LAUSR

BACKGROUND Decision-making (DM) capabilities are impaired in multiple sclerosis (MS). A variety of researchers hypothesized that this impairment is associated with reduced quality of life (QoL) and neuropsychiatric symptoms. Studies explicitly testing this hypothesis, however, are rare, provided inconclusive results, or evaluated only a limited selection of DM domains. Consequently, we conducted the first MS study on perceptual DM (e.g. deciding whether a car will fit into a parking lot based on a visual percept) to test this assumption. METHODS Specifically, we used an fMRI task that measured brain activity in 30 MS patients and 19 healthy controls (HCs) while the participants repeatedly decided whether objects referenced indirectly via their written object names would fit into a shoebox to investigate neural mechanisms of perceptual DM. The objects varied in size and thus decision difficulty. From these data, we determined voxel-wise brain activity parameters reflecting (i) decision difficulty and (ii) decision speed and related them to behavioral DM performance, QoL, mild to moderate depressive symptoms, and fatigue. RESULTS Patients showed reduced DM performance. Activity reflecting decision difficulty in the middle temporal gyrus was negatively related to DM performance across MS patients and HCs; activity reflecting decision speed in MS patients was associated with depressive symptoms and fatigue in areas of the dorsal visual stream. CONCLUSION The study shows that the perceptual DM capacity is reduced in MS. Moreover, the link between neural mechanisms of perceptual DM and neuropsychiatric symptoms suggests that an impairment in this domain is clinically relevant.