Vestibular Damage due to Noise Exposure Leads to Significant Sensory Adaptations During Quiet Stance

Noise exposure (NE), while long implicated in loss of hearing, has only recently gained recognition as a cause of vestibular loss. Depending on the type of NE, damage may be acute or cumulative, uni- or bilateral. In the case of incomplete, bilateral damage, sensory reweighting adaptations may effectively conceal noise-induced vestibular damage. In this study we examined the effect of lifetime NE on postural sway. We assessed lifetime NE in 8 participants using the Noise Exposure Structured Interview, which is designed to quantify lifetime NE due to recreational, occupational, and firearm noise. Postural stability was assessed standing on a force plate, under four conditions: eyes open, firm surface; eyes closed, firm surface; eyes open, foam; and eyes closed, foam. While participants did not show differences in sway area or sway velocity while standing with their eyes open regardless of NE level, perturbing visual and proprioceptive feedback (eyes closed, foam) led to significant correlations between level of NE and: sway velocity (R2 = 0.75, p = 0.005) and total sway area (R2 = 0.65, p = 0.015). Additionally, removal of visual feedback alone (eyes close, firm surface) leads to a significant correlation between level of NE and sway area (ρ = 0.90, p = 0.005). Preliminary analyses suggest this latter relationship can be affected by fitness (timed-up-and-go time) and age. Taken with our prior findings on gravity perception tasks, these data strongly suggest that NE leads to significant vestibular damage that may go undiagnosed due to sensory substitution mechanisms.