使用羅序分析交叉檢驗中風復健動作評估量表上肢／下肢動作次量表之心理計量特性

背景：中風復健動作評估量表 (Stroke Rehabilitation Assessment of Movement, STREAM) 目前已有許多古典測驗理論相關的心理計量特性研究。但仍有三個問題待解決：(1) STREAM上、下肢次量表題目是否符合單向度 (unidimensionality)? (2) 將順序量尺 (ordinal) 直接當作等距量尺 (interval) 加總計分，有數學運算不當的問題。(3) 題目難度之估計具有樣本依賴性。羅序分析 (Rasch analysis) 以數學模式為基礎，依據個案作答反應以等距量尺同時估計個案能力及題目難度，且當評量數據符合羅序模式 (Rasch model) 預期時，該題目符合單向度。然而至今僅有一研究使用羅序分析驗證STREAM，無法呈現充分且穩定的證據。研究目的：本研究目的為交叉檢驗STREAM上、下肢動作次量表之心理計量特性，包含建構效度之單向度、羅序信度，以及題目難度排序相關性。並且另外檢驗，以本研究及昔日研究之題目難度參數估計個案分數的相關性。研究方法：採用次級資料分析法。先自原始資料中篩選出符合收案標準的302位亞急性期中風患者，再以羅序分析之評等量尺模式 (rating scale model) 驗證：單向度以各題目之羅序模式適配度為指標，適配度良好表示該題目具有單向度；羅序信度則假設測量標準誤會隨著個案能力不同而有所差異。最後將分析結果與過去研究進行交叉檢驗，比較心理計量特性的一致性及相關性。結果：（一）上肢次量表僅有6題目具單向度，包含：舉手碰頭頂、手向後摸對側屁股、手臂舉高過頭、前臂旋前／後、握拳、手打開。下肢次量表有8題目具單向度，包含：大腿抬高、膝關節伸直、膝關節彎曲、於坐姿下腳板翹高且腳跟著地、腳跟翹高且腳尖著地、膝關節伸直且腳趾翹起、髖關節伸直且膝關節彎曲、於站姿下腳板翹高且腳跟著地。（二）上、下肢次量表羅序信度分別為 0.92、0.93，均略高於Hsueh等研究的0.86、0.91。上、下肢次量表之個案信度皆為243人大於0.90、59人介於0.80 ~ 0.90之間。（三）二篇研究之上、下肢次量表題目難度排序分別為低度及中度相關 (Spearman's rho = -0.31、0.48)。（四）二篇研究之上、下肢次量表題目難度參數估計個案分數之相關性分別為高度及中度相關 (Pearson's r = 0.96、0.62)。結論：交叉檢驗STREAM上、下肢動作次量表之心理計量特性，發現上肢次量表題目單向度結果不一致、其題目難度排序僅有低度相關，但其題目難度參數估計之個案分數具高度相關。下肢次量表單向度結果相對較一致、題目難度排序有中度相關，然而其難度參數估計之個案分數卻僅有中度相關。分析結果與預期之間的落差也許跟樣本特性有關，但僅憑二篇研究之比較，較難推論二數據之優劣。未來宜再驗證並釐清之。

關鍵字

中風復健動作評估量表；羅序分析；心理計量特性；動作功能評估量表

並列摘要

Background: There have been many studies based on classical test theory (CTT) which validated the psychometric properties of the Stroke Rehabilitation Assessment of Movement (STREAM). But there were at least 3 psychometric issues that needed to be investigated, including (1) the unidimensionality of upper extremity (UE) / lower extremity (LE) movements subscales of the STREAM; (2) the direct transformation of ordinal raw STREAM total scores into interval scores, which was not mathematically valid; and (3) the estimation of the item difficulty parameters was sample dependent. The Rasch analysis enables examining unidimensionality and Rasch reliability. Moreover, Rasch analysis could transform the STREAM from an ordinal-level measure into an interval-level measure, and estimate both person’s ability and item difficulty. However, so far there was only one study using the Rasch analysis to validate the STREAM, which couldn’t provide sufficient and solid evidence. Purpose: To cross-validate the psychometric properties of UE / LE movements subscales of the STREAM with the Rasch Analysis, including (1) the unidimensionality of construct validity; (2) the Rasch reliability; and (3) the correlation of the order of item difficulty parameters between previous study and this study. Besides, researchers validated the correlation of latent trait scores based on previous parameters and this study’s. Methods: Researchers employed secondary data analysis. First, 302 stroke patients during subacute period were derived by screening secondary data source. Then all items were examined with rating-scale model of Rasch analysis. For example, the unidimensionality was examined by each item’s goodness-of-fit index; and the Rasch reliability was estimated by standard error of measurement, which was assumed that it varied with different latent trait level. Last but not least, we cross-validated the outcomes between previous study and this study, and compared the consistency and the correlation of the psychometric properties. Results: (1) Only 6 items from UE subscale possessed the unidimensionality, including “Raises hand to touch top of the head”, “Places hand on sacrum”, “Raises arm overhead to fullest elevation”, “Supinates and pronates forearm”, “Closes hand from fully opened position”, and “Opens hand from fully closed position.” While 8 items from LE subscale possessed the unidimensionality, including “Flexes hip in sitting”, “Extends knee in sitting”, “Flexes knee in sitting”, “Dorsiflexes ankle in sitting”, “Plantar flexes ankle in sitting”, “Extends knee and dorsiflexes ankle in sitting”, “Flexes affected knee with hip extended”, and “Dorsiflexes affected ankle with knee extended.” (2) The Rasch reliabilities of UE / LE subscale of this study were 0.92 and 0.93 respectively, which were both slightly higher than Hsueh’s study (0.86 and 0.91 respectively). Besides, 243 patients’ person reliabilities of UE / LE subscale of this study were higher than 0.90, and remaining 59 patients’ person reliabilities were between 0.80 ~ 0.90. (3) The order of item difficulty parameters from UE / LE subscale between previous study and this study was modestly / moderately correlated,with Spearman's rho equaled to -0.31 and 0.48 respectively. (4) The latent trait scores from UE / LE subscale estimated by previous parameters and this study’s was highly / moderately correlated,with Pearson's r equaled to 0.96 and 0.62 respectively. Conclusions: With regard to UE subscale, although the outcome of the unidimensionality was inconsistent, and the order of item difficulty parameters was modestly correlated, the latent trait scores estimated by previous parameters and this study’s was highly correlated. On the contrary, LE subscale had more consistent outcome of the unidimensionality as well as moderately correlated order of item difficulty parameters, but the latent trait scores estimated by previous parameters and this study’s was just moderately correlated. The difference between analysis results and expectation was probably related to sample properties. But the limitation was that it’s still difficult to identify which parameter was better since the comparison was only between two studies. It’s suggested to revalidate the psychometric properties of STREAM with Rasch Analysis and clarify the problems in the future.

並列關鍵字

Stroke Rehabilitation Assessment of Movement (STREAM) ； Rasch analysis ； psychometric properties ； movement assessment

參考文獻

Duncan, P. W., Goldstein, L. B., Matchar, D., Divine, G. W., & Feussner, J. (1992). Measurement of motor recovery after stroke. Outcome assessment and sample size requirements. Stroke, 23, 1084-1089. doi:10.1161/01.str.23.8.1084

王文中（1997）。測驗的建構：因素分析還是Rasch分析？調查研究，3，129-166。