Depression and cognitive function in early multiple sclerosis: Multitasking is more sensitive than traditional assessments

Background: Persons with multiple sclerosis (MS) and depression symptoms report real-world cognitive difficulties that may be missed by laboratory cognitive tests. Objective: To examine the relationship of depressive symptoms to cognitive monotasking versus multitasking in early MS. Method: Persons with early MS (n = 185; ⩽5 years diagnosed) reported mood, completed monotasking and multitasking cognitive tests, and received high-resolution 3.0 T magnetic resonance imaging (MRI). Partial correlations analyzed associations between mood and cognition, controlling for age, sex, estimated premorbid IQ, T2 lesion volume, and normalized gray matter volume. Results: Depression symptoms were more related to worse cognitive multitasking (−0.353, p < 0.001) than monotasking (r = −0.189, p = 0.011). There was a significant albeit weaker link to cognitive efficiency composite score (r = −0.281, p < 0.001), but not composite memory (r = −0.036, p > 0.50). Findings were replicated with a second depression measure. Multitasking was worse in patients with at least mild depression than both patients with no/minimal depression and healthy controls. Multitasking was not related to mood in healthy controls. Conclusions: Depression symptoms are linked to cognitive multitasking in early MS; standard monotasking cognitive assessments appear less sensitive to depression-related cognition. Further investigation should determine directionality and mechanisms of this relationship, with the goal of enhancing treatment for cognitive dysfunction and depression in MS.