During the interictal phase, the cerebral cortex is characterised by hyperresponsiveness to repeated sensory stimuli, manifested by a lack of habituation or adaptation of cortical evoked responses. Such habituation deficit can be shown in the visual cortex by the study of visual evoked potentials (VEP) and it is possibly explained by a reduction in the cortical pre-activation level due to thalamo-cortical dysrhythmia. In healthy subjects and in migraineurs between attacks, anodal tDCS increases VEP habituation and 1st block amplitude. In a proof-of-concept trial, the investigators have shown in 10 episodic migraine without aura patients that 2 weekly 15-minute sessions for 8 weeks of anodal tDCS over the visual cortex significantly decreased attack frequency, migraine days, attack duration and acute medication intake for more than 4 weeks after the last treatment session.
This randomized trial was designed to prove the preventive effect in episodic migraine of anodal tDCS over the visual cortex compared to sham stimulation.
