Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) is an adult-onset slowly progressive neurologic disorder characterized by imbalance due to cerebellar gait and limb ataxia, impaired vestibular function bilaterally, and non-length-dependent sensory neuropathy (summary by Szmulewicz et al., ... Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) is an adult-onset slowly progressive neurologic disorder characterized by imbalance due to cerebellar gait and limb ataxia, impaired vestibular function bilaterally, and non-length-dependent sensory neuropathy (summary by Szmulewicz et al., 2011).
Migliaccio et al. (2004) reported 4 unrelated patients, 2 males and 2 females, with a syndrome comprising cerebellar ataxia and bilateral vestibulopathy with impaired ability of the eye velocity to match head velocity. All had a characteristic sign ... Migliaccio et al. (2004) reported 4 unrelated patients, 2 males and 2 females, with a syndrome comprising cerebellar ataxia and bilateral vestibulopathy with impaired ability of the eye velocity to match head velocity. All had a characteristic sign on clinical examination: impairment of the visually enhanced vestibuloocular reflex (VVOR), or 'doll's head reflex,' in which a normal individual shows compensatory saccades when the head is slowly and smoothly oscillated from side to side while trying to view an earth-fixed target straight ahead. None of the patients had a family history of a similar disorder. Each patient presented between 50 and 60 years of age with slowly increasing gait ataxia and later developed dysarthria. All had problems standing and showed a positive Romberg test. Limb ataxia was less prominent. Detailed vestibuloocular testing showed impaired smooth pursuit, impaired vestibuloocular reflex, and impaired optokinetic reflex. Gaze-evoked nystagmus was present under certain conditions. Three patients had clinical and electrophysiologic evidence of a sensory peripheral neuropathy. Sural nerve biopsy of 1 patient showed a severe axonal neuropathy. None had extrapyramidal features. Brain MRI showed cerebellar atrophy. Genetic testing for several common spinocerebellar ataxias (see, e.g., SCA1, 164400) was negative. Szmulewicz et al. (2011) reported retrospective data on 27 patients, including the 4 reported by Migliaccio et al. (2004), with a syndrome including cerebellar ataxia, neuropathy, and vestibular areflexia, which they termed 'CANVAS.' The median age at onset was 60 years (range, 33-71), and most (20 patients) presented with gait imbalance. Other presenting features included dysesthesia (8), oscillopsia (5), dizziness (2), and intrinsic falls (1). All patients had saccadic smooth pursuit, gaze-evoked nystagmus, gait and limb ataxia, and dysarthria. Brain MRI showed cerebellar atrophy in 22 patients. Detailed vestibular function testing showed that all had bilateral vestibulopathy manifest as decreased visual acuity on vertical head shaking, absent or reduced horizontal nystagmus on caloric stimulation, and absent or reduced nystagmus in response to constant acceleration rotational testing. VVOR deficit was demonstrated by videooculography. Hearing was unaffected. Temporal bone and brain pathology of 1 patient showed atrophy of the vestibular nerves and vestibular, trigeminal, and facial ganglion cells, but not of the cochlear ganglion cells. There was also a loss of cerebellar Purkinje cells. There was a non-length-dependent neuropathy with areflexia and decreased vibration and pinprick sensation in the upper and lower limbs associated with absence of sensory nerve action potentials.