TAAC - TMS Adaptable Auditory Control: A universal tool to mask TMS clicks

Area of Science:

• Neuroscience
• Biomedical Engineering
• Signal Processing

Background:

• Transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) enables non-invasive cortical perturbation studies.
• Auditory evoked potentials (AEPs) from TMS click noise are a significant confound in TMS-EEG.
• Masking noise played through earphones can prevent auditory contamination.

Purpose of the Study:

• To develop a flexible, open-source interface for generating real-time, customized auditory masking noises.
• To effectively and safely mask the auditory artifact (TMS click) in TMS-EEG.
• To improve the accuracy of TMS-evoked potential (TEP) measurements.

Main Methods:

• Release of TMS Adaptable Auditory Control (TAAC), a Matlab-based interface.
• TAAC generates customized noises by manipulating standard noises in time and frequency domains, tailored to individual TMS devices and subjects.
• Comparison of customized noises against standard noises using Sound Pressure Level (SPL) measurements with a Head and Torso Simulator (HATS).

Main Results:

• TAAC successfully generates effective and safe masking noises for TMS clicks.
• Customized noises required lower and safer SPLs compared to standard noises (white noise, click-only noise).
• Demonstrated efficacy in a population of 20 healthy subjects.

Conclusions:

• TAAC provides effective and safe, subject- and device-specific masking noises, outperforming previous methods.
• TAAC can aid in controlling auditory confounds, even in non-compliant patients, when combined with real-time TEP visualization.
• TAAC is a flexible, open-source tool adaptable for various experimental needs.