Tai Chi and vestibular rehabilitation improve vestibulopathic gait via different neuromuscular mechanisms: preliminary report

Abstract

Background: Vestibular rehabilitation (VR) is a well-accepted exercise program intended to remedy balance impairment caused by damage to the peripheral vestibular system. Alternative therapies, such as Tai Chi (TC), have recently gained popularity as a treatment for balance impairment. Although VR and TC can benefit people with vestibulopathy, the degree to which gait improvements may be related to neuromuscular adaptations of the lower extremities for the two different therapies are unknown.

Methods: We examined the relationship between lower extremity neuromuscular function and trunk control in 36 older adults with vestibulopathy, randomized to 10 weeks of either VR or TC exercise. Time-distance measures (gait speed, step length, stance duration and step width), lower extremity sagittal plane mechanical energy expenditures (MEE), and trunk sagittal and frontal plane kinematics (peak and range of linear and angular velocity), were measured.

Results: Although gait time-distance measures were improved in both groups following treatment, no significant between-groups differences were observed for the MEE and trunk kinematic measures. Significant within groups changes, however, were observed. The TC group significantly increased ankle MEE contribution and decreased hip MEE contribution to total leg MEE, while no significant changes were found within the VR group. The TC group exhibited a positive relationship between change in leg MEE and change in trunk velocity peak and range, while the VR group exhibited a negative relationship.

Conclusion: Gait function improved in both groups consistent with expectations of the interventions. Differences in each group's response to therapy appear to suggest that improved gait function may be due to different neuromuscular adaptations resulting from the different interventions. The TC group's improvements were associated with reorganized lower extremity neuromuscular patterns, which appear to promote a faster gait and reduced excessive hip compensation. The VR group's improvements, however, were not the result of lower extremity neuromuscular pattern changes. Lower-extremity MEE increases corresponded to attenuated forward trunk linear and angular movement in the VR group, suggesting better control of upper body motion to minimize loss of balance. These data support a growing body of evidence that Tai Chi may be a valuable complementary treatment for vestibular disorders.

Figures

Figure 1

Change scores in ankle, knee and hip total MEE(t) and leg total MEE(t) for VR and TC groups (in J %BW). Error bars represent 95% confidence intervals on the mean.

Figure 2

Change scores in percent contribution of ankle, knee and hip concentric MEE(+) to leg concentric MEE(+) for VR and TC groups (in J %BW). Error bars represent 95% confidence intervals on the mean.

Figure 3

Change scores in trunk velocity. (a) Linear velocity: anterior-posterior (A/P) velocity peak and range, and medial-lateral (M/L) velocity peak and range; (b) Angular velocity: pitch (sagittal plane) velocity peak and range, roll (frontal plane) velocity peak and range. Error bars represent 95% confidence intervals on the mean.

Figure 4

Change scores in trunk forward velocity range (in m/s) versus change scores in total leg MEE(t) (in J %BW) for VR (top plot) and TC (bottom plot) groups. Dashed lines represent the 95% confidence intervals on the mean.