Peterchev Angel V, Luber Bruce, Westin Gregory G, Lisanby Sarah H
Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA; Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.
Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA.
Brain Stimul. 2017 Jan-Feb;10(1):99-105. doi: 10.1016/j.brs.2016.09.007. Epub 2016 Oct 6.
Scalp sensation and pain comprise the most common side effect of transcranial magnetic stimulation (TMS), which can reduce tolerability and complicate experimental blinding.
We explored whether changing the width of single TMS pulses affects the quality and tolerability of the resultant somatic sensation.
Using a controllable pulse parameter TMS device with a figure-8 coil, single monophasic magnetic pulses inducing electric field with initial phase width of 30, 60, and 120 µs were delivered in 23 healthy volunteers. Resting motor threshold of the right first dorsal interosseus was determined for each pulse width, as reported previously. Subsequently, pulses were delivered over the left dorsolateral prefrontal cortex at each of the three pulse widths at two amplitudes (100% and 120% of the pulse-width-specific motor threshold), with 20 repetitions per condition delivered in random order. After each pulse, subjects rated 0-to-10 visual analog scales for Discomfort, Sharpness, and Strength of the sensation.
Briefer TMS pulses with amplitude normalized to the motor threshold were perceived as slightly more uncomfortable than longer pulses (with an average 0.89 point increase on the Discomfort scale for pulse width of 30 µs compared to 120 µs). The sensation of the briefer pulses was felt to be substantially sharper (2.95 points increase for 30 µs compared to 120 µs pulse width), but not stronger than longer pulses. As expected, higher amplitude pulses increased the perceived discomfort and strength, and, to a lesser degree the perceived sharpness.
Our findings contradict a previously published hypothesis that briefer TMS pulses are more tolerable. We discovered that the opposite is true, which merits further study as a means of enhancing tolerability in the context of repetitive TMS.
头皮感觉和疼痛是经颅磁刺激（TMS）最常见的副作用，这会降低耐受性并使实验性盲法复杂化。
我们探讨改变单个TMS脉冲的宽度是否会影响所产生的躯体感觉的质量和耐受性。
使用带有8字形线圈的可控脉冲参数TMS设备，对23名健康志愿者施加初始相位宽度为30、60和120微秒的单相位磁脉冲，这些脉冲可诱导电场。如先前报道，针对每个脉冲宽度确定右侧第一背侧骨间肌的静息运动阈值。随后，以三种脉冲宽度中的每一种在两个幅度（特定脉冲宽度运动阈值的100%和120%）下对左侧背外侧前额叶皮层施加脉冲，每种条件下随机顺序施加20次重复脉冲。每次脉冲后，受试者使用0至10的视觉模拟量表对不适感、尖锐感和感觉强度进行评分。
幅度归一化至运动阈值的更短TMS脉冲比更长脉冲感觉略更不舒服（与120微秒脉冲宽度相比，30微秒脉冲宽度在不适量表上平均增加0.89分）。更短脉冲的感觉明显更尖锐（与120微秒脉冲宽度相比，30微秒脉冲宽度增加2.95分），但不比更长脉冲更强。正如预期的那样，更高幅度的脉冲增加了感知到的不适感和强度，并且在较小程度上增加了感知到的尖锐感。
我们的发现与先前发表的一个假设相矛盾，该假设认为更短的TMS脉冲更具耐受性。我们发现事实恰恰相反，这作为在重复TMS背景下提高耐受性的一种手段值得进一步研究。
