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.

Hearing loss is associated with poor cognitive performance and incident dementia and may contribute to cognitive decline. Treating hearing loss with hearing aids may ameliorate cognitive decline. The purpose of this study was to test whether use of hearing aids was associated with better cognitive performance, and if this relationship was mediated via social isolation and/or depression. Structural equation modelling of associations between hearing loss, cognitive performance, social isolation, depression and hearing aid use was carried out with a subsample of the UK Biobank data set (n = 164,770) of UK adults aged 40 to 69 years who completed a hearing test. Age, sex, general health and socioeconomic status were controlled for as potential confounders. Hearing aid use was associated with better cognition, independently of social isolation and depression. This finding was consistent with the hypothesis that hearing aids may improve cognitive performance, although if hearing aids do have a positive effect on cognition it is not likely to be via reduction of the adverse effects of hearing loss on social isolation or depression. We suggest that any positive effects of hearing aid use on cognition may be via improvement in audibility or associated increases in self-efficacy. Alternatively, positive associations between hearing aid use and cognition may be accounted for by more cognitively able people seeking and using hearing aids. Further research is required to determine the direction of association, if there is any direct causal relationship between hearing aid use and better cognition, and whether hearing aid use results in reduction in rates of cognitive decline measured longitudinally.

Objectives: Listening effort can be defined as the cognitive resources required to perform a listening task. The literature on listening effort is as confusing as it is voluminous: measures of listening effort rarely correlate with each other and sometimes result in contradictory findings. Here, we directly compared simultaneously recorded multimodal measures of listening effort. After establishing the reliability of the measures, we investigated validity by quantifying correlations between measures and then grouping-related measures through factor analysis. Design: One hundred and sixteen participants with audiometric thresholds ranging from normal to severe hearing loss took part in the study (age range: 55 to 85 years old, 50.3% male). We simultaneously measured pupil size, electroencephalographic alpha power, skin conductance, and self-report listening effort. One self-report measure of fatigue was also included. The signal to noise ratio (SNR) was adjusted at 71% criterion performance using sequences of 3 digits. The main listening task involved correct recall of a random digit from a sequence of six presented at a SNR where performance was around 82 to 93%. Test–retest reliability of the measures was established by retesting 30 participants 7 days after the initial session. Results: With the exception of skin conductance and the self-report measure of fatigue, interclass correlation coefficients (ICC) revealed good test–retest reliability (minimum ICC: 0.71). Weak or nonsignificant correlations were identified between measures. Factor analysis, using only the reliable measures, revealed four underlying dimensions: factor 1 included SNR, hearing level, baseline alpha power, and performance accuracy; factor 2 included pupillometry; factor 3 included alpha power (during speech presentation and during retention); factor 4 included self-reported listening effort and baseline alpha power. Conclusions: The good ICC suggests that poor test reliability is not the reason for the lack of correlation between measures. We have demonstrated that measures traditionally used as indicators of listening effort tap into multiple underlying dimensions. We therefore propose that there is no “gold standard” measure of listening effort and that different measures of listening effort should not be used interchangeably. When choosing method(s) to measure listening effort, the nature of the task and aspects of increased listening demands that are of interest should be taken into account. The findings of this study provide a framework for understanding and interpreting listening effort measures.