The effect of hearing loss on age-related differences in neural distinctiveness.

Age differences in cognitive performance have been shown to be overestimated if age-related hearing loss is not taken into account. Here, we investigated the role of age-related hearing loss on age differences in functional brain organization by assessing its impact on previously reported age differences in neural differentiation. To this end, we analyzed the data of 36 younger adults, 21 older adults with clinically normal hearing, and 21 older adults with mild-to-moderate hearing loss who had taken part in a functional localizer task comprising visual (i.e., faces, scenes) and auditory stimuli (i.e., voices, music) while undergoing functional magnetic resonance imaging. Evidence for reduced neural distinctiveness in the auditory cortex was observed only in older adults with hearing loss relative to younger adults, whereas evidence for reduced neural distinctiveness in the visual cortex was observed both in older adults with normal hearing and in older adults with hearing loss relative to younger adults. These results indicate that age-related dedifferentiation in the auditory cortex is exacerbated by age-related hearing loss.