Autonomic failure in CANVAS syndrome

This scientific commentary refers to ‘Autonomic dysfunction is a major feature of cerebellar ataxia, neuropathy, vestibular areflexia “CANVAS” syndrome’, by Wu et al. (doi: 10.1093/brain/awu196). A series of papers published in the 1990s by the Bronstein group triggered—albeit unintentionally—intensified research into a clinical syndrome characterized by a combination of selective bilateral vestibulopathy and cerebellar ataxia (Bronstein et al. , 1991; Waterston et al. , 1992; Rinne et al. , 1995). The term ‘cerebellar ataxia, neuropathy, vestibular areflexia syndrome’ (CANVAS) was subsequently coined in 2011 by Szmulewicz and colleagues, following a retrospective analysis of case records of patients with cerebellar ataxia and bilateral vestibulopathy with an impaired visually enhanced vestibulo-ocular reflex (Szmulewicz et al. , 2011). The latter reflects a combined failure of all three compensatory eye movement systems, and can be demonstrated clinically by turning a patient’s head slowly from side to side, with the test considered to be positive if compensatory eye movements are saccadic rather than smooth. Our understanding of CANVAS syndrome has improved over recent years and there have been numerous publications on specific symptoms. The existence of affected sibling pairs suggests …