Environmental Sound Perception for Cochlear Implant Users
Degree GrantorUniversity of Canterbury
Degree NameMaster of Audiology
This study compared adult cochlear implant (CI) users to normally hearing (NH) listeners in their ability to identify various environmental sounds. It also assessed the impact of cochlear implantation on speech perception as well as the ability to identify environmental sounds. A comprehensive Environmental Sounds Perception Test (EST) was developed for this study. It was hypothesised that: (i) the NH participants would score higher than the experienced CI users on the EST; (ii) for the pre-to-post CI group, scores on the EST would be higher post-surgery than presurgery, and (iii) for the pre-to-post CI surgery group, scores on speech perception tests would be higher post-surgery than pre-surgery. 10 experienced adult Nucleus CI users and 24 similarly-aged NH subjects were compared on the EST. The study also tested four adults pre-surgery (with HAs), and subsequently post-surgery with the CI on speech perception tests as well as the EST. The closed-set EST consisted of 45 different sounds selected to be representative of everyday stimuli, classified into 9 groups; transport, nature, arriving home, bathroom, kitchen, household appliances, human, office and other. Each sound was represented by two different tokens, ranging in lengths from 2.5 to 12.5 seconds. The results showed that NH participants scored significantly higher than the experienced CI users on the EST (p < 0.001). For the participants tested pre- and post- surgery, the higher scores with the CI than with HAs was approaching significance (p = 0.068) for both the EST and the speech perception measures. No significant correlations were found between scores on the EST and a range of participant factors such as age or speech perception scores for any group. Overall these results suggest that CI users are poorer than NH participants, but better than HA users with severeto- profound hearing losses, in recognizing environmental sounds.