Effects of FM-receiver gain on speech-recognition performance of adults with cochlear implants

The primary aim of this study was to examine the effects of frequency-modulated (FM) settings on speech-recognition performance in noise of listeners using two different cochlear implant speech processors. Participants included eight users of ESPrit 3G speech processors and nine users of Auria speech processors. A modified adaptive-testing paradigm was used to assess speech recognition in noise with the cochlear implant and FM system at four receiver-gain settings: +6, +10, +14, or +20. In the no-FM condition, performance differences were not detected between the two processor groups. In the FM conditions, significantly better performance was found for participants with the Auria processor compared to those using the ESPrit 3G processor. Increases in receiver gain did not significantly improve speech recognition of participants using ESPrit 3G processors, but did significantly influence performance for those using Auria processors. For Auria users, the +6 setting resulted in significantly poorer performance than all other conditions, and optimal FM performance was found in the +14 and +20 gain settings. Clinical recommendations will be provided according to results of the study.