory brainstem response

We report the results of auditory brainstem response testing of 122 profoundly retarded institutionalized children, a segment of the retarded population heretofore generally regarded as untestable by behavioral audiometry. Major findings include: 32% of the study population showed, by auditory brainstem response, hearing loss exceeding 20 decibels of hearing level in one or both ears (12% showed conductive loss and 20% sensorineural loss); of the 15.6% with evidence of bilateral sensorineural loss, 7.37% had losses in the 30- to 50-dB range, and 8.19% had losses of 60 dB or greater; and evidence of abnormal brain-stem function was found in 11%. Results of otologic examinations and audiologic habilitative follow-up in selected children are also reported.