Utility of the Nih Toolbox Cognition Battery in Multiple Sclerosis

Background: There is growing interest in incorporating cognitive screening using brief, computerized assessments into clinical practice with individuals with multiple sclerosis (MS). However, the psychometric properties of the National Institutes of Health Toolbox Cognition Battery (NIHTB), a tool with a large normative sample, remain to be assessed.

Objectives: To assess utility of the NIHTB against gold standard neuropsychological tests of processing speed, working memory, episodic memory, and executive function. Second, to measure associations between the NIHTB summary measure of fluid cognition and disease severity, depression, and fatigue.

Methods: Eighty-eight individuals with relapsing-remitting MS aged 35-59 completed gold-standard neuropsychological tests from the Wechsler Adult Intelligence Scale-IV (WAIS-IV), the Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS), and the NIHTB. Concordance correlation coefficients quantified the convergent validity between normative scores for the NIHTB (corrected for age, gender, education, and race/ethnicity), MACFIMS (using regression-based norms), and WAIS-IV subtests (corrected for age). Disease severity, depression, and fatigue measured using the Expanded Disability Status Scale (EDSS), the Beck Depression Inventory-II, and the Modified Fatigue Impact Scale, respectively, were correlated with the NIHTB fluid cognition metric.

Results: Significant concordance between the NIHTB and gold-standard measures was observed for processing speed (CCC range = .28 - .48), working memory (CCC range = .27 - .37), and episodic memory (CCC range = .21 - .32), but not for executive function (CCC range = .096 - .11). The NIHTB summary measure of fluid cognition was significantly and inversely related to disease severity (r_s = -.30, p = .006), but was not associated with depression (r_s = -.096, p = .39), or fatigue (r_s = .056, p = .69).

Conclusions: Fast and valid screening of cognition is necessary in MS clinics. This study demonstrates adequate concordance between NIHTB and gold-standard measures of commonly impaired domains in MS (i.e., processing speed, working memory). Fluid cognition showed a significant relationship with the clinically valid disease severity measure of EDSS. These results provide the first line of evidence for the utility of the NIHTB in MS and supports further use of this toolbox given the availability of demographically-normed data, and clinically useful summary metrics.