Evaluation of postural control in quiet standing using center of mass acceleration: comparison among the young, the elderly, and people with stroke.

OBJECTIVE: To determine center of mass (COM) acceleration usefulness in the evaluation of postural control during quiet standing.

DESIGN: Three-group comparison design.

SETTING: A research laboratory.

PARTICIPANTS: Poststroke subjects (n=12), healthy elderly subjects (n=22), and healthy young subjects (n=25).

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: With a force platform, postural sway was evaluated by using the standard deviations of COM acceleration and center of pressure (COP) and COM (COP-COM) in which COP-COM represents the distance between the COP and the COM.

RESULTS: COM acceleration and COP-COM variables were greater in the poststroke group than in the healthy groups (elderly and young) in the mediolateral (ML) direction. Both variables in the anteroposterior (AP) direction were greater in the poststroke group and the elderly group than in the young group. Furthermore, the correlations between COM acceleration and COP-COM in each group in each direction were shown to be significantly high (r range, .906-.979; P<.001).

CONCLUSIONS: COM acceleration was useful in the evaluation of postural control during quiet standing when comparing the young, the elderly, and poststroke patients. Additionally, COM acceleration and COP-COM in both the AP and ML directions during quiet standing were significantly and highly correlated. Thus, we proposed that COM acceleration can be an alternative and convenient measure instead of COP-COM in the evaluation of postural control.