Effect of biofeedback techniques on balance control, anxiety and balance safety of healthy individuals in orthostatic position

Abstract

Introduction: Postural control involves the maintenance of orientation and postural balance, which are crucial aspects to allow the activities of daily living. The biofeedback technique has been of potential interest to the postural control rehabilitation, since it
seems to confine postural sway within the stability limits, ensuring postural balance during standing. However, whether the performance of postural balance is associated with other factors, such as anxiety and balance confidence, it is an open issue we
addressed here. Objective: This study aimed at investigating the effect of different biofeedback techniques on the anxiety and balance confidence and their association on posturographic parameters during standing balance. Methods: Twenty sixty participants were recruited in this study and tested in three tasks while standing on the force platform for 60s:1) standing with eyes open (EO); (2) posturography biofeedback (BFcp), consisting of keeping the center of pressure (COP) position as close as possible to a target located in front of the individual; (3) biofeedback of laser (BFlaser), consisting of pointing a laser as close as possible to the same target used before from the right wrist. The following posturographic parameters were computed: CP sway area standard deviation, mean velocity and mean frequency in the ântero posterior (AP) and medio-lateral (ML) directions. Scales for the assessment of balance confidence and anxiety, consisting of visual scales ranging from 0 to 100, were applied at the end of each postural task. Results: ANOVA revealed a smaller balance confidence in BFcp than EO, while no differences were observed between BFlaser and the other tasks. For the anxiety, ANOVA did not show differences among EO, BFcp and BFlaser. The correlations between subjective measures and posturographic parameters varied with the emotional aspect. The COP sway area, ML, standard deviation, and ML mean velocity showed a negative and moderate correlation with the balance confidence scale, indicating that lower values in these parameters are associated with a greater sense of balance confidence. However, no significant correlations were found between the balance anxiety scale and posturographic parameters. Conclusion: Balance confidence alterations were identified with BFcp in relation to the other postural tasks. These findings seem to suggest that psychological factors could contribute to explain, even if partially, alterations in the postural stability during the biofeedback.