Integrating the acoustics of running speech into the pure tone audiogram: a step from audibility to intelligibility and disability.

BACKGROUND/AIMS The aim of the present study is to construct a simple method for visualizing and quantifying the audibility of speech on the audiogram and to predict speech intelligibility. The proposed method involves a series of indices on the audiogram form reflecting the sound pressure level distribution of running speech. The indices that coincide with a patient's pure tone thresholds reflect speech audibility and give evidence of residual functional hearing capacity. PATIENTS AND METHODS Two validation studies were conducted among sensorineurally hearing-impaired participants (n = 56 and n = 37, respectively) to investigate the relation with speech recognition ability and hearing disability. RESULTS The potential of the new audibility indices as predictors for speech reception thresholds is comparable to the predictive potential of the ANSI 1968 articulation index and the ANSI 1997 speech intelligibility index. The sum of indices or a weighted combination can explain considerable proportions of variance in speech reception results for sentences in quiet free field conditions. The proportions of variance that can be explained in questionnaire results on hearing disability are less, presumably because the threshold indices almost exclusively reflect message audibility and much less the psychosocial consequences of hearing deficits. CONCLUSION The outcomes underpin the validity of the new audibility indexing system, even though the proposed method may be better suited for predicting relative performance across a set of conditions than for predicting absolute speech recognition performance.