Virtual reality-based visual vertical perception, fall risk, and vestibulo-ocular reflex evaluation in obstructive sleep apnea syndrome.

BackgroundIn obstructive sleep apnea syndrome (OSAS), intermittent hypoxia and oxygen desaturation resulting from recurrent apnea episodes may adversely affect vestibular function.ObjectiveThis study aimed to provide a multidimensional evaluation of vestibular function in individuals with OSAS by assessing objective and functional/subjective vestibulo-ocular reflex (VOR), visual perception, and fall risk.MethodsVideo Head Impulse Test (vHIT), functional Head Impulse Test (fHIT), Tinetti Balance and Gait Test, and static and dynamic subjective visual vertical and horizontal tests were administered to 22 individuals with moderate OSAS, 22 with severe OSAS, and 23 healthy controls aged 18-55 years.ResultsFall risk was significantly increased in both OSAS groups compared with controls. Dynamic visual perception and functional VOR performance were predominantly impaired in severe OSAS, whereas vHIT gains did not differ between groups. Tinetti scores were not associated with subjective visual perception but showed moderate-to-strong correlations with fHIT performance in moderate and severe OSAS.ConclusionsFall risk is increased in OSAS, and functional VOR deficits may occur despite normal vHIT findings, suggesting involvement of higher-level (central) vestibular processing and underscoring the need for comprehensive vestibular assessment.