Development of APHAB norms for WDRC hearing aids and comparisons with original norms

This study was undertaken for two purposes: First, to provide a comparison of subjective performance and benefit measured with the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire for two groups. One group included hearing-impaired individuals using 1990s-era linear processing hearing aids. The other group included hearing-impaired individuals using more current wide-dynamic range compression (WDRC)-capable hearing aids fit using current practice protocols. The second purpose of this study was to determine whether APHAB norms derived from scores for current hearing aid users were different from the original 1995 norms. It was hypothesized that technology improvements would result in improved subjective performance for modern hearing aid wearers.

A systematic sampling method was used to identify and recruit subjects from seven private-practice audiology clinics located across the United States. Potential subjects were limited to older hearing-impaired individuals who were wearing hearing aids capable of WDRC processing. One hundred fifty-four subjects returned completed APHAB questionnaires. Participants reported mostly moderate to moderately severe subjective hearing difficulty.

No differences in perceived difficulty with speech communication were observed between the two groups. However, aversiveness of amplified sound was less frequently reported for users of WDRC-capable hearing aids. Norms were generated using data from all of the operationally defined successful hearing aid users in the sample and compared with the original 1995 norms. Differences between the 1995 and 2005 norms were minimal for the speech communication subscales. However, the 2005 group consistently reported less frequent difficulties with sound aversiveness (AV subscale) in the aided condition. In addition to these findings, an improvement was observed in the rate of successful adjustment to hearing aids between 1995 (43%) and 2005 (82%).

Overall, problems understanding amplified speech did not decrease in frequency when hearing aids transitioned from linear to compression processing; however, the compression capabilities of current hearing aids (with a possible contribution from noise reduction algorithms) have resulted in less negative reactions to amplified environmental sounds. This suggests that modern technology has ameliorated (to some extent) the common complaint that hearing aids cause many everyday sounds to become objectionably loud. Although the results of this study suggest that the advantages of improved technology do not lie in the domains of improved subjective speech communication performance, substantial improvement in the rate of successful adjustment to hearing aids between the 1995 and 2005 subject groups provides evidence that modern hearing aid technology has produced progress in other outcome domains.