Hearing acuity and need for recovery affect time-on-task effects on psychophysiological activity during listening

Hard-of-hearing individuals experience increased levels of fatigue and listening effort. In experimental settings, psychophysiological responses to auditory demand manipulations are considered to be influenced by listening effort. This study investigated the effects of hearing acuity and occupational need-for-recovery (NFR) on trial-level psychophysiological activity during speech perception. A total of 125 normal hearing and hard-of-hearing participants (88 females and 37 males, 37-72 years old) completed speech reception threshold tasks. Outcome measures included baseline pupil size (BPS), mean pupil dilation (MPD), skin conductance response (SCR) amplitudes, and respiratory sinus arrhythmia (RSA). First, the interaction between time-on-task and hearing acuity was analyzed for the outcome measures. A second analysis included a subsample of 82 participants and tested for interactions between NFR, time-on-task, and hearing acuity. Overall, BPS, MPD, and SCR amplitude decreased over time-on-task, whereas RSA increased, as expected. Higher NFR showed contradicting effects on BPS and MPD: if hearing acuity was better, higher NFR was associated with a decrease in the pupil measures, but vice versa if hearing acuity was worse. Participants with worse hearing combined with higher NFR showed a relatively stable BPS and SCR amplitude over time-on-task, indicative of (preparatory) compensatory activity. Additionally, RSA increased with worse hearing in the employed subsample, but was not sensitive to NFR. The effects of NFR, specifically on the pupil measures, were strongest in those with poorer hearing suggesting higher vulnerability to daily life fatigue.