Safety and effects on motor cortex excitability of five cathodal transcranial direct current stimulation sessions in 25Â hours

Five cathodal-tDCS sessions in 25 hours are safe. Inter-individual variability in MEP suppression is considerable but response to one cathodal-tDCS highly predicts the response to other sessions. Duration of MEP suppression is limited to three hours. These findings should be considered in trials utilizing repeated cathodal-tDCS.