Dimensionality and construct validity of the Fugl-Meyer Assessment of the upper extremity.
OBJECTIVE
To investigate the dimensionality and construct validity of the Fugl-Meyer Assessment of the upper extremity by using Rasch analysis.


METHODS
Secondary analysis of pooled data from 2 existing datasets: a randomized therapeutic exercise clinical trial and a cohort longitudinal study of stroke recovery.


METHODS
University research center.


METHODS
A total of 512 subjects, ages 69.8+/-11.1 years, who were 0 to 145 days poststroke.


METHODS
Not applicable.


METHODS
Dimensionality was examined with principal components analysis and Rasch item-fit statistics. The Rasch-derived item hierarchy was examined for consistency with the expected course of poststroke upper-extremity recovery suggested by the reflex-hierarchical conceptual model underlying the assessment.


RESULTS
Factor loadings and item infit statistics suggested that the 3 reflex items were empirically disconnected from other assessment items. The reflex items were removed. The modified 30-item assessment showed a unidimensional structure. The Rasch-item-difficulty order was not consistent with the expected item order.


CONCLUSIONS
The items testing resting-state reflexes may threaten the assessment's dimensionality. With reflex items removed, the assessment is a unidimensional measure of volitional movement. The Rasch-generated item-difficulty order challenges the hierarchical structure implied by the instrument's underlying conceptual framework.
Woodbury
Michelle L
ML
Brain Rehabilitation Research Centers, Malcolm Randall VA Medical Center, Gainesville FL, USA. mwoodbur@phhp.ufl.edu
Velozo
Craig A
CA
Richards
Lorie G
LG
Duncan
Pamela W
PW
Studenski
Stephanie
S
Lai
Sue-Min
SM
D000368:Aged; D003627:Data Interpretation, Statistical; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology; D025341:Principal Component Analysis; D020127:Recovery of Function; D015203:Reproducibility of Results; D020521:Stroke / Q000503:physiopathology; D000071939:Stroke Rehabilitation; D034941:Upper Extremity / Q000503:physiopathology*