A MODEL TO EVALUATE AND MAXIMIZE HEARING-AID PERFORMANCE BY INTEGRATING THE ARTICULATION INDEX ACROSS LISTENING CONDITIONS

A method for integrating the articulation index (AI) across listening conditions was developed and applied to a preliminary model for evalua ting and optimizing Prescriptions of hearing aid characteristics. The model takes hearing threshold, masking of noise, self-masking of speec h, high level cochlear distortion, and the peak-clipping effects of a hearing aid into account. The integrated AI (IAI) across a range of li stening conditions is used as a criterion for evaluating a specific he aring aid response characteristic and calculating an optimal frequency -gain characteristic that maximizes the IAI. For a high-frequency hear ing loss, the frequency-gain characteristics and IAI's derived from an optimal IAI (OIAI), POGO, and NAL prescriptions are compared for two of listening situations: a quiet setting and a setting with a signal-t o-noise ratio of -3 dB. The results predict that, in quiet, the OIAI p rescription is not significantly different from the well-established p rescriptive procedures such as the POGO and the NAL. For the noise con dition, however, the optimal IAI model is predicted to be better in te rms of speech intelligibility.