Simultaneous whole-head electrophysiological recordings using EEG and OPM-MEG.

Area of Science:

• Neuroscience
• Biophysics
• Medical Instrumentation

Background:

• Electroencephalography (EEG) and magnetoencephalography (MEG) are non-invasive techniques for measuring human brain electrophysiology.
• While MEG offers superior performance, EEG is more practical as a wearable platform.
• Concurrent EEG/MEG acquisition offers advantages over individual modalities, leading to clinical recommendations for simultaneous use in epilepsy.

Purpose of the Study:

• To investigate whether simultaneous, wearable, whole-head EEG and OPM-MEG degrade signal quality in either modality.
• To assess the performance of EEG alone, OPM-MEG alone, and concurrent EEG/OPM-MEG during specific cognitive tasks.

Main Methods:

• Utilized two tasks: a motor task modulating beta oscillations and an eyes-open/closed task modulating alpha oscillations.
• Characterized signal quality by comparing EEG alone, OPM-MEG alone, and concurrent EEG/OPM-MEG recordings.
• Evaluated signal-to-noise ratio (SNR) and signal contrast for specific brain oscillations.

Main Results:

• The signal-to-noise ratio (SNR) for beta oscillations remained consistent across individual and concurrent recordings.
• Alpha band recordings showed stable signal contrast irrespective of concurrent OPM-MEG acquisition.
• Optically pumped magnetometer-magnetoencephalography (OPM-MEG) demonstrated reduced cross-channel correlation and lower susceptibility to non-brain interference.

Conclusions:

• Simultaneous wearable EEG and OPM-MEG do not compromise signal quality in either modality.
• The combined technique is suitable for widespread neuroscientific and clinical adoption.
• Concurrent EEG/OPM-MEG recordings will improve the interpretation of OPM-MEG data in clinical settings, particularly for epilepsy diagnosis.