Objective: To describe through a systematic clinical-instrumental approach speech, gait and vestibular alterations in cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS).

Background: CANVAS is a neurological disorder characterized by the association of late-onset slowly progressive cerebellar ataxia, bilateral vestibulopathy and sensory neuronopathy mostly due to biallelic RFC1 expansion.

Method: Four patients with CANVAS underwent a standardized clinical-instrumental examination, including perceptual and acoustic analysis of speech, instrumental gait analysis and vestibular assessment with video-oculography.

Results: All patients reported progressive unsteadiness of gait with postural imbalance, oscillopsia, paresthesia or hypoesthesia in the extremities, and a history of unexplained cough. Brain-MRI documented cerebellar atrophy. The biallelic AAGGG repeat expansion in RFC1 gene was identified in all patients confirming the genetic diagnosis of CANVAS. Video-oculography documented spontaneous downbeat nystagmus enhanced on bilateral gaze (n=3), saccadic pursuit (n=2); overshot saccades (n=1); ocular flutter (n=1); slight downbeat nystagmus in supine position (n=1). All patients exhibited different degrees of reduced VOR-gain for all the six semicircular canals on video-head impulse test and all of them exhibited an unexpectedly normal (“false negative”) VOR-suppression test. Concerning gait assessment, the execution times of the iTUG resembled with those of the elderly population with no deterioration in performance during the dual task. Gait analysis exams of the patients were different from each other, showing varying degrees of impairments and alterations due to the overactivity of the posterior chain and muscular stiffness. Finally, perceptual-acoustic evaluation of speech showed in three out of four patients a mild ataxic dysarthria characterized by scanning pattern of speech, articulatory distortion of consonants and slower speaking rate. Dysdiadochokinesis, rhythm instability and irregularity were found at the oral diadochokinesis task. Mild oropharyngeal dysphagia was observed in all patients.

Conclusion: We report a case-series of four patients affected by CANVAS with distinctive clinical-instrumental findings including ataxic dysarthria, ataxic gait and bilateral vestibulopathy with oculomotor abnormalities consistent with cerebellar dysfunction.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/speech-gait-and-vestibular-instrumental-assessment-in-canvas-a-case-series/