Hearing Loss Alters Neural Activation Patterns Of Cognitive-motor Control During Gait In Older Adults

Background

Age-related hearing loss has been linked to declines in both cognition and mobility, yet the neural mechanisms underlying this relationship remain unexplored. This study examined gait performance, cognitive function, and cortical activation during single-task (ST) and dual-task (DT) walking.

Methods

This cross-sectional study examined 63 participants across three groups: young adults with normal hearing (YNH; 30–40 years; n=24), older adults with normal hearing (ONH; 60–70 years; n=20), and older adults with hearing impairment (OHI; 60–70 years; n=19). Gait speed and variability were assessed using wearable inertial sensors, cognitive function using the NIH Toolbox battery, and cortical activation using 40-channel functional near-infrared spectroscopy (fNIRS) over bilateral prefrontal and motor regions.

Results

The OHI group demonstrated the slowest gait speed and the greatest dual-task cost for gait speed (30.14% ± 12.74), along with a selective increase in gait speed variability under DT conditions not observed in the other groups. Neurally, OHI exhibited elevated prefrontal activation during ST walking across multiple regions of interest relative to ONH, yet showed a paradoxical widespread decrease in activation from ST to DT, consistent with a neural resource ceiling effect. A progressive gradient of ST neural-gait coupling was observed, indicating loss of gait automaticity. Hierarchical regression revealed a lateralized dorsolateral prefrontal cortex trade-off unique to OHI, predicting opposing gait outcomes.

Conclusion

These findings suggest that hearing loss fundamentally alters the neural organization of cognitive-motor control, supporting its role as a modifiable risk factor for mobility decline and falls.