Sommer Jens, Jansen Andreas, Dräger Bianca, Steinsträter Olaf, Breitenstein Caterina, Deppe Michael, Knecht Stefan
Department of Neurology, University of Muenster, Albert-Schweitzer-Str. 33, 48149 Muenster, Germany.
Clin Neurophysiol. 2006 Feb;117(2):440-6. doi: 10.1016/j.clinph.2005.09.025. Epub 2005 Dec 22.
To improve the quality of TMS studies by developing a new sham condition.
We describe a novel and easily arranged TMS set-up of two standard TMS coils and a magnetic shield, stacked like a sandwich. In a first step we compare the magnetic field in the sham and verum conditions. In a second step we ask six subjects to rate the stimulation intensity.
The magnetic field in the sham mode is reduced to about one eighth of that during verum stimulation. The attenuation of the magnetic field is not limited to the actual stimulation site but also effective at neighbouring brain areas, avoiding direct and indirect stimulation via connected neural pathways. This also minimizes stimulation of the skin, but as a consequence allows subjects to distinguish between verum and sham conditions when these are contrasted directly. The position of the coil system and the acoustic sensations are indistinguishable between sham and verum condition. Subjects are not able to discriminate TMS position and condition by external cues.
The proposed TMS setup is simple and allows verum and sham TMS without interaction of the researcher. If used with the magnetic shield, the magnetic field in the brain is attenuated most.
With the sandwich TMS coil system it is possible to improve the quality of TMS studies.
通过开发一种新的伪刺激条件来提高经颅磁刺激（TMS）研究的质量。
我们描述了一种新颖且易于设置的TMS装置，由两个标准TMS线圈和一个磁屏蔽组成，像三明治一样堆叠。第一步，我们比较伪刺激和真刺激条件下的磁场。第二步，我们让6名受试者对刺激强度进行评分。
伪刺激模式下的磁场降低至真刺激时的约八分之一。磁场的衰减不仅限于实际刺激部位，对邻近脑区也有效，避免了通过相连神经通路的直接和间接刺激。这也将对皮肤的刺激降至最低，但结果是当直接对比真刺激和伪刺激条件时，受试者能够区分两者。线圈系统的位置和听觉感受在伪刺激和真刺激条件下无法区分。受试者无法通过外部线索辨别TMS的位置和条件。
所提出的TMS装置简单，无需研究人员干预即可进行真刺激和伪刺激TMS。如果与磁屏蔽一起使用，大脑中的磁场衰减最大。
使用三明治式TMS线圈系统可以提高TMS研究的质量。
