A clinical trial of the ReSound IC4 hearing device

A manufacturer-sponsored clinical trial was conducted of ReSound Corporation's IC4 hearing device (HD), an in-the-ear application of their two-channel, fast-acting, wide-dynamic range compression sound processor. This study was a follow-up to an earlier clinical trial of ReSound's behind-the-ear version of the same sound processor, the BT2 Personal Hearing System (Walden, B. E., Surr, R. K., Cord, M. T., & Pavlovic, C. V. (1998). A clinical trial of the ReSound BT2 Personal Hearing System. American Journal of Audiology, 7, 85-100). Forty adult males with gradually sloping, moderate sensorineural hearing losses participated. All were experienced hearing aid users who wore linear Class D instruments with input compression limiting at the time of their enrollment in this study. The Connected Speech Test, presented at several presentation levels and under various conditions of signal degradation, and the scales and subscales of the Profile of Hearing Aid Benefit were used to evaluate hearing aid performance and benefit under four relatively independent prototype listening situations (Walden, B. E., Demorest, M. E., & Hepler, E. L. (1984). Self-report approach to assessing benefit derived from amplification. Journal of Speech and Hearing Research, 27, 49-56). Aided performance with the IC4 HD was compared with (a) unaided performance, (b) performance of persons with normal hearing, and (c) performance with linear amplification. Participants with hearing loss obtained significant benefit from the IC4 HD, although IC4-aided performance remained well below that of unaided performance of persons with normal hearing, especially on laboratory measures of speech recognition. Furthermore, small mean performance advantages were observed for the IC4 HD compared to linear hearing aids, although there was substantial variability across participants. Finally, when given a choice to either purchase the IC4 HD at a discount from the manufacturer or continue using their own government-issued linear hearing aids, the majority of the participants chose to purchase the IC4 HD.