Efficient perceptual tuning of hearing aids with genetic algorithms

We describe a system for integrating a genetic algorithm (GA) with perceptual feedback to perform an efficient search in a perceptual space. The main system components are an efficient method for estimating perceptual rank order and genetic operators that take advantage of the types of parameters found in certain classes of audio processing systems. Preference judgments are used, resulting in a lightweight user interface. The application to subjectively fitting a portable hearing aid based solely on binary feedback is discussed. An experiment was conducted using eight normal and eight hearing impaired subjects. Three parameters were varied to control cancellation of acoustic feedback. The GA worked well for fitting this system, as indicated by both objective and subjective measures. In addition, users had greatly differing preferences for feedback cancellation parameters and these preferences did not change much when subjects were retested.