NIDCD/VA hearing aid clinical trial and follow-up: coupler and real-ear measurement.

A total of 190 individuals participated in a clinical visit during the Cooperative Studies Program (CSP) 418-A Long Term Follow-Up Study. Of this cohort, 158 participants were considered current hearing aid users, and 32 were non-hearing aid users. Of the current hearing aid users, 81 were still using their original 418 study devices, and 77 had acquired new hearing aids. Coupler and real ear measurements were completed on all available hearing aids. Results showed that study aids had remained relatively stable over the six years between CSP 418 and CSP 418-A. On average, these hearing aid wearers preferred use gain settings that were 6-9 dB less than current NAL-RP insertion gain targets. Mean real ear insertion gain (REIG) was comparable to the mean real ear insertion gain of the same participants in the original study, and users did not tend to increase gain as hearing decreased. Real ear saturation responses (RESR) remained unchanged. Loudness discomfort levels (LDL) obtained during 418-A were significantly lower than LDLs obtained on those same participants at both the initial and final visits in the previous study.