Frequency and spatial characteristics of highfrequency neuromagnetic signals in childhood epilepsy

Authors

Jing Xiang, Cincinnati Children’s Hospital Medical Center
Yang Liu, Cincinnati Children’s Hospital Medical Center
Yingying Wang, Cincinnati Children’s Hospital Medical CenterFollow
Elijah G. Kirtman, Cincinnati Children’s Hospital Medical Center
Cincinnati Children’s Hospital Medical Center Kotecha, Cincinnati Children’s Hospital Medical Center
Yangmei Chen, Cincinnati Children’s Hospital Medical Center
Xiaolin Huo, Cincinnati Children’s Hospital Medical Center
Hisako Fujiwara, Cincinnati Children’s Hospital Medical Center
Nat Hemasilpin, Cincinnati Children’s Hospital Medical Center
Ki Lee, Cincinnati Children’s Hospital Medical Center
Francesco T. Mangano, Cincinnati Children’s Hospital Medical Center
James Leach, Cincinnati Children’s Hospital Medical Center
Blaise Jones, Cincinnati Children’s Hospital Medical Center
Ton DeGrauw, Cincinnati Children’s Hospital Medical Center
Douglas Rose, Cincinnati Children’s Hospital Medical Center

Date of this Version

4-9-2009

Document Type

Article

Citation

2009 Authors

Comments

Epileptic Disord 2009; 11 (2): 113-25 doi: 10.1684/epd.2009.0253

Abstract

Purpose. Invasive intracranial recordings have suggested that high-frequency oscillation is involved in epileptogenesis and is highly localized to epileptogenic zones. The aim of the present study is to characterize the frequency and spatial patterns of high-frequency brain signals in childhood epilepsy using a non-invasive technology. Methods. Thirty children with clinically diagnosed epilepsy were studied using a whole head magnetoencephalography (MEG) system. MEG data were digitized at 4 000 Hz. The frequency and spatial characteristics of high-frequency neuromagnetic signals were analyzed using continuous wavelet transform and beamformer. Threedimensional magnetic resonance imaging (MRI) was obtained for each patient to localize magnetic sources. Results. Twenty-six patients showed highfrequency (100-1 000 Hz) components (26/30, 86%). Nineteen patients showed more than one high-frequency component (19/30, 63%). The frequency range of high-frequency components varied across patients. The highest frequency band was identified around 910 Hz. The loci of high-frequency epileptic activities were concordant with the lesions identified by magnetic resonance imaging for 21 patients (21/30, 70%). The MEG source localizations of high-frequency components were found to be concordant with intracranial recordings for nine of the eleven patients who underwent epilepsy surgery (9/11, 82%). Conclusion. The results have demonstrated that childhood epilepsy was associated with high-frequency epileptic activity in a wide frequency range. The concordance of MEG source localization, MRI and intracranial recordings suggests that measurement of high-frequency neuromagnetic signals might provide a novel approach for clinical management of childhood epilepsy.