TRAINING EFFECTS DURING REPEATED THERAPY SESSIONS OF BALANCE TRAINING USING VISUAL FEEDBACK

Visual biofeedback of postural sway is currently being investigated as a therapeutic technique to reduce postural instability in selected patient populations. Before the efficacy of this type of therapy can be determined in a clinical setting, the performance curves of a normal population doing the static and dynamic balance training exercises have to be delineated. Two groups of normal subjects were evaluated during a daily and weekly protocol of dynamic balance exercises using visual feedback of their center of gravity (COG) and theoretical limits of stability. Static stability in a central position was measured with eyes open, eyes closed, and with visual feedback of the COG in a pre-therapy to post-therapy assessment. No significant change was observed in any of these variables from the pre-therapy to the post-therapy evaluation; as well there was no difference between the scores of both groups. Dynamic variables were evaluated in both a pre-therapy to post-therapy assessment, and over the course of therapy. Each of these protocols required the subjects to track targets representing 75% of their limits of stability on a computer screen with their COG. The time taken and the accuracy to move the COG cursor from target to target, as well as the body sway upon reaching the target were evaluated. Transition time and sway area both decreased significantly (p < 0.01) from the pre-therapy to the post-therapy assessment for both groups, with path error decreasing significantly for the daily therapy group only. No significant difference was demonstrated between groups. Path error and sway area decreased significantly (p < 0.01) over the course of therapy with a plateau occurring after day 3 for path error, and after day 4 for sway area in both groups. There was no relative change in transition time during the therapy protocol. Performance curves have been delineated for a group with no balance disorders, and there appears to be no difference in performance between the daily and weekly therapy groups.