Evaluation of fitting rules with a programmable hearing aid.

A study was performed with the 3M 8200 multi-programmable hearing aid in order to try to identify an optimal frequency-gain response, based on the standard calculation rules: NAL, POGO, Berger and Half gain. Furthermore, we examined to what extent multiple programs are used and appreciated. The 3M hearing aid was presented to 126 hearing-impaired patients for a trial period. The participants undertook several tests of speech intelligibility and sound quality. In comparison to the final settings after the trial period, it transpired that the NAL rule came f1p4est to the most used program and gave the best prediction of the gain at 1000 Hz. The attempt to optimize standard calculation rules according to indications made by the patients failed. The SRT-in-noise test showed improvements of the S/N ratio of 2.5 dB. The results of this study point towards separate processing of low- and high-frequency sounds as a useful concept.