Clinical, electrophysiological, and MRI findings in patients with cerebellar ataxia and a bilaterally pathological head-impulse test.

A significant number of patients with bilateral vestibulopathy suffer from cerebellar ataxia and central vestibular symptoms and vice versa. We examined 31 patients presenting with the combination of gait and stance ataxia, cerebellar ocular motor signs, and a bilaterally pathological head-impulse test (HIT). Tests included neuro-orthoptical examination, electromyography and neurography, caloric irrigation, pure-tone audiogram, vestibular-evoked myogenic potentials, and volumetric magnetic resonance imaging (MRI). Only 17 of 31 patients had a pathological caloric irrigation. Twenty-three patients had evidence of polyneuropathy (predominantly mixed sensorimotor involving axonal loss and demyelination) and twenty of hypoacusis (1 unilateral and 19 bilateral). Voxel-based morphometry comparing local gray matter brain volume between patients and controls revealed cerebellar atrophy involving both the vermis and the hemispheres. We conclude that there is a clinically relevant combination of cerebellar ataxia with cerebellar atrophy, bilaterally pathological HIT, polyneuropathy, and hypoacusis. This multisensory syndrome is most likely caused by a neurodegenerative disorder affecting different systems, leading to severe impairment of affected patients.