Frequency and spatial characteristics of high-frequency neuromagnetic signals in childhood epilepsy.
OBJECTIVE
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. Three-dimensional magnetic resonance imaging (MRI) was obtained for each patient to localize magnetic sources.


RESULTS
Twenty-six patients showed high-frequency (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%).


CONCLUSIONS
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.
Xiang
Jing
J
MEG Center, Division of Neurology, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45220, USA. Jing.xiang@cchmc.org
Liu
Yang
Y
Wang
Yingying
Y
Kirtman
Elijah G
EG
Kotecha
Rupesh
R
Chen
Yangmei
Y
Huo
Xiaolin
X
Fujiwara
Hisako
H
Hemasilpin
Nat
N
Lee
Ki
K
Mangano
Francesco T
FT
Leach
James
J
Jones
Blaise
B
DeGrauw
Ton
T
Rose
Douglas
D
D000293:Adolescent; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D002648:Child; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods; D004827:Epilepsy / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D015225:Magnetoencephalography / Q000379:methods; D008297:Male