Correlations Between Multi-plane vHIT Responses and Balance Control After Onset of an Acute Unilateral Peripheral Vestibular Deficit

Objective: Previous studies reported that balance deficits in pitch (sagittal) and roll (lateral) planes during stance and gait after onset of an acute unilateral peripheral vestibular deficit (aUPVD) due to vestibular neuritis are weakly correlated with deficits in commonly explored lateral canal vestibular ocular reflex (VOR) responses. Theoretically, stronger correlations with roll and pitch balance deficits could be expected for vertical canal VOR responses. Therefore, we investigated these correlations. Setting: University Hospital. Study Design: Retrospective case review. Patients: Thirty three patients examined on average 5 days following onset of aUPVD. Main Outcome Measures: Video head impulse test (vHIT) VOR gains in each vertical canal plane were converted to roll and pitch response asymmetries and correlated with patients' roll and pitch balance control measured during stance and gait with body-worn gyroscopes mounted at lumbar 1 to 3. Results: Mean caloric canal paresis was 92 +/- 12%. Deficit side lateral vHIT mean gain was 0.4 +/- 0.12, anterior gain 0.44 +/- 0.18, and posterior gain, greater, 0.69 +/- 0.15. Lateral VOR response gain asymmetries (37.2 +/- 11.0%) were greater than roll VOR asymmetries calculated from all four vertical canal vHIT gains (16.2 +/- 10.2%, p < 0.0001) and correlated (R = 0.56, p = 0.002). Pitch gain VOR asymmetries were less (4.9 +/- 9.9%, p < 0.0001). All gait, but no stance, trunk roll angular velocity measures were correlated (p <= 0.03) with VOR roll asymmetries. Conclusions: This report links roll balance control deficits during gait with roll VOR deficits and emphasises the need to perform anterior canal vHIT to judge effects of an aUPVD on balance control. Pitch VOR asymmetries were weakly affected by vestibular neuritis.