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Figure 2 | BMC Neurology

Figure 2

From: Item response theory-based measure of global disability in multiple sclerosis derived from the Performance Scales and related items

Figure 2

Bifactor CFA model of self-assessed neurological disability in NARCOMS registrants. Note: “Global” represents the general factor of global disability; “Physical” and “Mental” represent the auxiliary factors of “physical” and “mental” disability. Correlations among the three factors are all forced to be zero. Thus, the physical and mental factors each explain a fraction of the variability in PS scores left unexplained by the general factor. Comparisons of “Residual variances” in Figure 2 and Figure 1, provide information about the fraction of variability in PS scores that the two auxiliary factors explain above and beyond the general factor.

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