Validity of the Neuromuscular Recovery Scale: a measurement model approach.
OBJECTIVE
To determine how well the Neuromuscular Recovery Scale (NRS) items fit the Rasch, 1-parameter, partial-credit measurement model.


METHODS
Confirmatory factor analysis (CFA) and principal components analysis (PCA) of residuals were used to determine dimensionality. The Rasch, 1-parameter, partial-credit rating scale model was used to determine rating scale structure, person/item fit, point-measure item correlations, item discrimination, and measurement precision.


METHODS
Seven NeuroRecovery Network clinical sites.


METHODS
Outpatients (N=188) with spinal cord injury.


METHODS
Not applicable.


METHODS
NRS.


RESULTS
While the NRS met 1 of 3 CFA criteria, the PCA revealed that the Rasch measurement dimension explained 76.9% of the variance. Ten of 11 items and 91% of the patients fit the Rasch model, with 9 of 11 items showing high discrimination. Sixty-nine percent of the ratings met criteria. The items showed a logical item-difficulty order, with Stand retraining as the easiest item and Walking as the most challenging item. The NRS showed no ceiling or floor effects and separated the sample into almost 5 statistically distinct strata; individuals with an American Spinal Injury Association Impairment Scale (AIS) D classification showed the most ability, and those with an AIS A classification showed the least ability. Items not meeting the rating scale criteria appear to be related to the low frequency counts.


CONCLUSIONS
The NRS met many of the Rasch model criteria for construct validity.
Division of Occupational Therapy, Medical University of South Carolina, Charleston, SC. Electronic address: velozo@musc.edu.
Craig
C
Velozo
Department of Behavioral Science and Community Health, University of Florida, Gainesville, FL.
Michael
M
Moorhouse
Doctor of Physical Therapy Program-Austin, University of St. Augustine for Health Sciences, Austin, TX.
Elizabeth
E
Ardolino
Department of Biostatistics and Informatics, University of Louisville, Louisville, KY.
Doug
D
Lorenz
Department of Occupational Therapy, University of Florida, Gainesville, FL.
Sarah
S
Suter
School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH.
D Michele
DM
Basso
Department of Neurological Surgery, University of Louisville, Louisville, KY; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY.
Andrea L
AL
Behrman
D000293:Adolescent; D000328:Adult; D000368:Aged; D004185:Disability Evaluation; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D026741:Physical Therapy Modalities; D025341:Principal Component Analysis; D020127:Recovery of Function; D012047:Rehabilitation Centers; D015203:Reproducibility of Results; D013119:Spinal Cord Injuries / Q000534:rehabilitation*; D055815:Young Adult
Outcome assessment (health care); Recovery of function; Rehabilitation; Spinal cord injuries