Methods for Improving Movement Compatibility of Wearable OPM-MEG: A Review

Magnetoencephalography (MEG) is a powerful noninvasive neuroimaging technique with high spatiotemporal resolution. Recently, a new generation of MEG, optically pumped magnetometer (OPM)-based wearable MEG (OPM-MEG), has been developed. Compared to the conventional MEG based on superconducting quantum interference devices with a fixed sensor array, the OPM-MEG is closer to the scalp and is movement-compatible. This provides an excellent opportunity for MEG to expand its further application scenarios, such as virtual reality interactive tasks and the scanning of participants with movement disorders. In this study, we reviewed the hardware composition and performed artifact analysis of wearable OPM-MEGs. The hurdle for the OPM-MEG in achieving movement compatibility is its susceptibility to large head-movement artifacts, which is related to the magnitude and gradient levels of the background magnetic fields. Therefore, we analyzed hardware and software methods to suppress movement artifacts. In addition, we summarize the performed experiments and applications involving the participants' movements to illustrate the current movement-compatible performance of the OPM-MEG. Finally, we discussed the implications, challenges, and future research priorities of improving movement compatibility. This study aims to provide a reference for researchers who attempt to use and apply wearable OPM-MEG in movement-related neuroscience or clinical research.