The influence of momentary listening effort on accumulated fatigue

People with hearing impairment report listening fatigue as a major barrier to social communication, but most investigations examine momentary effort without establishing its connection to longer-term fatigue. In this study, listeners completed a 60-min sentence-repetition task with an easy condition (intact sentences) or an effortful condition (sentences that demanded mentally repairing missing words). Pre- versus post-listening tasks were used to measure fatigue, including (1) reaction times, (2) verbal creativity, and (3) subjective report. During listening, tonic changes in pupil dilation, verbal reaction times, and repetition accuracy were measured. We hypothesize that repeated moments of effortful listening result in slower decay in pupil size as well as reduced verbal creativity, and increased reaction times in the later parts of the testing block. Conversely, listeners who hear only easy intact sentences are expected to have equivalent performance before and after the testing block. A lack of differences across conditions would contradict the notion that fatigue is a linear product of repeated moments of elevated effort. The value of effects shown in this paradigm will be to demonstrate the impact of fatigue on other concurrent abilities beyond speech perception.