TY - JOUR
T1 - Associations Between Physiological Correlates of Cochlear Synaptopathy and Tinnitus in a Veteran Population
AU - Bramhall, Naomi F.
AU - Theodoroff, Sarah M.
AU - McMillan, Garnett P.
AU - Kampel, Sean D.
AU - Buran, Brad N.
N1 - Publisher Copyright:
© 2023 The Authors.
PY - 2023/11
Y1 - 2023/11
N2 - Purpose: Animal models and human temporal bones indicate that noise expo-sure is a risk factor for cochlear synaptopathy, a possible etiology of tinnitus. Veterans are exposed to high levels of noise during military service. Therefore, synaptopathy may explain the high rates of noise-induced tinnitus among Vet-erans. Although synaptopathy cannot be directly evaluated in living humans, animal models indicate that several physiological measures are sensitive to syn-apse loss, including the auditory brainstem response (ABR), the middle ear muscle reflex (MEMR), and the envelope following response (EFR). The purpose of this study was to determine whether tinnitus is associated with reductions in physiological correlates of synaptopathy that parallel animal studies. Method: Participants with normal audiograms were grouped according to Veteran status and tinnitus report (Veterans with tinnitus, Veterans without tinnitus, and non-Veteran controls). The effects of being a Veteran with tinnitus on ABR, MEMR, and EFR measurements were independently modeled using Bayesian regression analysis. Results: Modeled point estimates of MEMR and EFR magnitude showed reductions for Veterans with tinnitus compared with non-Veterans, with the most evident reduction observed for the EFR. Two different approaches were used to provide context for the Veteran tinnitus effect on the EFR by comparing to age-related reductions in EFR magnitude and synapse numbers observed in previous studies. These analyses suggested that EFR magnitude/synapse counts were reduced in Veterans with tinnitus by roughly the same amount as over 20 years of aging. Conclusion: These findings suggest that cochlear synaptopathy may contribute to tinnitus perception in noise-exposed Veterans.
AB - Purpose: Animal models and human temporal bones indicate that noise expo-sure is a risk factor for cochlear synaptopathy, a possible etiology of tinnitus. Veterans are exposed to high levels of noise during military service. Therefore, synaptopathy may explain the high rates of noise-induced tinnitus among Vet-erans. Although synaptopathy cannot be directly evaluated in living humans, animal models indicate that several physiological measures are sensitive to syn-apse loss, including the auditory brainstem response (ABR), the middle ear muscle reflex (MEMR), and the envelope following response (EFR). The purpose of this study was to determine whether tinnitus is associated with reductions in physiological correlates of synaptopathy that parallel animal studies. Method: Participants with normal audiograms were grouped according to Veteran status and tinnitus report (Veterans with tinnitus, Veterans without tinnitus, and non-Veteran controls). The effects of being a Veteran with tinnitus on ABR, MEMR, and EFR measurements were independently modeled using Bayesian regression analysis. Results: Modeled point estimates of MEMR and EFR magnitude showed reductions for Veterans with tinnitus compared with non-Veterans, with the most evident reduction observed for the EFR. Two different approaches were used to provide context for the Veteran tinnitus effect on the EFR by comparing to age-related reductions in EFR magnitude and synapse numbers observed in previous studies. These analyses suggested that EFR magnitude/synapse counts were reduced in Veterans with tinnitus by roughly the same amount as over 20 years of aging. Conclusion: These findings suggest that cochlear synaptopathy may contribute to tinnitus perception in noise-exposed Veterans.
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U2 - 10.1044/2023_JSLHR-23-00234
DO - 10.1044/2023_JSLHR-23-00234
M3 - Article
C2 - 37889209
AN - SCOPUS:85176509370
SN - 1092-4388
VL - 66
SP - 4635
EP - 4652
JO - Journal of Speech, Language, and Hearing Research
JF - Journal of Speech, Language, and Hearing Research
IS - 11
ER -