背景：選擇適當的認知測試對使用雙重作業設計的平衡測試相當重要。然而，很少研究著重在比較不同認知測試對步態的影響，尤其是對狹窄步道行走能力的影響。目的：本實驗的目的乃在探討同時做兩件事對快步行走能力的影響；同時也想討論不同的分心方式在限制寬度和無限制寬度的步道上對快步行走能力的影響。方法：本實驗選取15位健康老人，在10公尺長的步道上快步行走：包括限制寬度與無限制寬度兩種情況；認知測驗為兩種：包括數學測驗（連續倒算數學，每次減3）；以及記憶測驗（連續說出不同種類的動物名稱）。一共有八種測試狀況，每個狀況受測者重複3次，最後求取步態變數平均值做分析用。統計方法使用的是多變數分析重複型評量。結果：狹窄步道明顯地使受試者走路速度變慢，步頻變小(p<.05)。兩種認知測試影響步態的程度不同，尤其在老人身上更為明顯(p<.05)。結論：老人的步態較易受到認知測驗內容的影響，可能因為倒算數學較依賴工作記憶區，而它則和大腦的執行功能有直接的關係。

Background and purposes: Choosing an appropriate cognitive task for a dual task situation is critical for balance assessment. Few studies have tried to explore whether the type of cognitive task matters for gait changes, especially for narrow path walking. This experiment was aimed to examine whether the subjects would change their fast walking speed for the dual task, narrow path trials. The effect of two cognitive tasks on the narrow path walking ability was also investigated. Methods: Fifteen young and fifteen healthy old adults were recruited from the Tainan, Taiwan area. Two walking path conditions (wide path fast walking vs narrow path fast walking) and two cognitive tasks (arithmetic task and animal recitation task) combination were encountered. Dual task related gait changes were evaluated. Results: Narrow path made our subjects walk slower and lower their cadence when they had to walk and perform an arithmetic task simultaneously (p<.05). Two cognitive tasks affected gait parameters differently, especially for the old adults (p=.005). Conclusions: Narrow path walking might increase the physiological arousal and it also required more resource of attention. Two cognitive tasks affected gait parameters differently might be due to the arithmetic task depending on working memory which is directly related to executive functions.