Derivative-free optimization of hearing aid parameters

Loudness restoration approaches to hearing aid fitting prescribe gain and compression so as to restore the loudness perceived by a hearing-impaired listener to that perceived by a listener with normal-hearing. Restoring the loudness perception to normal is complicated by the spread of excitation at high stimulus levels that causes intense stimuli at low frequencies to be “heard” and to contribute to the perceived loudness at high frequencies, producing excess loudness growth and poor sound quality. We apply derivative-free optimization algorithms to find a configuration of hearing aid gain and compression parameters that restores specific loudness perception of a hearing impaired listener to that of a normal hearing listener, while simultaneously minimizing the across-frequency spreading of excitation, and ensuring the feasibility of the resulting hearing aid parameters.