Improved Speech Intelligibility with a Chimaera Hearing Aid Algorithm

It is recognised that current hearing aid fitting algorithms can corrupt fine timing cues in speech. This paper presents a fitting algorithm that aims to improve speech intelligibility, while preserving the temporal fine structure. The algorithm combines the signal envelope amplification from a standard hearing aid fitting algorithm with the fine timing information available to unaided listeners. The proposed “chimaera aid” is evaluated with computer simulated listener tests to measure its speech intelligibility for 3 sample hearing losses. In addition, the experiment demonstrates the potential application of auditory nerve models in the development of new hearing aid algorithm designs using the previously developed Neurogram Similarity Index Measure (NSIM) to predict speech intelligibility. The results predict that the new aid restores envelope without degrading fine timing information.