Acoustic cue weighting strategy and the impact of training for cochlear implant users and normal hearing listeners with acoustic simulation

This project investigates the impact and plasticity of perceptual cue weighting strategy for normal hearing (NH) listeners with cochlear implant (CI) acoustic simulation and CI users. It is hypothesised that how listeners allocate perceptual attention on different speech cues is related to how accurately and effectively they can restore the phonemic structures from the acoustic inputs. Therefore, it can be beneficial to use auditory training to guide listeners’ attention to the more reliable and informative cues for their own specific language, in order to improve speech recognition and ease listening effort. The first part of this project investigated the impact of perceptual weighting strategy for both groups of listeners. Listeners’ sentence recognition and pupillary response (taken as a measure of listening effort) were measured. They were then taken into the same model with listeners’ acoustic cue weighting ratio and auditory sensitivity to explore their relation. The second aim of this project was to examine the possibility of using auditory training to change listeners’ acoustic cue weighting strategy towards an optimal one. A distributional training method was used here, with the sampling of spectral and temporal cues in the training word stimuli manipulated in a way that only the spectral cue followed a bimodal distribution that resembled the natural speech. This was to increase the saliency of the spectral cue, in order to direct listeners’ attention to the spectral cue. Sentence recognition performance in quiet, acoustic cue weighting strategy and pupillary responses were measured before and after the training to examine the effectiveness of the training. Findings from this project will extend the current understanding on CI users’ perceptual cue weighting strategy and provide inspiration for a more comprehensive rehabilitation scheme for CI users.