High-density full-head on-scalp MEG for epilepsy

Brisbane Convention & Exhibition Centre 

Optically-pumped magnetometers (OPMs) have been identified as a possible candidate for use in evaluations of patients with epilepsy. OPMs combine high spatial and temporal resolution with the ability to track brain activity even when a subject is moving, making them ideal for long-term monitoring - especially for children who have difficulty staying still. OPMs offer the advantage of being cryogen-free, potentially lowering operational costs and simplifying the setup compared to traditional MEG systems. Although several research sites have begun using wearable OPM-based MEG systems in children and adults with epilepsy (Feys et al., 2022; Hillebrand et al., 2023; Pedersen et al., 2022; Sequeiros & Hamandi, 2024; Vivekananda et al., 2020), the technology has not yet been systematically tested in larger groups. We present first results of an ongoing cross-validation study performed in 12 adult patients with drug-resistant focal epilepsy to date. To assess the OPM data quality, subjects underwent simultaneously EEG and MEG recordings on a cryogenic MEG system and an on-scalp MEG system. Interictal activity was localized from resting-state recordings and the locations were compared between the recordings with different modalities. In addition, somatosensory-evoked activity was recorded and localized. The goal of the study is to compare the data quality between OPM-based MEG and conventional cryogenic MEG, using simultaneous EEG and MEG recordings.