Measurement Structure of the Wolf Motor Function Test: Implications for Motor Control Theory

Abstract

Background Tools chosen to measure poststroke upper-extremity rehabilitation outcomes must match contemporary theoretical expectations of motor deficit and recovery because an assessment’s theoretical underpinning forms the conceptual basis for interpreting its score. Objective The purpose of this study was to investigate the theoretical framework of the Wolf Motor Function Test (WMFT) by (1) determining whether all items measured a single underlying trait and (2) examining the congruency between the hypothesized and the empirically determined item difficulty orders. Methods Confirmatory factor analysis (CFA) and Rasch analysis were applied to existing WMFT Functional Ability Rating Scale data from 189 participants in the EXCITE (Extremity Constraint-Induced Therapy Evaluation) trial. Fit of a 1-factor CFA model (all items) was compared with the fit of a 2-factor CFA model (factors defined according to item object-grasp requirements) with fit indices, model comparison test, and interfactor correlations. Results One item was missing sufficient data and therefore removed from analysis. CFA fit indices and the model-comparison test suggested that both models fit equally well. The 2-factor model yielded a strong interfactor correlation, and 13 of 14 items fit the Rasch model. The Rasch item difficulty order was consistent with the hypothesized item difficulty order. Conclusion The results suggest that WMFT items measure a single construct. Furthermore, the results depict an item difficulty hierarchy that may advance the theoretical discussion of the person ability versus task difficulty interaction during stroke recovery.

Randomized Trial on the Effects of Attentional Focus on Motor Training of the Upper Extremity Using Robotics With Individuals After Chronic Stroke

“…25 The WMFT consists of 15 performance-based items and 2 strength items, reflecting impairment and activity-level tasks. 26 It has high interrater and test/retest reliability, internal consistency, adequate stability, 27 and good construct and criterion validity. 28 Items are scored on performance time and/or a 6-point ordinal scale measuring functional ability.…”

“…The final score is the mean of individual task scores. 26 This study used functional ability scores and not performance time scores. All primary outcomes were assessed by an experienced occupational therapist uninvolved with the arm training and unaware of participants' group assignment.…”

Functional Test of the Hemiparetic Upper Extremity: A Rasch Analysis With Theoretical Implications

“…A revision of the FTHUE’s scoring method could help better inform a treatment program consistent with contemporary perspectives of motor control and learning. In a similar way, Woodbury, et al, 2010, 32 investigated the theoretical framework of the Wolf Motor Function Test and found that the assessment does measure a single construct related to motor learning theory. In particular, the relationship between a stroke survivor’s ability and the task difficulty is important.…”

Methods of assessment of movement functions in the upper limb

“…Первоначально тест состоял из 21 пун-кта, но в дальнейшем для повышения удобства и функци-ональности был сокращен до 17. Впоследствии предпри-нимались попытки модернизации до 6 пунктов [15,[17][18][19][20][21][22]. Хотя модернизированный WMFT оказался несколько менее чувствительным, принципиальной разницы между Журнал неврологии и психиатрии, 7,2016 оценка ВыраженноСти дВигательных нарушений двумя версиями найдено не было [23].…”