Initial-fit approach versus verified prescription: comparing self-perceived hearing aid benefit

Despite evidence suggesting inaccuracy in the default fittings provided by hearing aid manufacturers, the use of probe-microphone measures for the verification of fitting accuracy is routinely used by fewer than half of practicing audiologists.

The present study examined whether self-perception of hearing aid benefit, as measured through the Abbreviated Profile of Hearing Aid Benefit (APHAB; Cox and Alexander, 1995), differed as a function of hearing aid fitting method, specifically, manufacturer's initial-fit approach versus a verified prescription. The prescriptive fit began at NAL-NL1 targets, with adjustments based on participant request. Each of the two fittings included probe-microphone measurement.

A counterbalanced, cross-over, repeated-measures, single-blinded design was utilized to address the research objectives.

Twenty-two experienced hearing aid users from the general Bay Pines VA Healthcare System audiology clinic population were randomized into one of two intervention groups.

At the first visit, half of the participants were fit with new hearing aids via the manufacturer's initial fit while the second half were fit to a verified prescription using probe-microphone measurement. After a wear period of 4-6 wk, the participants' hearing aids were refit via the alternate method and worn for an additional 4-6 wk. Participants were blinded to the method of fitting by utilizing probe-microphone measures with both approaches.

The APHAB was administered at baseline and at the end of each intervention trial. At the end of the second trial period, the participants were asked to identify which hearing aid fitting was "preferred." The APHAB data were subjected to a general linear model repeated-measures analysis of variance.

For the three APHAB communication subscales (i.e., Ease of Communication, Reverberation, and Background Noise) mean scores obtained with the verified prescription were higher than those obtained with the initial-fit approach, indicating greater benefit with the former. The main effect of hearing aid fitting method was statistically significant [F (1, 21) = 4.69, p = 0.042] and accounted for 18% of the variance in the data (partial eta squared = 0.183). Although the mean benefit score for the APHAB Aversiveness subscale was also better (i.e., lower) for the verified prescription than the initial-fit approach, the difference was not statistically significant. Of the 22 participants, 7 preferred their hearing aids programmed to initial-fit settings and 15 preferred their hearing aids programmed to the verified prescription.

The data support the conclusion that hearing aids fit to experienced hearing aid wearers using a verified prescription are more likely to yield better self-perceived benefit as measured by the APHAB than if fit using the manufacturer's initial-fit approach.