ABSTRACT
OBJECTIVE: 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. RESEARCH DESIGN: Crossover with repeated-measures design. SETTING: This multi-center study was conducted across four cochlear implant clinics in the United States. PATIENTS: 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. INTERVENTION: 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. MAIN OUTCOME MEASURES: 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. RESULTS: 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. CONCLUSION: 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.
