Safety Study of Transcranial Static Magnetic Field Stimulation (tSMS) of the Human Cortex

•Transcranial static magnetic field stimulation (tSMS) in humans reduces cortical excitability.•Safety limits for this technique have not been described.•tSMS did not induce any significant increase in NSE or S100.•tSMS did not induce any significant cognitive alteration.•The application of tSMS is safe in healthy human subjects

BackgroundTranscranial static magnetic field stimulation (tSMS) in humans reduces cortical excitability.ObjectiveThe objective of this study was to determine if prolonged tSMS (2 h) could be delivered safely in humans. Safety limits for this technique have not been described.MethodstSMS was applied for 2 h with a cylindric magnet on the occiput of 17 healthy subjects. We assessed tSMS-related safety aspects at tissue level by measuring levels of neuron-specific enolase (NSE, a marker of neuronal damage) and S100 (a marker of glial reactivity and damage). We also included an evaluation of cognitive side effects by using a battery of visuomotor and cognitive tests.ResultstSMS did not induce any significant increase in NSE or S100. No cognitive alteration was detected.ConclusionsOur data indicate that the application of tSMS is safe in healthy human subjects, at least within these parameters.