A REVIEW OF PAST RESEARCH ON CHANGES IN HEARING-AID BENEFIT OVER TIME

Hearing aid benefit refers to a relative change in performance on a pa rticular measure between aided and unaided listening conditions. A num ber of studies in recent years have investigated the hypothesis that h earing aid benefit increases over time after the initial fitting of th e aid. Both objective (speech recognition) and subjective (questionnai re) measures have been used to measure hearing aid benefit. Some studi es have reported a positive increase over time in group mean benefit, and some have reported no change in benefit, whereas none have reporte d a group mean negative change in benefit. However, individual subject s in these studies can show changes in benefit in either a positive or negative direction. The variability across subjects in each study has been large in comparison with the observed amount of benefit increase . in this review of the literature, it is argued that the studies pres ent essentially similar results and the range of values across subject s in the various studies shows considerable overlap. Although there do es appear to be a tendency for hearing aid benefit to increase over ti me, there are other, much stronger, factors influencing changes in hea ring aid benefit that make it impossible at present to predict which p atients will show a reliable increase (or decrease) in hearing aid ben efit over time.