Introduction: Cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome (CANVAS) is a recently described multisystem ataxia defined by the presence of cerebellar ataxia, bilateral vestibulopathy, and a somatosensory deficit. The characteristic clinical sign is an abnormal visually enhanced vestibuloocular reflex. The somatosensory deficit contributes to a significant level of disability in CANVAS.
Methods: This study was a neurophysiological investigation of 14 patients with CANVAS.
Results: Findings revealed uniformly absent sensory nerve action potentials in all limbs, abnormal blink reflexes in 13 of 14 patients, and abnormal masseter reflexes in 6 of 11 patients. Tibial H-reflexes were absent in 11 of 14 patients. Somatosensory evoked potentials were abnormal in 10 of the 11 patients tested, and brainstem auditory evoked responses were abnormal in 3 of 8. Cutaneous silent period responses were abnormal in 7 of 14 patients.
Conclusions: We suggest that a sensory neuronopathy should be sought in cerebellar and/or vestibular ataxias, particularly where the degree of ataxia is out of proportion to the clinically identified cerebellar and/or vestibular dysfunction.
Keywords: ataxia; cerebellar; ganglionopathy; neuronopathy; vestibular.
© 2014 Wiley Periodicals, Inc.