title: Attention and postural control in patients with conversion paresis.
abstract: OBJECTIVE
  Current theories of conversion disorder (CD) propose that motor symptoms are related to heightened self-monitoring and excessive cognitive control of movements. We tested this hypothesis using quantification of performance on a continuous perceptuo-motor task involving quiet standing.
  
  
  METHODS
  Twelve CD patients and matched controls maintained static balance on a force platform under various attention conditions: (1) with eyes open; (2) with eyes closed (requiring enhanced attention to proprioceptive information to regulate posture); and (3) while performing an attention demanding cognitive task.
  
  
  RESULTS
  Compared to controls, CD patients displayed a greater decrease in postural stability in the 'eyes-closed' versus 'eyes-open' condition. In contrast, cognitive distraction led to a normalization of balance in CD. Moreover, sensitivity to the balance interventions correlated significantly with trauma reports and dissociative symptoms.
  
  
  CONCLUSIONS
  These results indicate that attention plays a crucial role in postural control in CD. More specifically, patients seem to inadvertently use deliberate control of posture (i.e., cognitive investment) of an otherwise nearly automatized perceptuo-motor task. Attentional distraction resulted in a temporary normalization of balance, which may be used to train individuals with CD to guide their attention in a more effective way.
authors.affiliation: Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands. Electronic address: j.stins@fbw.vu.nl.
authors.forename: John F
authors.initials: JF
authors.lastname: Stins
authors.affiliation: Department of Mood Disorders, PsyQ, Parnassia Groep, The Hague, The Netherlands.
authors.forename: C Lianne A
authors.initials: CL
authors.lastname: Kempe
authors.affiliation: Behavioural Science Institute, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, The Netherlands.
authors.forename: Muriel A
authors.initials: MA
authors.lastname: Hagenaars
authors.affiliation: Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands; School of Sport and Education, Brunel University, London, UK.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Beek
authors.affiliation: Behavioural Science Institute, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, The Netherlands.
authors.forename: Karin
authors.initials: K
authors.lastname: Roelofs
mesh_terms: D000328:Adult; D001288:Attention; D016022:Case-Control Studies; D003071:Cognition; D003291:Conversion Disorder / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010291:Paresis / Q000503:physiopathology* / Q000523:psychology*; D004856:Postural Balance; D011187:Posture; D011434:Proprioception; D011597:Psychomotor Performance
keywords: Balance; Cognition; Conversion disorder; Postural control