Detection of interictal epileptiform discharges: A comparison of on-scalp MEG and conventional MEG measurements
Journal article, 2020

Objective: Conventional MEG provides an unsurpassed ability to, non-invasively, detect epileptic activity. However, highly resolved information on small neuronal populations required in epilepsy diagnostics is lost and can be detected only intracranially. Next-generation on-scalp magnetencephalography (MEG) sensors aim to retrieve information unavailable to conventional non-invasive brain imaging techniques. To evaluate the benefits of on-scalp MEG in epilepsy, we performed the first-ever such measurement on an epilepsy patient.
Methods: Conducted as a benchmarking study focusing on interictal epileptiform discharge (IED) detectability, an on-scalp high-temperature superconducting quantum interference device magnetometer (high-Tc SQUID) system was compared to a conventional, low-temperature SQUID system. Coregistration of electroencephalopraphy (EEG) was performed. A novel machine learning-based IED-detection algorithm was developed to aid identification of on-scalp MEG unique IEDs.
Results: Conventional MEG contained 24 IEDs. On-scalp MEG revealed 47 IEDs (16 co-registered by EEG, 31 unique to the on-scalp MEG recording). Conclusion: Our results indicate that on-scalp MEG might capture IEDs not seen by other non-invasive modalities. Significance: On-scalp MEG has the potential of improving non-invasive epilepsy evaluation. 


High-critical temperature SQUIDs


Interictal epileptiform discharges



Karin Westin

Karolinska University Hospital

Karolinska Institutet

Christoph Pfeiffer

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Lau M. Andersen

Aarhus University

Karolinska Institutet

Silvia Ruffieux

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Gerald Cooray

Karolinska Institutet

Karolinska University Hospital

Alexei Kalaboukhov

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Dag Winkler

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Martin Ingvar

Karolinska Institutet

Justin Schneiderman

University of Gothenburg

Daniel Lundqvist

Karolinska Institutet

Clinical Neurophysiology

1388-2457 (ISSN)

Vol. 131 8 1711-1720

Subject Categories

Medical Laboratory and Measurements Technologies

Other Medical Engineering

Other Physics Topics

Biomedical Laboratory Science/Technology





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4/5/2022 5