Effect of Dual Task on Dynamic Stability in Subjects with Spinal Cord Injury During Arm-Trunk Coordinated Movement
|Keywords:||脊髓損傷;雙項任務;注意力;動態坐姿穩定;SCI;Dual task;Attention;Dynamic sitting stability||Issue Date:||2007||Abstract:||
方法：本研究共徵召12位健康受試者(平均年齡37歲)與12位胸髓第7到12節完全損傷患者(T7-T12，平均年齡36.3歲)接受雙項任務測試。主要任務是在坐姿的情境下藉由移動軀幹來帶動上肢畫圈動作的上肢-軀幹協調性動作，次要任務是藉由聽到數字而快速回答減1答案的聽算數減法任務。受試者在單項上肢-軀幹協調穩定任務情境下，執行2回試驗，每回試驗上肢連續重複劃10圈。於單項聽算數減法任務情境下，每回受試者於靜態坐姿下回答所聽隨機出現6次雙位數字（10∼99）減1的答案。於雙項任務情境下，受試者在執行上肢-軀幹協調穩定任務同時隨機接受聽算數減法任務 (10圈隨機出現6次)共2回 (即上肢共劃20圈，其中有12次為雙項任務)。動態姿勢穩定表現是評估以身體壓心(COP)的動力學、上肢-軀幹協調性運動學與神經肌肉反應等變數。注意力需求則以對聽算數減法任務的口語反應時間為指標，在任務(單項對雙項)與組別(健康組對脊髓損傷組)雙變異數與Bonferroni adjustment分析，區別任務與組別效應。
Objective: The purpose of this study was to examine the effects of attentional demands on dynamic postural stability between subject with spinal cord injured and age-matched healthy adults during arm-trunk coordinated movement combined with arithmetic subtraction task.
Method: Twelve age-matched healthy adults (mean age= 37 years) and 12 subjects with complete T7-T12 thoracic cord injury (mean age= 36.3 years) were recruited. They received dual task paradigm test at seated position. The primary task was an arm-trunk coordinated movement by using the body and shoulder to performed repetitive arm circular drawing movement on sitting position. The secondary task was an auditory arithmetic subtraction task by listening two-digit number and answering minus one quickly. In the single, primary task condition, subjects performed 2 sets of arm-trunk coordinated stability task with totally 10 repetitive circles/set. In the single, secondary task condition, subjects performed 2 sets of auditory arithmetic subtraction task, and two-digit number (10~99) appeared randomly in 6 trials per set during quiet sitting. In the dual task condition, subjects performed 2 sets arm-trunk coordinated stability task combined with arithmetic subtraction task randomly. (i.e., totally 20 circles with 12 dual trials). The performance of dynamic postural stability was reflected by kinetics of center of pressure (COP), kinematics of arm-trunk coordinated movement, and neuromuscular electromyographic (EMG) responses. The attentional demand was reflected by verbal reaction time (VRT). A two-way repeated measure ANOVA and Bonferroni adjustment were performed to determine the group effect and task effect for each variable.
Results: In the performance of single, primary arm-trunk coordinated task, the main findings included: (1) the COP maximal M-L displacement, the COP path and COP elliptical area were smaller (p<0.01) in the SCI group than the healthy group, (2) the shoulder adduction/abduction angle of the SCI group was bigger than the healthy group (p<0.001), but trunk flexion/extension angle, pelvic anterior/posterior tilt angle and rotation angle of SCI group were smaller than healthy group (p<0.05), (3) the SCI group increased significantly (p<0.016) their cylinder tip error of x-y-component and total cylinder tip error, compared with the healthy group, (4) the NARMS right erector spinae (RT6PS), right abdominal oblique (ROA) and posterior deltoid (PD) were larger (p<0.025) in SCI group than the healthy group when trunk flexion. The NARMS of left erector spinae (LT6PS), right abdominal oblique (ROA) and pectoralis major (PEC) were larger (p<0.05) in SCI group than the healthy group conditions when trunk extension. In the performance of single, secondary auditory arithmetic subtraction task, it was found that VRT was significantly longer than the healthy group (p<0.001). In the dual task condition, the VRTs of the both groups were significantly longer than single task, and the VRT of the SCI group was longer than the healthy group. In the performance of arm-trunk coordinated dual task, the main findings were as follows. (1) The movement time (MT) of each cycle was significantly longer (p<0.001) in both groups comparison with the single task condition. (2) The COP maximal A-P displacement, the COP path and COP elliptical area increased significantly (p<0.05) in the SCI group compared with a single task performance, but smaller than the healthy groups (p<0.005). (3) Both the groups displayed an arm circular drawing trajectory with a significantly larger total cylinder tip error, cylinder tip error of x-y-dimension and z- dimension (p<0.05) than single task condition. The SCI group increased significantly (p<0.05) their cylinder tip error of x-y-component and total cylinder tip error, compared with the healthy group. (4) The SCI group displayed an arm-trunk movement with a significantly larger shoulder adduction/abduction angle, shoulder flexion/extension angle, trunk flexion/extension, rotation and pelvic anterior/posterior tilt (p<0.001) than single task condition, but the healthy group displayed significantly larger shoulder adduction/abduction and flexion/extension angles (p<0.01) than single task condition. (5) The NARMS of RT6PS, ROA and PD were larger (p<0.025) in SCI group than the healthy group when trunk flexion. The NARMS of RT6PS, LT6PS, ROA and PEC were larger (p<0.05) in SCI group than the healthy group during trunk extension. The NARMS of RT6PS, LT6PS, left abdominal oblique (LOA), PEC, and PD in SCI group (p<0.05) were increased more than single task condition whenever trunk in flexion or extension. In contrast, The NARMS of PEC, and PD were increased more than single task condition whenever trunk in flexion or extension.
Conclusions: The attentional demand for dynamic postural stability during arm-trunk coordinated circular movement in subjects with SCI was more than that in age-matched healthy adults during performing dual task. This study indicated that both groups would exceed the central processing capacity during performing dual task. The attention of healthy subjects focused more in maintaining dynamic sitting stability which made a less efficient performance in secondary task, and also needed longer movement time in performing primary task, so dynamic sitting stability of healthy subjects depended on attentional demand. When SCI subjects performed dual task, not only the performance of secondary task became less efficient, their performance in primary task also became less efficient. Therefore, SCI subjects needed more attentional demand than healthy subjects in maintaining dynamic sitting stability during dual task. This study provided clinical physical therapists in assessment and training with deficits in attention and dynamic sitting stability. In clinical practice, we could assess the attentional demand in maintaining dynamic sitting stability by dual task test, and understood the effect of attention on postural control.
|Appears in Collections:||物理治療學系所|
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