Impact of Microphone Configuration on Speech Perception of Cochlear Implant Users in Traffic Noise

Objective: The aim of this study was to investigate the impact of microphone configuration and noise reduction algorithm on speech perception of cochlear implant (CI) users in a moving noise setup. Method: Eleven CI users provided with Advanced Bionics implant systems participated in this study. All tests were conducted with three different microphone settings: (a) omnidirectional behind the ear (BTE), (b) inside the pinna (ITP), and (c) adaptive directional microphone (adaptive beamformer, ABF). Speech reception thresholds (SRTs) were measured using the Oldenburg sentence test in a moving noise source condition. Furthermore, the effect of a noise reduction algorithm on speech perception was measured in a condition with an additional static noise source. Results: The ABF setting significantly improved SRT by 5.7 dB compared with the BTE microphone, and by 4.7 dB compared with the ITP microphone in the moving noise condition. In the presence of an additional static noise source, there was a significant improvement in SRT of 0.9 dB with the use of NR in addition to ABF. Conclusion: Adaptive beamforming can significantly improve speech perception in moving noise. Depending on the noise condition, the combination of ABF with NR can provide additional benefit.