Pupillometry reveals a more sustained pattern of effortful listening in older adults

Abstract

Listening to speech in adverse conditions can be challenging and effortful, especially for older adults (OAs). This study examinedage-related differences in effortful listening by recording changes in the task-evoked pupil response (TEPR; a physiological marker of listening effort) both at the level of sentence processing and over the entire course of a listening task.A total of 65 (32 young adults; 27 older adults) participants performed a speech recognition task in thepresence of a competing talker,while moment-to-moment changes in pupil size were continuously monitored. Participants were also administered the Vanderbilt Fatigue Scale; a questionnaire assessing daily life listening fatiguewithin four domains (social, cognitive, emotional, physical).Normalised TEPRs were overall larger and more steeply rising and falling around the peakin OAs versusyoung adults(YAs)during sentence processing. Additionally, mean TEPRsover the course of the listening taskwere more stable in the OA versus the YA group, consistent with a more sustainedrecruitment of compensatory attentional resources to maintain task performance. No age-related differences were found in terms of total daily life listening fatigue; however, OAs reported higherscoresthan YAswithinthe social domain. Overall, this study provides evidence for qualitatively distinct patternsof physiological arousal during effortful listening between OAs and YAs which broadly supports age-related neuralcompensation hypotheses.A more detailed understanding of age-related changes in the subjective and physiological mechanisms that underlieeffortful listening will ultimately help to address complex communication needs in ageing listeners.