Neuromagnetic high frequency spikes are a new and noninvasive biomarker for localization of epileptogenic zones. (July 2021)

• Record Type: Journal Article
• Authors: Xiang, Jing; Maue, Ellen; Tong, Han; Mangano, Francesco T; Greiner, Hansel; Tenney, Jeffrey
• Is Part Of: Seizure. Volume 89(2021)
• Page Start: 30
• Page End: 37
• Publication Date: 2021-07
• Subjects: Epilepsy -- Magnetoencephalography -- High-frequency oscillation -- High frequency spike -- High frequency activity -- Magnetic Source Imaging; Epilepsy -- Periodicals; Epilepsy -- Periodicals; Seizures -- Periodicals; Épilepsie -- Périodiques; Electronic journals; Electronic journals; 616.853
• DOI: 10.1016/j.seizure.2021.04.024
• Languages: English
• ISSNs: 1059-1311

Abstract

Highlights: Epileptic brain generates interictal high frequency spikes (HFSs) in 80–600 Hz. HFSs include spikelets (80–250 Hz) and fast spikelets (250–600 Hz). HFSs are a new epileptogenic biomarker for localizing epileptogenic zones. HFSs can be noninvasively detected and localized by magnetoencephalography. Abstract: Objective: One barrier hindering high frequency brain signals (HFBS, >80 Hz) from wide clinical applications is that the brain generates both pathological and physiological HFBS. This study was to find specific biomarkers for localizing epileptogenic zones (EZs). Methods: Twenty three children with drug-resistant epilepsy and age/sex matched healthy controls were studied with magnetoencephalography (MEG). High frequency oscillations (HFOs, > 4 oscillatory waveforms) and high frequency spikes (HFSs, > 1 spiky or sharp waveforms) in 80–250 Hz and 250–600 Hz bands were blindly detected with an artificial intelligence method and validated with visual inspection. The magnitude of HFOs and HFSs were quantified with spectral analyses. Sources of HFSs and HFOs were localized and compared with clinical EZs determined by invasive recordings and surgical outcomes. Results: HFOs in 80–250 Hz and 250–600 Hz were identified in both epilepsy patients (18/23, 12/23, respectively) and healthy controls (6/23, 4/23, respectively). HFSs in 80–250 Hz and 250–600 Hz were detected in patients (16/23, 11/23, respectively) but not in healthy controls. A combination of HFOs and HFSs localized EZs for 22 (22/23, 96%) patients. Conclusions: The results indicate, for the first time, that HFSs are a newer and more specific biomarker than HFOs for localizing EZs because HFOs appeared in both epilepsy patients and healthy controls while HFSs appeared only in epilepsy patients.