Digital filtering in hearing aid system for the hearing impaired

A great proportion of human population suffers from hearing loss. Hearing loss is a measure of shift in auditory system compared to that of a normal ear for detection of a pure tone. But with the availability of modern day technologies and the recent developments in signal processing area, sophisticated artificial hearing aid systems can be designed that relax the job of damaged auditory systems to a great extent and make much of the sound available to the hearing impaired. In this project, the simulation of the simple digital hearing aid was developed using MATLAB programming language. The implementation of this configurable digital hearing aid (DHA) system includes noise reduction filter, frequency-dependent amplification and amplitude compression. We tested our filters on a mock patient and successfully reduced white Gaussian noise, increased the gain for frequencies which were difficult to hear, and shaped the amplitude to prevent any of the frequencies from becoming too loud. Finally, future trends and expected innovations in the hearing aid industry are discussed.