Trial manufacture of high freguency repetitive magnetic stimuletor : stability, safety and clinical usefulness

高频重复磁刺激器的试制：稳定性、安全性和临床实用性

基本信息

批准号：
06558109
负责人：
KIMURA Jun
金额：
$ 9.47万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

项目摘要

Although there were many technical difficulties in developing the stimulators, we finally completed to manufacture a new stable high frequency repetitive magnetic stimulator. The stimulator operates from a standard 100V AC supply. Two types of magnetic stimulus pulses, induced by alternating capacitor voltage, were available : 1) a monophasic pulse with a rise time of 65 microseconds for single stimuli or paired stimuli and 2) a biphasic pulse with pulse width of 260 microseconds for single stimuli or repetitive stimuli. The maximum magnetic field gradient induced is 15.4T/sec.The maximum repetition rate is 20 Hz at 100% of maximal output and 30 Hz at 80%. Coil temperature is always monitored and if the temperature rises too high, the stimulator stops automatically. The stimulator worked without major troubles through the experiments.In order to clarify the effect of the repetitive brain stimulation on the primates, compound muscle action potentials (CMAPs) evoked by repetitive transcranial magnetic stimulation were recorded from the forearm muscles in a Japanese monkey. All experiments were also recorded on a videotape. Stimulus intensity and rate were varied from 50% to 100% and from 1 Hz to 30 Hz respectively. The number of stimuli in a train was 20 and 99.The results were as follows : 1) In general, high frequency repetitive stimuli augmented CMAP amplitude, suggesting increased excitability of corticospinal pathway. 2) However, in 10 Hz stimuli, CMAP were sometimes diminished, possibly due to frequency dependent cortical suppression in the brain. 3) No seizure occurred during the experiments. 4) No obvious side effect after the experiments.In our experiments, the repetitive brain stimulation was carried out without any trouble, but further studies are needed to establish the safety and usefulness of this new method.

尽管开发刺激器有许多技术困难，但我们终于完成了制造新的稳定高频重复磁刺激器。刺激器由标准的100V AC电源运行。通过交替电容器电压诱导的两种类型的磁性刺激脉冲可用：1）单个刺激或配对刺激的单个脉冲，其上升时间为65微秒，而2）双相脉冲，单脉冲脉冲，脉冲宽度为260微秒，用于单个刺激或重复性刺激。最大磁场梯度诱导的是15.4T/秒。在最大输出的100％，最大重复率为20 Hz，在80％时为30 Hz。始终监测线圈温度，如果温度升高过高，刺激器会自动停止。为了阐明重复的大脑刺激对灵长类动物的影响，刺激器在没有重大麻烦的情况下起作用，复杂的肌肉动作电位（CMAP）是由重复的经颅磁刺激记录在日本猴子中前臂肌肉中的。所有实验也记录在录像带上。刺激强度和速率分别从50％到100％，分别从1 Hz到30 Hz。火车中刺激的数量为20和99。结果如下：1）一般而言，高频重复刺激增加了CMAP振幅，表明皮质脊髓途径的兴奋性增加。 2）然而，在10 Hz刺激中，CMAP有时会减小，这可能是由于大脑中频率依赖性皮质抑制所致。 3）在实验过程中没有癫痫发作。 4）实验后没有明显的副作用。在我们的实验中，重复的大脑刺激是没有任何麻烦的，但是需要进一步的研究来确定这种新方法的安全性和实用性。