Cervical Dystonia and Executive Function: A Pilot Magnetoencephalography Study

Abstract

Background: Cervical dystonia (CD) patients have impaired working memory, processing speed and visual-motor integration ability. We used magnetoencephalography (MEG) to investigate changes in cerebral oscillations in CD patients during an executive function test, before and after administration of botulinum toxin. Methods: MEG data were collected from five CD patients while they performed a visual continuous performance task (CPT), before and after they received a botulinum toxin injection. MEG data was also collected on five controls matched for age and gender. Coherence source imaging was performed to quantify network connectivity of subjects. Results: Controls demonstrated two errors with visual CPT; CD patients demonstrated six and three errors pre- and post-botulinum toxin respectively. After botulinum toxin, mean time from cue to correct response was 0.337 s in controls, 0.390 s in patients before botulinum toxin injection, and 0.366 s after the injection. Differences in coherence between controls and patients were found in the following brain regions: Fronto-frontal, fronto-parietal, fronto-striatal, fronto-occipital, parieto-parietal and temporo-parietal. Intrahemispheric and interhemispheric networks were affected. Post injection, there was minimal change in coherence in the above-mentioned networks. Discussion: Neuropsychological testing suggests difference in coherence in frontal circuits between CD cases and controls during the visual CPT, which may reflect subjects’ increased difficulty with the task. Botulinum toxin is associated with minimal improvement with executive function in CD.

Impaired Inhibitory Control of Saccadic Eye Movements in Cervical Dystonia: An Eye‐Tracking Study

“…Importantly, imaging studies suggest that this network is altered in CD 11 . In accordance with our findings, neuropsychological tests have revealed impairment in working memory, cognitive flexibility, and frontal lobe function in patients with CD 9,32,33 . Finally, disruption of sensory‐motor integration in patients with focal dystonia 34 may also affect oculomotor performance 35 …”

Attention-Demanding Cognitive Tasks Worsen Postural Control in Patients With Cervical Dystonia: A Case-Control Study

“…Since CD patients and HCs were age-matched, we can exclude the possibility that any differences in Stabilometric results between patients and HCs were due to age (20). The worse performance of CD patients on the Stroop test as compared to HCs may be attributable to mild impairment in different cognitive domains (21,22), especially in domains involved in executive functions (23). However, all CD patients had a MoCA score >26, therefore excluding the presence of overt cognitive dysfunction, a condition that would have precluded the execution of the Stroop test.…”

A microstructural neural network biomarker for dystonia diagnosis identified by a DystoniaNet deep learning platform

“…Structural abnormalities in the corpus callosum were previously reported within the dystonia spectrum, including laryngeal dystonia, cervical dystonia, and blepharospasm, as well as focal hand dystonia, musician’s dystonia, X-linked dystonia-parkinsonism, and poststroke lingual dystonia (e.g., refs. 19 , 20 , 29 , and 33 – 45 ). These alterations were related to the broader spread of cortical changes in dystonia and attributed to aberrant interhemispheric information transfer.…”

“…Other regions that were identified by DystoniaNet as informative features included inferior temporal and superior orbital gyri as well as the white matter pathways and the inferior fronto-occipital and uncinate fasciculi, connecting these cortical regions with the frontal, temporal, and occipital lobes ( 47 ). Alterations in these regions are thought to contribute to abnormal heteromodal sensorimotor processing and executive control of goal-oriented motor behaviors in patients with isolated dystonia ( 32 , 33 , 43 – 45 ). Taken together, pathophysiologically relevant alterations of white matter commissural, association, and projection fibers, as automatically detected by DystoniaNet, capture and reflect wider spread abnormalities in their target gray matter regions and likely represent a unifying neural biomarker of isolated dystonia.…”