Biology subjects

Devolder, P.

Publications and source records attributed to Devolder, P..

3 recordsLinked to original sources

bioRxiv2026

Auditory Profiles in Tinnitus are Age-Dependent: Electrophysiological and Behavioral Evidence

Tinnitus is commonly associated with hearing loss, yet it can also occur in individuals with clinically normal audiometric thresholds. This dissociation has led to the hypothesis that hidden sensorineural hearing loss underlies tinnitus in audiometrically normal-hearing individuals. However, identifying such subclinical deficits non-invasively is challenging because audiometric measures are influenced by age-related changes and interactions among sensorineural processes. In this study, we disentangled the contributions of tinnitus, age, and hearing status to sensorineural encoding and speech perception. We included 113 participants, divided into age- and hearing-status-matched groups with and without tinnitus, and assessed them using otoacoustic emissions, auditory evoked potentials, auditory reflex measurements, and behavioral tasks of speech perception. This design enabled a rigorous evaluation of whether hidden sensorineural deficits underlie tinnitus. Age and hearing status had substantial effects on objective measures of sensorineural function, whereas tinnitus-related effects were subtle and age specific. Young adults with tinnitus and normal audiometric thresholds exhibited enhanced auditory brainstem responses, elevated envelope following responses, and better vowel discrimination. In contrast, middle-aged adults with tinnitus showed no such enhancements and demonstrated poorer speech-in-noise performance. Correlation analyses revealed a tinnitus-related shift toward greater reliance on central auditory processing, compared with the predominantly peripheral associations observed in controls. The middle ear muscle reflex was unaffected by tinnitus but was correlated with hyperacusis-related parameters. Together, these findings suggest distinct tinnitus-related auditory profiles across the lifespan: neural enhancement and improved vowel discrimination in young adults, versus degraded sensorineural encoding and reduced speech intelligibility in middle-aged adults. Significance StatementTinnitus affects a significant portion of the population, yet its underlying origins are still unclear. While hearing loss is a common cause, individuals with tinnitus may also have normal hearing thresholds. This suggests that subtle sensorineural damage may also play a role. This study critically investigates tinnitus-, age-, and hearing-related sensorineural encoding using non-invasive electrophysiological measures, auditory reflexes, and speech perception tasks in carefully matched participant groups. The study reveals distinct tinnitus-related auditory profiles throughout the lifespan; including enhanced sensorineural processing in young adults and degraded encoding with impaired speech perception in middle-aged adults. These findings provide critical insight into the mechanisms underlying tinnitus and offer objective markers for future research on tinnitus diagnosis and treatment

neuroscience↗

bioRxiv2024

Age-related decline in neural phase-locking to envelope and temporal fine structure revealed by frequency following responses: A potential signature of cochlear synaptopathy impairing speech intelligibility

Assessing the contribution of cochlear synaptopathy (CS) to the variability in speech-in-noise intelligibility among individuals remains a challenge. While several studies have proposed biomarkers for CS based on neural phase-locking to the temporal envelope (ENV), fewer have investigated how CS affects the coding of temporal fine structure (TFS), despite its crucial role in speech-in-noise perception. In this study, we specifically examined whether TFS-based markers of CS could be derived from electrophysiological responses and psychophysical detection thresholds of spectral modulation (SM) in a complex tone, which serves as a parametric model of speech. We employed an integrated approach, combining psychophysical testing with frequency-following response (FFR) measurements in three groups of participants: young normal-hearing (yNH), older normal-hearing (oNH), and older hearing-impaired (oHI) individuals. We expanded on previous work by assessing phase-locking to both ENV, using a 4 kHz rectangular amplitude-modulated (RAM) tone, and TFS, using a low-frequency (<1.5 kHz) SM complex tone. Overall, FFR results showed significant reductions in neural phase-locking to both ENV and TFS components with age and hearing loss. Specifically, the strength of TFS-related FFRs, particularly the component corresponding to the harmonic closest to the peak of the spectral envelope ([~]500 Hz), was negatively correlated with age, even after adjusting for audiometric thresholds. This TFS marker also correlated with ENV-related FFRs derived from the RAM tone, suggesting a shared decline in phase-locking capacity across low and high cochlear frequencies. Computational simulations of the auditory periphery indicated that the observed FFR strength reduction with age is consistent with approximately 50% loss of auditory nerve fibers, aligning with histopathological data. However, the TFS-based FFR marker did not account for variability in speech intelligibility observed in the same participants. Psychophysical measurements showed no age-related effects and were unrelated to the TFS-based FFR marker, highlighting the need for further psychophysical research to establish a behavioral counterpart. Altogether, our results demonstrate that FFRs to vowel-like stimuli can serve as a complementary electrophysiological marker for assessing neural coding fidelity to stimulus TFS. This approach could provide a valuable tool for better understanding the impact of CS on an important coding dimension for speech-in-noise perception.

neuroscience↗

bioRxiv2024

The role of hidden hearing loss in tinnitus: insights from early markers of peripheral hearing damage

Since the presence of tinnitus is not always associated with audiometric hearing loss, it has been hypothesized that hidden hearing loss may act as a potential trigger for increased central gain along the neural pathway leading to tinnitus perception. In recent years, the study of hidden hearing loss has improved with the discovery of cochlear synaptopathy and several objective diagnostic markers. This study investigated three potential markers of peripheral hidden hearing loss in subjects with tinnitus: extended high-frequency audiometric thresholds, the auditory brainstem response, and the envelope following response. In addition, speech intelligibility was measured as a functional outcome measurement of hidden hearing loss. To account for age-related hidden hearing loss, participants were grouped according to age, presence of tinnitus, and audiometric thresholds. Group comparisons were conducted to differentiate between age- and tinnitus-related effects of hidden hearing loss. All three markers revealed age-related differences, whereas no differences were observed between the tinnitus and non-tinnitus groups. However, the older tinnitus group showed improved performance on low-pass filtered speech in noise tests compared to the older non-tinnitus group. These low-pass speech in noise scores were significantly correlated with tinnitus distress, as indicated using questionnaires, and could be related to the presence of hyperacusis. Based on our observations, cochlear synaptopathy does not appear to be the underlying cause of tinnitus. The improvement in low-pass speech-in-noise could be explained by enhanced temporal fine structure encoding or hyperacusis. Therefore, we recommend that future tinnitus research takes into account age-related factors, explores low-frequency encoding, and thoroughly assesses hyperacusis.

neuroscience↗