In patients with bilateral vestibular hypofunction (BVH), the outcome of vestibular rehabilitation is mixed. The aim of the study was to identify factors associated with outcome of vestibular rehabilitation (VR) in patients with BVH. A retrospective case notes review identified 69 patients diagnosed with BVH over a five-year period. BVH was diagnosed using bithermal caloric and rotatory chair testing. The outcome measures were visual blurring (oVAS), disequilibrium (dysVAS), dizziness induced by head movement (hmVAS), balance confidence scale (ABC), Disability Score, Quality of Life (TSI), Dynamic Visual Acuity (DVA), Dynamic Gait Index (DGI) and gait speed.
As a group, improvement in all outcome measures except for Disability Score was identified. However the degree of improvement varied widely in individual patients (37.5% to 87.5%).
Not all patients improved; in fact some had worse scores after VR. Several factors measured at baseline identiﬁed as potential factors associated with rehabilitation outcome included age, DGI, gait speed and intensity of disequilibrium. Older patients improved more than younger patients probably because of worse scores at baseline. Older patients had higher DVA scores at discharge. Lower (poorer) initial DGI scores were related to higher Disability scores at discharge. Initial gait speed correlated with DGI and gait speed at discharge which may be a reflection of the walking speed criteria that are part of the DGI score. As expected VR outcome was poorer in BVH compared with unilateral vestibular hypofunction. This study provides some guidance on prognosis of VR in BVF. Would the results be different if the definition of BVF was not based only on lateral semicircular function but on the function of all five vestibular receptors?