LAUSR

Introduction Transcutaneous supraorbital nerve stimulation (tSNS) was found to be superior to sham stimulation for episodic migraine prevention in a randomized trial Schoenen et al. (2013) . It resulted to be a safe and well-tolerated treatment. The tSNS’s mode of action in migraine is not known. In healthy volunteers, high-frequency stimulation with the tSNS has acutely a sedative effect Piquet et al. (2011) . Whether this plays a role in chronically treated migraine patients is not known, but it suggests that the stimulation can change central nervous system activity. Objective In this study, we explored the effects of tSNS on objective pain and on evoked responses induced by laser stimulation (LEPs). Materials & methods Seventeen patients and twenty-one controls were randomized to receive real or sham tSNS. Laser Evoked potentials were recorded by stimulating the right hand and the right frontal zone in basal condition (T0), during (T1) and after a single session of sham stimulation or tSNS (T2). Results We didn’t find significant acute changes in LEPs parameters (N1, N2-P2 amplitude and latency) and pain perception among subjects during and after sham stimulation and after real stimulation. Throughout real tSNS we found, in both migraine and control subjects, a significant reduction of N2-P2 but not of N1 amplitude of Evoked Potentials elicited from right front laser stimulation ( p  = 0.002). This reduction was not evident in T2 and for hand stimulation. Conclusion The absence of a significant effect on N1 component suggest a lack of pain perception inhibition from A-Beta fibers activation induced by electrical stimulation. tSNS may have an indirect cognitive effect on somatic afferents with a prevalent simultaneous and transient modulation.