P071 tDCS effects over the left DLPFC versus the right PPC in multiple sclerosis fatigue

Abstract

Background Fatigue is a frequent and debilitating symptom in patients with multiple sclerosis (MS). Its classical treatments are still faced with limited benefits and numerous side effects. Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique currently investigated in treating MS related symptoms. Objective The primary objective of this study was to evaluate the tDCS effects on MS fatigue. The secondary outcomes included the assessment of its effects on mood and attention symptoms, commonly encountered in MS. Methods 10 fatigued MS patients were enrolled in a double-blind, sham-controlled, and cross-over study. Each patient randomly received three anodal tDCS blocks: active stimulation over the left dorsolateral prefrontal cortex (DLPFC), active stimulation of the right posterior parietal cortex (PPC), and sham stimulation over either cortical site. To note, both cortical targets are key components in MS fatigue networks. tDCS blocks consisted of five consecutive daily sessions and were held apart by a washout interval of three weeks. Results Only active left DLPFC stimulation significantly ameliorated fatigue. Mood improvement was exclusively obtained following active right PPC stimulation. Neither intervention had effects on attention. Conclusion This small-scale study supports the role of left prefrontal anodal tDCS in treating MS fatigue. The lack of effects on attention might be related to the heterogeneity of the studied cohort, the relatively small sample size, the adapted stimulation parameters and the short protocol duration.