Thalamic shape abnormalities in patients with multiple sclerosis-related fatigue.

Thalamus plays an important role in the pathogenesis of multiple sclerosis-related fatigue (MSrF). However, the thalamus is a heterogeneous structure and the specific thalamic subregions that are involved in this condition are unclear. Here, we used thalamic shape analysis for the detailed localization of thalamic abnormalities in MSrF. Using the Modified Fatigue Impact Scale, we measured fatigue in 42 patients with relapsing-remitting multiple sclerosis (MS). The thalamic shape was extracted from T1w images using an automated pipeline. We investigated the association of thalamic surface deviations with the severity of global fatigue and its cognitive, physical and psychosocial subdomains. Cognitive fatigue was correlated with an inward deformity of the left anteromedial thalamic surface, but no other localized shape deviation was observed in correlation with global, physical or psychosocial fatigue. Our findings indicate that the left anteromedial thalamic subregions are implicated in cognitive fatigue, possibly through their role in reward processing and cognitive and executive functions.