巴氏量表－補充量表之發展暨應用於中風病人之心理計量特性驗證

Abstract

背景與目的：中風後所帶來之後遺症可能導致個案在日常生活活動 (activities of daily living, ADL)執行上遭遇困難，進而影響其生活獨立自主與生活品質之維持。ADL至少包含3個層面：平常表現、自覺困難程度及執行能力。平常表現，是指個案在平常生活中實際從事ADL的獨立程度；自覺困難程度，是指個案主觀認為從事各項ADL之困難程度；執行能力，是指在標準化環境下個案執行各項ADL之能力。評量ADL之三層面可協助治療師瞭解個案在真實生活中獨立狀況，可針對個案困難部分提供諮詢或協助，有助於治療師擬定治療計畫。然而由文獻回顧發現，學術與臨床領域目前尚缺乏一個可快速施測且涵蓋完整ADL三層面之中風病人評估工具。 巴氏量表 (Barthel Index, BI)為一國內外廣泛使用之基本ADL功能評估工具。因BI具備項目精簡、良好心理計量特性及經濟實惠等優點，BI可作為發展其他ADL層面之藍圖。本研究包含四子研究，各子研究之目的為：研究1：發展自覺困難程度量表與執行能力量表，合稱為巴氏量表-補充量表 (Barthel Index-based Supplementary Scales, BI-SS)；研究2：檢驗BI-SS之建構效度；研究3：檢驗BI-SS之信度；研究4：檢驗BI-SS之反應性等應用於中風病人之心理計量特性。 方法：研究1為發展BI-SS。發展BI-SS階段，共分為二步驟：第一步驟為專家訪談，建立初版之BI-SS，第二步驟為臨床實際測試，以確認項目指導語與選項是否易於個案理解與作答，並檢驗執行方式之可行性。 研究2為檢驗BI-SS之建構效度。樣本為復健部住院或門診之中風病人。所得資料使用Mokken scale之monotone homogeneity (MH)模型檢驗各層面項目之單向度 (unidimensionality)。分別計算個別項目Hi值及整組項目同質性係數H值。此外，並使用Spearman’s rho correlation coefficient (rho)檢定BI-SS與BI之關聯程度，以檢驗收斂效度。 研究3為檢驗BI-SS之信度，包含自覺困難程度量表與執行能力量表之再測信度。收案對象為門診慢性中風病人（發病至少6個月以上）。資料以組內相關係數 (intraclass correlation coefficient, ICC)檢驗重複評量結果之一致性。此外，並依據ICC值計算BI-SS各層面之最小可偵測之變化值 (minimal detectable change, MDC)。 研究4為檢驗BI-SS施測於住院中風病人之反應性，包含（一）團體層級反應性，以(1)效應強度 (standardized effect size, SES)；(2)標準化反應平均值 (standardized response mean, SRM)；(3)配對t檢定，檢驗BI-SS之內在反應性；以BI為外在效標，計算Pearson correlation coefficient (r)，檢驗BI-SS之外在反應性。（二）個別層級反應性：二量表偵測個案於入出院總分數改變超過最小可偵測變化值之人數。 結果：研究1：經二次專家小組會議及三次臨床測試後，完成BI-SS之發展。自覺困難程度量表共有10個項目，總分為20分。評估方式以口頭訪問個案為主。執行能力量表共有8個項目，總分為18分。評估方式為評估者直接觀察個案於標準環境下，使用一套評估者所準備之評估材料實際操作。 研究2：共306位中風病人參與此研究。Mokken scale之MH模型檢驗結果顯示，自覺困難程度量表10項目與執行能力量表8項目之Hi值皆大於0.3，整體H值各自都大於0.5。此外，兩量表總分各自與BI總分間的關聯程度高（分別為rho=0.78及rho=0.90）。 研究3：共84位門診中風病人完成自覺困難程度量表與執行能力量表再測信度研究。結果顯示，自覺困難程度量表與執行能力量表再測信度ICC值分別為0.78及0.97; MDC值分別為5.5及1.9分。 研究4：56位復健病房住院中風病人完成反應性研究。團體層級反應性:自覺困難程度量表與執行能力量表具中至大的內在反應性 (0.78-1.56)。此二量表總分於前後二次測量之平均分數具備統計顯著差異 (P<0.001)。外在反應性方面，個案入出院於二量表之分數變化與個案之入出院BI分數變化間之r值分別為0.23及0.61。個別層級反應性，二量表分別有25及48人之進步量超過MDC值。 討論與結論：BI-SS以原始BI項目為藍圖，加入評量自覺困難程度及執行能力兩層面。本研究所發展之BI-SS其項目指導語與選項易於個案理解與作答。BI-SS具有良好之建構效度。此外，結果證實執行能力量表使用於慢性中風病人具高度之再測信度，評估結果穩定，可重複施測於慢性中風病人。自覺困難程度量表因其隨機測量誤差較大，具中度再測信度。BI-SS用於復健病房住院中風病人具中度至高度內在反應性，可適度反應個案住院期間自覺困難程度及執行能力之變化。整體而言，BI-SS具備良好心理計量特性，其結果有助於臨床人員進行決策，並可作為療效評量。此研究結果可作為BI-SS應用於研究與臨床之實證依據。

Background: Stroke is the most common cause of disability or dependence in activities of daily living (ADL) among the elderly. Three distinct constructs of ADL measures have been proposed: actual performance, self-perceived difficulty, and ability. Assessing these three ADL constructs can be useful for identifying disability in performing ADL and thus, also for intervention planning. However, according to literatures, there is still no ADL measure that assesses all three ADL constructs simultaneously which might overlook the relationships between constructs that affect patients’ ADL functions. The Barthel Index (BI) has been widely used in both clinical and research settings due to its advantages: it is quick and easy to administer, has sound psychometric properties, and is economical and practical to use. The BI is an appropriate instrument to be used as a basis to further develop other ADL constructs to comprehensively assess ADL functions. Objective: This dissertation aims to: (1) develop two BI-based Supplementary Scales (BI-SS), namely the Self-perceived Difficulty Scale and Ability Scale; (2) examine the construct validity of the BI-SS; (3) examine the reliability of the BI-SS; (4) investigate the responsiveness of the BI-SS in inpatients with stroke. Method: This dissertation consists of four studies. Study 1 was to develop the BI-SS. The development of the BI-SS had two stages. Stage one was to consult with experts to develop the draft version of the BI-SS. Stage two was to conduct pilot studies to examine the clarity of the administrative instructions and the feasibility of administration of the BI-SS. Study 2 was to examine the construct validity of the BI-SS. Patients undergoing outpatient or inpatient rehabilitation were recruited from the Department of Physical Medicine and Rehabilitation (PM&R). The construct validity of the BI-SS was investigated using the model of monotone homogeneity of Mokken scale analysis and analyzing associations between scales. Study 3 was to investigate the test-retest reliability of the Self-perceived Difficulty Scale and the Ability Scale. One convenience samples of outpatients with chronic stroke were recruited from the PM& R. Intra-class correlation coefficients (ICC2, 1) were calculated to examine the extent of agreement between repeated assessments. The minimal detectable change (MDC) was also calculated to determine whether the change score of an individual patient is real at the 95% confidence level. Study 4 was to examine: (1) The group-level responsiveness, including the internal responsiveness and external responsiveness. Three indices, standardized effect size (SES), standardized response mean (SRM), and paired t test, were used to examine the internal responsiveness. The Pearson correlation coefficient (r) was used to examine the association between the changes in scores on both scales and the changes in scores on the BI (treat as an external criterion). (2) The individual-level responsiveness (the number of patients whose change score on the BI-SS exceeded the respectively MDC). Results: Study 1: Based on the results of expert panel discussion and pilot testing, the Self-perceived Difficulty Scale consisted of 10 items with the total score of 20. The Self-perceived Difficulty Scale was assessed with a face to face interview format. The Ability Scale had 8 items with total score ranges of 18. The Ability Scale was assessed by observing patients doing a specific ADL task with assessment tools. Study 2: A total of 306 participants participated in this study. The results showed that items in each scale of BI-SS were unidimensional (Hi ≥ 0.3). The unidimensionality of each individual scale were strong (H ≥ 0.5). The scores of both scales were highly correlated with those of the BI (rho=0.78 and 0.90, respectively) and were significantly different from each other (p<0.001). These results indicate that the BI-SS each scale assesses unique construct. Study 3: A total of 84 patients participated in the test-retest reliability of the Self-perceived Difficulty Scale and the Ability Scale. The ICC values for the Self-perceived Difficulty Scale and the Ability Scale were 0.78 and 0.97, respectively. The MDC values were 5.5 and 1.9 points. Study 4: Fifty-seven patients completed both baseline and follow-up assessments. (1) The group-level responsiveness, the internal responsiveness of the BI-SS was moderate to large (0.78-1.56). For the external responsiveness, the change in score of the both scales had weak to moderation association with that of the BI (r=0.23 and 0.61, respectively). (2) The individual-level responsiveness, the numbers of patients having change scores exceeding the MDC of the both scales were 25 and 48, respectively. Discussion and Conclusion: The BI-SS was developed from the BI as supplementary scales in order to comprehensively assess ADL functions. The BI-SS had clear and understandable instructions and overall sufficient construct validity in patients with stroke. The results of reliability studies showed that the Ability Scale had appropriated test-retest reliability and reasonable responsiveness in patients with stroke undergoing inpatient rehabilitation. Further studies are needed to minimize the random measurement error of the Self-perceived Difficulty Scale. These results provide empirical evidence of the BI-SS in assessing stroke patients’ level of difficulty and ability in performing ADL tasks.