Detection of interictal epileptiform discharges: A comparison of on-scalp MEG and conventional MEG measurements. Issue 8 (August 2020)

• Record Type: Journal Article
• Authors: Westin, Karin; Pfeiffer, Christoph; Andersen, Lau M.; Ruffieux, Silvia; Cooray, Gerald; Kalaboukhov, Alexei; Winkler, Dag; Ingvar, Martin; Schneiderman, Justin; Lundqvist, Daniel
• Is Part Of: Clinical neurophysiology. Volume 131:Issue 8(2020:Aug.)
• Page Start: 1711
• Page End: 1720
• Publication Date: 2020-08
• Subjects: Epilepsy -- Interictal epileptiform discharges -- Magnetoencephalography -- High-critical temperature SQUIDs -- Instrumentation; Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2020.03.041
• Languages: English
• ISSNs: 1388-2457

Abstract

Highlights: First ever on-scalp magnetoencephalography (MEG) measurement on an epilepsy patient. Twice as many interictal epileptiform discharges seen with on-scalp MEG. Indicates that on-scalp MEG detects more epileptic activity than conventional MEG. Abstract: 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. Co-registration 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.