目的：本研究的目的是探討同時性的視覺空間操作任務與姿勢任務之間的交互作用對中風病患認知及／或姿勢控制表現的影響。方法：重複量測之研究設計，共收集19位中風 受試者，需在三種姿勢任務（與肩同寬站立、健側在後跟尖站立、患側在後跟尖站立）下，分別從事單一任務，及從事認知任務（視覺空間任務，包括簡單及複雜程度）。以壓力中心之總移動路徑長、壓力中心在前後與左右方向最大位移、承重對稱性三種參數代表姿勢穩定度，以認知任務之作答正確率及平均反應時間代表視覺空間任務之表現。採用重複量數雙因子變異數統計分析。結果：中風病患在執行雙重任務時，壓力中心晃動減少，但在認知表現則不受影響。結論：中風病患在雙重任務下採用姿勢優先的策略，此結果建議治療師以雙重任務姿勢穩定度來訓練病患，其效果可能會優於單一任務姿勢控制訓練。

Objectives: To investigate the interference of suprapostural tasks on performance of postural tasks. The suprapostural tasks involved cognitive tasks requiring mental rotation processing. Methods: Repeated measures design. Nineteen subjects post 1st stroke onset were recruited. All subjects underwent both single-task and dual-task experiment conditions. In single-task conditions, the postural stability of stroke patients were measured while standing on the pressure mat with the following three stance configurations (a) shoulder-width double stance, (b) step stance with sound leg in the back, (c) step stance with affected leg in the back. In dual task conditions, the postural stability was measured while stance as in single task conditions and reacted to the hard and easy visuospatial mental rotation task. Repeated-measures two-way analysis of variance was used to examine the effects of dual tasks on postural stability performance with significant level setting at α=.05. Results: The dual task conditions decreased the postural sway significantly comparing with single-task conditions. Performance of cognitive tasks showed no significant differences among different stance configurations. Conclusion: Stroke patients tend to adopt "postural first" strategy in dual-ask conditions. The result suggests clinical therapists to provide postural stability training in dual-ask settings which may cause better training effects than in single-task conditions.