Factors Influencing Postural Instability in Bilateral Vestibulopathy.

BACKGROUND: Bilateral vestibulopathy (BVP) causes chronic postural instability refractory to treatments, leading to a reduced quality of life and increased risk of falls. However, the severity of postural instability varies considerably among individuals with BVP. OBJECTIVE: This study aimed to identify clinical factors associated with postural instability in patients with BVP. METHODS: Fifty-two patients with BVP (26 males, 26 females; mean age: 57.0±15.5 y) were enrolled. Associations between postural stability assessed by center of pressure (COP) velocity during posturography (4 conditions: eyes open, eyes closed, eyes open with foam rubber, and eyes closed with foam rubber) and clinical parameters were examined using the Spearman rank correlation. Extent of vestibular dysfunction was quantified as the number of abnormal vestibular end organs assessed by the video head impulse test and vestibular evoked myogenic potentials. Multiple regression analyses were performed to identify factors associated with COP velocity, including extent of vestibular dysfunction, Dizziness Handicap Inventory (DHI), and Hospital Anxiety and Depression Scale (HADS) scores. RESULTS: Correlation analyses of COP velocity measured under the 4 posturography conditions revealed significant positive correlations with age and the number of abnormal vestibular function tests. In contrast, no significant correlations were observed with illness duration, caloric test results, DHI, or HADS. Multiple regression analyses demonstrated that the number of abnormal vestibular function tests was the only factor significantly associated with COP velocity across all 4 posturography conditions. CONCLUSIONS: In patients with BVP, postural instability is positively correlated with the number of abnormal vestibular end organs. Conversely, demographic factors (age, sex), subjective level of disability (DHI score), and psychological status (HADS score) are weakly, if at all, correlated with postural instability.