外在任務難度對半側腦麻孩童執行汲取抓握任務時上肢軀幹動作的影響

Effects of External Task Difficulty on Arm-Trunk Movement during a Reach-to-Grasp Task in Children with Hemiplegic Cerebral Palsy

葉淳輔(Chun-Fu Yeh)

指導教授 ： 陳顥齡

國立臺灣大學/醫學院/職能治療研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.10433

摘要

背景
上肢動作控制受損是半側腦性麻痺孩童常見之特徵，而上肢動作控制受損會進而影響其日常生活中的表現與參與。與健康發展孩童相比，半側腦性麻痺孩童在執行日常生活中之汲取抓握任務時會使用代償性動作策略，如較多的軀幹前移。因此，在一次的汲取抓握任務中，半側腦麻孩童與健康發展孩童所使用的上肢軀幹動作策略可能不同。除了上肢軀幹動作策略的不同外，半側腦麻孩童亦可能有動作計畫不足的問題。也就是，在面對不同外在任務難度時，他們會難以調整自己的上肢軀幹動作策略以順利完成汲取抓握任務。過去文獻顯示，當所需汲取的物品在越遠的位置時，腦麻孩童患側手的動作路徑會越筆直而軀幹移動會更多。然而，距離遠近對上肢軀幹動作的端點控制參數與關節角度控制的影響並未被深入探討。除此之外，所需汲取物品的方向亦會影響上肢軀幹動作策略。為了設計適當的復健計畫，物品的距離與放置方向對半側腦麻孩童執行汲取抓握任務時上肢軀幹動作策略的影響並與健康發展兒童做比較是需要被探討的。

方法
16位年齡介於5至13歲之半側腦麻孩童及年齡相符之16位健康發展孩童納入此研究。評估時，孩童先成直立坐姿，再以慣用手或非慣用手（患側手），伸手抓取前方的差棒，動作過程越快越準越好。插棒放置於（1）任務手同側並於手長範圍內、（2）任務手同側並於手長範圍外、（3）任務手對側並於手長範圍外。上肢軀幹動作的端點控制以及關節角度從高速攝影機所汲取之資料來分析。所有計算參數之組別差異、慣用手非慣用手差異、物品位置影響則以混合模式的變異數分析進行統計分析（α = 0.05）。

結果
半側腦麻孩童相較於健康發展孩童在汲取三個物品時都有較高的反應時間，顯示半側腦麻孩童動作計畫的不足或不佳。再者，隨著物品距離越遠並放置對側，反應時間會有顯著的上升趨勢，說明對側的汲取動作需要較長時間也可能較複雜的動作計畫。隨著物品距離增加，半側腦麻孩童對於上肢軀幹動作策略的調整與健康發展兒童有相似的特徵。然而，半側腦麻孩童在上肢動作的神經控制參數上則不因物品距離而改變，尤其是使用患側手時。這個現象顯示半側腦麻孩童可能無法彈性地調整端點控制策略以符合任務的需求。此外，當物品放置於對側時，半側腦麻孩童的慣用手與患側手都會表現出在垂直向手部動作彈性不足的力量調控，而使他們在垂直向手部動作的路徑校正次數較多。就軀幹動作方面而言，半側腦麻孩童雖然會將軀幹前彎以及軀幹旋轉納入上肢動作的一環，但上肢動作與軀幹動作間的協調性是不足的，這可能與事先的動作計畫不足有相關。

結論
半側腦麻孩童能夠調整上肢多關節間的動作控制以完成汲取抓握任務之任務要求，但會呈現出彈性不足的上肢力量控制與上肢神經動作控制，尤其是物品放置在對側與手長範圍外時。雖然半側腦麻孩童的患側手有動作控制損傷，但其慣用手與患側手在面對距離越來越遠的物品時會使用相似的上肢動作策略。此外，半側腦麻孩童對於上肢軀幹動作間的動作計畫可能尚未完善，致使上肢軀幹動作的協調性不足。總結而言，汲取對側物品相對汲取同側物品對半側腦麻孩童是個有難度的任務，可被視為一個治療介入的要點。再者，訓練上肢軀幹動作間的協調有助於增進上肢動作控制的效率與彈性。

關鍵字

腦性麻痺 ； 運動學分析 ； 汲取抓握 ； 上肢軀幹動作 ； 任務難度

並列摘要

Background
Impaired motor control of upper extremity (UE) is a common characteristic in children with hemiplegic cerebral palsy (HCP), hampering their participation in activities of daily living (ADL). Compared with typically developing (TD) children, children with HCP may use compensatory strategies (e.g. trunk flexion) during a reach-to-grasp (RTG) task, which constitutes parts of ADL. As a result, strategies of the arm-trunk movement, in children with HCP during RTG task may be different from those in TD children. In addition to those strategies, the children with HCP may have deficits in motor planning. That is, they may be deficient in adapting their strategies to external task difficulties during RTG task. To date, it was demonstrated that the straightness of arm movement and the trunk displacement in children with HCP may scale to the target distances during RTG task, but this distance effect on the neural control strategies of arm-trunk movement and joint kinematics was not fully discovered. Besides the distance effect, the direction effect would also affect the motor planning and the strategies of arm-trunk movement. To design appropriate rehabilitative programs for children with HCP, the distance and direction effects on strategies of arm-trunk movement during RTG task in children with HCP compared with TD children may need to be discovered.

Methods
16 children with HCP and 16 TD children, aged 5~13 year-old, were recruited. During this experiment, the children were in seated position and then reached to grasp the peg with the dominant / non-dominant hand as quickly and accurately as possible. The peg was located at (1) within arm length on ipsilateral side, (2) beyond arm length on ipsilateral side and (3) beyond arm length on contralateral side. The end-point control of arm-trunk movement and joint kinematics were calculated from the data obtained by Vicon camera. The effects of group, hand, target location on calculated variables were evaluated using mixed-model analysis of variance for repeated measures (α= 0.05).

Results
Children with HCP had higher reaction time than TD children during reaching each target, showing the inefficiency in their motor planning; and reaction time would increase as the target distance increased and the target direction changed to the contralateral side, indicating that the motor planning for reaching to contralateral side may be more demanding than that to ipsilateral side. As distance of the target on ipsilateral side increased, the adjustments of the arm strategies in children with HCP would be similar to those in TD children. However, their neural control strategy of arm movement remained unchanged, especially during reaching with their affected hand. This may indicate that they could not flexibly adapt their neural control strategies to the task demands. Furthermore, as the target was placed on contralateral side, both hands in the children with HCP may demonstrate an inflexible force control strategy in vertical arm movement, consequently enhancing the movement corrections in vertical plane. In terms of trunk movements, children with HCP could incorporate trunk forward flexion and trunk internal rotation into arm kinematic chain, but the coordination between the trunk and upper extremities was somewhat impaired. It could be related to their insufficiency in motor planning.

Conclusion
Children with HCP would adjust the multi-segment control to fulfill the task demands but demonstrate the inflexible force control and neural control strategies of arm movement, especially during reaching the target beyond arm length on contralateral side. While the affected hand in children with HCP had some motor deficits, both hands in children with HCP may adopt similar arm strategies as the task difficulty increased. Furthermore, the incorporation of trunk movement into arm movement in children with HCP may be not well planned, leading to the less coordinated arm-trunk kinematic chain. It is suggested that reaching to contralateral side be considered a task difficulty in intervention programs for children with HCP, and the task involving the arm-trunk coordination should be addressed to enhance the flexibility and efficiency of arm movement.

並列關鍵字

Cerebral palsy ； Kinematic analysis ； Reach-to-Grasp ； Arm-trunk movement ； Task difficulty

參考文獻

Levin, M. F., Michaelsen, S. M., Cirstea, C. M., & Roby-Brami, A. (2002). Use of the trunk for reaching targets placed within and beyond the reach in adult hemiparesis. Exp Brain Res, 143(2), 171-180. doi: 10.1007/s00221-001-0976-6

References

Blair, E., & Watson, L. (2006). Epidemiology of cerebral palsy. Semin Fetal Neonatal Med, 11(2), 117-125. doi: 10.1016/j.siny.2005.10.010

Butler, E. E., Ladd, A. L., Lamont, L. E., & Rose, J. (2010). Temporal-spatial parameters of the upper limb during a Reach & Grasp Cycle for children. Gait Posture, 32(3), 301-306. doi: 10.1016/j.gaitpost.2010.05.013

Choi, H. J., & Mark, L. S. (2004). Scaling affordances for human reach actions. Hum Mov Sci, 23(6), 785-806. doi: 10.1016/j.humov.2004.08.004