Department of Neurology, Division of Neuroscience, Graduate School of Medicine, University of Tokyo, Bunkyo-Ku, Tokyo, Japan.
Clin Neurophysiol. 2011 Oct;122(10):2044-8. doi: 10.1016/j.clinph.2011.03.025. Epub 2011 May 4.
To investigate inter-individual variation in the efficiency of magnetic brainstem stimulation (BST) with regard to the stimulation site.
We studied 31 healthy subjects, using a right hand muscle as a recording site. Three stimulation sites were compared: BST over the inion (inion BST), and BST over the midpoint between the inion and the right (ipsilateral BST) or left (contralateral BST) mastoid process. Five suprathreshold BSTs were performed for each stimulation site using the same stimulation intensity. The mean peak-to-peak amplitudes of motor evoked potential (MEP) were compared. The active motor threshold (AMT) and onset latency for inion BST and ipsilateral BST were also measured and compared.
Contralateral BST did not evoke discernible MEPs in most subjects. In 21 subjects (67.7%), ipsilateral BST elicited larger MEPs than inion BST did, and AMT for ipsilateral BST was lower than or equal to the AMT for inion BST in all subjects. Ipsilateral BST elicited shorter latency in such subjects.
The suitable stimulation site for BST differed among subjects. About two-thirds showed larger MEP to ipsilateral BST.
These findings might help us to find an efficient stimulation site for BST in each subject.
研究个体间磁刺激脑干（BST）刺激部位效率的个体差异。
我们研究了 31 名健康受试者，以手部肌肉作为记录部位。比较了三个刺激部位：枕骨隆突上的 BST（枕骨 BST）、枕骨隆突与右侧（同侧 BST）或左侧（对侧 BST）乳突中点之间的 BST。每个刺激部位使用相同的刺激强度进行 5 次超阈值 BST。比较运动诱发电位（MEP）的平均峰峰值幅度。还测量并比较了枕骨 BST 和同侧 BST 的主动运动阈值（AMT）和起始潜伏期。
在大多数受试者中，对侧 BST 未引起可识别的 MEP。在 21 名受试者（67.7%）中，同侧 BST 比枕骨 BST 引起更大的 MEP，并且在所有受试者中，同侧 BST 的 AMT 低于或等于枕骨 BST 的 AMT。在这些受试者中，同侧 BST 诱发的潜伏期较短。
BST 的合适刺激部位因人而异。大约三分之二的受试者对同侧 BST 的 MEP 更大。
这些发现可能有助于我们为每个受试者找到有效的 BST 刺激部位。
