Acute effects of spaced cathodal transcranial direct current stimulation in drug resistant focal epilepsies

Abstract

ObjectiveTo evaluate the safety and temporal dynamic of the antiepileptic effect of spaced transcranial direct current stimulation (tDCS) in different focal epilepsies. MethodsCathodal tDCS with individual electrode placement was performed in 15 adults with drug resistant focal epilepsy. An amplitude of 2 mA was applied twice for 9 minutes, with an interstimulation interval of 20 minutes. Tolerability was assessed via the Comfort Rating Questionnaire and the frequency of interictal epileptiform discharges (IEDs) was sequentially compared between the 24 hours before and after tDCS. ResultsTDCS led to a significant reduction in the total number of IEDs/24 h by up to 68% (mean ± SD: −30.4 ± 21.1%, p = 0.001) as well as in seizure frequency (p = 0.041). The maximum IED reduction was observed between the 3rd and 21st hour after stimulation. Favorable clinical response was associated with structural etiology and clearly circumscribed epileptogenic foci but did not differ between frontal and temporal epilepsies. Overall, the tDCS treatment was well tolerated and did not lead to severe adverse events. ConclusionsThe spaced stimulation approach proved to be safe and well-tolerated in patients with drug-resistant unifocal epilepsies, leading to sustained IED and seizure frequency reduction. SignificanceSpaced tDCS induces mediate antiepileptic effects with promising therapeutic potential.