Older Adults’ Resting Oscillatory Alpha Power and Peak Frequency Track Fatigue Induced by a Listening Task

Objectives: Listening fatigue seems to reduce the quality of life for people with hearing loss. However, it has mostly been measured with subjective questionnaires. The present study investigates neural oscillatory activity in the resting electroencephalogram as a marker of the development of listening fatigue. It was hypothesized that alpha and theta power and subjective fatigue would increase after, compared with before, a challenging listening task, and that alpha peak frequency would decrease post-task. Design: Before and after completing an approximately hour-long task of listening to speech-in-noise, resting electroencephalogram in eyes-closed and eyes-open conditions and subjective fatigue ratings were collected from older adults with age-appropriate hearing abilities and healthy cognitive status (n = 41; 29 female; mean age: 69.22 years; range 50 to 85). Paired t tests were used to analyze pre- to post-task changes, and correlations were used to explore relations among variables. Results: Subjective fatigue on a visual-analogue scale increased post-task, indicating that the listening task induced the experience of fatigue. Alpha power increased post-task, whether eyes were open or closed. By contrast, numerical trends for theta power to increase post-task were not significant. In addition, peak alpha frequency decreased post-task. Exploratory analyses indicated a relation of the post-task increases in subjective fatigue and alpha power with eyes closed, and a relation of age and hearing ability to the extent of post-task reduction in peak alpha frequency. Disaggregating results by sex indicated stronger, more consistent trends for women than for men, both for the main effects of time-on-task on alpha power and for relations between oscillatory power and subjective fatigue. Conclusions: Alpha power and peak alpha frequency appear to be promising objective markers of the development of mental fatigue induced by challenging listening tasks in older adults.