Central auditory function in Alzheimer's disease.

The central auditory (dichotic) function of 38 patients with Alzheimer's disease was found to be significantly impaired when compared with a control group. Significant relationships were observed between dichotic scores and intelligence quotient, cortical atrophy in the temporal lobes, and cerebral glucose metabolism in the left temporal lobe. Comparing atrophy and glucose metabolism in the temporal lobes, we observed contralateral ear effects in dichotic performance as well as an interaction of asymmetry of atrophy with dichotic performance, consistent with previous models of dichotic listening in other forms of temporal lobe pathology.