Reduced glucose metabolism in the frontal cortex and basal ganglia of multiple sclerosis patients with fatigue: a 18F-fluorodeoxyglucose positron emission tomography study - Roelcke, U; Kappos, L; Lechner-Scott, J; Brunnschweiler, H; Huber, S; Ammann, W; Plohmann, A; Dellas, S; Maguire, RP; Missimer, J; Radu, EW; Steck, A; Leenders, KL (Neurology, 1997)