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Updated: Feb 18, 2026
Remotely Supervised Transcranial Direct Current Stimulation: An Update on Safety and Tolerability
Published on: October 7, 2017
Extended Multiple-Field High-Definition transcranial direct current stimulation (HD-tDCS) is well tolerated and safe
Christopher A Turski1, Alanna Kessler-Jones1, Clara Chow1
1Department of Neurology, University of Wisconsin, Madison, WI, USA.
Background:
High definition transcranial direct current stimulation (HD-tDCS) has been administered over single brain regions for small numbers of sessions. Safety, feasibility and tolerability of HD-tDCS over multiple brain regions, multiple daily stimulations and long periods are not established.
Objective:
We studied safety, feasibility and tolerability of daily HD-tDCS over 2-4 brain regions for 20 sessions in healthy adults.
Methods:
Five healthy adults underwent physical and neurological examination, electrocardiogram (EKG), electroencephalogram (EEG) and cognitive screening (ImpACT) before, during and after HD-tDCS. Four networks (left/right temporoparietal and frontal) were stimulated in sequence (20 min each) using HD-tDCS in 20 daily sessions. Sessions 1-10 included sequential stimulation of both temporoparietal networks, sessions 11-15 stimulations of 4 networks and sessions 16-20 two daily stimulation cycles of 4 networks/cycle (1.5 mA/network). Side effects, ImpACT scores and EEG power spectrum were compared before and after HD-tDCS.
Results:
All subjects completed the trial. Adverse events were tingling, transient redness at the stimulation site, perception of continuing stimulation after end of session and one self-resolving headache. EEG power spectrum showed decreased delta power in frontal areas several days after HD-tDCS. While at the group level ImpACT scores did not differ before and after stimulations, we found a trend for correlation between decreased EEG delta power and individual improvements in ImpACT scores after HD-tDCS.
Conclusion:
Prolonged, repeat daily stimulation of multiple brain regions using HD-tDCS is feasible and safe in healthy adults. Preliminary EEG results suggest that HD-tDCS may induce long lasting changes in excitability in the brain.
