Punding behaviour observed in a person with Cerebellar Ataxia with Neuropathy and Vestibular Areflexia Syndrome (CANVAS): A Case Report.

Background Punding describes a stereotypical pattern of behaviour that has been described most frequently in people with Parkinson’s disease who are receiving dopamine-related therapy. Punding has been reported in detail in just three people with genetic ataxia – including spinocerebellar ataxia types 1, 2 and 3. We describe punding in another form of genetic ataxia, cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) for the first time. Case Presentation A man with CANVAS was found to have a ten-month history of ripping or cutting up paper for over ten hours each day. There was no clear motivation nor goal for this paper ripping. Further review of his history confirmed that his behaviour fitted the diagnosis of punding. Neurological examination otherwise showed typical CANVAS features with no motor or extrapyramidal involvement. Neuroimaging only showed typical degeneration typical of CANVAS with no basal ganglia involvement. The patient was noted to have mild cognitive impairment on cognitive screening. Literature review confirmed that the vast majority of punding cases were due to Parkinson’s disease and its associated therapy. Conclusions We describe punding in CANVAS for the first time in a patient with no previous history of dopaminergic therapy or substance abuse. The occurrence of punding in this patient suggests that dopamine signalling may be important in the pathogenesis of this disease.