Neural Noise- Optically pumped magnetoencephalography (OP-MEG) has been used to record ictal events in epilepsy.1
- OP-MEG is a magnetoencephalography method with clinical relevance for seizure localization.1 1
Weekly enrichment (2026-07-20)
- The source is a Letter to the Editor, “Experiences of ictal OP-MEG,” by Mellor and colleagues at UCL Queen Square Institute of Neurology, published in Clinical Neurophysiology vol. 184 (2026), article 2111504, accepted 8 January 2026.2
- Ictal (seizure) events were recorded from two adult male epilepsy patients; both had routine scalp EEGs within normal limits, which is why prolonged recording was needed to capture events.2
- OPM hardware was 42 sensors (patient 1) and 38 sensors (patient 2) of zero-field Gen-2.0 QZFM optically pumped magnetometers from QuSpin, mounted in a bespoke 3D-printed scanner cast made from each patient’s MRI; 3 and 4 sensors respectively were rejected for excessive noise.2
- Data were collected in a magnetically shielded room at UCL with head position and rotation tracked by 6 OptiTrack Flex 13 cameras; each patient sat unconstrained on a beanbag for roughly 1 hour, with patient 1 doing a verb-generation task and patient 2 (musicogenic epilepsy) listening to seizure-triggering music.2
- Patient 1 had a focal impaired-awareness seizure with increased 13–30 Hz oscillatory power localizing to the left parietal/temporal boundary, with the peak 20.2 mm from the boundary of a left temporal grey-matter heterotopia and concordant with prior clinical assessment.2
- For patient 2, analysis focused on 60–130 Hz high-frequency power (to avoid movement artifact from head turning) that localized bilaterally, right greater than left, adjacent to the inferior frontal gyrus (MNI peak 55.5, 20.1, 0.2), near regions associated with musicogenic seizures.2
- Signals were processed in SPM using Homogeneous Field Correction, band-stop/low-pass/high-pass Butterworth filters, and an LCMV beamformer with a Nolte single-shell forward model on a 5 mm source grid; analysis code was released on GitHub.2
- The work extends earlier OP-MEG milestones: Feys et al. (2022, Radiology) showed higher interictal-discharge SNR in school-aged children versus cryogenic MEG, and Feys et al. (2023, Annals of Neurology) first recorded ictal on-scalp discharges in a child with drug-resistant focal epilepsy.3 4
- Hillebrand et al. (2023, Scientific Reports) reported OPM data comparable to cryogenic SQUID-MEG while offering lower cost, greater movement tolerance, and sensitivity to deep sources such as the hippocampus, supporting wearable MEG for presurgical epilepsy evaluation.5
- The funding involved a Wellcome award with a collaboration agreement with QuSpin (a commercial OPM vendor); the authors emphasize OP-MEG’s patient-friendly, head-restraint-free recording as an advantage for children and patients who cannot stay still.2 6