Effects of Peripheral Magnetic Stimulation on Cortical Excitability in Healthy Individuals

Condition(s) studied

Investigational drug(s) / intervention(s)

Peripheral magnetic stimulation (90% of RMT + 1 Hz): Low-frequency stimulation (1 Hz) at 90% of resting motor threshold intensity, delivering a total of 2400 pulses.

Peripheral magnetic stimulation (90% of RMT + 10 Hz): High-frequency stimulation (10 Hz) at 90% of resting motor threshold intensity, totaling 2400 pulses.

Peripheral magnetic stimulation (90% of RMT + 25 Hz): High-frequency stimulation (25 Hz) at 90% of resting muscle threshold intensity, with 2400 pulses.

Peripheral magnetic stimulation (100% of RMT + 1 Hz): Low-frequency (1 Hz), at resting motor threshold intensity (100%) protocol delivering 2400 pulses.

Peripheral magnetic stimulation (100% of RMT + 10 Hz): High-frequency (10 Hz), at resting motor threshold intensity (100%) protocol delivering 2400 pulses.

Peripheral magnetic stimulation (100% of RMT + 25 Hz): High-frequency (25 Hz), at resting motor threshold intensity (100%) protocol delivering 2400 pulses.

Peripheral magnetic stimulation (110% of RMT + 1Hz): Low-frequency (1 Hz), above resting motor threshold intensity (110%) protocol delivering 2400 pulses.

Peripheral magnetic stimulation (110% of RMT + 10Hz): High-frequency (10 Hz), above resting motor threshold intensity (110%) protocol delivering 2400 pulses.

Peripheral magnetic stimulation (110% of RMT + 25Hz): High-frequency (25 Hz), above resting motor threshold intensity (110%) protocol delivering 2400 pulses.

Study summary

This study investigates the immediate effects of different parameters (frequency, intensity, and pulse number) of peripheral magnetic stimulation (rPMS) on cortical excitability in healthy individuals. Using a randomized, double-blind crossover design, the research aims to identify optimal stimulation protocols for modulating neural activity. Outcomes include measurements of motor-evoked potentials (MEPs), intracortical inhibition (ICI), and facilitation (ICF). Findings may enhance non-invasive therapeutic strategies for neurological disorders.

Eligibility

Primary outcome measure(s)

• Cortical excitabilty — Baseline (T0), immediately post-stimulation (T1), 15 minutes (T2), and 30 minutes (T3) post-stimulation.
  Cortical excitability will be assessed through motor-evoked potentials (MEPs) elicited by single-pulse transcranial magnetic stimulation (TMS) over the primary motor cortex (M1), targeting the first dorsal interosseous (FDI) representation area. The hotspot will be determined as the site producing the largest MEP amplitude at the lowest intensity, with stimulation delivered at 100% of the resting motor threshold (RMT). Additionally, paired-pulse TMS protocols will evaluate intracortical inhibition (ICI) and facilitation (ICF) using conditioning stimuli at 80% RMT (3 ms interstimulus interval for ICI, 10 ms for ICF) and test stimuli at 120% RMT. MEP amplitudes will be recorded via surface electromyography (EMG) from the FDI muscle using bipolar electrode placement, with signals sampled at 20,000 Hz (bandpass 5-10,000 Hz) to capture corticospinal excitability changes across timepoints (baseline, post-intervention, and follow-ups).

Trial sites (1)

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