雙重作業與單一作業模式之姿勢－認知訓練對巴金森輕度認知障礙患者於雙重作業行走表現及大腦活動的影響

Abstract

研究背景與目的：雙重作業行走為行走時同時進行另一項動作或認知作業，是維持日常生活的重要功能。雙重作業行走能力下降與跌倒風險增加息息相關。巴金森輕度認知障礙患者行走能力受損伴隨認知功能下降，因此相較於認知功能正常的巴金森患者，有更嚴重的雙重作業行走困難。雙重作業行走訓練為改善老化與神經疾病患者雙重作業行走困難的有效方法之一，但巴金森輕度認知障礙患者由於認知功能下降，可能造成雙重作業行走訓練成效下降。考量大腦注意力資源與認知功能的限制，雙重作業訓練模式對巴金森輕度認知障礙患者而言，可能非改善雙重作業行走控制的最佳訓練方式。因此，本研究目的為探討雙重作業模式與單一作業模式之姿勢－認知訓練，何者更能有效促進巴金森輕度認知障礙患者的雙重作業行走表現，並配合腦波分析，探討不同訓練模式對大腦可塑性的影響。 研究方法：本研究共22名巴金森輕度認知障礙患者完成評估測試，雙重作業模式組與單一作業模式組各11人。受試者接受每週2次、總共6週的姿勢－認知訓練。訓練時，雙重作業模式組需同時執行平衡、行走作業與認知作業，單一作業模式組則分開執行兩項作業。本研究於訓練前、訓練後、後測結束8週後進行雙重作業行走評估。評估項目包含雙重作業步態參數、上姿勢作業表現、腦波各頻帶相對強度(delta (1-4 Hz)、theta (4-8 Hz)、alpha (8-12 Hz)、beta (12-30 Hz)、low gamma (30-50 Hz))、以及臨床量表分數。另外，本研究評估受試者自參與實驗第一週起，連續20週的跌倒發生次數。 結果：在進行六週姿勢－認知訓練之後，雙重作業模式組與單一作業模式組在單一作業行走、動作雙重作業行走、以及認知雙重作業行走情境時的行走速度與步長皆顯著增加。然而，僅有單一作業模式組在三種行走情境下，步幅時間變異性皆顯著下降。在腦波頻帶相對強度變化上，單一作業模式組在三種行走情境下theta 頻帶強度上升，而雙重作業模式組僅於額葉區呈現theta頻帶上升。於單一作業行走與動作雙重作業行走情境時，僅有單一作業模式組呈現beta頻帶上升以及delta頻帶下降。臨床量表評估顯示，雙重作業模式組與單一作業模式組經訓練後，巴金森病綜合評量表第三部分以及福康量表分數降低、伯格式平衡量表分數增加。另外，兩組於巴金森病綜合評量表第三部分以及福康量表之進步皆可延續至追蹤測試。 重要性與預估貢獻：本研究探討不同作業模式之姿勢－認知訓練對於雙重作業行走表現及大腦神經可塑性的影響。研究顯示雖然雙重作業、單一作業訓練模式皆能促進雙重作業行走速度與步長，但單一作業訓練模式對降低步幅時間變異性的效果更加顯著。另外，相較於雙重作業模式組，單一作業模式組經訓練後可以較少大腦注意力資源達到較佳的行走控制。考量巴金森輕度認知障礙患者大腦注意力資源之限制，於臨床上建議以單一作業模式進行姿勢－認知訓練，可有效改善患者的雙重作業行走控制，進而降低患者潛在的跌倒風險。

Background and Purpose: Dual-task walking indicates walking and performing a concurrent motor/cognitive task, which is a critical ability in daily life. Decreased dual-task walking control is associated with high risk of falling. Due to more impaired gait control and cognitive function, patients affected by Parkinson’s disease (PD) with mild cognitive impairment (MCI) often have more severe dual-task walking deficits than PD patients without MCI. Dual-task walking paradigm has been proved as an effective treatment to improve dual-task walking control in patients with PD. However, the benefits of dual-task walking training may be affected by the cognitive function of patients with PD. Due to insufficient brain attentional resources and cognitive function, dual-task paradigm may be not the optimal model to improve dual-task walking ability in patients with PD-MCI. Therefore, this study aimed to investigate the effects of integrated and consecutive postural-cognitive training on dual-task walking and related brain activity in patients with PD-MCI. Methods: Twenty-two patients with PD-MCI were randomly allocated to the integrated training group or the consecutive training group. All participants completed a 6-week postural-cognitive training, with 2 training sessions per week. In training sessions, the integrated training group were trained with dual-task paradigms by performing a postural task and a cognitive task simultaneously, while the consecutive training group performed a postural task and a cognitive task separately. Walking assessments (e.g. single-task walking, motor dual-task walking, and cognitive dual-task walking) with electroencephalogram (EEG) recordings and clinical evaluations were conducted at baseline (pre-test), after training (post-test), and 8 weeks after post-test (follow-up test). The EEG relative power was calculated in delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12-30 Hz), and low gamma band (30-50 Hz). Clinical evaluations included the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III, Berg Balance Scale (BBS), Falls Risk for Older People Community setting (FROP-Com), and the falling events recorded for 20 consecutive weeks from the first week of the experiment. Results: Both consecutive and integrated training groups increased gait velocity and step length in single-task walking, motor dual-task walking, and cognitive dual-task walking after a 6-week postural-cognitive training. However, only the consecutive training group showed smaller stride time variability in the three walking conditions. Theta power generally decreased in the consecutive training group at post-test, while the theta power increased at frontal area for all walking conditions in the integrated training group. In addition, increased beta power and decreased delta power at post-test for single-task walking and motor dual-task walking conditions were observed only in the consecutive training group. In terms of clinical evaluations, both consecutive and integrated training groups showed increased scores of BBS and reduced scores of MDS-UPDRS Part III and FROP-Com after intervention. Moreover, the improvements of MDS-UPDRS Part III and FROP-Com maintained to follow-up test for both groups. Significance and Contribution: This study investigated the effects of integrated and consecutive postural-cognitive training on dual-task walking performance and the related neural plasticity. Although both integrated and consecutive postural-cognitive training could improve walking performance in patients with PD-MCI, consecutive paradigm led to superior training effect on gait variability in single-task and motor dual-task walking conditions. Besides, the consecutive training group might need less attentional resources for gait control and had higher motor flexibility after training. Therefore, we suggest that consecutive postural-cognitive training model is a more appropriate strategy to enhance gait control for PD-MCI in clinical practice.