Wearable Magnetoencephalography in a Lightly Shielded Environment.

Area of Science:

• Neuroscience
• Biophysics
• Biomedical Engineering

Background:

• Optically pumped magnetometer magnetoencephalography (OPM-MEG) offers advanced brain activity measurement.
• OPM-MEG requires specialized, large, and expensive magnetically shielded rooms (MSRs) due to high sensitivity to interference.
• Current MSRs limit the accessibility and widespread adoption of OPM-MEG technology.

Purpose of the Study:

• To investigate the efficacy of Maxwell filtering techniques, specifically signal space separation (SSS) and spatiotemporal SSS (tSSS), for OPM-MEG.
• To determine if OPM-MEG data can be accurately analyzed in a lightly shielded environment, reducing reliance on heavy MSRs.
• To assess the potential for making OPM-MEG more accessible and affordable.

Main Methods:

• Phantom recordings and human participant data (motor task) were collected in both a state-of-the-art 5-layer MSR and a lightly shielded room.
• Spatiotemporal signal space separation (tSSS) was applied to OPM-MEG data acquired in both environments.
• The accuracy of source localization was compared between the MSR and lightly shielded room conditions.

Main Results:

• Application of tSSS to OPM-MEG data recorded in a lightly shielded room successfully isolated neural signals.
• Accurate localization of a dipole source in phantom recordings was achieved in the lightly shielded room.
• Neuronal sources in the human brain were accurately localized using OPM-MEG data collected in the lightly shielded room with tSSS.

Conclusions:

• Maxwell filtering techniques, particularly tSSS, can effectively mitigate interference in OPM-MEG.
• OPM-MEG can be performed with high fidelity in less restrictive, lightly shielded rooms.
• This advancement paves the way for smaller, more affordable, and widely deployable OPM-MEG systems.