A model of speech intelligibility and quality in hearing aids

This paper describes new intelligibility and sound-quality calculation procedures that are accurate for both noise and non-linear distortion. The new procedures are based on the speech intelligibility index (SII) [ANSI 1997], but replace the estimated SNR by a signal-to-distortion ratio (SDR) computed from the coherence between the input and output signals of the system under test. The coherence SII procedure is evaluated for normal-hearing and hearing-impaired listeners, and it is shown to be accurate in predicting both speech intelligibility and quality for additive noise, peak-clipping distortion, and center-clipping distortion.