Rapid reduction of listening effort resulting from predicting speech processing, and delays associated with cochlear implantation

Abstract

Speech communication involves not only the recognition of words, but also processing and prediction resulting from those words. This study explored the question of whether prediction guided by semantic context reduces physiological listening effort, and whether this process is as quick and effective in people who use cochlear implants (CIs). To examine this issue, pupil dilation was used as a time-varying index of effort during sentence perception by CI users and listeners with normal hearing. NH listeners also heard spectrally degraded vocoded versions of the stimuli, which consisted of high-and low-context sentences. For NH listeners, context resulted in rapid effort reduction for normal speech; predictable sentences yielded reduced responses even before stimulus offset. For degraded stimuli, this effect was not observed until after the stimulus was over, suggesting that listeners normally process and take benefit from context in real time, but poor signal quality delays that process. For CI listeners, ...