Psychoacoustic dynamic range and cochlear implant speech-perception performance in Nucleus 22 users

BACKGROUND: Cochlear implant speech processors compress a wide acoustical dynamic range of sounds into a smaller electrical dynamic range. Some patients show wider electrical dynamic ranges than others and most of them have good speech perception performance. The knowledge of the average psycho-acoustical dynamic range in adults will help the audiologist program children who do not give reliable responses. AIM: This study was conducted to analyse the dynamic ranges of experienced Nucleus 22 cochlear implant users with good speech-perception and patients with poor speech-perception performances. METHOD: Thirty-one maps of adult subjects with Nucleus 22 cochlear implants using the SPEAK processing strategy, in bipolar stimulation were analysed. By the time of this study, all of them had used a cochlear implant for over a year. They were divided into two groups: group 1, composed of those with good speech perception for sentences (better than 80%), and group 2, composed of those with speech perception results for sentences worse than 70%. RESULTS: Results showed that both dynamic ranges were wide in the two groups (average 50 units). CONCLUSION: Although dynamic ranges vary among subjects and electrodes, a lower variability was observed within the group of patients with better speech perception.