Variability in Response to Quadripulse Stimulation of the Motor Cortex

Brain Stimulation

Masashi Hamada¹  Hiroyuki Enomoto²  Yoshikazu Ugawa²  Shunsuke Kobayashi³  Stefan Jun Groiss³  Mitsunari Abe³  Fangyu Chang³  Ritsuko Hanajima³  Takenobu Murakami³  Koichiro Nakamura³  Winnugroho Wiratman³  Suguru Kadowaki³  Yasuo Terao⁴ 

[1] Department of Neurology, Center for Movement Disorders and Neuromodulation, Institute of Clinical Neuroscience, Medical Psychology Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany;Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan;Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, Japan;Department of Neurology, School of Medicine, Kitasato University, Sagamihara, Japan;

关键词: Quadripulse stimulation (QPS);    Plasticity;    Motor cortex;    Variability;   

DOI  :  

来源: DOAJ

【 摘 要 】

Background: Responses to plasticity-inducing brain stimulation protocols are highly variable. However, no data are available concerning the variability of responses to quadripulse stimulation (QPS). Objective: We assessed the QPS parameters of motor cortical plasticity induction in a systematic manner, and later investigated the variability of QPS using optimal parameters. Methods: First, two different interburst intervals (IBI) with the same total number of pulses were compared. Next we investigated three different IBIs with a different total number of pulses but with same duration of intervention. We also compared the after-effects of monophasic and biphasic QPS. Finally, variability of QPS was tested in 35 healthy subjects. Twenty motor evoked potentials (MEPs) were measured every 5–10 min for up to one hour after intervention. Results: QPS at an IBI of 5 s produced MEPs changes that are dependent on the interstimulus interval of the four magnetic pulses, consistent with previous reports. Unexpectedly, QPS at an IBI of 2.5 s did not induce any plasticity, even with the same total number of pulses, that is, 1440. QPS at an IBI of 7.5 s produced a variable response but was likely to be comparable to conventional QPS. Biphasic QPS had shorter lasting after-effects compared with monophasic QPS. Finally, the after-effects of QPS were relatively consistent across subjects: more than 80% of subjects responded as expected in the excitatory QPS at an IBI of 5 s. Conclusions: The IBI, total duration of the procedure and pulse waveform strongly affected the magnitude or duration of the plasticity induced by QPS. In this cohort, 80% of subjects responded to excitatory QPS as expected.

【 授权许可】

Unknown