Cervical dystonia and visual processing speed: Insights from magnetoencephalography

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Conference Proceeding

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Publication Title

Ann Neurol


Background Patients with cervical dystonia (CD) have been found to have impaired working memory, processing speed, visual motor ability and short term memory. We aimed to investigate changes in cerebral oscillations at the network level during a visual processing speed test (executive function), pre-and-post administration of botulinum toxin, using MEG in CD patients. Methods MEG data was collected on 5 CD patients while performing a visual continuous performance task (CPT), a go-no-go test, pre-and-post botulinum toxin injection. Similar MEG data was also collected on 5 age and gender-matched controls. Coherence source imaging was performed to quantify executive function network connectivity of subjects. Results In controls, there were 2 errors with visual CPT, with CD patients demonstrating 6 and 3 errors pre-and-post botulinum toxin, respectively. Average time from visual cue to correct response was 0.337 seconds in controls, 0.390 seconds in patients, pre and 0.366 seconds post botulinum toxin. Our study with visual CPT reveals a difference in coherence between controls and patients in the following regions: fronto-frontal, fronto-parietal, fronto-striatal, fronto-occipital, parieto-parietal and temporo-parietal. Intrahemi-spheric and interhemispheric networks were affected. After 2 weeks of botulinum toxin injection, there was minimal change in coherence in frontal and temporal networks. Conclusion The overall difference in coherence in the frontal circuits between cases and controls during the visual CPT may reflect increased difficulty with task, which is suggested by clinical testing. Botulinum toxin is associated with minimal improvement with visual speed processing in CD patients.




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