Objective measures of perceptual quality for predicting speech intelligibility in sensorineural hearing loss

An objective method to predict speech intelligibility in sensorineural hearing loss of different types and increasing degrees of severity is proposed and validated with experimental data. The novel approach is based on the combined use of acoustic simulations of impaired perception and objective measures of perceptual speech quality (PESQ). Acoustic simulations were obtained after degradation of the original, non distorted, speech waveforms by spectral smearing, expansive nonlinearity, and level scaling. PESQ was used to measure perceptual quality of the acoustic simulations obtained by varying the degree of the simulated hearing loss. A logistic function was applied to transform PESQ scores into predicted intelligibility scores. A set of CV and VC syllables in /a/, /u/, and /i/ contexts was used as reference test material. The method was validated with subjective measures of intelligibility of the degraded speech obtained in a group of 10 normal hearing subjects. Overall, prediction of experimental speech intelligibility through the transformed PESQ measures was good (R2=0.7; RMSE=0.08) revealing that the proposed approach could be a valuable aid in real clinical applications.