Cognitive fatigue in patients with multiple sclerosis (PwMS) is not independently related to objective cognitive impairment, according to a recent study. Depression may influence cognitive function of PwMS, primarily when it is severe. Therefore, cognitive impairment in PwMS should not be ascribed to fatigue or mild depression. PwMS (n=699) completed a computerized cognitive testing battery with age- and education-adjusted cognitive domain scores. Disability (Expanded Disability Status Scale [EDSS]), cognitive fatigue, and depression were concurrently evaluated. Researchers found:
- Both cognitive fatigue and depression were significantly and negatively correlated with the same cognitive domains: information processing speed, executive function, attention, motor function, and memory.
- Multivariate analysis revealed significant, but small, independent correlations only between depression and neuropsychological test results, while cognitive fatigue had no independent correlation with objective cognitive function except for a trend toward impaired motor function in highly-fatigued PwMS.
- Depression and cognitive fatigue accounted for no more than 6% of the variance in objective cognitive domain scores.
Golan D, Doniger GM, Wissemann K, et al. The impact of subjective cognitive fatigue and depression on cognitive function in patients with multiple sclerosis. Mult Scler. 2018;24(2):196-204. doi:10.1177/1352458517695470.