Reducing procedural pain and discomfort associated with transcranial direct current stimulation

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. (C) 2011 Elsevier Inc. All rights reserved.