Chitralakshmi K Balasubramanian1, Chih-Ying Li2, Mark G Bowden3, Pamela W Duncan4, Steven A Kautz3, Craig A Velozo5. 1. Department of Clinical and Applied Movement Sciences, University of North Florida, Jacksonville, FL. Electronic address: c.k-balasubramanian@unf.edu. 2. Department of Health Science and Research and Division of Physical Therapy, College of Health Profession, Medical University of South Carolina, Charleston, SC. 3. Department of Health Science and Research and Division of Physical Therapy, College of Health Profession, Medical University of South Carolina, Charleston, SC; Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC. 4. Department of Neurology, Wake Forest University, Winston-Salem, NC. 5. Division of Occupational Therapy, College of Health Profession, Medical University of South Carolina, Charleston, SC.
Abstract
OBJECTIVE: To investigate the dimensionality and item-difficulty hierarchy of the Fugl-Meyer Assessment of the lower extremity (FMA-LE). DESIGN: Secondary analyses of data pooled from 4 existing datasets: a phase III randomized controlled trial investigating the effectiveness of body weight support and a treadmill for rehabilitation of walking poststroke, and 3 cross-sectional studies investigating the link between impaired motor performance poststroke and walking. SETTING: University research centers and rehabilitation centers. PARTICIPANTS: A pooled sample of individuals with a stroke (N=535, men=313; mean age ± SD, 61.91±12.42y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Confirmatory factor analyses (CFA) and Rasch residual principal component analysis (PCA) investigated the dimensionality of the FMA-LE. The Rasch analysis rating scale model investigated item-difficulty hierarchy of the FMA-LE. RESULTS: The CFA showed adequate fit of a 3-factor model, with 2 out of 3 indices (CFA=.95; Tucker-Lewis Index=.94; root mean square error of approximation=.124) showing good model fit. Rasch PCA showed that removal of the reflex and coordination items explained 90.8% of variance in the data, suggesting that the abnormal synergy items contributed to the measurement of a unidimensional construct. However, rating scale model results revealed deviations in the item-difficulty hierarchy of the unidimensional abnormal synergy items from the originally proposed stepwise sequence of motor recovery. CONCLUSIONS: Our findings suggest that the FMA-LE might represent a multidimensional construct, challenging the use of a total score of the FMA-LE to predict lower extremity motor recovery. Removal of the misfit items resulted in creation of a unidimensional scale composed of the abnormal synergy items. However, this unidimensional scale deviates from the originally proposed hierarchical ordering.
OBJECTIVE: To investigate the dimensionality and item-difficulty hierarchy of the Fugl-Meyer Assessment of the lower extremity (FMA-LE). DESIGN: Secondary analyses of data pooled from 4 existing datasets: a phase III randomized controlled trial investigating the effectiveness of body weight support and a treadmill for rehabilitation of walking poststroke, and 3 cross-sectional studies investigating the link between impaired motor performance poststroke and walking. SETTING: University research centers and rehabilitation centers. PARTICIPANTS: A pooled sample of individuals with a stroke (N=535, men=313; mean age ± SD, 61.91±12.42y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Confirmatory factor analyses (CFA) and Rasch residual principal component analysis (PCA) investigated the dimensionality of the FMA-LE. The Rasch analysis rating scale model investigated item-difficulty hierarchy of the FMA-LE. RESULTS: The CFA showed adequate fit of a 3-factor model, with 2 out of 3 indices (CFA=.95; Tucker-Lewis Index=.94; root mean square error of approximation=.124) showing good model fit. Rasch PCA showed that removal of the reflex and coordination items explained 90.8% of variance in the data, suggesting that the abnormal synergy items contributed to the measurement of a unidimensional construct. However, rating scale model results revealed deviations in the item-difficulty hierarchy of the unidimensional abnormal synergy items from the originally proposed stepwise sequence of motor recovery. CONCLUSIONS: Our findings suggest that the FMA-LE might represent a multidimensional construct, challenging the use of a total score of the FMA-LE to predict lower extremity motor recovery. Removal of the misfit items resulted in creation of a unidimensional scale composed of the abnormal synergy items. However, this unidimensional scale deviates from the originally proposed hierarchical ordering.
Authors: Pamela W Duncan; Katherine J Sullivan; Andrea L Behrman; Stanley P Azen; Samuel S Wu; Stephen E Nadeau; Bruce H Dobkin; Dorian K Rose; Julie K Tilson; Steven Cen; Sarah K Hayden Journal: N Engl J Med Date: 2011-05-26 Impact factor: 91.245