The pursuit of 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 SNHL-markers remains elusive. To address these gaps, this study covers the intra-subject variability of potential EEG-biomarkers for cochlear synaptopathy (CS) and other SNHL-markers to determine their clinical suitability. 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 show high reliability in pure-tone audiometry, whereas the matrix sentence-test showed a significant learning effect. DP-grams and input-output functions' reliability varied across three evaluation methods with distinct SNR-based criteria for DPOAE-datapoints. EFRs demonstrated superior test-retest reliability compared to ABR-amplitudes. Our findings underscore careful interpretation of presumed noninvasive SNHL measures. While we confirm the robustness of tonal-audiometry, we found a confounding learning effect in longitudinal speech audiometry. DPOAE variability underscores the need for consistent ear probe replacement and meticulous measurement techniques and renders I/O-functions unsuitable for clinical application. As potential EEG-biomarkers of CS, EFRs are favored over ABR-amplitudes.

The authors have declared no competing interest.

This work was supported by UGent BOF-IOP project: Portable Hearing Diagnostics: Monitoring of Auditory-nerve Integrity after Noise Exposure (EarDiMon), European research counsil proof of concept grant CochSyn (899858) and EU Innovation counsil Grant EarDiTech (101058278).

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Ethics committee of Ghent University Hospital gave ethical approval for this work.

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