Reducing procedural pain and discomfort associated with transcranial direct current stimulation.

Author(s): McFadden JL, Borckardt JJ, George MS, Beam W

Affiliation(s): Brain Stimulation Laboratory, Medical University of South Carolina, Charleston, South Carolina, USA.

Publication date & source: 2011-01, Brain Stimul., 4(1):38-42. Epub 2010 Jun 17.

Publication type: Randomized Controlled Trial; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.

BACKGROUND: Transcranial direct current stimulation (tDCS) appears to have modulatory effects on the excitability of cortical brain tissue. Though tDCS as presently applied causes no apparent harm to brain structure or function, a number of uncomfortable sensations can occur beneath the electrodes during stimulation, including tingling, pain, itching, and burning sensations. Therefore, we investigated the effect of topically applied Eutectic mixture of local anesthetics (EMLA) on tDCS-related discomfort. METHODS: Nine healthy adults received both anodal and cathodal 2.0 mA tDCS for 5 minutes over the prefrontal cortex with the skin pretreated for 20 minutes with either EMLA or placebo cream. Participants rated procedural discomfort six times across eight dimensions of sensation. RESULTS: On average, the mean sensation ratings for EMLA-associated tDCS stimulation were significantly lower than placebo-associated stimulation for every cutaneous sensation evaluated. Cathodal stimulation was associated with higher ratings of "sharpness" and intolerability than anodal stimulation. CONCLUSIONS: Topical EMLA may reduce tDCS-related discomfort. Copyright A(c) 2011 Elsevier Inc. All rights reserved.