The overarching effects of vestibular deficit: Imbalance, anxiety, and spatial disorientation

Background: Comorbid Balance, Anxiety, and Spatial symptoms are observed in neurodevelopmental disorders and aging. Each of these symptoms was studied separately in association with vestibular hypofunction. We aimed to investigate whether such a diffuse range of symptoms has common vestibular pathophysiology. Specifically, we tested whether this Triad of dysfunctions is associated with central or peripheral vestibular hypofunction. We also assessed the possible contribution of semicircular canals (SCCs) vs. saccular function. Methods: We tested patients with Peripheral bilateral and unilateral Vestibular Hypofunction (PVH), Machado Joseph Disease (MJD) with cerebellar and central bilateral vestibular hypofunction, and healthy controls. SCCs and sacculi functioning were evaluated by the video Head Impulse Test (vHIT) and cervical Vestibular Evoked Myogenic Potentials (cVEMP), respectively. Balance was assessed by the Activities-specific Balance Confidence scale (ABC), anxiety by the Hamilton Anxiety Rating Scale (HAM-A), and spatial orientation by the Object Perspective Taking test (OPT-t). Results: PVH patients with vestibular SCCs and saccular hypofunction presented the Triad of symptoms, imbalance, anxiety, and spatial disorientation. MJD patients with SCCs-related vestibular hypofunction but preserved saccular-related vestibular function presented with a partial profile of imbalance and spatial disorientation. Conclusions: The present study provides evidence that peripheral vestibular hypofunction is associated with the Triad of dysfunctions, i.e., imbalance, anxiety, and spatial disorientation. The combination of SCCs and saccular hypofunction seems to contribute to the emergence of the Triad of symptoms.