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 ( = 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,  < 0.001) than monotasking ( = -0.189,  = 0.011). There was a significant albeit weaker link to cognitive efficiency composite score ( = -0.281,  < 0.001), but not composite memory ( = -0.036,  > 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.