Preferred hearing aid gain and bass-cut in relation to prescriptive fitting.

The insertion gain versus frequency, preferred by a group of moderately hearing-impaired, elderly, untrained hearing aid users was investigated both in everyday listening situations and in an acoustically specified test situation in the laboratory. The subjects used experimental binaural hearing aids with modified controls, which could be easily and accurately operated. They adjusted both gain and bass-cut while using the aids. Preferred insertion gain was compared with recommendations from three methods of prescriptive fitting. These methods significantly overestimated preferred gain by about 10 dB. Preliminary fittings should allow a gain reserve of about 15 db. Intra-individually, a gain range of about 11 dB is often sufficient for different everyday situations.