Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2012 Apr;5(2):155-62.
doi: 10.1016/j.brs.2011.02.007. Epub 2011 Mar 27.

Differences in the experience of active and sham transcranial direct current stimulation

Sudha Kilaru Kessler  1 , Peter E Turkeltaub, Jennifer G Benson, Roy H Hamilton
Affiliations
Comparative Study

Differences in the experience of active and sham transcranial direct current stimulation

Sudha Kilaru Kessler et al. Brain Stimul. 2012 Apr.

Abstract

Background: A limited number of studies have shown that modulation of cortical excitability using transcranial direct current stimulation (tDCS) is safe and tolerable. Few have directly evaluated whether sham and active stimulation are indistinguishable.

Objective: We aimed to demonstrate tDCS safety and tolerability in a large cohort, and to compare the occurrence and severity of side effects between sham and active stimulation sessions.

Methods: One hundred thirty-one healthy subjects undergoing 277 tDCS sessions rated on a 1 to 5 scale the perception of side effects during and after stimulation. Proportions of active and sham sessions associated with side effects were compared using Fisher exact test, and distributions of severity ratings were compared using the Kruskal-Wallis test.

Results: No serious adverse effects occurred. Side effects most commonly reported were tingling (76%), itching (68%), burning (54%), and pain (25%). Side effect severity was mild, with fewer than 2% of responses indicating a severity > 3 on all questions except tingling (15%), itching (20%), burning (7%), pain (5%), and fatigue (3%) during stimulation. Rates of sensory side effects were statistically significantly higher in active stimulation sessions compared with sham sessions. No other stimulation parameters had a statistically significant impact on side effect occurrence.

Conclusions: TDCS is a safe well-tolerated technique with no evidence of risk for serious adverse effects. Sensory side effects are common, but the severity is typically low. Because sensory side effects are more frequent and more severe in active compared with sham tDCS, the current method of sham stimulation may not be an adequate control condition for some studies.

PubMed Disclaimer

Conflict of interest statement

The authors have no actual or potential financial conflicts of interest to report.

Figures

Figure 1
Figure 1
Box plots for severity of side effects during stimulation. Boxes represent the interquartile range, with median represented by a thick black line. Whiskers represent inner and outer adjacent values and circles represent outliers.
Figure 2
Figure 2
Box plots for severity of side effects experienced after stimulation. Boxes represent the interquartile range, with median represented by a thick black line. Whiskers represent inner and outer adjacent values and circles represent outliers.
See this image and copyright information in PMC

References

    1. Nitsche MA, Paulus W. Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation. J Physiol. 2000 Sep 15;527(Pt 3):633–9. - PMC - PubMed
    1. Priori A, Berardelli A, Rona S, Accornero N, Manfredi M. Polarization of the human motor cortex through the scalp. Neuroreport. 1998 Jul 13;9(10):2257–60. - PubMed
    1. Nitsche MA, Paulus W. Sustained excitability elevations induced by transcranial DC motor cortex stimulation in humans. Neurology. 2001 Nov 27;57(10):1899–901. - PubMed
    1. Ardolino G, Bossi B, Barbieri S, Priori A. Non-synaptic mechanisms underlie the after-effects of cathodal transcutaneous direct current stimulation of the human brain. J Physiol. 2005 Oct 15;568(Pt 2):653–63. - PMC - PubMed
    1. Rango M, Cogiamanian F, Marceglia S, Barberis B, Arighi A, Biondetti P, et al. Myoinositol content in the human brain is modified by transcranial direct current stimulation in a matter of minutes: a 1H-MRS study. Magn Reson Med. 2008 Oct;60(4):782–9. - PubMed

Publication types