title: Does the type of visual feedback information change the control of standing balance?
abstract: OBJECTIVE
  The aim of this study was to evaluate whether different types of visual feedback influence the control of standing balance.
  
  
  METHODS
  Twenty-six subjects performed three tasks on a force platform: (1) standing with eyes open; (2) maintaining the own center of pressure (COP) displacement (internal feedback) on a target; and (3) pointing with a handheld laser pointer (external feedback) on a target. The COP and ankle displacements were measured through a force platform and a biaxial electrogoniometer, respectively, during 60 s in each task. Global posturographic parameters were computed in the anterior-posterior and medial-lateral directions. In addition, the standard deviation and mean frequency of the ankle movements were also calculated in the sagittal plane.
  
  
  RESULTS
  The sway area and standard deviation of COP differed between conditions, wherein smaller and higher values were typically observed during the internal and external feedback, respectively. Conversely, both the mean frequency and the mean velocity of COP were greater during internal feedback compared with other tasks, while external feedback usually leads to smaller values. Additionally, smaller and higher values for the ankle standard deviation and the ankle mean frequency, respectively, were observed during internal feedback, with the external feedback condition showing an opposite behavior.
  
  
  CONCLUSIONS
  These results showed that the global postural sway and the postural adjustments at ankle during standing balance change depending on the type of visual feedback information.
authors.affiliation: Núcleo de Estudos do Movimento Humano (NEMoH), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. fv.dosanjos@gmail.com.|Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics, Politecnico di Torino, Via Cavalli 22/H, 10138, Turin, Italy. fv.dosanjos@gmail.com.
authors.forename: Fabio
authors.initials: F
authors.lastname: Dos Anjos
authors.affiliation: Núcleo de Estudos do Movimento Humano (NEMoH), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.|Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.|Programa de Pós-Graduação em Ciências da Reabilitação, Centro Universitário Augusto Motta-UNISUAM, Rio de Janeiro, Brazil.
authors.forename: Thiago
authors.initials: T
authors.lastname: Lemos
authors.affiliation: Núcleo de Estudos do Movimento Humano (NEMoH), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Luís Aureliano
authors.initials: LA
authors.lastname: Imbiriba
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000843:Ankle Joint / Q000502:physiology; D056228:Feedback, Sensory / Q000502:physiology*; D005528:Foot / Q000502:physiology; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011312:Pressure; D011597:Psychomotor Performance / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D055815:Young Adult
keywords: Ankle motion; Postural control; Posturography; Visual feedback