Intrasubject variability in Potential Early Markers of Sensorineural Hearing Damage

Abstract

ABSTRACTThe quest for noninvasive early markers for sensorineural hearing loss (SNHL) has yielded diverse measures of interest. However, comprehensive studies evaluating the test-retest reliability of multiple measures and stimuli within a single study are scarce, and a standardized clinical protocol for robust early markers of SNHL remains elusive. To address these gaps, this study explores the intra-subject variability of various potential EEG-biomarkers for cochlear synaptopathy (CS) and other SNHL-markers in the same individuals. Fifteen normal-hearing young adults underwent repeated measures of (extended high-frequency) pure-tone audiometry, speech-in-noise intelligibility, distortion-product otoacoustic emissions (DPOAEs), and auditory evoked potentials; comprising envelope following responses (EFR) and auditory brainstem responses (ABR). Results confirm high reliability in pure-tone audiometry, whereas the matrix sentence-test exhibited a significant learning effect. The reliability of DPOAEs varied across three evaluation methods, each employing distinct SNR-based criteria for DPOAE-datapoints. EFRs exhibited superior test-retest reliability compared to ABR-amplitudes. Our findings underscore the necessity for cautious interpretation of presumed noninvasive SNHL measures. While tonal-audiometry’s robustness was corroborated, we observed a confounding learning effect in longitudinal speech audiometry. The variability observed in DPOAEs highlights the importance of consistent ear probe replacement and meticulous measurement techniques, suggesting that DP-thresholds may be less suitable for clinical application. As potential EEG-biomarkers of CS, EFRs are preferred over ABR-amplitudes based on the current study results.