Dimensionality and Item-Difficulty Hierarchy of the Lower Extremity Fugl-Meyer Assessment in Individuals With Subacute and Chronic Stroke

Chitralakshmi K Balasubramanian; Chih-Ying Li; Mark G Bowden; Pamela W Duncan; Steven A Kautz; Craig A Velozo

doi:10.1016/j.apmr.2015.12.012

Dimensionality and Item-Difficulty Hierarchy of the Lower Extremity Fugl-Meyer Assessment in Individuals With Subacute and Chronic Stroke

Arch Phys Med Rehabil. 2016 Apr;97(4):582-589.e2. doi: 10.1016/j.apmr.2015.12.012. Epub 2015 Dec 29.

Authors

Chitralakshmi K Balasubramanian¹, Chih-Ying Li², Mark G Bowden³, Pamela W Duncan⁴, Steven A Kautz³, Craig A Velozo⁵

Affiliations

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.

Keywords: Lower extremity; Rehabilitation; Stroke.

Publication types

Meta-Analysis
Research Support, N.I.H., Extramural
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Aged
Chronic Disease
Cross-Sectional Studies
Disability Evaluation*
Exercise Test / methods
Exercise Test / statistics & numerical data*
Factor Analysis, Statistical
Female
Humans
Lower Extremity / physiopathology*
Male
Middle Aged
Principal Component Analysis
Psychometrics
Randomized Controlled Trials as Topic
Recovery of Function*
Retrospective Studies
Stroke / physiopathology*
Stroke Rehabilitation
Walking

Abstract

Publication types

MeSH terms

Grants and funding