Neural indices of listening effort in noisy environments

Andrew Dimitrijevic,Darren S Kadis,Michael L Smith,David R Moore

doi:10.1038/s41598-019-47643-1

Abstract

Listening in a noisy environment is challenging for individuals with normal hearing and can be a significant burden for those with hearing impairment. The extent to which this burden is alleviated by a hearing device is a major, unresolved issue for rehabilitation. Here, we found adult users of cochlear implants (CIs) self-reported listening effort during a speech-in-noise task that was positively related to alpha oscillatory activity in the left inferior frontal cortex, canonical Broca’s area, and inversely related to speech envelope coherence in the 2–5 Hz range originating in the superior-temporal plane encompassing auditory cortex. Left frontal cortex coherence in the 2–5 Hz range also predicted speech-in-noise identification. These data demonstrate that neural oscillations predict both speech perception ability in noise and listening effort.

Highlights

Listening in a noisy environment is challenging for individuals with normal hearing and can be a significant burden for those with hearing impairment
All the Digits in Noise Test (DIN) stimuli for the electrophysiological recordings were presented at a digit signal-to-noise ratio (SNR) corresponding to the individual’s speech reception threshold (SRT)
Three novel findings were observed: (1) left frontal inferior frontal gyrus (IFG) alpha power was positively associated with listening effort; (2) speech envelope auditory cortex coherence in the 2–5 Hz range was negatively associated with listening effort; (3) accuracy of speech identification was positively associated with envelope speech-brain coherence in the left frontal cortex

Summary

Introduction

Listening in a noisy environment is challenging for individuals with normal hearing and can be a significant burden for those with hearing impairment. We found adult users of cochlear implants (CIs) self-reported listening effort during a speech-in-noise task that was positively related to alpha oscillatory activity in the left inferior frontal cortex, canonical Broca’s area, and inversely related to speech envelope coherence in the 2–5 Hz range originating in the superior-temporal plane encompassing auditory cortex. Left frontal cortex coherence in the 2–5 Hz range predicted speechin-noise identification These data demonstrate that neural oscillations predict both speech perception ability in noise and listening effort. The common feature of these studies is that effortful listening was associated with recruitment of primary auditory cortex, the canonical language network (left perisylvian regions, including Broca’s and Wernicke’s areas), and extracanonical regions involved in language processes[9]. Decreases in temporal-lobe alpha, related to auditory cortex activation, have been observed during speech perception in noise and were a better predictor of speech identification than parietally-generated alpha[12]

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