PTMS21 Cortical excitability changes in high-frequency repetitive transcranial magnetic stimulation for central post-stroke pain

It is generally accepted that low- and high-frequency repetitive transcranial magnetic stimulation (rTMS) induces changes in cortical excitability, but there is only indirect evidence of its effects despite a large number of studies employing different stimulation parameters. Typically the cortical modulations are inferred through indirect measurements, such as recording the change in electromyographic responses. Recently it has become possible to directly evaluate rTMS-induced changes at the cortical level using electronencephalography (EEG). The present study investigates the modulation induced by high-frequency rTMS via EEG by evaluating changes in the latency and amplitude of TMS-evoked responses. In this study, rTMS was applied to the left primary motor cortex (MI) in 16 participants while an EEG was simultaneously acquired from 29 scalp electrodes. The rTMS consisted of 40 trains at 20 Hz with 10 stimuli each (a total of 400 stimuli) that were delivered at the individual resting motor threshold. The on-line modulation induced by the high-frequency TMS was characterized by a sequence of EEG responses. Two of the rTMS-induced responses, P5 and N8, were specifically modulated according to the protocol. Their latency decreased from the first to the last TMS stimuli, while the amplitude values increased. These results provide the first direct, on-line evaluation of the effects of high-frequency TMS on EEG activity. In addition, the results provide a direct demonstration of cortical potentiation induced by rTMS in humans.

Download Full-text

Preliminary evidence of the effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) on swallowing functions in post-stroke individuals with chronic dysphagia

International Journal of Language & Communication Disorders ◽

10.1111/1460-6984.12144 ◽

2015 ◽

Vol 50 (3) ◽

pp. 389-396 ◽

Cited By ~ 11

Author(s):

Ivy K. Y. Cheng ◽

Karen M. K. Chan ◽

C. S. Wong ◽

Raymond T. F. Cheung

Keyword(s):

Transcranial Magnetic Stimulation ◽

High Frequency ◽

Magnetic Stimulation ◽

Repetitive Transcranial Magnetic Stimulation ◽

Preliminary Evidence ◽

Post Stroke

Download Full-text

Repetitive transcranial magnetic stimulation in combination with neuromuscular electrical stimulation for treatment of post-stroke dysphagia

Journal of International Medical Research ◽

10.1177/0300060518807340 ◽

2018 ◽

Vol 47 (2) ◽

pp. 662-672 ◽

Cited By ~ 8

Author(s):

Chengliang Zhang ◽

Xiuqin Zheng ◽

Rulan Lu ◽

Wenwei Yun ◽

Huifang Yun ◽

...

Keyword(s):

Electrical Stimulation ◽

Transcranial Magnetic Stimulation ◽

Magnetic Stimulation ◽

Cortical Excitability ◽

Repetitive Transcranial Magnetic Stimulation ◽

Neuromuscular Electrical Stimulation ◽

Motor Evoked Potential ◽

Swallowing Function ◽

Post Stroke ◽

Representative Area

Objective This study was performed to determine whether repetitive transcranial magnetic stimulation (rTMS) combined with neuromuscular electrical stimulation (NMES) effectively ameliorates dysphagia and how rTMS protocols (bilateral vs. unilateral) combined with NMES can be optimized. Methods Sixty-four patients were randomly divided into four groups using a random distribution table: the sham rTMS plus NMES (Sham-rTMS/NMES), ipsilesional 10-Hz rTMS plus NMES (Ipsi-rTMS/NMES), contralesional 1-Hz rTMS plus NMES (Contra-rTMS/NMES), and bilateral rTMS plus NMES (Bi-rTMS/NMES) groups. Cortical excitability as measured by the amplitude of the motor evoked potential at the mylohyoid muscle cortical representative area, swallowing function as measured by the Standardized Swallowing Assessment, and the degree of dysphagia were evaluated at baseline, after the stimulation course, and at the 1-month follow-up. Results Bi-rTMS/NMES produced higher cortical excitability and better swallowing function recovery. Compared with NMES alone, unilateral rTMS plus NMES had additional effects on cortical excitability and rehabilitation of dysphagia, but there were no differences between the Contra-rTMS/NMES and Ipsi-rTMS/NMES groups. No adverse events occurred. Conclusion The combination of rTMS with NMES was superior to NMES alone in improving the recovery of post-stroke dysphagia, and the combination of bilateral rTMS with NMES was more effective than unilateral rTMS combined with NMES.

Download Full-text

High-Frequency Transcranial Magnetic Stimulation on Motor Cortex of Patients Affected by Migraine With Aura: A Way to Restore Normal Cortical Excitability?

Cephalalgia ◽

10.1111/j.1468-2982.2009.01870.x ◽

2009 ◽

Vol 30 (1) ◽

pp. 46-52 ◽

Cited By ~ 35

Author(s):

F Brighina ◽

A Palermo ◽

O Daniele ◽

A Aloisio ◽

B Fierro

Keyword(s):

Transcranial Magnetic Stimulation ◽

Motor Cortex ◽

Migraine With Aura ◽

High Frequency ◽

Magnetic Stimulation ◽

Cortical Excitability ◽

Repetitive Transcranial Magnetic Stimulation ◽

Motor Evoked Potential ◽

Intracortical Inhibition ◽

Healthy Controls

We showed reduced motor intracortical inhibition (ICI) and paradoxical increase of intracortical facilitation (ICF) to 1 Hz repetitive transcranial magnetic stimulation (rTMS) in patients affected by migraine with aura (MA). In conditions of enhanced excitability due to a reduced inhibition, high-frequency rTMS was found to potentiate intracortical inhibition. Here we explored the conditioning effects of high-frequency priming stimulation of motor cortex with the aim of normalizing excitability reverting paradoxical facilitation by 1 Hz rTMS in MA. Nine patients with MA and nine healthy controls underwent a paired-pulse TMS paradigm to evaluate motor intracortical excitability (ICI and ICF) before and after the following rTMS conditions: 1 Hz alone or preceded by a real or sham conditioning high-frequency (10 Hz) rTMS. Sham was used to control for rTMS specificity. In baseline, ICI was significantly lower in migraineurs with respect to controls. One hertz stimulation reduced motor evoked potential amplitude and ICF in healthy controls, while it caused a significant paradoxical ICF increase in migraineurs. High-frequency rTMS conditioning normalized excitability in migraine, increasing short ICI and so reversing the paradoxical effects of 1 Hz rTMS. These findings raise the possibility that the interictal reduced intracortical inhibition in migraine could be normalized by high-frequency rTMS. This would open perspectives for new treatment strategies in migraine prevention.

Download Full-text