Present and future developments in hearing aid design.

Abstract

Although hearing aids have shown little outward change in the past decade, the development of new components has produced a steady reduction in size and improvement in performance. The near-perfect electret condenser microphone occupies a mere 50 cubic millimeters and its low vibrational sensitivity permits close packing of components without acoustic feedback problems. The integrated circuit packs a hundred components into each cubic millimeter and has allowed the miniaturization of complex aids while simultaneously boosting performance. Integrated circuits will permit future aids to compensate distorted loudness perception as a function of frequency, and extract speech signals buried in noise. These sophisticated, computerized, hearing aids will demand new evaluation and fitting methods and it is the methodology rather than the technology that will pace their development.