Cognitive effects and autonomic responses to transcranial pulsed current stimulation

Abstract

Transcranial pulsed current stimulation (tPCS) is emerging as an option in the field of neuromodulation; however, little is known about its effects on cognition and behavior and its neurophysiological correlates as indexed by autonomic responses. Our aim was to identify the effects of tPCS on arithmetic processing and risk-taking behavior, and to further categorize physiological autonomic responses by heart rate variability (HRV) and electrodermal activity measurements before, during, and after exposure to task performance and stimulation. Thirty healthy volunteers were randomized to receive a single session of sham or active stimulation with a current intensity of 2 mA and a random frequency between 1 and 5 Hz. Our results showed that tPCS has a modest and specific effect on cognitive performance as indexed by the cognitive tasks chosen in this study. There was a modest effect of active tPCS only on performance facilitation on a complex-level mathematical task as compared to sham stimulation. On autonomic responses, we observed that HRV total power increased while LF/HF ratio decreased in the tPCS active group compared to sham. There were no group differences for adverse effects. Based on our results, we conclude that tPCS, in healthy subjects, has a modest and specific cognitive effect as shown by the facilitation of arithmetical processing on complex mathematical task. These effects are accompanied by modulation of the central autonomic network providing sympathetic-vagal balance during stressful conditions. Although behavioral results were modest, they contribute to the understanding of tPCS effects and cognitive enhancement.

Duration Dependent Effects of Transcranial Pulsed Current Stimulation (tPCS) Indexed by Electroencephalography

“…Based on our previous studies, we used an ear clip montage consisting of two circular metallic plate electrodes (0.5 cm in diameter each one). These electrodes were covered by cotton felt attached to a plastic ear clip frame and placed in the inferior lobule of each ear . The position of the anode or cathode electrodes in the ear did not matter since tPCS has an alternating bilateral pattern.…”

Safety of Transcranial Direct Current Stimulation: Evidence Based Update 2016

“…We are aware of no direct evidence from human trials involving tDCS that suggests tissue damage or behavioral changes suggestive of irreversible brain injury. Though methodology and rigor for reporting adverse events in tDCS are inconsistent across studies [53], [54], [55], [29], [56], [57], [58], [59], [60] human trials (per IRB guidance) should have specifically designed safety monitoring and reporting. Especially given the severity of a serious adverse event as defined above and mandatory reporting requirements defined in CFR, the lack of Serious Adverse Effect report in any trial supports the absence of occurrence.…”

Does transcranial electrical stimulation enhance corticospinal excitability of the motor cortex in healthy individuals? A systematic review and meta‐analysis

“…Finally, tPCS is a novel neuromodulatory paradigm that involves unidirectional flow of positive pulses separated by a predetermined interpulse interval (IPI) (Jaberzadeh et al ., ; Morales‐Quezada et al ., ). Thus, it induces both static and dynamic current components.…”