Effects of noise exposure on auditory brainstem response and speech-in-noise tasks: a review of the literature

Abstract

Objective: Short-term noise exposure that induces transient changes in thresholds has induced permanent cochlear synaptopathy in multiple species. Here, the literature was reviewed to gain translational insight into the relationships between noise exposure, ABR metrics, speech-in-noise performance and TTS in humans. Design: PubMed-based literature search, retrieval and review of full-text articles. Study Sample: Peerreviewed literature identified using PubMed search. Results: Permanent occupational noise-induced hearing loss (NIHL) is frequently accompanied by abnormal ABR amplitude and latency. In the absence of NIHL, there are mixed results for relationships between noise exposure and ABR metrics. Interpretation of speech-in-noise deficits is difficult as both cochlear synaptopathy and outer hair cell (OHC) loss can drive deficits. Reductions in Wave I amplitude during TTS may reflect temporary OHC pathology rather than cochlear synaptopathy. Use of diverse protocols across studies reduces the ability to compare outcomes across studies. Conclusions: Longitudinal ABR and speech-in-noise data collected using consistent protocols are needed. Although speech-in-noise testing may not reflect cochlear synaptopathy, speech-in-noise testing should be completed as part of a comprehensive test battery to provide the objective measurement of patient difficulty.

Effects of age on electrophysiological measures of cochlear synaptopathy in humans

“…Although the results of this single study do not exclude the possibility of small or moderate effects of noise exposure on ABR measures (e.g. the CIs are compatible with wave amplitude reductions of ~ 10% for a tenfold increase in lifetime noise exposure), they add to the results of the majority of studies on the topic, that have failed to find an effect of lifetime noise exposure on ABR amplitude and latency measures (see Bramhall, Beach, Epp, Le Prell, Lopez-Poveda, Plack, Schaette, Verhulst, Canlon, 2019 , Le Prell, 2019 , for reviews).…”

An overview of occupational noise-induced hearing loss among workers: epidemiology, pathogenesis, and preventive measures

“…Along with the degeneration of cochlear nerve fibers, there is simultaneous degeneration within the central nervous system [ 30 ]. Because hair cells in mammalian species do not regenerate, once hair cells are destroyed, ONIHL is present permanently, regardless of the pathway of hair cell destructions [ 85 ].…”

The search for noise-induced cochlear synaptopathy in humans: Mission impossible?

“…Using ABR wave I amplitude as an indicator of synaptopathy is further complicated by the fact that high frequency OHC loss also reduces the wave I ABR amplitude by decreasing the contribution of high frequency AN fibers to the ABR generation (e.g., Lewis et al 2015;Verhulst et al 2016). In addition, it must be remembered that the OHCs provide significant level-dependent amplification of the cochlear response, and loss of the OHCs decreases the input to the IHCs (Dallos et al 2006; for recent review see Le Prell 2019). This makes it difficult to use ABR wave I amplitude to diagnose synaptopathy when OHC dysfunction is also present.…”