探討腦性麻痺孩童於虛擬實境、物理實境與混合實境三種情境中的表現差異

Abstract

腦性麻痺為常見造成孩童功能缺損的疾病之一，常伴隨有動作、姿勢、認知、知覺等方面的功能缺損。其成因來自腦部發展時先天的受損、病變、傷害等，造成發展性障礙。近年來，許多研究者與臨床工作者認為虛擬實境 (virtual reality) 能夠作為腦性麻痹孩童的復健工具，因為虛擬實境可提供大量的感覺刺激，並藉由有趣的遊戲情境提升孩童復健動機，使他們不會抗拒高強度且重複的練習。過去研究顯示，腦性麻痺孩童接受虛擬實境介入後，動作技巧上有顯著的進步，然而這些動作上進步似乎無法直接轉化到物理實境 (physical reality) 之中。造成轉化效果不彰的最主要因素，可能在於虛擬實境缺乏實際物品的觸動覺回饋 (haptic feedback)。為解決此問題，研究者將實際物品加進虛擬實境之中，形成一種新的型態－－混合實境 (hybrid reality)。過去研究認為，混合實境可提升一般發展孩童的現實感 (presence)，促使他們用較為自然的動作模式完成任務，減少怪異、不符常理的代償動作出現。然而，腦性麻痺孩童有先天動作功能上的限制，混合實境是否能作為有效之復健工具並加強轉化效果，還需進一步的探討。 這個研究的目的在於探討腦性麻痺孩童在虛擬實境、物理實境及混合實境中的差異，包含動作覺、功能表現與主觀經驗感受，同時也有一組一般發展孩童作為對照。總共有12位腦性麻痺孩童與9位一般發展孩童參與此研究，每位受試者都須完成三種情境中的打鼓任務。執行任務時，受試者的動作會被紅外線攝影機捕捉並錄下，同時遊戲系統會記錄功能性表現。每一個情境結束後，受試者都須填答主觀經驗感受問卷，最後進行三種情境的排名。 根據研究結果，我們發現混合實境中添加的實際物品－－鼓棒－－對受試者的動作參數有正面影響，與虛擬實境相比，動作更趨近物理實境。與物理實境相比，腦性麻痺孩童的患側手在虛擬實境中的打鼓動作時間及動作路徑較長，且動作較不平順，但最大速度較大。混合實境則有效降低其動作速度及動作距離，並且使腦性麻痺孩童的患側手以較平順的模式完成任務。一般發展孩童的非慣用手在虛擬實境中也呈現較長的動作路徑及較快的動作速度，但健側手並未出現此差異。由此推論，任務的難度會影響加入觸動覺回饋的效果。此外，一般發展孩童雙手的手腕在虛擬實境中伸展 (extension) 的角度較另外兩種實境小，顯示握有實際鼓棒對關節動作的顯著影響。 功能表現部分，腦性麻痺孩童在物理實境的準確度比另外兩種實境高，但一般發展孩童在三種情境中無顯著差異。這表示除了動作功能外，擊鼓準確度也受到腦性麻痺孩童先天視知覺功能缺損的影響。 受試者主觀經驗感受部分，腦性麻痺孩童認為混合實際可以提升控制感，握有鼓棒也讓他們感覺較貼近一般的打鼓活動。但是，他們也認為以混合實境執行任務，比另外兩種情境較為無趣及困難，可能使他們動機降低。對於一般發展孩童來說，握住鼓棒的要求僅提升任務的自然度。 根據以上結果，混合實境作為虛擬實境與物理實境的結合，可同時涵蓋兩者的優點。但由於對動作功能要求較高，在應用於腦性麻痺孩童復健計劃時，應審慎調整任務難度，符合孩童能力，才能在良好動機下進行有效的訓練。

Cerebral Palsy (CP) is described as a primary disorders showing deficits in movement, posture, cognitive and other abilities originated from a non-progressive disturbances in a developing brain. Virtual reality (VR) system has been considered as a potential rehabilitation tool in recent years for its high intensity, multisensory stimulations, and enjoyable gaming environments. Although VR rehabilitation of children with CP showed strong effects on motor skills, the improvements on motor abilities showed no direct transfer from VR to physical reality (PR). The loss of haptic feedback in virtual environments may be crucial. Adding physical objects into VR games, in terms of hybrid reality (HR), may be a solution to combine both advantages of two realities; however, whether HR games are potential for children CP to transfer attained motor skills from VR to PR or not should be further investigated. This study aimed to investigate the differences of kinematics and functional motor performance among VR, PR and HR conditions in children with hemiplegic CP as well as typically developing children (TDC). 12 children with CP and 9 TDC were recruited to execute a drum task presented in three different conditions: VR, HR and PR. The motor kinematics data was collected, and the functional performance was presented by the records in the gaming system. Participant’s experience was examined through a questionnaire. In this study, I found that the additional physical object in HR, in terms of the drumstick, had positive impact on the participants’ performance in kinematics variables. The affected hand of children with CP spent a longer time and longer movement path to hit the drum in VR condition with a less smooth movement, but the PV was higher in VR condition. These results showed that HR efficiently lowered down the speed of the movements, decreased the movement distance, and made children with CP hit the drum with a smoother pattern. Respecting to TDC, the non-dominant hand showed a longer and faster hand path under VR condition while no significant difference was found in the dominant hand. The result indicates that the difficulty of the task may influence the impact of haptic feedback. In additional, the angles of both hand wrists of TDC were less extended in VR than in HR and PR conditions, demonstrating the significant impact of holding a physical object in hand. As for the functional performance, children with CP showed a higher accuracy in PR condition than in both HR and VR conditions. TDC showed no difference of accuracy among three conditions. For participant’ subjective experience, children with CP reported that HR enhanced a sense of control, and the drumstick in hand improved the naturalness of the task. However, they also reported that the task in HR condition was less interesting and more difficult, which may lower their motivation. As for TDC, the ability acquired in HR condition had no impact on their enjoyment, but the physicality did enhance the sense of naturalness. According to the results, HR takes advantages of both VR and PR’s assets for rehabilitation, such as the flexibility of VR and tangibility of PR, but the task should be carefully altered to meet the capacity of children with CP for enhancing motivation.