title: Scalp EEG Ictal gamma and beta activity during infantile spasms: Evidence of focality.
abstract: We investigated temporal and spatial characteristics of ictal gamma and beta activity on scalp EEG during spasms in patients with West syndrome (WS) to evaluate potential focal cortical onset.
  
  
  
  A total of 1,033 spasms from 34 patients with WS of various etiologies were analyzed on video-electroencephalography (EEG) using time-frequency analysis. Ictal gamma (35-90 Hz) and beta (15-30 Hz) activities were correlated with visual symmetry of spasms, objective EMG (electromyography) analysis, and etiology of WS.
  
  
  
  Prior to the ictal motor manifestation, focal ictal gamma activity emerged from one hemisphere (71%, 24/34) or from midline (26%, 9/34), and was rarely simultaneously bilateral (3%, 1/34). Focal ictal beta activity emerged from either one hemisphere (68%, 23/34) or from midline (32%, 11/34). Onsets of focal ictal gamma and beta activity were most commonly observed around the parietal areas. Focal ictal gamma activity propagated faster than ictal beta activity to adjacent electrodes (median: 65 vs. 170 msec, p < 0.01), and to contralateral hemisphere (median: 100 vs. 170 msec, p = 0.01). Asymmetric peak amplitude of ictal gamma activity in the centroparietal areas (C3-P3 vs. C4-P4) correlated with asymmetric semiology. On the other hand, most of the visually symmetric spasms showed asymmetry in peak amplitude and interhemispheric onset latency difference in both ictal gamma and beta activity.
  
  
  
  Spasms may be a seizure with focal electrographic onset regardless of visual symmetry. Asymmetric involvement of ictal gamma activity to the centroparietal areas may determine the motor manifestations in WS. Scalp EEG ictal gamma and beta activity may be useful to demonstrate localized seizure onset in infants with WS.
authors.affiliation: Saul R. Korey Department of Neurology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.|Department of Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.
authors.forename: Hiroki
authors.identifier: 0000-0002-8318-2924
authors.initials: H
authors.lastname: Nariai
authors.affiliation: Saul R. Korey Department of Neurology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.|Department of Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.
authors.forename: Jules
authors.initials: J
authors.lastname: Beal
authors.affiliation: Saul R. Korey Department of Neurology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.|Dominick P. Purpura Department Neuroscience, Albert Einstein College of Medicine, Bronx, New York, U.S.A.
authors.forename: Aristea S
authors.initials: AS
authors.lastname: Galanopoulou
authors.affiliation: Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, U.S.A.
authors.forename: Wenzhu B
authors.initials: WB
authors.lastname: Mowrey
authors.affiliation: Saul R. Korey Department of Neurology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.
authors.forename: Stephan
authors.initials: S
authors.lastname: Bickel
authors.affiliation: Department of Pediatrics and Neurology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, U.S.A.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Sogawa
authors.affiliation: Saul R. Korey Department of Neurology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.|Department of Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.
authors.forename: Rana
authors.initials: R
authors.lastname: Jehle
authors.affiliation: Saul R. Korey Department of Neurology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.|Department of Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.|Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, U.S.A.
authors.forename: Shlomo
authors.initials: S
authors.lastname: Shinnar
authors.affiliation: Saul R. Korey Department of Neurology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.|Department of Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.|Dominick P. Purpura Department Neuroscience, Albert Einstein College of Medicine, Bronx, New York, U.S.A.
authors.forename: Solomon L
authors.initials: SL
authors.lastname: Moshé
mesh_terms: D001611:Beta Rhythm / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D004576:Electromyography; D004828:Epilepsies, Partial / Q000175:diagnosis / Q000503:physiopathology; D065818:Gamma Rhythm / Q000502:physiology*; D006801:Humans; D007223:Infant; D017286:Polysomnography; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted; D013036:Spasms, Infantile / Q000175:diagnosis / Q000503:physiopathology*; D014741:Video Recording
keywords: Beta activity; Gamma activity; High-frequency oscillations; Infantile spasms; Seizure semiology; West syndrome