A predictive model of speech intelligibility in noise for normal and hearing-impaired listeners wearing hearing protectors

摘要

A speech intelligibility model was developed and validated for use in workplace environments characterized by hazardous noise levels requiring the use of hearing protection devices(HPDs). The model takes into account the characteristics of the noise field,the signal-to-noise ratio (SNR),the attenuation of the device,and the hearing status of the listener.Good prediction of speech intelligibility scores in noise with HPDs required the use of correction factors to deal with both audibility(threshold)and distortion(supra threshold)effects arising from the hearing loss. Correction factors due to audibility effects were computed from the Speech Intelligibility Index and the pure-tone audiogram of the subjects.Correction factors due to distortion effects were based on the clinical Hearing-In-Noise Test.The model can be used in the context of two important applications of direct relevance to the military and industrial environments:(1)the optimal selection of hearing protectors,and(2)the establishment of hearing fitness standards for workers in hearing-critical jobs.