Work

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

Year: 2025

Type: article

Abstract: • TMS-Pulse and Decay Artifacts hinder immediate and early EEG responses after TMS • High sampling rate EEG recordings reduce the TMS-pulse artifact to under 1 ms • The Decay Artifact is mainly affected by TMS intensity • Even in ideal conditions, the Decay Artifact lasts longer than the TMS-pulse artifact • The Decay Artifact is currently the main issue to measure immediate TMS-EEG responses In studies combining transcranial magnetic stimulation and electroencephalography (TMS-EEG), two artifacts appear instantly after the TMS pulse, i.e., the TMS-pulse Artifact and the Decay Artifact, and limit the possibility to measure immediate cortical excitability responses. High-frequency sampling rates in EEG recordings have shown promise in reducing artifact duration, allowing more rapid signal recovery. However, the features of early TMS-induced artifacts for sampling rates above 5000 Hz are still not fully characterized. Here, we explored the duration of TMS artifacts to understand how they can be further reduced to allow the measure of immediate TMS-EEG responses (i.e., 2-3 ms after the TMS pulse). We recorded from two phantom head models, namely a melon and a simple electrical circuit, with a sampling rate of 4800 Hz, 9600 Hz, and 19200 Hz and at three TMS intensities (40%, 70%, 100% of maximum stimulator output) in two commercial stimulators. A non-parametric Aligned Rank Transform Analysis of Variance was applied with a 2 × 3 × 3 design, with Phantom, Sampling rate and TMS Intensity as factors. Results showed an initial sharp TMS-pulse Artifact lasting less than 1 ms and decreasing in duration at higher sampling rates ( p <0.001). However, the signal was back to baseline at about 2-3 ms due to the presence of a Decay Artifact that was evident even in optimal conditions of low impedance and mostly dependent on stimulation intensity (p <0.001) . These results highlight the need to develop efficient ways to eliminate the Decay Artifact in order to measure immediate TMS-EEG responses.

Source: NeuroImage

DOI: 10.1016/j.neuroimage.2025.121526

Authors: Antonietta Stango, Agnese Zazio, Guido Barchiesi, Natale Salvatore Bonfiglio, Marta Bortoletto

Institutions: Centro San Giovanni di Dio Fatebenefratelli, University of Milan, IMT School for Advanced Studies Lucca

Language: English

Topic: Transcranial Magnetic Stimulation Studies

Subfield: Neurology

Field: Neuroscience

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $3,540