Motion Analysis of Patients With Stroke During Obstacle Crossing With and Without Hinged Ankle-Foot Orthoses

目的：本研究目的在探討中風病患穿戴踝足矯具，對於跨越障礙時動作學參數及肌電訊號的影響，以助於瞭解跨越障礙之表現與動作控制。 方法：十一位能獨立行走十公尺的中風病患(平均年齡52.36歲) 參與跨越障礙物實驗。受試者接受量身訂做的鉸接式踝足矯具。實驗在有穿及無穿踝足矯具跨越4公分高的障礙物的兩種情形下進行。採用三度空間動作分析系統(Vicon motion analysis system; Oxford, UK)及肌電訊號擷取系統(Gould polygraph)收取患側腳先跨及患側腳後跨兩種動作。分析的動作學參數包括：跨越腳跨越時與障礙物之間的距離(obstacle clearance)、患側腳關節角度、跨越時的身體質量中心（center of mass）位移範圍、身體質量中心的位移速度、以及跨越時患側腳的肌肉共同收縮比 (co-contraction ratio) 。 結果：本研究結果中，中風病人在穿戴踝足矯具時跨越腳與障礙物之間的距離 (obstacle clearance)較無穿戴時的距離有顯著降低，同時表現在患側腳先跨(t(10)=2.320, p<0.05)及後跨(t(10)=3.313, p<0.01)兩種情形中。身體質量中心垂直方向的位移量，患側腳當支撐腳(stance)時穿戴踝足矯具較無穿戴時小(t(10)=2.295, p<0.05)；後跨時穿戴踝足矯具亦較無穿戴時小(t(10)=2.859, p<0.05) 。而身體質量中心垂直方向的位移量，患側腳當支撐腳時穿戴踝足矯具較無穿戴時大(t(10)=4.236, p<0.01) 。在關節角度以及跨越時肌肉共同收縮比例上，不管前跨或後跨，在有穿與無穿踝足矯具之間並無顯著差異。 結論：中風病人在有無穿戴踝足矯具跨越障礙物時，於跨越障礙間距與身體質量中心垂直方向的位移量皆有顯著差異。由此結果推論，中風病患穿戴踝足矯具跨越障礙物，主要改善其跨越時身體上抬程度的需求，進而減少其跨越時能量的消耗。而當患側當支撐腳時，穿戴踝足矯具亦提供較高的穩定度。Objective: The aims of this study were to analyze the kinematics effects of ankle-foot orthoses (AFO) and electromyographic (EMG) activities during obstacle crossing in subjects with stroke to understand the clearance and the movement control pattern. Method: Eleven subjects with stroke (mean age: 52.36 y.o.) who were able to walk independently for 10 m were recruited in this study. They were instructed to perform 4-cm high obstacle crossing with and without hinged AFO. The Vicon motion analysis system (Oxford, UK) was used to obtain the kinematic data. The Gould polygraph was used to collect the surface EMG of bilateral lower extremities. The obstacle clearance, center of mass (COM) displacement, COM peak velocity, joint angles, and the EMG co-contraction ratio of the crossing limb were calculated. Results: The obstacle clearance reduced significantly both in lead-limb (t(10)=2.320, p<0.05) and trail-limb (t(10)=3.313, p<0.01) of subjects during crossing with AFO. The Medial-Lateral COM displacement was significantly increased while affected limb in stance with AFO (t(10)=4.236, p<0.01). The vertical COM displacements reduced significantly both in affected trail-limb crossing (t(10)=2.859, p<0.05) and in stance (t(10)=2.295, p<0.05) with AFO. The hip, knee, and ankle joint angles and co-contraction ratio of the affected lead-limb and trail-limb were not significantly different between hemiplegic subjects with and without AFO during crossing. Conclusion: When hemiplegic subjects cross with AFO, the obstacle clearance and the COM displacement are different from those without AFO. The application of AFO on hemiplegic subjects results in the reduction of body elevation which may decrease the energy cost during obstacle crossing. Furthermore, the support from AFO may increase the stability of the affected limb in stance during unaffected lead-limb crossing.摘要 4 Abstract 5 Chapter 1 Introduction 6 1.1 Background 6 1.2 Aims and Hypotheses 7 1.3 Operational definition 10 1.3.1 Obstacle 10 1.3.2 Lead limb and trail limb 11 1.3.3 Obstacle clearance 11 1.3.4 Crossing Cycle 12 1.3.4 Center of mass 12 1.3.5 Symmetry Index (SI) 13 1.3.6 Root mean square (RMS) of EMG amplitude 13 1.3.7 Co-contraction ratio 13 Chapter 2 Literature Review 14 2.1 Kinematics of obstacle crossing in healthy subjects 14 2.2 Strategies of obstacle crossing in healthy subjects 16 2.3 Kinematics responses of obstacle crossing in subjects with stroke 18 2.4 Effect of ankle-foot orthosis on gait and balance in patients with stroke 20 Chapter 3. Research Methods 22 3.1 Participants 22 3.2 Study design 22 3.3 Experimental equipment 22 3.3 Experimental protocol 24 3.3.1 Clinical assessment 24 3.3.2 Motion assessment 25 3.4 Data analysis 27 Chapter 4. Results 32 4.1 Participants 32 4.2 Crossing event 34 4.3 Obstacle clearance 37 4.3.1 Affected lead-limb 37 4.3.2 Affected trail-limb 37 4.4 Joint angles 38 4.4 COM displacement 41 4.4.1 Affected lead-limb 41 4.4.2 Affected trail-limb 41 4.4.3 Affected limb in stance 42 4.5 COM peak velocity 43 4.5.1 Affected lead-limb 44 4.5.2 Affected trail-limb 44 4.5.3 Affected limb in stance 44 4.6 EMG co-contraction ratio 46 4.6.1 Affected lead-limb 46 4.6.2 Affected trail-limb 46 Chapter 5 Discussion 50 5.1 Obstacle clearance 50 5.2 Joint angles 51 5.3 COM displacement 52 5.4 COM medial-lateral peak velocity 53 5.5 EMG co-contraction 53 5.4 Influences of crossing speed 54 5.5 Research limitations 55 5.6 Further research 56 5.7 Conclusion 56 References 58 Appendix 6