Hearing impairment as a predictor of cognitive decline in dementia.

Thirty-eight patients with dementia of various etiologies were studied longitudinally to determine the change in cognition over time in subjects with and without hearing impairment. Hearing impaired subjects were older (P less than .0001), but subject groups were otherwise comparable with respect to living arrangements, medical illness, number of drugs taken, mood, years of education, and cognitive functioning at the beginning of the study period. Decline in cognitive functioning at follow-up was greater in hearing impaired subjects and this difference persisted after adjustment for the greater age of hearing impaired subjects (P less than .009). Further division of subject by diagnosis showed that only in the Alzheimer's group did hearing impairment predict more rapid cognitive decline at follow-up.