Event-related potentials provide clues to understanding motor conversion disorder

Abstract

Event Abstract Back to Event Event-related potentials provide clues to understanding motor conversion disorder Greg M. Anson1*, Rebekah F. Scott2 and Brian M. Hyland2 1 University of Auckland, New Zealand 2 University of Otago, New Zealand Motor conversion disorder is, the inability to initiate voluntary movement in the absence of organic neurological cause, and often characterised by hemiparesis. We have used event-related potentials, specifically the contingent negative variation (CNV) to assess changes in brain activity during performance of discrete upper limb movements. The CNV, a gradual increase in negativity recorded over the primary motor cortex between a warning signal and an imperative stimulus, is associated with preparation of an upcoming motor task. In simple and choice reaction time tasks CNV amplitude is linked to the degree of uncertainty about the nature of the response to be performed. We investigated the effect of motor conversion disorder (n = 6 patients; upper limb hemiparesis) on the temporal and amplitude characteristics of the CNV during preparation and performance of a voluntary finger flexion task. These data were compared with the results of age and gender matched participants (n = 12) performing an identical task. Behavioural measures (reaction time, maximal force, movement time) indicated that patients generated less force, and reacted and moved more slowly than participants in the control group. In patients, responses of the hemiparetic limb were significantly slower (p < .05) than the unaffected limb. CNV results for patients revealed a paradoxical outcome. CNV amplitude over the contralateral motor cortex of the affected limb was significantly diminished (approx 2 µV) if patients knew, prior to stimulus onset that they had to prepare to move their affected limb. But, when the µV affected limb was not specified until stimulus onset, CNV amplitude was much greater (approx 6 µV). Despite neurological assessment to the contrary, feigning cannot be ruled out. Keywords: ERP, Neuropsychiatry Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Poster Presentation Topic: Poster Sessions: Neuropsychiatric Applications Citation: Anson GM, Scott RF and Hyland BM (2011). Event-related potentials provide clues to understanding motor conversion disorder. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00118 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 17 Nov 2011; Published Online: 25 Nov 2011. * Correspondence: Dr. Greg M Anson, University of Auckland, Auckland, New Zealand, g.anson@auckland.ac.nz Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Greg M Anson Rebekah F Scott Brian M Hyland Google Greg M Anson Rebekah F Scott Brian M Hyland Google Scholar Greg M Anson Rebekah F Scott Brian M Hyland PubMed Greg M Anson Rebekah F Scott Brian M Hyland Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.