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Impact of high-frequency sampling rate and stimulation intensity on early TMS artifacts: considerations for immediate TMS-EEG responses

  • 0Neurophysiology Lab, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.
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October 16, 2025

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October 16, 2025

View abstract on PubMed

Summary

This summary is machine-generated.

High-frequency sampling rates reduce transcranial magnetic stimulation (TMS) pulse artifacts in TMS-electroencephalography (EEG) recordings. However, a persistent decay artifact limits measuring immediate cortical responses.

Area Of Science

  • Neuroscience
  • Biomedical Engineering
  • Signal Processing

Background

  • Transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) is crucial for studying cortical excitability.
  • TMS-EEG recordings are often limited by immediate TMS-pulse and decay artifacts, hindering the measurement of rapid neural responses.
  • Higher EEG sampling rates show potential for reducing artifact duration, but their impact on early TMS artifacts requires further investigation.

Purpose Of The Study

  • To characterize the duration of early TMS-induced artifacts at sampling rates exceeding 5000 Hz.
  • To investigate methods for reducing TMS artifacts to enable the measurement of immediate TMS-EEG responses (2-3 ms post-pulse).

Main Methods

  • TMS-EEG data were collected from phantom head models (melon, electrical circuit) using sampling rates of 4800 Hz, 9600 Hz, and 19,200 Hz.
  • Three TMS intensities (40%, 70%, 100% MSO) were applied using two commercial stimulators.
  • A non-parametric Aligned Rank Transform ANOVA was used to analyze the effects of Phantom, Sampling Rate, and TMS Intensity.

Main Results

  • The TMS-pulse artifact duration was less than 1 ms and decreased with higher sampling rates (p < 0.001).
  • A significant decay artifact persisted, returning the signal to baseline around 2-3 ms post-pulse, independent of sampling rate.
  • Decay artifact duration was primarily dependent on stimulation intensity (p < 0.001).

Conclusions

  • While high sampling rates shorten the initial TMS-pulse artifact, the decay artifact remains a significant limitation for measuring immediate cortical excitability.
  • Developing effective strategies to mitigate the decay artifact is essential for advancing TMS-EEG research and clinical applications.

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