title: Characterization of ictal slow waves in epileptic spasms.
abstract: We characterized the clinico-neurophysiological features of epileptic spasms, particularly focusing on high-voltage slow waves during ictal EEG. We studied 22 patients with epileptic spasms recorded during digital video-scalp EEG, including five individuals who still had persistent spasms after callosotomy. We analysed the duration, amplitude, latency to onset of electromyographic bursts, and distribution of the highest positive and negative peaks of slow waves in 352 spasms. High-voltage positive slow waves preceded the identifiable muscle contractions of spasms. The mean duration of these positive waves was 569±228 m, and the mean latency to electromyographic onset was 182±127 m. These parameters varied markedly even within a patient. The highest peak of the positive component was distributed in variable regions, which was not consistent with the location of lesions on MRI. The peak of the negative component following the positivity was distributed in the neighbouring or opposite areas of the positive peak distribution. No changes were evident in the pre- or post-surgical distributions of the positive peak, or in the interhemispheric delay between both hemispheres, in individuals with callosotomy. Our data imply that ictal positive slow waves are the most common EEG changes during spasms associated with a massive motor component. Plausible explanations for these widespread positive slow waves include the notion that EEG changes possibly reflect involvement of both cortical and subcortical structures.
authors.affiliation: Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo, Department of Pediatrics, National Hospital Organization Nagasaki Medical Center, Nagasaki.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Honda
authors.affiliation: Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo, Department of Child Neurology, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, Yonago.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Akihisa
authors.initials: A
authors.lastname: Okumura
authors.affiliation: Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Shinpei
authors.initials: S
authors.lastname: Abe
authors.affiliation: Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo.
authors.forename: Takashi
authors.initials: T
authors.lastname: Saito
authors.affiliation: Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo.
authors.forename: Eiji
authors.initials: E
authors.lastname: Nakagawa
authors.affiliation: Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugai
authors.affiliation: Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Sasaki
mesh_terms: D001921:Brain / Q000503:physiopathology*; D058256:Brain Waves / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D013036:Spasms, Infantile / Q000503:physiopathology*
keywords: epileptic spasms; high-voltage positive slow waves; scalp electroencephalography