Comparison of three hearing aid prescription procedures.

The gain recommendations for twenty-five hearing aid condidates with sensorineural hearing loss were determined by direct measurement of most comfortable loudness level and by two different formulas which were based on air-conduction thresholds for 500, 1000, 2000, and 4000 Hz. At 500 Hz, one formula recommended significantly less gain than did the other two procedures. At the other frequencies, there were no systematic, clinically significant mean differences among the three methods. However, the direct measurement of most comfortable loudness level resulted in markedly greater variability in gains as a function of hearing level than did the two formula methods. This variability suggested that wherever possible, gain should be determined by most comfortable loudness level measurement rather than by prediction from pure-tone threshold.