Abstract
BACKGROUND: Routine cognitive screening is a priority in MS clinical care. The National Institutes of Health Toolbox (NIHTB) Cognition Battery is a 30-min instrument validated in neurological populations excluding MS. OBJECTIVES: To assess construct validity of NIHTB tests and compare classification of cognitive impairment with gold-standard tests. To evaluate relationships between fluid cognition and clinical measures. METHODS: Eighty-seven individuals, aged 30-59 years, completed the NIHTB, Minimal Assessment of Cognitive Function in MS (MACFIMS), Wechsler Adult Intelligence Scale-IV subtests, and measures of disease severity, depression, and fatigue. RESULTS: The NIHTB showed adequate convergent validity for processing speed, working memory, and episodic memory. Although fluid cognition scores from the NIHTB and MACFIMS classified a similar proportion of participants as cognitively impaired, the two batteries differed in which individuals were classified as impaired versus preserved. NIHTB fluid cognition was inversely correlated with disease severity but not related to depression or fatigue. CONCLUSIONS: The NIHTB concords with gold-standard measures, and classifies cognitive impairment at similar rates to the MACFIMS. Adjusted NIHTB fluid cognition was negatively associated with disease severity suggesting clinical utility. Psychometric validation of the NIHTB in clinical practice will elucidate its promise as a cognitive screener in MS.