跌倒危險因子評估工具於中風患者的信度效度與反應性分析

Abstract

背景: 隨著國家逐漸邁入高齡化社會，跌倒議題在銀髮族中更顯為重要。研究顯示，有中風病史的老年人為跌倒的高危險群。跌倒會造成身體傷害，重則骨折或頭部外傷，輕則軟組織受傷。對於中風病患，內在因子的生理損傷程度是相當重要。澳洲 (雪梨威爾斯醫學研究中心) Lord博士於1991年發展出跌倒危險因子評估工具 (Physiological Profile Assessment , PPA)，即是設計量化評估老年人的生理損傷程度，此工具應用於老年人跌倒危險因子的信效度分析已有相關研究，但未施行於中風患者。目的: 探討此工具應用於中風病患的信效度與反應性。方法: 本研究收案60位中風病患，中風病人姿勢控制評估量表 (STREAM)平均分數是65.4 。研究方法是選用簡短版的跌倒危險因子評估工具 (PPA-Short Form)，此工具評估五個主要的生理層面：視覺、本體感覺、肌力、反應時間與站姿平衡能力。首先，評估再測信度，在ㄧ個禮拜的間隔，以組內相關係數評估此工具於中風病患的再測信度。第二部份評估再分析此工具與其他跌倒危險因子評估工具(例如：柏格氏平衡量表)的相關性。藉由此工具比較中風病患中跌倒與非跌倒者的差別，進ㄧ步探討此工具的效度，以接受器操作控制曲線分析此工具是否可正確區辫中風病患中有無跌倒經驗者。第三部份評估反應性，將以此工具比較中風病患接受一個月平衡訓練前後的差別，得知此工具對改變的反應性。 結果: 簡短版跌倒危險因子評估工具內每一個評估面向皆有中等至良好的再測信度 (n= 53 , 組內相關係數= 0.83~0.96)。簡短版跌倒危險因子評估工具所測得的整體跌倒風險值與柏格氏量表總分有高度相關 (n= 60, 皮爾森相關係數= -0.605)。且中風病患中跌倒 (n= 28)與非跌倒者 (n= 32)在簡短版跌倒危險因子評估工具內的每一個評估項目皆有顯著差異 (p<0.05)。另外，此工具可正確區辨91%有跌倒經驗的中風病患。 除了視覺測驗 (效應值= 0.1; 標準化反應平均值= 0.3)，此工具的其他測試項目都可明顯反應中風病患 (n=12)接受一個月平衡訓練前後的改變 (效應值= 0.8~4.7; 標準化反應平均值= 3~41) 。結論: 簡短版跌倒危險因子評估工具對於輕中度的中風患者有良好的信度，區辫效度，且能反映出訓練前後的改變量。故此工具可應用於輕中度的中風患者的跌倒風險評估。

Background and Purpose: Previous studies have found the physical impairments of intrinsic factors were important risk factors for falls in subjects with stroke. One approach for assessing intrinsic fall risk was Physiological profile Assessment (PPA), which was developed in 1991 by Dr. Lord. To be practical in clinical setting, present study chose the short form of PPA which contained five components, i.e., vision, peripheral sensation, muscle force, reaction time, and balance. The aim of this study was to assess the reliability, acuuracy, and responsiveness of PPA-short form for subjects with stroke. Methods: Sixty subjects with stroke aged 52-81 years were recruited in the study (Mean STREAM= 65.4). We chose PPA-short form to assess the population. The short form contained 5 items: a test of vision (edge contrast sensitivity), proprioception, knee extension force, hand choice reaction time and body sway (sway when standing on the medium-density foam rubber mat). The method included three major parts. The first part was to examine the test-retest reliability of PPA among subjects with stroke on two occasions with one week apart by intraclass correlation coefficient (ICC) analysis. The second part was to calculate the association validity of the PPA to the other measures for fall risk (i.e., Berg balance scale) in subjects with stroke by the Pearson correlation coefficient. The PPA was also be analyzed between fallers and non-fallers for subjects with stroke, and the accuracy was analyzed with receiver operating characteristics curve (ROC-curve). The third part was to assess the responsiveness of PPA by investigating the changes after four weeks balance training in subjects with stroke. The results would help the fall risk assessment in clinics. Results: A strong correlation was observed between PPA overall fall risk score and Berg balance scale (r=-0.605). All PPA tests showed good test-retest reliability (ICC= 0.83-0.96). Twenty-two participants were classified as fallers. Significant differences were found between fallers and non-fallers on all physiological domains (p<0.05). The PPA classified 91% subjects into faller and non-faller group. All PPA variables showed moderate to large responsiveness (ES=0.5-4.8; SRM=3-41) except vision (ES=0.1; SRM=0.3). Conclusions: The PPA which demonstrated good reliability, accuracy and responsiveness was recommended as a good fall risk assessment tool for mild to moderate stroke.