Whole-body reaching as a measure of dynamic balance in patients with stroke

Objectives: To investigate whether whole-body reaching (WBR) could be a task with adequate and gradable dynamic balance challenges for stroke patients. Design: A total of 23 subjects with hemiplegia, after their first stroke, participated in this study. The degree of dynamic balance challenges of WBR was graded by varying the distance to the targets that the subjects had to reach. A foot-pressure measurement system was used to measure the amount of center-of-pressure shift during performance of WBR and sit-to-stand transfer. The Berg Balance Scale (BBS) was administered, and the BBS total score was calculated. Static and dynamic BBS subscores were separately calculated to further understanding of the subject performance regarding balance. Paired t tests were used to examine the effects of target distance on center-of-pressure shift. Correlations between measures of center-of-pressure shift during performance of WBR and of sit-to-stand transfer, BBS total score, BBS static subscores, and BBS dynamic subscores and measures of center-of-pressure shift during performance of sit-to-stand transfer were analyzed. Results: Significant effects of distance on three of the variables representing amount of center-of-pressure shift were found (P < 0.05). The correlations between WBR and sit-to-stand transfer were positive and moderate. The correlations between WBR and sit-to-stand transfer were stronger when the subjects were reaching for a closer target than when reaching for a farther target. The correlations between WBR and BBS total score were weak to moderate; the correlations between WBR and three scores of the BBS across target distance were inconsistent; and the correlations were higher when the subjects were reaching for a farther target than when reaching for a closer target. Conclusions: WBR for targets at different distances imposed graded dynamic balance challenges on stroke patients and might be an appropriate dynamic balance measure. However, WBR, as applied in this study, showed limitations in measuring the lateral dynamic stability of stroke patients.