Factor analysis of the National Institutes of Health Stroke Scale in patients with large strokes.
BACKGROUND
The National Institutes of Health Stroke Scale (NIHSS) was created to detect treatment-related differences in clinical trials and was designed to measure right- and left-sided cerebral hemispheric function.


OBJECTIVE
To validate the original design in patients with very large strokes.


METHODS
A previously published factor structure was fit to the data. Then, a new analysis was conducted to explore the underlying structure of the scale in this population. Finally, NIHSS scores and infarction volumes were compared.


METHODS
The Clomethiazole for Acute Stroke Study-Ischemic, conducted in academic and community hospitals.


METHODS
Individuals with acute stroke seen within 12 hours of onset. Of 1191 records available, 98% had complete NIHSS scores.


METHODS
Goodness-of-fit statistic (Bentler) for each factor solution.


RESULTS
Two factors were found underlying the NIHSS, corresponding to the left and right hemispheres (goodness of fit = 0.97), using the previously published factor analysis. The new exploratory analysis also suggested 2 factors representing left and right brain function. The median (range) NIHSS scores were 15 (5-25) for right brain strokes and 19 (6-32) for left brain strokes (P<.001). The median (range) infarction volumes were 56.2 mL (0.1-381.5 mL) for right brain strokes and 37.8 mL (0.2-255.1 mL) for left brain strokes (P<.001). The correlation coefficient between NIHSS score and lesion volume was 0.37 (P<.001).


CONCLUSIONS
The underlying structure of the NIHSS conforms to cerebral hemispheric lateralization, confirming previous findings in a new population of large hemispheric strokes. Left- brain strokes score 4 points higher on the NIHSS than right brain strokes of larger volume.
Lyden
Patrick
P
Department of Neurology, Veterans Administration Medical Center, San Diego, Calif., USA.
Claesson
Lennart
L
Havstad
Suzanne
S
Ashwood
Tim
T
Lu
Mei
M
D000208:Acute Disease; D002544:Cerebral Infarction / Q000145:classification / Q000473:pathology; D002986:Clinical Trials as Topic; D023381:Endpoint Determination; D005163:Factor Analysis, Statistical; D007839:Functional Laterality; D006801:Humans; D012720:Severity of Illness Index; D020521:Stroke / Q000145:classification* / Q000473:pathology* / Q000628:therapy