Variables affecting the use of prescriptive formulae to fit modern nonlinear hearing aids.

It is routine for audiologists to fit nonlinear hearing aids by using one of several current prescriptive formulae. While such an approach might result in acceptable fittings for single-channel analog compression hearing aids, its direct application to fitting current multichannel compression hearing aids may result in less than an optimal fit. In this paper, the effects of filter bandwidth, number of channels, detector type, compression threshold, attack and release times, and distortion on the final output of a nonlinear compression hearing aid are discussed. The subjective results of such effects and its implications on our clinical practice will be explored as well.