Hearing aids based on models of cochlear compression

Abstract

Methods and devices for audio amplification suitable for hearing aid, hearing aid fitting, and diagnostic purposes include audio amplification having at least one variable gain channel configured to provide relatively higher gain at low levels, rapid gain compression at intermediate levels converging to linear gain at high signal levels, and slow feedback control of the compressive gain. Several such audio channels may be provided in a hearing aid or diagnostic device, and instantaneous gain compression is preferred. An analog implementation provides nonlinear elements in a feedback path to simulate a multiple feedback band-pass non-linearity cochlear filterbank hearing model (MFBPNL), while a digital implementation uses logarithmic representations of signals to minimize functional components in a multiple band-pass non-linearity cochlear filterbank hearing model (MBPNL). When used as a hearing aid, annoying amplification of weak sounds during brief interruptions of sustained intense sounds is prevented. Moreover, the quality of processing of intense sounds is improved, while still protecting the ear from uncomfortable, sudden intense sounds that occur too rapidly for effective correction by conventional automatic gain control.