title: Postural Control Can Be Well Maintained by Healthy, Young Adults in Difficult Visual Task, Even in Sway-Referenced Dynamic Conditions.
abstract: OBJECTIVE
  To challenge the validity of existing cognitive models of postural control, we recorded eye movements and postural sway during two visual tasks (a control free-viewing task and a difficult searching task), and two postural tasks (one static task in which the platform was maintained stable and a dynamic task in which the platform moved in a sway-referenced manner.) We expected these models to be insufficient to predict the results in postural control both in static-as already shown in the literature reports-and in dynamic platform conditions.
  
  
  METHODS
  Twelve healthy, young adults (17.3 to 34.1 years old) participated in this study. Postural performances were evaluated using the Multitest platform (Framiral®) and ocular recording was performed with Mobile T2 (e(ye)BRAIN®). In the free-viewing task, the participants had to look at an image, without any specific instruction. In the searching task, the participants had to look at an image and also to locate the position of an object in the scene.
  
  
  RESULTS
  Postural sway was only significantly higher in the dynamic free-viewing condition than in the three other conditions with no significant difference between these three other conditions. Visual task performance was slightly higher in dynamic than in static conditions.
  
  
  CONCLUSIONS
  As expected, our results did not confirm the main assumption of the current cognitive models of postural control-i.e. that the limited attentional resources of the brain should explain changes in postural control in our conditions. Indeed, 1) the participants did not sway significantly more in the sway-referenced dynamic searching condition than in any other condition; 2) the participants swayed significantly less in both static and dynamic searching conditions than in the dynamic free-viewing condition. We suggest that a new cognitive model illustrating the adaptive, functional role of the brain to control upright stance is necessary for future studies.
authors.affiliation: UMR 1141, INSERM-Université Paris 7, Robert Debré University Hospital, Paris, France.|Vestibular and Oculomotor Evaluation Unit, ENT Department, Robert Debré University Hospital, Paris, France.|Lyon Neuroscience Research Center, INSERM U1028, CNRS UMR 5292, Claude Bernard Lyon 1 University, Lyon, France.|Department of Audiology and Otoneurological Evaluation, Hospices Civils de Lyon, Lyon, France.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Lions
authors.affiliation: UMR 1141, INSERM-Université Paris 7, Robert Debré University Hospital, Paris, France.|Vestibular and Oculomotor Evaluation Unit, ENT Department, Robert Debré University Hospital, Paris, France.
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Bucci
authors.affiliation: SCALab, Laboratoire de Sciences Cognitives et de Sciences Affectives, UMR CNRS 9193, University of Lille, Lille, France.
authors.forename: Cédrick
authors.initials: C
authors.lastname: Bonnet
mesh_terms: D000293:Adolescent; D000328:Adult; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D004856:Postural Balance / Q000502:physiology*; D013647:Task Performance and Analysis; D014785:Vision, Ocular / Q000502:physiology; D055815:Young Adult