Comparison of the Effects of Two Cochlear Implant Fine Structure Coding Strategies on Speech Perception

Purpose: This study aims to investigate the effect of upgrading from the fine structure processing (FSP) coding strategy to the novel fine structure strategy "FS4" in adults in adults with cochlear implants manufactured by MED-EL GmbH (Innsbruck, Austria). Method: A crossover, double-blinded study was conducted for 12 weeks. Twelve adult participants were randomly assigned to two groups. During the first 6-week test interval, one group continued to use their everyday FSP strategy, whereas the other group was upgraded to the FS4 strategy. In the second 6-week interval, the two groups switched coding strategies. Speech perception was measured at the end of each test interval with the Oldenburg Sentence Test and the Gottingen Sentence Test. Participants completed the Speech, Spatial and Qualities of Hearing Scale at the end of each test interval and a simple preference test at the end of the study. Results: There was no significant difference in speech perception test results obtained with the Oldenburg Sentence Test and the Gottingen Sentence Test, neither in quiet nor in noise. Participants' Speech, Spatial and Qualities of Hearing Scale self-evaluation and preference test results showed that the two coding strategies had similar effects on their hearing perception. No clear preference for either of the strategies was found. Conclusions: Speech perception test results and the participants' level of satisfaction were similar for the two FS coding strategies. Despite differences in the presentation of temporal fine structure between FSP and FS4, a clear benefit of the newer FS4 strategy could not be shown.