Assessment and improvement of sound quality in cochlear implant users

OBJECTIVES Cochlear implants (CIs) have successfully provided speech perception to individuals with sensorineural hearing loss. Recent research has focused on more challenging acoustic stimuli such as music and voice emotion. The purpose of this review is to evaluate and describe sound quality in CI users with the purposes of summarizing novel findings and crucial information about how CI users experience complex sounds. DATA SOURCES Here we review the existing literature on PubMed and Scopus to present what is known about perceptual sound quality in CI users, discuss existing measures of sound quality, explore how sound quality may be effectively studied, and examine potential strategies of improving sound quality in the CI population. RESULTS Sound quality, defined here as the perceived richness of an auditory stimulus, is an attribute of implant-mediated listening that remains poorly studied. Sound quality is distinct from appraisal, which is generally defined as the subjective likability or pleasantness of a sound. Existing studies suggest that sound quality perception in the CI population is limited by a range of factors, most notably pitch distortion and dynamic range compression. Although there are currently very few objective measures of sound quality, the CI-MUSHRA has been used as a means of evaluating sound quality. There exist a number of promising strategies to improve sound quality perception in the CI population including apical cochlear stimulation, pitch tuning, and noise reduction processing strategies. CONCLUSIONS In the published literature, sound quality perception is severely limited among CI users. Future research should focus on developing systematic, objective, and quantitative sound quality metrics and designing therapies to mitigate poor sound quality perception in CI users. LEVEL OF EVIDENCE NA.