Supra-threshold auditory brainstem response amplitudes in humans: Test-retest reliability, electrode montage and noise exposure

Wenhe Tu,Christopher J Plack,Rebecca E Millman,Hannah Guest,Garreth Prendergast,Samuel Couth,Karolina Kluk,Kevin J Munro

doi:10.1016/j.heares.2018.04.002

Abstract

The auditory brainstem response (ABR) is a sub-cortical evoked potential in which a series of well-defined waves occur in the first 10 ms after the onset of an auditory stimulus. Wave V of the ABR, particularly wave V latency, has been shown to be remarkably stable over time in individual listeners. However, little attention has been paid to the reliability of wave I, which reflects auditory nerve activity. This ABR component has attracted interest recently, as wave I amplitude has been identified as a possible non-invasive measure of noise-induced cochlear synaptopathy. The current study aimed to determine whether ABR wave I amplitude has sufficient test-retest reliability to detect impaired auditory nerve function in an otherwise normal-hearing listener. Thirty normal-hearing females were tested, divided equally into low- and high-noise exposure groups. The stimulus was an 80 dB nHL click. ABR recordings were made from the ipsilateral mastoid and from the ear canal (using a tiptrode). Although there was some variability between listeners, wave I amplitude had high test-retest reliability, with an intraclass correlation coefficient (ICC) comparable to that for wave V amplitude. There were slight gains in reliability for wave I amplitude when recording from the ear canal (ICC of 0.88) compared to the mastoid (ICC of 0.85). The summating potential (SP) and ratio of SP to wave I were also quantified and found to be much less reliable than measures of wave I and V amplitude. Finally, we found no significant differences in the amplitude of any wave components between low- and high-noise exposure groups. We conclude that, if the other sources of between-subject variability can be controlled, wave I amplitude is sufficiently reliable to accurately characterize individual differences in auditory nerve function.

Highlights

The auditory brainstem response (ABR) is a well-established diagnostic tool widely used in the clinic to assess auditory function
The ABR is evoked by transient stimuli, typically clicks or tone bursts, and consists of a series of waves, with wave I reflecting auditory nerve function, and wave V resulting from generators in the rostral brainstem
At medium-tohigh sound intensities there was a permanent reduction in the amplitude of wave I of the ABR, reflecting decreased auditory nerve activity. These results suggest that wave I of the ABR might have potential as a non-invasive measure of cochlear synaptopathy in human listeners

Summary

Introduction

The auditory brainstem response (ABR) is a well-established diagnostic tool widely used in the clinic to assess auditory function (see Hall, 1992, for an overview). The ABR is evoked by transient stimuli, typically clicks or tone bursts, and consists of a series of waves, with wave I reflecting auditory nerve function, and wave V resulting from generators in the rostral brainstem. The threshold and latency of wave V are the most common clinical metrics of the response. Wave I amplitude has attracted considerable interest recently, following the demonstration of noise-induced cochlear synaptopathy in the mouse model by Kujawa and Liberman (2009). In the base of the cochlea, up to 50% of synapses between inner hair cells and auditory nerve fibers were destroyed after a 2-hour exposure to 100 dB SPL noise

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