COMPUTATIONAL MODELING OF OUTER HAIR CELL DAMAGE: IMPLICATIONS FOR HEARING AID SIGNAL PROCESSING

This paper describes a number of computer simulations illustrating the main effects of outer hair loss upon the representation of sounds on the basilar membrane. These include (1) a basalward shift of the place of maximum vibration, (2) a decreased gain near the place of maximum vibration, (3) a broadening of the tuning curves, (4) an altered summation of activity across frequency components, and (5) an altered temporal response. It is argued that, for large classes of sounds, the basilar membrane patterns resulting from a loss of outer hair cells cannot, in principle, be compensated for by hearing aid signal processing techniques, such as multi-band amplitude compression and spectral sharpening.