Movement Related Beta-Band Modulation with OPM-MEG: A Pilot Study

Optically pumped magnetometers (OPMs) represent a significant advancement in magnetoencephalography (MEG), offering high sensitivity without cryogenic cooling and enabling flexible sensor placement. In this pilot study, we evaluated whether a small, zero-contact 16-channel OPM array can capture movement-related beta-band modulation (event-related desynchronization/synchronization; ERD/ERS) in healthy participants and explored feasibility in a single patient with amyotrophic lateral sclerosis (ALS). MEG responses to visually cued active and passive finger movements were recorded in a magnetically shielded room with the OPM array and separately with 306-channel superconducting quantum interference device (SQUID). Time-frequency analyses focused on beta-band activity across baseline, ERD, and ERS periods. In healthy participants, both OPM and SQUID successfully captured movement-related beta oscillations, with no significant differences between active and passive conditions or between measurement systems, based on non-parametric tests. In the ALS patient, movement-related responses were attenuated and more affected by artifacts in the OPM data compared with SQUID, limiting interpretability. Although movement artifacts were noted, the OPM system provided group-level results in healthy controls comparable to SQUID-based MEG, demonstrating its viability and potential for rapid, flexible deployment. These findings indicate that a compact zero-contact OPM array can reliably measure movement-related cortical beta activity and may offer a cost-effective alternative to cryogenic MEG systems. In ALS, however, the present results should be interpreted strictly as a feasibility demonstration, and larger patient cohorts will be required to establish reliability and clinical utility.