High-intensity, low-frequency repetitive transcranial magnetic stimulation enhances excitability of the human corticospinal pathway

2020 ◽  
Vol 123 (5) ◽  
pp. 1969-1978
Author(s):  
Jessica M. D’Amico ◽  
Siobhan C. Dongés ◽  
Janet L. Taylor
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
High Intensity ◽  
Magnetic Stimulation ◽  
Corticospinal Tract ◽  
Motor Evoked Potentials ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Intracortical Inhibition ◽  
Corticospinal Pathway ◽  
Plastic Changes

In this study, we present a novel, intensity-dependent repetitive transcranial magnetic stimulation (rTMS) protocol that induces lasting, plastic changes within the corticospinal tract. High-intensity rTMS at a frequency of 0.1 Hz induces facilitation of motor evoked potentials (MEPs) lasting at least 35 min. Additionally, these changes are not limited only to small MEPs but occur throughout the recruitment curve. Finally, facilitation of MEPs following high-intensity rTMS does not appear to be due to changes in intracortical inhibition or facilitation.

Effect of Low-Frequency Repetitive Transcranial Magnetic Stimulation on Interhemispheric Inhibition

2005 ◽  
Vol 94 (3) ◽  
pp. 1668-1675 ◽  
Author(s):  
Pramod Kr. Pal ◽  
Ritsuko Hanajima ◽  
Carolyn A. Gunraj ◽  
Jie-Yuan Li ◽  
Aparna Wagle-Shukla ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Evoked Potentials ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Conditioning Stimulus ◽  
Interhemispheric Inhibition ◽  
Resting Motor Threshold ◽  
Low Frequency Rtms

We studied the effects of 1-Hz repetitive transcranial magnetic stimulation (rTMS) on the excitability of interhemispheric connections in 13 right-handed healthy volunteers. TMS was performed using figure-eight coils, and surface electromyography (EMG) was recorded from both first dorsal interosseous (FDI) muscles. A paired-pulse method with a conditioning stimulus (CS) to the motor cortex (M1) followed by a test stimulus to the opposite M1 was used to study the interhemispheric inhibition (ppIHI). Both CS and TS were adjusted to produce motor-evoked potentials of ∼1 mV in the contralateral FDI muscles. After baseline measurement of right-to-left IHI (pre-RIHI) and left-to-right IHI (pre-LIHI), rTMS was applied over left M1 at 1 Hz with 900 stimuli at 115% of resting motor threshold. After rTMS, ppIHI was studied using both the pre-rTMS CS (post-RIHI and post-LIHI) and an adjusted post-rTMS CS set to produce 1-mV motor evoked potentials (MEPs; post-RIHIadj and post-LIHIadj). The TS was set to produce 1-mV MEPs. There was a significant reduction in post-LIHI ( P = 0.0049) and post-LIHIadj ( P = 0.0169) compared with pre-LIHI at both interstimulus intervals of 10 and 40 ms. Post-RIHI was significantly reduced compared with pre-RIHI ( P = 0.0015) but pre-RIHI and post-RIHIadj were not significantly different. We conclude that 1-Hz rTMS reduces IHI in both directions but is predominantly from the stimulated to the unstimulated hemisphere. Low-frequency rTMS may be used to modulate the excitability of IHI circuits. Treatment protocols using low-frequency rTMS to reduce cortical excitability in neurological and psychiatric conditions need to take into account their effects on IHI.

scholarly journals Effects of low-frequency repetitive transcranial magnetic stimulation in adductor laryngeal dystonia: a safety, feasibility, and pilot study

2021 ◽  
Author(s):  
Cecília N. Prudente ◽  
Mo Chen ◽  
Kaila L. Stipancic ◽  
Katherine L. Marks ◽  
Sharyl Samargia-Grivette ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Effect Size ◽  
Magnetic Stimulation ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Controlled Trial ◽  
Voice Quality ◽  
Low Frequency ◽  
Intracortical Inhibition ◽  
Laryngeal Dystonia ◽  
Small Effect Size

Abstract Purpose The effects of neuromodulation are virtually unexplored in adductor laryngeal dystonia (AdLD), a disorder characterized by involuntary contraction of intrinsic laryngeal muscles. Recent findings indicated that intracortical inhibition is reduced in people with AdLD. Low-frequency repetitive transcranial magnetic stimulation (rTMS) induces prolonged intracortical inhibition, but the effects in AdLD are unexplored. This pilot and feasibility study aimed to examine the safety, feasibility, and effects of a single session 1 Hz rTMS over the laryngeal motor cortex (LMC) in people with AdLD and healthy individuals. Methods The stimulation location was individualized and determined through TMS-evoked responses in the thyroarytenoid muscles using fine-wire electrodes. 1200 pulses of 1 Hz rTMS were delivered to the left LMC in two groups: Control (n = 6) and AdLD (n = 7). Tolerance, adverse effects, intracortical inhibition, and voice recordings were collected immediately before and after rTMS. Voice quality was assessed with acoustic-based and auditory-perceptual measures. Results All participants tolerated the procedures, with no unexpected adverse events or worsening of symptoms. No significant effects on intracortical inhibition were observed. In the AdLD group, there was a large-effect size after rTMS in vocal perturbation measures and a small-effect size in decreased phonatory breaks. Conclusions One rTMS session over the LMC is safe and feasible, and demonstrated trends of beneficial effects on voice quality and phonatory function in AdLD. These preliminary findings support further investigation to assess clinical benefits in a future randomized sham-controlled trial. ClinicalTrials.gov NCT02957942, registered on November 8, 2016.

scholarly journals Repetitive transcranial magnetic stimulation as a prophylactic treatment in migraine

2021 ◽  
Vol 57 (1) ◽  
Author(s):  
Azza B. Hammad ◽  
Rasha E. Elsharkawy ◽  
Ghada S. Abdel Azim
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Serum Level ◽  
Pain Intensity ◽  
Magnetic Stimulation ◽  
Prophylactic Treatment ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Control Group ◽  
Neurokinin A ◽  
Abortive Treatment

Abstract Background Clinical applications of transcranial magnetic stimulation (TMS) have shown promising results in the treatment of headache disorders, with migraine being one of the most encountered. Objective To assess the role of low-frequency repetitive transcranial magnetic stimulation as a preventive treatment of migraine (with and without aura) and correlate the results with the serum level of the inflammatory biomarker (neurokinin A). Methods Forty patients, with age ranging from 15 to 55 years, diagnosed with migraine (30 migraine without aura and 10 with aura) and 20 apparently healthy individuals, who were age and sex matched with the patient group, were included in this study. A low-frequency (1 Hz) rTMS protocol was applied for all patients for five consecutive days interictally. Assessment of pain intensity using visual analogue scale and frequency and duration of attacks as well as number of pills taken by patients as an abortive treatment according to the Basic Diagnostic Headache Diary for 4 weeks before and 4 weeks after TMS sessions was done. In addition, the Migraine Disability Assessment scale (MIDAS) was applied to assess the severity and degree of disability caused by migraine. Measurement of neurokinin A serum level was done by using ELISA for all patients before and after TMS and for control group once. Results There was a significant reduction in pain intensity, frequency and duration of migraine attacks, migraine disability scores, and number of pills taken as abortive treatment for attacks after rTMS (P < 0.001). Also, serum level of neurokinin A in the patients was significantly reduced after rTMS (P < 0.001). Conclusion Low-frequency rTMS is an effective prophylactic treatment for migraine with and without aura.

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