title: Infraslow EEG changes in infantile spasms.
abstract: OBJECTIVE
  Infantile spasms (IS) are a devastating epileptic encephalopathy syndrome of infancy. Analysis of infraslow EEG activity (ISA) has shown potential in the presurgical evaluation of patients with epilepsy and in differentiating between focal and generalized epilepsy syndromes. Infraslow EEG activity analysis may provide insights into the pathophysiology of some difficult-to-treat epilepsy syndromes, such as IS. To our knowledge, there are no published reports describing ISA in patients with IS. The purpose of this study was to describe ictal patterns of ISA in patients with IS and to correlate with clinical data.
  
  
  METHODS
  EEG recordings of all cases of IS in the past 10 years at the Alberta Children's Hospital were reviewed. Inclusion criteria were a technically adequate video EEG recording that captured at least one spasm. For each patient, the first 10 confirmed spasms were examined. Spasms were evaluated for changes in ISA, which were either generalized, lateralized, or absent ISA (g-ISA, l-ISA, or n-ISA, respectively). Results were correlated with treatments, clinical course, and information pertinent to likely etiology of the IS.
  
  
  RESULTS
  A total of 77% of spasms were associated with ISA; 57% with g-ISA, 20% l-ISA, and 21% n-ISA. All patients with exclusively g-ISA showed at least a partial response to initial therapy, while this was the case in 66.7% of those with at least some l-ISA and 50% of those with exclusively n-ISA. Other seizure types occurred in 60% of patients with exclusively g-ISA versus 83% with some l-ISA and all patients with exclusively n-ISA.
  
  
  CONCLUSIONS
  Ictal ISA was observed in the majority of IS. Trends were observed suggesting that the presence of exclusive g-ISA changes may be a positive prognostic factor in IS.
authors.affiliation: *Section of Neurology, Department of Paediatrics, Faculty of Medicine, University of Calgary, Calgary, Canada; †Department of Clinical Neurosciences, Faculty of Medicine, University of Calgary, Calgary, Canada; ‡Alberta Children's Hospital Research Institute for Child and Maternal Health, Calgary, Canada; and §Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Canada.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Myers
authors.forename: Luis E
authors.initials: LE
authors.lastname: Bello-Espinosa
authors.forename: Xing-Chang
authors.initials: XC
authors.lastname: Wei
authors.forename: Morris H
authors.initials: MH
authors.lastname: Scantlebury
mesh_terms: D000416:Alberta; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D058256:Brain Waves; D004569:Electroencephalography; D006776:Hospitals, Pediatric; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D011237:Predictive Value of Tests; D013036:Spasms, Infantile / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D013788:Thalamus / Q000473:pathology / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome