What they found
TL;DR (qwen3.6:35b): This study found that while neural responses to speech envelopes decline with age and hearing loss, behavioral discrimination of fine-structure cues worsens even when those neural responses remain stable. The authors suggest that combining electrophysiological and behavioral measures offers a sensitive framework for detecting hidden hearing loss before clinical thresholds change.
Speech perception difficulties in noise are common among older adults and individuals with hearing impairment, but also among younger adults whose audiometric thresholds are within the clinically-normal range. We examined how aging, cochlear synaptopathy (CS), and outer hair cell (OHC) damage affect speech encoding and phoneme discrimination. Envelope-following responses (EFRs) to rectangular amplitude-modulated (RAM) tones and speech-like phoneme pairs were recorded in quiet using EEG, and behavioral discrimination was assessed in quiet, ipsilateral, and contralateral noise. Stimuli were designed to target temporal envelope (TENV) or temporal fine structure (TFS) encoding. Results showed that RAM-EFR amplitudes decreased gradually with increasing age, consistent with emerging CS, while magnitudes of high-frequency TENV-based EFRs in quiet were most reduced in older hearing-impaired subjects with combined CS and OHC damage. In contrast, EFRs targeting low-frequency TENV encoding in quiet remained preserved. Behaviorally, discrimination of predominantly TFS-based phoneme contrasts worsened with OHC loss and age in quiet and contralateral noise, respectively, whereas discrimination of predominantly TENV-based contrasts showed no significant age effect. Considering that high-frequency contrasts are discriminated via place-based spectral cues, low-frequency contrasts rely on TFS, and the EFR reflects primarily TENV, this framework explains why EFRs decline for high-frequency cues without perceptual loss, while EFRs remain stable for low-frequency cues even as TFS-based discrimination deteriorates. These findings highlight the need to further investigate how neural coding deficits relate to perception. Combining electrophysiological and behavioral measures might provide a sensitive framework for detecting subclinical auditory deficits to earlier diagnose age-related and hidden hearing loss.
How this applies to our program
This paper is relevant to the STRC/DFNB16 program because it investigates cochlear synaptopathy (CS), the loss of synapses between inner hair cells and auditory nerve fibers, which is the primary pathological mechanism underlying STRC/DFNB16-related hearing loss. Understanding how CS affects speech encoding in noise provides a critical functional context for the sensory deficits caused by STRC mutations.
Key numbers
- EFR amplitudes decreased gradually with increasing age
- High-frequency TENV-based EFRs were most reduced in subjects with combined CS and OHC damage
- Discrimination of TFS-based phoneme contrasts worsened with OHC loss and age
Links
- biorxiv_id: https://www.biorxiv.org/content/10.64898/2026.01.27.702044
- DOI: https://doi.org/10.64898/2026.01.27.702044
Connections
[source]auto-indexed 2026-06-02 by strc-lit-watch