Effects of biofeedback on trunk sway during dual tasking in the healthy young and elderly.

We examined the effect of biofeedback of trunk sway on balance control while walking and performing a simultaneous cognitive or motor task. Thirteen healthy elderly (mean age (+/-S.E.M.) 70.8+/-2.0 years) and 16 healthy young (mean age 21.5+/-0.7 years) subjects performed three gait tasks while wearing body-worn gyroscopes, mounted at L1-3, to measure trunk sway. The gait tasks were walking normally, walking and counting backwards in 7's, and walking while carrying a tray with cups of water. Differences in trunk sway were examined when subjects performed the gait tasks with or without a head mounted actuator system which provided subjects with vibro-tactile, auditory and visual biofeedback of trunk sway. In the young, trunk pitch (fore-aft) angles, and trunk roll (sideways) and pitch angular velocities were significantly reduced using biofeedback across all three gait tasks. In the elderly, the same angle and angular velocities were also significantly reduced while walking normally. During walking while carrying a tray, only trunk sway velocities were significantly reduced, whereas no improvements were seen for walking while counting backwards. Counting backwards ability significantly improved with feedback. Young participants were able to perform a dual task during gait and employ biofeedback to reduce trunk sway. Elderly participants were not able to reduce sway using biofeedback during the cognitive task but were able to reduce sway velocities with biofeedback during the motor task.