Benefit of a Commercially Available Cochlear Implant Processor With Dual-Microphone Beamforming

Abstract

Previous research shows that cochlear implant users experience significant difficulty with speech perception in noisy listening situations. There is a paucity of research evaluating the potential improvement in speech recognition in noise provided by a dual-microphone directional system in a commercial implant sound processor. The primary objective of this study was to compare speech recognition in quiet and in noise for the Nucleus Freedom and Nucleus 5 CP810 sound processors set to the manufacturer's default user programs for quiet and noisy environments. Crossover with repeated-measures design. This multi-center study was conducted across four cochlear implant clinics in the United States. Thirty-five adults with unilateral Nucleus Freedom cochlear implants. All subjects had used their cochlear implant for at least 6 months and had substantial open-set word recognition as evidenced by a score of at least 40% correct on the Consonant-Nucleus-Consonant (CNC) monosyllabic word recognition test in quiet. All subjects (previous users of the Nucleus Freedom sound processor) were fitted with the Nucleus 5 sound processor. Performance was assessed while these subjects used each sound processor in the default user program the manufacturer recommends for quiet and noisy conditions. Speech recognition was assessed with CNC monosyllabic words in quiet and sentences in noise from the BKB-SIN (Bamford-Kowal-Bench Sentences in Noise) test. The data were analyzed with descriptive statistics and performance with each processor in each listening condition was compared using a repeated-measures analysis of variance. Word recognition in quiet was significantly better with the Nucleus 5 sound processor when compared to performance with the Nucleus Freedom processor. In noise, the Nucleus 5 sound processor also provided a significant improvement in speech recognition relative to the performance with the Nucleus Freedom. The results of the study suggest that the Nucleus 5 sound processor provides significantly better speech recognition in quiet and in noise when compared with performance with the Nucleus Freedom processor.