Effects of Recreational Noise on Threshold and Suprathreshold Measures of Auditory Function

Abstract

Noise exposure that causes a temporary threshold shift but no permanent threshold shift can cause degeneration of synaptic ribbons and afferent nerve fibers, with a corresponding reduction in wave I amplitude of the auditory brainstem response (ABR) in animals. This form of underlying damage, hypothesized to also occur in humans, has been termed , and it has been hypothesized that there will be a hidden hearing loss consisting of functional deficits at suprathreshold stimulus levels. This study assessed whether recreational noise exposure history was associated with smaller ABR wave I amplitude and poorer performance on suprathreshold auditory test measures. Noise exposure histories were collected from 26 men and 34 women with hearing thresholds ≤ 25 dB hearing loss (HL; 250 Hz to 8 kHz), and a variety of functional suprathreshold hearing tests were performed. Wave I amplitudes of click-evoked ABR were obtained at 70, 80, 90, and 99 dB (nHL) and tone-burst evoked ABR were obtained at 90 dB nHL. Speech recognition performance was measured in quiet and in competing noise, using the Words in Noise test, and the NU-6 word list in broadband noise (BBN). In addition, temporal summation to tonal stimuli was assessed in quiet and in competing BBN. To control for the effects of subclinical conventional hearing loss, distortion product otoacoustic emission amplitude, an indirect measure of outer hair cell integrity, was measured. There was no statistically significant relationship between noise exposure history scores and ABR wave I amplitude in either men or women for any of the ABR conditions. ABR wave I amplitude and noise exposure history were not reliably correlated with suprathreshold functional hearing tests. Taken together, this study found no evidence of noise-induced decreases in ABR wave I amplitude or signal processing in noise in a cohort of subjects with a history of recreational noise exposure.

Impaired speech perception in noise with a normal audiogram: No evidence for cochlear synaptopathy and no relation to lifetime noise exposure

“…However, its results accord with an existing body of literature that finds little evidence for relations of SPiN to noise exposure and AN function, or finds evidence that could reasonably be attributed to pathologies other than synaptopathy. Links between brainstem response measures and perceptual performance have been reported by some ( Bharadwaj et al., 2015 ; Liberman et al., 2016 ), but not others ( Bramhall et al., 2015 ; Fulbright et al., 2017 ). Reported relations of SPiN to occupational noise exposure are complicated by the possible influence of audiometric deficits ( Alvord, 1983 ; Kumar et al., 2012 ; Hope et al., 2013 ).…”

“… Fulbright et al. (2017) also recorded previous-12-months’ noise exposure, this time from 60 young, normally hearing participants.…”

Applicability of subcortical EEG metrics of synaptopathy to older listeners with impaired audiograms

“…For example, a study investigating how noise exposure history related to suprathreshold functional hearing and the ABR Wave-I amplitude did not find significant relations between the metrics. Following a similar approach, noise exposure history did not relate to the ABR Wave-I amplitude, or EFR measures, in young adults with and without tinnitus (Fulbright et al, 2017;Guest et al, 2017), or in 100 participants with normal audiometric thresholds (Prendergast et al, 2017). From the listed studies, we can either conclude that noiseinduced cochlear synaptopathy might not play an important role in young adults with normal audiometric hearing thresholds, or that the adopted electrophysiological measures are not sensitive enough to reveal subtle differences in neural fibre populations in this particular group (see Bramhall et al (2019) for an overview).…”

‘Normal’ hearing thresholds and fundamental auditory grouping processes predict difficulties with speech-in-noise perception

“…However, in humans, links between cochlear synaptopathy and electrophysiological measures have not been established (Hickox et al, 2017) and proposed measures of cochlear synaptopathy do not correlate well (Guest et al, 2019). Some studies relate poorer speech-in-noise performance to lower EFR (Bharadwaj et al, 2015; or lower ABR wave 1 (Bramhall et al, 2015) amplitudes, but others have found no evidence for an association with EFRs (Guest et al, 2018) or ABRs (Fulbright et al, 2017;Guest et al, 2018). These mixed results imply that either cochlear synaptopathy is not a prominent source of variability in speech-in-noise perception in humans, or we do not currently have a good way to assess it (see Guest et al, 2018).…”