Lisanby S H, Gutman D, Luber B, Schroeder C, Sackeim H A
Department of Biological Psychiatry, New York State Psychiatric Institute, New York, New York 10032, USA.
Biol Psychiatry. 2001 Mar 1;49(5):460-3. doi: 10.1016/s0006-3223(00)01110-0.
Testing the therapeutic potential of transcranial magnetic stimulation (TMS) in controlled trials requires a valid sham condition. Sham TMS is typically administered by tilting the coil 45--90 degrees off the scalp, with one or two wings of the coil touching the scalp. Lack of cortical effects has not been verified. We compared sham manipulations in their thresholds for eliciting motor-evoked potentials (MEPs) in human volunteers and in intracerebral measurements of voltage induced in the prefrontal cortex of a rhesus monkey. Three types of sham (one-wing 45 degrees and 90 degrees and two-wing 90 degrees tilt) induced much lower voltage in the brain than active TMS (67--73% reductions). However, the two-wing 45 degrees sham induced values just 24% below active TMS. This sham was about half as potent in inducing MEPs over the motor cortex as active TMS. Some sham TMS conditions produce substantial cortical stimulation, making it critical to carefully select the sham manipulation for clinical trials.
在对照试验中测试经颅磁刺激（TMS）的治疗潜力需要一个有效的假刺激条件。假刺激TMS通常通过将线圈倾斜与头皮成45至90度角进行，使线圈的一翼或两翼接触头皮。但尚未证实其缺乏皮质效应。我们比较了不同假刺激操作在人类志愿者中诱发运动诱发电位（MEP）的阈值以及在恒河猴前额叶皮质中脑内电压测量方面的情况。三种类型的假刺激（一翼45度和90度倾斜以及两翼90度倾斜）在大脑中诱发的电压比有效TMS低得多（降低了67 - 73%）。然而，两翼45度假刺激诱发的值仅比有效TMS低24%。这种假刺激在运动皮质上诱发MEP的效力约为有效TMS的一半。一些假刺激TMS条件会产生显著的皮质刺激，因此为临床试验仔细选择假刺激操作至关重要。
