Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA.
Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.
Eur J Neurosci. 2021 Apr;53(8):2696-2702. doi: 10.1111/ejn.15070. Epub 2020 Dec 7.
Interest in transcranial direct current stimulation (tDCS) to alter cortical excitability, facilitate neural plasticity, and improve performance is increasing. Subjects often report temporary stimulation-related sensations, which might distract from the task being performed or compromise blinding. tDCS is also prone to high outcome irregularity and one potential variability source is the biological sex of the subject. The purpose of this study was to re-analyze existing tolerability data to ascertain any sex differences in sensation severity and blinding guesses from tDCS at 2 mA and 4 mA. Each subject underwent tDCS at three randomly ordered intensities (sham, 2 mA, 4 mA), reported the severity sensations experienced, and guessed which tDCS condition they underwent (blinding). Women reported higher sensation severities than men from 2 mA and 4 mA tDCS and higher severities with increasing intensity (sham < 2 mA < 4 mA). Men reported similar severities in all stimulation conditions. Both sexes distinguished sham from 2 mA and 4 mA, and neither were able to discriminate between 2 mA from 4 mA. This study highlights differences in severity reports between women and men and adds to the growing body of literature, indicating that current sham methodologies might be inadequate to maintain blinding.
人们对经颅直流电刺激（tDCS）改变皮质兴奋性、促进神经可塑性和提高表现的兴趣日益增加。受试者通常会报告暂时的刺激相关感觉，这可能会分散正在进行的任务注意力，或者破坏盲法。tDCS 也容易出现结果不规则，一个潜在的变异性来源是受试者的生物性别。本研究的目的是重新分析现有的耐受性数据，以确定在 2 mA 和 4 mA 时，感觉严重程度和 tDCS 致盲猜测是否存在性别差异。每位受试者在三种随机顺序的强度下（假刺激、2 mA、4 mA）接受 tDCS，报告所经历的感觉严重程度，并猜测他们接受了哪种 tDCS 条件（致盲）。女性在 2 mA 和 4 mA tDCS 时报告的感觉严重程度高于男性，且随着强度的增加感觉严重程度也增加（假刺激 < 2 mA < 4 mA）。男性在所有刺激条件下报告的严重程度相似。两性均能区分假刺激与 2 mA 和 4 mA，且均无法区分 2 mA 与 4 mA。本研究强调了女性和男性之间在严重程度报告上的差异，并增加了越来越多的文献，表明当前的假刺激方法可能不足以维持盲法。
