Sensation and pain thresholds of transcranial stimulation with direct and alternating electric current

Abstract

Transcranial electrical stimulation with direct and alternating current (tDCS and tACS) is non-invasive methods used for therapeutic purposes as well as cognitive effects. The sensation and the pain thresholds as well as the adverse effects were recorded for anodal tDCS, cathodal tDCS, tACS at 6 Hz, 10 Hz, 20 Hz and 40 Hz administered to healthy participants via sponge electrodes placed at AF7 and AF8. The lowest sensation thresholds were found for 10-40 Hz tACS. The pain thresholds less than 2.0 mA were reached only with anodal tDCS in a few participants. Mild prickle, itching, tickling or tingling were referred by all participants for all kinds of stimulations with current thresholds highly scattered. Feelings of burning or tingling were observed in more than half participants mostly for anodal tDCS. Phosphenes were referred by most participants with tACS even for very low currents.