Measuring listening-related effort and fatigue in school-aged children using pupillometry

Stress and fatigue from effortful listening may compromise well-being, learning, and academic achievement in school-aged children. The aim of this study was to investigate the effect of a signal-to-noise ratio (SNR) typical of those in school classrooms on listening effort (behavioural and pupillometric) and listening-related fatigue (self-report and pupillometric) in a group of school-aged children. Forty-one normal-hearing children aged 8 – 11 years performed a narrative speech-picture verification task in a condition with recommended levels of background noise (‘ideal’; +15 dB SNR), and a condition with typical classroom background noise levels (‘typical’; -2 dB SNR). Participants showed increased task-evoked pupil dilation in the ‘typical’ versus the ‘ideal’ listening condition, consistent with an increase in listening effort. No differences were found between listening conditions in terms of performance accuracy and response time on the behavioural task. Similarly, no differences were found between listening conditions in self-report and pupillometric markers of listening-related fatigue. This is the first study to: (i) examine listening-related fatigue in children using pupillometry, and (ii) demonstrate physiological evidence consistent with increased listening effort while listening to spoken narratives, despite ceiling level task performance accuracy. Understanding of the physiological mechanisms that underpin listening-related effort and fatigue could inform intervention strategies and ultimately mitigate listening difficulties in children.