Bilateral frontal transcranial direct current stimulation: Failure to replicate classic findings in healthy subjects

Abstract

Objective There has been no modern effort to replicate, further characterize, or quantify the dramatic effects on affect described in controlled studies from the 1960s using bilateral frontal electrodes with an extra-cephalic reference in a mixed group composed primarily of mildly depressed individuals. We performed a comprehensive, quantitative assessment of the effects of bifrontal TDCS on emotion in 21 healthy subjects. Methods In a double-blind crossover study, we administered tests of emotional state, affect, emotional decision-making, arousal, and psychomotor functions during sham, anodal, and cathodal TDCS. Results We found no systematic effects on any measure, despite two subjects who had pronounced mood effects in the predicted direction. There were no adverse events. Conclusions In line with some other studies, we found no consistent effects of bifrontal TDCS on measures of emotional function of psychomotor performance. Significance These results demonstrate the safety of bilateral anterior frontal TDCS with an extra-cephalic reference, but raise questions about its effectiveness as a modulator of mood and emotional cognition, at least in healthy subjects.

Prefrontal direct current stimulation modulates resting EEG and event-related potentials in healthy subjects: A standardized low resolution tomography (sLORETA) study

“…The results in the PANAS questionnaire did not differ between real and sham stimulation. These data are consistent with a previous study of Koenigs et al 2009 that did not find any significant mood effects of bifrontal tDCS in a double-blind crossover study where participants underwent a single session of anodal, sham and cathodal tDCS (Koenigs et al, 2009).…”

“…In depressed subjects promising pilot data of prefrontal tDCS were reported, suggesting a therapeutic action of real tDCS compared to sham tDCS (Boggio et al, 2007(Boggio et al, , 2008aFerrucci et al, 2009;Fregni et al, 2006;Rigonatti et al, 2008), whereas the effect of one single tDCS-session on healthy subjects had no mood-altering effects (Koenigs et al, 2009).…”

Long-term effects of transcranial direct current stimulation combined with computer-assisted cognitive training in healthy older adults

“…Moreover, previous reports on the safety of tDCS in healthy adults were also taken into consideration in this study. Koenigs et al [9] Values are expressed as mean±SD. Day 0, on the day of completion of the sessions; Day 7, 7 days after completion of the sessions; Day 28, 28 days after completion of the sessions; RT, reaction time; WM, working memory.…”

“…Sponge electrodes of 5 Â 5 cm (25 cm 2 ) were attached to the scalp. Using two stimulators, anodes were attached on the bilateral prefrontal cortex (F3 and F4 of the 10/20 international system) and cathodes were attached on the nondominant arm for bilateral prefrontal cortex stimulation [9]. The electrodes were doused in water and elastic bandages were applied to secure maximum adhesion to the respective area.…”

Transcranial direct current stimulation: neurophysiology and clinical applications

“…The first tDCS studies on mood, dating back to the 1960s and 1970s, reported mood elevation, giddiness and talkativeness following bifrontal stimulation in depressed patients [22][23][24][25]. By contrast, emotional state, affect, emotional decisionmaking, arousal and psychomotor functions remained unchanged with bi-frontal anodal and cathodal tDCS in mentally healthy volunteers (n = 25) when tested in a double-blind crossover study [25].…”