Future approaches to seizure source localisation using optically pumped magnetoencephalography and electrical impedance tomography. Issue 9 (12th August 2022)

• Record Type: Journal Article
• Authors: Vivekananda, U; Mellor, S; Tierney, T; Aristovich, K; Barnes, G; Walker, M
• Is Part Of: Journal of neurology, neurosurgery and psychiatry. Volume 93:Issue 9(2022)
• Page Start: e2
• Publication Date: 2022-08-12
• Subjects: Neurology -- Periodicals; Nervous system -- Surgery -- Periodicals; Psychiatry -- Periodicals; 616.8
• DOI: 10.1136/jnnp-2022-abn2.38
• Languages: English
• ISSNs: 0022-3050

Abstract

Abstract : A third of patients with epilepsy are drug resistant, and epilepsy surgery (i.e. removal of the brain epilepsy focus) may present a powerful alternative in achieving seizure freedom. Magnetoencephalography (MEG) has been increasingly used in identifying the epilepsy focus due to its inherent properties of high spatial resolution and relative immunity to muscle artefact. However current MEG systems are cumbersome and restrictive for the patient, meaning that recording sessions are usually brief (1-2 hours). Here we demon- strate the first use of Optically Pumped Magnetoencephalography (OP-MEG) worldwide in three epilepsy patients with unrestricted head movement. We use a different type of sensor, which operates at room temperature and can be placed directly on the patient's scalp, permitting free head movement. We show that OP-MEG could reliably identify abnormal epileptiform activity, even in cases where EEG could not, and localise this activity to the abnormal brain region. In patients who undergo intracranial EEG i.e. electrodes surgically placed within the brain, we have also demonstrated the first use of Electrical Impedance Tomography (EIT), a method for producing images of the internal electrical impedance of a subject due to nerve cell swelling. This method can produce images of seizure propagation similar to fMRI, but can be recorded continuously at any time during presurgical video-telemetry. Both methods have the potential to revolutionise how functional imaging is performed in epilepsy.