A Study on Cochlear Synaptic Damage in Normal Hearing Individuals Exposed to Occupational Noise

WANG Pian; MAO Hangzhe; PENG Da; ZHENG Shukun; ZHAO Wulan

doi:10.3969/j.issn.1672-2922.2024.01.017

Abstract：Objective To identify audiological assessment methods effective in detecting cochlear synaptic dam-age in normal hearing population exposed to occupational noise for further study of this condition.Methods Individu-als undergoing routine health examination at the Zhejiang Traditional Chinese Medicine University from April 2021 to April 2022(n=104,104 ears)were recruited and grouped based on their noise exposure history,including among 52 fac-tory workers exposed to high intensity noise(noise-exposed group)and 52 controls.Pure tone audiometry(PTA)thresh-olds,speech in noise(SIN),distortion product otoacoustic emissions(DPOAEs)and speech-evoked auditory brainstem responses(s-ABRs)were collected and compared between the two groups,and the correlation among the tests analyzed.Results PTA thresholds over 9-16 kHz were better in the control group than in the noise-exposed group(P<0.01).Sig-nal/noise ratio loss in SIN was greater in the noise-exposed group than in the control group(P<0.05).DPOAE differenc-es between the two groups were statistically significant for 4-10 kHz(P<0.05).Differences in latencies of s-ABR waves V,Aand O(P<0.01),V/A slope(P<0.05),and F1 amplitude(P<0.05)were also statistically significant between the two groups.PTAEHF and D wave latency were negatively correlated with DPmean.Latencies of all waves,except wave E,were negatively correlated with V/A slope.Conclusion Potential cochlear synaptic damage caused by occupational noise exposure can be manifested as elevated PTAEHF,deteriorated SNR in DPOAEs,deteriorated SIN performance,and delayed s-ABR latencies.Multimodality assessment can improve the accuracy of detection for timely intervention.