Magnetoencephalographic analysis of hypsarrhythmia in West syndrome

Magnetoencephalography (MEG) was performed in 7 patients with West syndrome (WS). In patients who had localized lesions such as tuberous sclerosis and porencephaly in the cerebral cortex, MEG showed clusters of sources of epileptiform discharges (EDs) of hypsarrhythmia at these lesions. On the other hand, in patients whose underlying cerebral lesions were considered to be distributed, such as hydrocephalus, lissencephaly, and hypoxic encephalopathy, MEG showed wide distribution of sources of EDs of hypsarrhythmia. In patients with cryptogenic WS, estimated sources were distributed over a wide area on the brain in one case, and in the other case, sources converged in 2 foci. MEG allowed estimation of three-dimensional localization of sources of electric currents, and the relationship between cerebral lesions observed by head magnetic resonance imaging (MRI) and sources of electric currents of hypsarrhythmia observed by MEG was clear. In view of the improvements in surgical treatments for epilepsy in WS, MEG is considered an effective method of diagnosis, considering that it allows the accurate evaluation of cerebral lesions associated with hypsarrhythmia by the complementary use of magnetic resonance imaging (MRT), single photon emission computed tomography (SPECT), and electroencephalography (EEG). (C) 1997 by Elsevier Science Inc.