Intrasubject variability in potential early markers of sensorineural hearing damage

Area of Science:

• Auditory Neuroscience
• Audiology
• Biomarker Discovery

Background:

• Noninvasive early markers for sensorineural hearing loss (SNHL) are needed, but studies evaluating test-retest reliability of multiple measures are scarce.
• A standardized clinical protocol for robust early SNHL markers is currently elusive.
• Cochlear synaptopathy (CS) is an early indicator of SNHL, necessitating reliable detection methods.

Purpose of the Study:

• To explore the intra-subject variability of potential electroencephalogram (EEG) biomarkers for CS and other SNHL markers.
• To compare the test-retest reliability of various auditory measures in normal-hearing young adults.
• To identify robust, noninvasive markers for early SNHL detection.

Main Methods:

• Fifteen normal-hearing young adults participated in repeated measures.
• Evaluated measures included extended high-frequency pure-tone audiometry, speech-in-noise intelligibility, distortion-product otoacoustic emissions (DPOAEs), envelope following responses (EFRs), and auditory brainstem responses (ABRs).
• Analyzed intra-subject variability and test-retest reliability across different measurement techniques and criteria.

Main Results:

• Pure-tone audiometry demonstrated high reliability.
• Speech-in-noise testing showed a significant learning effect.
• Distortion-product otoacoustic emissions (DPOAEs) reliability varied based on signal-to-noise ratio (SNR) criteria and measurement conditions.
• Envelope following responses (EFRs) exhibited superior test-retest reliability compared to auditory brainstem response (ABR) amplitudes.

Conclusions:

• Careful interpretation of noninvasive SNHL measures is crucial.
• Tonal audiometry is robust, but speech audiometry has a confounding learning effect.
• DPOAE reliability is sensitive to measurement techniques and ear probe consistency.
• EFRs are preferable to ABR amplitudes as potential EEG biomarkers for cochlear synaptopathy based on this study's findings.