title: Analysis of Epileptic Discharges from Implanted Subdural Electrodes in Patients with Sturge-Weber Syndrome.
abstract: OBJECTIVE
  Almost two-thirds of patients with Sturge-Weber syndrome (SWS) have epilepsy, and half of them require surgery for it. However, it is well known that scalp electroencephalography (EEG) does not demonstrate unequivocal epileptic discharges in patients with SWS. Therefore, we analyzed interictal and ictal discharges from intracranial subdural EEG recordings in patients treated surgically for SWS to elucidate epileptogenicity in this disorder.
  
  
  METHODS
  Five intractable epileptic patients with SWS who were implanted with subdural electrodes for presurgical evaluation were enrolled in this study. We examined the following seizure parameters: seizure onset zone (SOZ), propagation speed of seizure discharges, and seizure duration by visual inspection. Additionally, power spectrogram analysis on some frequency bands at SOZ was performed from 60 s before the visually detected seizure onset using the EEG Complex Demodulation Method (CDM).
  
  
  RESULTS
  We obtained 21 seizures from five patients for evaluation, and all seizures initiated from the cortex under the leptomeningeal angioma. Most of the patients presented with motionless staring and respiratory distress as seizure symptoms. The average seizure propagation speed and duration were 3.1 ± 3.6 cm/min and 19.4 ± 33.6 min, respectively. Significant power spectrogram changes at the SOZ were detected at 10-30 Hz from 15 s before seizure onset, and at 30-80 Hz from 5 s before seizure onset.
  
  
  CONCLUSIONS
  In patients with SWS, seizures initiate from the cortex under the leptomeningeal angioma, and seizure propagation is slow and persists for a longer period. CDM indicated beta to low gamma-ranged seizure discharges starting from shortly before the visually detected seizure onset. Our ECoG findings indicate that ischemia is a principal mechanism underlying ictogenesis and epileptogenesis in SWS.
authors.affiliation: Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Iimura
authors.affiliation: Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Sugano
authors.affiliation: Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan.
authors.forename: Madoka
authors.initials: M
authors.lastname: Nakajima
authors.affiliation: Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Higo
authors.affiliation: Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan.
authors.forename: Hiroharu
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Nakanishi
authors.affiliation: Department of Neurosurgery, Epilepsy Center, Juntendo University, Tokyo, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Arai
mesh_terms: D001921:Brain / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D004567:Electrodes, Implanted / Q000009:adverse effects*; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000209:etiology* / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012640:Seizures / Q000209:etiology* / Q000473:pathology; D013341:Sturge-Weber Syndrome / Q000150:complications*