Ronan Mcgarrigle

Listening effort and fatigue: what exactly are we measuring? A British Society of Audiology Cognition in Hearing Special Interest Group 'white paper'.

Abstract Objective: There is growing interest in the concepts of listening effort and fatigue associated with hearing loss. However, the theoretical underpinnings and clinical meaning of these concepts are unclear. This lack of clarity reflects both the relative immaturity of the field and the fact that research studies investigating listening effort and fatigue have used a variety of methodologies including self-report, behavioural, and physiological measures. Design: This discussion paper provides working definitions for listening effort and listening-related fatigue. Using these definitions as a framework, methodologies to assess these constructs are reviewed. Results: Although each technique attempts to characterize the same construct (i.e. the clinical presentation of listening effort and fatigue), different assumptions are often made about the nature of these phenomena and their behavioural and physiological manifestations. Conclusion: We suggest that researchers consider these assumptions when interpreting their data and, where possible, make predictions based on current theoretical knowledge to add to our understanding of the underlying mechanisms of listening effort and listening-related fatigue. Foreword Following recent interest in the cognitive involvement in hearing, the British Society of Audiology (BSA) established a Special Interest Group on Cognition in Hearing in May 2013. In an exploratory group meeting, the ambiguity surrounding listening effort and fatigue was discussed. To address this problem, the group decided to develop a ‘white paper’ on listening effort and fatigue. This is a discussion document followed by an international set of commentaries from leading researchers in the field. An approach was made to the editor of the International Journal of Audiology who agreed to this suggestion. This paper, and the associated commentaries that follow, are the result.

Pupillometry reveals changes in physiological arousal during a sustained listening task.

Hearing loss is associated with anecdotal reports of fatigue during periods of sustained listening. However, few studies have attempted to measure changes in arousal, as a potential marker of fatigue, over the course of a sustained listening task. The present study aimed to examine subjective, behavioral, and physiological indices of listening-related fatigue. Twenty-four normal-hearing young adults performed a speech-picture verification task in different signal-to-noise ratios (SNRs) while their pupil size was monitored and response times recorded. Growth curve analysis revealed a significantly steeper linear decrease in pupil size in the more challenging SNR, but only in the second half of the trial block. Changes in pupil dynamics over the course of the more challenging listening condition block suggest a reduction in physiological arousal. Behavioral and self-report measures did not reveal any differences between listening conditions. This is the first study to show reduced physiological arousal during a sustained listening task, with changes over time consistent with the onset of fatigue.

Behavioural measures of listening effort in school-aged children: Examining the effects of SNR, hearing loss, and amplification

Objectives: Increased listening effort in school-age children with hearing loss (CHL) could compromise learning and academic achievement. Identifying a sensitive behavioral measure of listening effort for this group could have both clinical and research value. This study examined the effects of signal-to-noise ratio (SNR), hearing loss, and personal amplification on 2 commonly used behavioral measures of listening effort: dual-task visual response times (visual RTs) and verbal response times (verbal RTs). Design: A total of 82 children (aged 6–13 years) took part in this study; 37 children with normal hearing (CNH) and 45 CHL. All children performed a dual-task paradigm from which both measures of listening effort (dual-task visual RT and verbal RT) were derived. The primary task was word recognition in multi-talker babble in three individually selected SNR conditions: Easy, Moderate, and Hard. The secondary task was a visual monitoring task. Listening effort during the dual-task was quantified as the change in secondary task RT from baseline (single-task visual RT) to the dual-task condition. Listening effort based on verbal RT was quantified as the time elapsed from the onset of the auditory stimulus to the onset of the verbal response when performing the primary (word recognition) task in isolation. CHL completed the task aided and/or unaided to examine the effect of amplification on listening effort. Results: Verbal RTs were generally slower in the more challenging SNR conditions. However, there was no effect of SNR on dual-task visual RT. Overall, verbal RTs were significantly slower in CHL versus CNH. No group difference in dual-task visual RTs was found between CNH and CHL. No effect of amplification was found on either dual-task visual RTs or verbal RTs. Conclusions: This study compared dual-task visual RT and verbal RT measures of listening effort in the child population. Overall, verbal RTs appear more sensitive than dual-task visual RTs to the negative effects of SNR and hearing loss. The current findings extend the literature on listening effort in the pediatric population by demonstrating that, even for speech that is accurately recognized, school-age CHL show a greater processing speed decrement than their normal-hearing counterparts, a decrement that could have a negative impact on learning and academic achievement in the classroom.