Effects of Aging Versus Noise Exposure on Auditory System in Individuals With Normal Audiometric Thresholds

Megha, Kondli Nagaraj; Kappadi, Suprabha; Kaverappa, Ganapathy Mechiyanda; Konadath, Sreeraj

doi:10.5152/iao.2021.8789

Cited by 7 publications

(10 citation statements)

References 33 publications

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“…Studies enrolling human participants in order to probe potential evidence of cochlear synaptopathy have followed several distinct approaches. The first of these approaches is enrollment of discrete groups differentiated by their history of a particular type of noise exposure ( Bramhall et al, 2017 ; Grose et al, 2017 ; Bal and Derinsu, 2021 ; Megha et al, 2021 ; Nam et al, 2021 ; Suresh and Krishnan, 2021 ). A second approach is the enrollment of diverse participants with varied amounts of lifetime noise exposures, with lifetime exposure at least roughly quantified using survey tools ( Prendergast et al, 2017a , b ; Valderrama et al, 2018 ; Marmel et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of hidden hearing loss in normal-hearing firearm users

Grinn

Prell²

2022

Front. Neurosci.

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Some noise exposures resulting in temporary threshold shift (TTS) result in cochlear synaptopathy. The purpose of this retrospective study was to evaluate a human population that might be at risk for noise-induced cochlear synaptopathy (i.e., “hidden hearing loss”). Participants were firearm users who were (1) at-risk for prior audiometric noise-induced threshold shifts, given their history of firearm use, (2) likely to have experienced complete threshold recovery if any prior TTS had occurred, based on this study’s normal-hearing inclusion criteria, and (3) not at-risk for significant age-related synaptopathic loss, based on this study’s young-adult inclusion criteria. 70 participants (age 18–25 yr) were enrolled, including 33 firearm users experimental (EXP), and 37 non-firearm users control (CNTRL). All participants were required to exhibit audiometric thresholds ≤20 dB HL bilaterally, from 0.25 to 8 kHz. The study was designed to test the hypothesis that EXP participants would exhibit a reduced cochlear nerve response compared to CNTRL participants, despite normal-hearing sensitivity in both groups. No statistically significant group differences in auditory performance were detected between the CNTRL and EXP participants on standard audiom to etry, extended high-frequency audiometry, Words-in-Noise performance, distortion product otoacoustic emission, middle ear muscle reflex, or auditory brainstem response. Importantly, 91% of EXP participants reported that they wore hearing protection either “all the time” or “almost all the time” while using firearms. The data suggest that consistent use of hearing protection during firearm use can effectively protect cochlear and neural measures of auditory function, including suprathreshold responses. The current results do not exclude the possibility that neural pathology may be evident in firearm users with less consistent hearing protection use. However, firearm users with less consistent hearing protection use are also more likely to exhibit threshold elevation, among other cochlear deficits, thereby confounding the isolation of any potentially selective neural deficits. Taken together, it seems most likely that firearm users who consistently and correctly use hearing protection will exhibit preserved measures of cochlear and neural function, while firearm users who inconsistently and incorrectly use hearing protection are most likely to exhibit cochlear injury, rather than evidence of selective neural injury in the absence of cochlear injury.

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Section: Introductionmentioning

confidence: 99%

Evaluation of hidden hearing loss in normal-hearing firearm users

Grinn

Prell²

2022

Front. Neurosci.

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“…Findings from animal models suggest that aging accelerates AN damage associated with environmental exposures (Fernandez et al, 2015). Despite these findings in animals, few studies have tested both the effects of age and noise exposure on AN response amplitudes in humans (Johannesen et al, 2019; Megha et al, 2021; Prendergast et al, 2019). Unfortunately, these studies did not include participants over the ages of 60 (Prendergast et al, 2019), 65 (Megha et al, 2021), and 68 (Johannesen et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

“…Despite these findings in animals, few studies have tested both the effects of age and noise exposure on AN response amplitudes in humans (Johannesen et al, 2019; Megha et al, 2021; Prendergast et al, 2019). Unfortunately, these studies did not include participants over the ages of 60 (Prendergast et al, 2019), 65 (Megha et al, 2021), and 68 (Johannesen et al, 2019). The results are also conflicting between studies, with one study finding an effect of both age and noise exposure history (Megha et al, 2021), another finding no effect of either age or noise exposure (Prendergast et al, 2019), and the last study finding an effect of age, but not noise exposure (similar to our own CAP study) (Johannesen et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

“…The large number of studies returned by these search queries (1,278 ABR, 223 CAP) were checked by three experts (authors Dias, Harris, and McClaskey) to confirm they matched our search criteria and further filtered to include only those studies that measured ABR WI or CAP N1 response amplitude and explicitly tested and reported the relationship between ABR WI or CAP N1 response amplitude and age or noise exposure. As a consequence, some studies that motivated our study were excluded from one or both meta-analyses for reporting the relationships of other metrics of AN function instead of ABR WI/CAP N1 response amplitude (e.g., Gómez-Álvarez et al, 2023;Johannesen et al, 2019) or for not providing descriptive or inferential statistics needed to calculate the effect size of the relationship between ABR WI/CAP N1 response amplitude and age or noise exposure history, typically for non-significant relationships (e.g., Maele et al, 2021;Megha et al, 2021;Prendergast et al, 2019;Ripley et al, 2022). The latter is important to consider because the mean effect size computed across studies may be biased by significant effects reported within published studies, providing an inflated mean effect size that is larger than the true population mean (Cumming, 2012;Rosenthal, 1991).…”

Section: Methodsmentioning

confidence: 99%

“…This is important because both increased age and noise exposure history are hypothesized to contribute to changes in ABR WI and CAP N1 response amplitudes. Most studies of noise-induced AN dysfunction have included participants in their 20s and 30s, few studies have included middle-aged and older adults, and among those, few test or control for age effects, and none test for interactions between the effects of age and noise exposure (Johannesen et al, 2019; Megha et al, 2021; Prendergast et al, 2019). A study of the effects of age and noise exposure history on AN response amplitudes within a single large sample can help disentangle how they each independently affect AN function and how they may interact to exacerbate AN dysfunction in older adults with a history of noise exposure.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of Age and Noise Exposure History on Auditory Nerve Response Amplitudes: A Systematic Review, Study, and Meta-Analysis

Dias,

McClaskey,

Alvey

et al. 2024

Preprint

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Auditory nerve (AN) function has been hypothesized to deteriorate with age and noise exposure. Here, we perform a systematic review of published studies and find that the evidence for age-related deficits in AN function is largely consistent across the literature, but there are inconsistent findings among studies of noise exposure history. Further, evidence from animal studies suggests that the greatest deficits in AN response amplitudes are found in noise-exposed aged mice, but a test of the interaction between effects of age and noise exposure on AN function has not been conducted in humans. We report a study of our own examining differences in the response amplitude of the compound action potential N1 (CAP N1) between younger and older adults with and without a self-reported history of noise exposure in a large sample of human participants (63 younger adults 18-30 years of age, 103 older adults 50-86 years of age). CAP N1 response amplitudes were smaller in older than younger adults. Noise exposure history did not appear to predict CAP N1 response amplitudes, nor did the effect of noise exposure history interact with age. We then incorporated our results into two meta-analyses of published studies of age and noise exposure history effects on AN response amplitudes in neurotypical human samples. The meta-analyses found that age effects across studies are robust (r=-0.407), but noise-exposure effects are weak (r=-0.138). We conclude that noise-exposure effects may be highly variable depending on sample characteristics, study design, and statistical approach, and researchers should be cautious when interpreting results. The underlying pathology of age-related and noise-induced changes in AN function are difficult to determine in living humans, creating a need for longitudinal studies of changes in AN function across the lifespan and histological examination of the AN from temporal bones collected post-mortem.

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