身體活動量對老年人執行控制功能影響之探討

The effect of physical activity on the function of executive control in older adults

緒論：探討不同程度身體活動量對於健康老年人在大腦執行控制功能中干擾控制表現的影響。方法：本研究徵召51位參與者，分別為低身體活動量老人組 (17人)、高身體活動量老人組 (17人) 及年輕人組 (17人) ，採用腦波之事件關連電位進行評估，並以Stroop作業 (相容性作業及不相容性作業) 作為測試工具，以瞭解各組參與者在執行控制功能中干擾控制表現的情形。結果：(一) 行為表現的資料顯示相容情境時，年輕人與高身體活動量老人的反應時間均顯著的快於低身體活動量老人；不相容情境時，年輕人顯著快於二組老人，高身體活動量老人顯著快於低身體活動量老人。(二) 二個老人組的Stroop效果在作業二時均顯著大於年輕人，但是低身體活動量老人之Stroop效果顯著大於高身體活動老人。(三) 事件關連電位的P300潛伏時間資料顯示：低身體活動量老人在Fz、Cz、Pz三個電極之P300潛伏時間均顯著慢於高身體活動量老人，並在Pz電極也顯著慢於年輕人。(四) P300振幅資料顯示：高活動量老人在Fz電極之P300振幅顯著大於年輕人及低身體活動量老人，年輕人則在Cz電極之P300振幅顯著大於二個老人組，同時高身體活動量老人也顯著大於低身體活動量老人；年輕人及高身體活動量老人在Pz電極之P300振幅顯著大於低身體活動量老人。結論：本研究結果發現高身體活動量的老年人較低身體活動量的老年人在進行與干擾控制有關的Stroop作業中擁有較快速的行為反應，在大腦訊息處理的刺激評估階段也有較高的注意力資源投入及較快的訊息處理速度，並且發展出較全面的額葉補償機制，以維持與年輕人相當的認知處理效率，同時也驗證了身體活動量這個因素對於高齡族群在認知表現的重要影響。

Introduction: Physical activity (PA) has been shown to counteract the age-related decline of cognition, particularly the function of executive control. Specifically, evidence has attributed this benefit to the compensatory mechanism of brain due to chronical participation of PA. However, among various domains of executive function, interference control is a less studied, yet important, component in relation to PA in older adults. Therefore, the main purpose of current study is to investigate the effect of PA on the aspect of interference control of executive control function and the underlying neuroelectrical processes among healthy aging adults. Secondly, task difficulty was manipulated to test its effect on the relationship between executive function and PA. Methods: Fifty-one participants were recruited in this study, including 17 low PA older adults (LPAO), 17 high PA older adults (HPAO), and 17 younger adults (YA), who were served as a reference point of optimal or unimpaired executive control function. Interference control was measured using Stroop tasks (congruent v.s incongruent) with various task difficulties (3 v.s 4 colors) while event-related potentials (ERPs) were recorded. Results: The behavioral data shows shorter reaction time (RT) for HAPO and YA relative for LPAO in congruent condition, while shorter RT was observed for YA relative for two older groups in incongruent condition. The difference of Stroop effect between three groups was selectively observed in task with 4 colors, with larger Stroop effect for two older groups relative for YA and with larger Stroop effect for LPAO relative for HPAO. The results of P300 component revealed longer latency for LPAO relative for HPAO at Fz, Cz, and Pz electrodes and for YA at Pz. As for P300 amplitude, HPAO exhibited larger amplitude than LPAO and YA at Fz; YA exhibited larger amplitude than other two older groups at Cz, and HPAO exhibited larger amplitude than LPAO at Cz; YA and HPAO exhibited larger amplitude than LPAO at Pz. Conclusion: Current study provides evidence that higher PA in older adults is associated with faster reaction time, larger input of attentional resources, and faster information-processing rate during Stroop tasks requiring various extent of interference control. In addition, the association between higher PA and reduced Stroop effect in task requiring increased cognitive demand suggests that the benefit of PA on the aspect of interference control of executive function may be selective. Furthermore, the posterior-anterior shift of P300 amplitude in HPAO suggests a more developed compensatory mechanism which maintains a rather efficient function of executive control function. Collectively, these findings suggest that PA has significant influence on the function of executive control in aging population.