注意力聚焦策略對有無凍凝步態之巴金森症患者於雙重作業行走的影響

Abstract

研究背景與目的：雙重作業行走指的是在行走時同時進行另一項作業(上姿勢作業)。由於同時執行兩項作業會競爭有限的大腦注意力資源，因此適當的注意力配置為達到雙重作業表現的關鍵因素。巴金森症患者(包含有凍凝步態者與無凍凝步態者)由於大腦注意力資源減少、作業轉換能力不佳與動作自動化控制能力降低，相較於其他族群使雙重作業之干擾更劇。然而，目前關於注意力聚焦策略對巴金森症患者於雙重作業行走的研究結果並不一致，且其相對應的神經生理機制仍未被仔細探討。因此本研究的主要目的為探討注意力聚焦策略(無聚焦、行走內聚焦、行走外聚焦、上姿勢聚焦)對有無凍凝步態之巴金森症患者於雙重作業行走情境下的影響。 研究方法：本研究共招募20位有凍凝步態(平均年齡：65.1 ± 7.7歲)及19位無凍凝步態(平均年齡：63.0 ± 8.0歲)之原發性巴金森症患者進行雙重作業行走測試。受試者使用四種不同的注意力聚焦策略(無聚焦策略、行走內聚焦策略、行走外聚焦策略、上姿勢聚焦策略)，於行走時同時維持手中兩個鑲嵌的鐵環不互相碰觸（上姿勢作業）。本研究之分析參數包含：步態參數、鐵環穩定之錯誤率，以及腦電圖之theta (4-8赫茲)與alpha (8-12赫茲)的頻譜強度及其互頻強度。統計分析依據常態分佈的有無，使用4 × 2混合變異數分析(4 × 2 mixed ANOVA)或無母數分析，及最小顯著差異法(least significant difference)進行事後檢定，分析注意力聚焦策略與有無凍凝步態對各行為表現參數及腦電圖頻譜強度及其互頻強度的影響。 結果與討論：相較於無聚焦策略情境，給予注意力聚焦策略可藉由增加注意力控制的專注度提升雙重作業表現，且有無凍凝步態之巴金森症患者其表現與適用的注意力聚焦策略不同。有凍凝步態之巴金森症患者於雙重作業行走時相較於無凍凝步態之患者，步長較短、走路速度較慢，腦波之頻譜強度於theta及alpha頻帶較小，其可能原因為有凍凝步態之患者動作自動化控制能力較低、注意力資源容量較少。對於無凍凝步態之患者，使用行走外聚焦策略可促進行走控制的自動化與作業轉換的彈性，降低步長變異性與提升上姿勢作業表現；而對於有凍凝步態之患者，使用行走內聚焦策略可藉由增加自主意識控制以提升整體行走表現，且不影響上姿勢作業表現。 結論與臨床應用：在執行雙重作業行走時，行走外聚焦策略對於無凍凝步態之患者較佳，不但能有較穩定的步態及良好的上姿勢表現且有較佳的大腦注意力資源配置；而對於有凍凝步態之患者，行走內聚焦策略可增加自主意識控制以改善其動作障礙，為較佳的動作控制策略。本研究結果可應用於臨床治療巴金森患者的防跌衛教與雙重作業行走訓練。依據凍凝步態的有無，給予不同注意力聚焦策略的建議，使患者在日常活動中運用最適當的動作控制策略，以安全有效率的方式提升雙重作業行走之整體動作表現。

Background and Purpose: Dual-task walking is defined as walking and performing another task (the suprapostural task) simultaneously. Because walking task and the concurrent task would compete in a limited attentional capacity, appropriate attention allocation between the two subtasks is critical for optimizing dual-task performance. For patients with Parkinson's disease (PD), including freezers and non-freezers, dual-task interference is greater due to reduced attentional capacity, impaired task switch ability, and decreased movement automaticity. However, the researches about attentional focus strategies in dual-task walking in PD have inconsistent results and lack of neural evidences. The purpose of this study was to investigate the effects of different attentional focus strategies (no instruction, walking-internal focus, walking-external focus, and supraposture-focus) on dual-task walking performance and its related cortical activity in PD with freezers and non-freezers. Methods: Twenty freezers and nineteen non-freezers with idiopathic PD were recruited in this study. Each participant was requested to stabilize two interlocking sticks (suprapostural task) and walk simultaneously with different attentional focus strategies. Both behavioral and cortical data, including gait parameters, error movement rate of the stick stabilization, relative power spectrum and coherence peak of electroencephalography signals in theta (4-8 Hz) and alpha (8-12 Hz), were measured. Results: Giving attentional focus instruction would improve the dual-task performance by increasing concentration and attentional control than the no instruction condition. The FOG group had smaller step length, slower gait velocity, lower theta and alpha power than the non-FOG group in dual-task conditions. For the non-FOG group, the walking-EF strategy resulted in small walking variability and better suprapostural performance. In contrast to the non-FOG, the walking-IF strategy increased step length and gait velocity without sacrificing suprapostural performance. Conclusion and Clinical Application: In dual-task walking, the walking-EF strategy could improve walking and suprapostural performance with more effective resource allocation for non-freezers. While freezers could increase attentional control to improve the performance with walking-IF strategy, which is a safe motor control strategy for them. The present study provides an appropriate attentional strategy suggestion and training for patients with PD depending on the characteristic of FOG. This could help patients with PD to use the suitable movement strategy to improve dual-task walking performance safely and effectively.