Opportunities for Quantum Sensing in Epilepsy Diagnostics

Diagnosis in epilepsy depends on several distinct objectives-including interictal epileptiform discharge (IED) detection, source localisation of epileptiform activity, and seizure classification-each shaped by the underlying sensing technology. This review examines the opportunities that quantum magnetic sensing offers within this diagnostic framework, with particular emphasis on translational readiness and clinical potential. Seizure classification is included to situate the broader clinical context of epilepsy diagnostics, whereas the review of quantum sensing evidence is focused on IED detection and presurgical source localisation, the objectives for which such evidence currently exists. Magnetoencephalography (MEG) provides non-invasive source localisation that complements electroencephalography (EEG), and its clinical adoption is increasingly determined by advances in magnetic sensor technology. Optically pumped magnetometer (OPM)-based MEG represents the most clinically developed quantum sensing application, progressing from proof-of-concept in 2020 toward small-cohort clinical feasibility studies from 2022 onwards. By enabling on-scalp recordings at reduced sensor-to-brain distance, OPM-MEG improves signal amplitude and permits flexible sensor placement, with early evidence of benefit in paediatric populations and mesial temporal lobe epilepsy. However, current evidence derives from small, heterogeneous cohorts, and no prospective data yet link OPM-MEG to surgical outcomes. ⁴He-OPMs represent an early feasibility stage with IED detection comparable to superconducting quantum interference device (SQUID)-MEG in small case series; nitrogen-vacancy centres in diamond and silicon carbide divacancy magnetometry remain preclinical, constrained by a fundamental standoff-sensitivity trade-off. We conclude that OPM-MEG is best positioned as a complementary modality within established presurgical workflows, with prospective multicentre outcome studies representing the critical next step toward clinical translation.