Novel sounds as a psychophysiological measure of listening effort in older listeners with and without hearing loss

OBJECTIVE To investigate whether task-irrelevant novel sounds presented during an auditory task can provide information about the level of listening effort. METHODS Event-related potentials (ERPs) were recorded for novel sounds presented during two Experiments, a frequency discrimination task and a speech-perception-in-noise (SPIN) test, each with varying degrees of task difficulty (easy, medium, hard). Difficulty was adjusted to the individual frequency discrimination threshold and 50% speech recognition signal-to-noise ratio (SNR), respectively. Older listeners (age range 60-86 years) with either normal hearing for their age or a mild-to-moderate hearing loss participated. RESULTS Amplitudes of Novelty P3 and late positive potential (LPP) increased with increasing task difficulty, whereas amplitudes of N1 and N2 decreased. Participants with hearing loss had significantly larger LPP amplitudes in the easy condition of the SPIN test than did normal-hearing listeners. Most correlations between ERP amplitudes and behavioral data were not significant suggesting that listening effort is not a simple equivalent of behavioral performance. CONCLUSIONS LPP amplitude appeared to be the most sensitive component for capturing listening effort reflecting the arousal level of the listener. SIGNIFICANCE ERPs to novel sounds could be easily recorded during hearing tests and provide an objective physiological measure of listening effort, thus supplementing behavioral performance data.