Assessing age-related temporal processing deficits with single word contrasts in cochlear-implant users

Abstract

For listeners with acoustic hearing, aging and hearing loss are associated with temporal processing deficits. For those with enough hearing loss, a cochlear implant (CI) becomes the preferred intervention. However, a CI degrades acoustic information by delivering primarily temporal envelope information through modulated electrical pulse trains. Therefore, if older CI listeners experience temporal processing deficits like acoustic-hearing listeners, they are compelled to understand speech primarily through a process that is affected by aging. We will present temporal processing data from a series of experiments that use word contrasts that vary primarily in a temporal dimension (silence duration: Dish-Ditch; voice-onset time: Buy-Pie). Participants include CI listeners and normal-hearing listeners presented with a CI simulation via a channel vocoder and range in age from younger (<45 yrs) to older (>65 yrs). Results show that CI listeners and NH listeners presented with CI simulations need longer temporal cues to discriminate temporally based word contrasts. In addition, such deficits are differentially worse at higher stimulation levels for the older CI listeners compared to the younger CI and all NH listeners. In conclusion, aging may lead to temporal processing deficits in CI listeners. These results have implications for CI programming and directions for technological improvements.