Standing balance after vestibular stimulation in Tai Chi-practicing and nonpracticing healthy older adults

Objective: To compare the effects of vestibular stimulation on standing balance control between Tai Chi practitioners and older subjects. Design: Cross-sectional study. Setting: University-based rehabilitation center. Participants: Tai Chi practitioners (n=24; age +/- standard deviation, 69.3 +/- 5.0y) and control subjects (n=24; age, 71.6 +/- 6.1y) were recruited. Interventions: Not applicable. Main Outcome Measures: Subjects stood on a force platform with eyes closed before and after stimulation of their horizontal semicircular canals, applied by means of whole head-and-body rotation at 80 degrees/s for 60 seconds, with subjects seated in a rotational chair. Body sway during stance was measured as total sway path, peak amplitudes, and mean velocities of sway in both anteroposterior (AP) and mediolateral (ML) directions. Results: After head-and-body rotation, significant within-group increases were found in all measures in both AP and ML directions during stance with eyes closed in older control subjects but not in Tai Chi practitioners along the AP direction. In fact, significantly smaller increases in total sway path, peak amplitude, and mean velocity of body sway in the AP direction were found in the Tai Chi practitioners when compared with those of control subjects. Conclusions: Our results show that long-term Tai Chi practitioners had better AP standing balance control after vestibular stimulation than older control subjects.