R. Meddis - A Computer model of the benefits of auditory efferent feedback

 
The auditory peripheral efferent system consists of both the acoustic reflex and medial olivo-cochlear reflex. There is, as yet, no generally agreed view on the signal-processing role of this system but has been widely predicted to play a beneficial role in speech perception in addition to obvious protective functions. To study this we have extended an existing auditory model of the physiology of the auditory periphery and examined its response to speech stimuli both in quiet and in the presence of interfering talkers. Our measure of intelligibility benefits is based on automatic speech recognition performance using the model as a front end to a standard recogniser. The model results clearly show better performance when the MOC and AR are active and the signal to noise ratio is positive. This supports the idea that these systems contribute to intelligibility in normal human listening conditions. While the recognition performance of the model is inferior to human performance, it is surprisingly robust in the presence of noise compared to many other recognition algorithms. The problems experienced by hearing impaired listeners in noisy environments will be considered in this context.