姿勢注意力聚焦策略對雙重作業行走訓練之影響： 以具凍凝步態之巴金森患者為例

Abstract

研究背景與目的:凍凝步態是巴金森患者特有的行走異常問題，尤其於雙重作業情境下更容易誘發凍凝步態。大腦注意力資源分布能力不佳為導致具凍凝步態之巴金森患者雙重作業行走困難的關鍵因素。注意力聚焦包含「內聚焦」與「外聚焦」，是影響動作控制與學習的重要因子。研究顯示外聚焦策略可促進動作自動化控制；而內聚焦策略則可增加動作的意識控制。然而，注意力策略對於凍凝步態之巴金森患者的雙重作業行走效果尚未被探討。因此，本研究目的為探討雙重作業訓練時，以內聚焦或外聚焦策略訓練姿勢作業，何者會有較佳的雙重作業行走控制，同時也配合腦波圖量測，探討注意力聚焦策略對大腦神經可塑性的影響。 研究方法:本研究招募34位具凍凝步態巴金森氏症患者，隨機分配至內聚焦組及外聚焦組(每組各17位受試者)，進行雙重作業行走訓練。訓練時，內聚焦組將注意力放置在動作本身，即注意動作的肢體或關節。外聚焦組則是將注意力放置在動作效應，即以外在環境物體為目標。訓練為一週2次，連續6週。於訓練前一週進行前測、訓練結束後一週進行後測，且於有藥效與無藥效情況皆進行評估。評估項目包括動作雙重作業行走、認知雙重作業行走、雙重作業行走時之腦波相對頻帶強度、臨床評估量表(新版世界動作障礙學會巴金森病綜合評量表第三部分、伯格氏平衡量表、雙重作業坐站起走、特定活動平衡信心量表、新式凍凝步態量表)、並紀錄訓練前2週與訓練後2週患者發生凍凝步態與跌倒之次數。 結果：經6週訓練後，內聚焦組與外聚焦組在有藥效情況下之動作雙重作業行走、認知雙重作業行走速度均有顯著增加，然內聚焦組主要是以增大步伐長度來增進速度、而外聚焦組則以增加步伐長度與步頻來增進速度。但無藥效情況下，僅內聚焦組可改善動作雙重作業行走步態(速度增加、步伐長度增加)。在腦波相對頻帶強度改變上，經訓練後在有藥效情況下，內聚焦組與外聚焦組均出現delta頻帶強度降低。在無藥效情況下執行動作雙重作業時，經訓練後內聚焦組顯著增加前額葉區alpha頻帶強度、但外聚焦組則增加前額葉與額葉區theta頻帶強度。臨床量表評估除無藥效雙重作業坐站起走僅有內聚焦組可顯著降低執行時間，其餘評估經訓練後皆有進步，但在兩組間並無顯著差異。 結論與臨床應用:本篇研究探討注意力聚焦策略對雙重作業行走訓練的影響，以及不同的注意力聚焦策略應用於雙重作業訓練的神經可塑性。研究結果顯示經6週雙重作業行走訓練，無論使用何種注意力策略，皆可有效提升有藥效下雙重作業行走速度，但考量凍凝步態患者步伐距離較短，外聚焦策略伴隨之步頻增加並非最佳行走模式。以內聚焦行走訓練策略不僅可有效增加步伐長度，且其效果也可轉移至無藥效情況下之雙重作業行走表現。臨床上，建議可以行走內聚焦方式對有凍凝步態巴金森患者進行雙重作業行走訓練，以有效提升行走安全並降低跌倒與凍凝步態發生率。

Background and Purpose: Freezing of gait (FOG) is one kind of gait impairment specific in patients with Parkinson’s disease (PD). FOG is often triggered under dual-task condition. It has been reported that attentional control and movement automaticity is more impaired in PD with FOG than PD without FOG, resulting in severe declining of gait performance during dual-task walking in freezers. Attentional focus strategies include internal focus (IF) and external focus (EF), which are an important factor for motor learning and motor control. It has been reported that EF enhances movement automaticity, and IF increased conscious control of movement. However, how the attentional focus strategies affect dual task walking training in freezers hasn’t been investigated. The purpose of this study is to investigate the effects of attentional focus strategies in dual- task training on dual task walking performance and its related neural mechanism in freezers. Methods: Thirty-four subjects of PD with FOG were recruited and randomly assigned to IF and EF groups. During dual-task walking training, the IF group was instructed to focus on body movements of the walking task; in contrast, the EF group was instructed to focus on the effects of movements on the environment or the end goal of the walking task. There were 2 training sessions each week, and lasted for 6 weeks. The performance of motor dual-task walking, cognitive dual-task walking, and related brain activity were recorded by 64-channel electroencephalogram (EEG) at one week before the start of intervention (pre-test) and one week after the end of intervention (post-test) under both ON and OFF medication states. In addition, clinical evaluation including Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III, Berg Balance Scale (BBS), Activities-specific Balance Confidence Scale (ABC), dual-task timed up and go (TUG), New Freezing of Gait Questionnaire (NFOG-Q), and occurrence of FOG and fall were also assessed. Results: After 6-weeks dual-task training, both the IF and EF groups increased gait velocity in motor dual-task walking and cognitive dual-task walking under ON medication state. However, the IF group increased gait velocity by increased step length, but the EF group increased gait velocity by increased step length and cadence. In motor dual-task walking under OFF medication state, only the IF group increased gait velocity and step length. In terms of brain activity related to dual-task walking, both IF and EF groups decreased delta power after 6-weeks intervention. When performing motor dual-task walking under OFF medication state, the IF group increased alpha power in prefrontal cortex, but the EF group increased theta power in prefrontal and frontal cortices after intervention. For each clinical evaluation, both IF and EF groups showed improvements except that only the IF group reduced time duration when performing dual-task TUG under OFF medication state. Conclusion and Clinical Applications: This study investigated the application of attentional focus theory on dual-task walking. According to our results, although both IF and EF attentional strategies led to improvements in dual-task walking control under ON medication state, only the IF group could transfer the training benefits to OFF medication state. In clinic, the IF strategy was suggested to be an effective and safe movement strategy of dual-task walking training for improving dual-task walking under both ON and OFF medication states, and reducing occurrences of FOG and falling.