Relation Between Listening Effort and Speech Intelligibility in Noise

Subjective ratings of listening effort might be applicable to estimate hearing difficulties at positive signal-to-noise ratios (SNRs) at which speech intelligibility scores are near 100%. Hence, ratings of listening effort were compared with speech intelligibility scores at different SNRs, and the benefit of hearing aids was evaluated. Two groups of listeners, 1 with normal hearing and 1 with hearing impairment, performed adaptive speech intelligibility and adaptive listening effort tests (Adaptive Categorical Listening Effort Scaling; Krueger, Schulte, Brand, & Holube, 2017) with sentences of the Oldenburg Sentence Test (Wagener, Brand, & Kollmeier, 1999a, 1999b; Wagener, Kühnel, & Kollmeier, 1999) in 4 different maskers. Model functions were fitted to the data to estimate the speech reception threshold and listening effort ratings for extreme effort and no effort. Listeners with hearing impairment showed higher rated listening effort compared with listeners with normal hearing. For listeners with hearing impairment, the rating extreme effort, which corresponds to negative SNRs, was more correlated to the speech reception threshold than the rating no effort, which corresponds to positive SNRs. A benefit of hearing aids on speech intelligibility was only verifiable at negative SNRs, whereas the effect on listening effort showed high individual differences mainly at positive SNRs. The adaptive procedure for rating subjective listening effort yields information beyond using speech intelligibility to estimate hearing difficulties and to evaluate hearing aids.