title: Electroencephalographic evolution of hypsarrhythmia: toward an early treatment option.
abstract: OBJECTIVE
  A retrospective study for a classification of prehypsarrhythmic elecroencephalographies (EEGs) was carried out to enable an early treatment option for West syndrome.
  
  
  METHODS
  Out of 39 infants with symptomatic West syndrome, 18 infants (age 3-14 months) with 61 serial non-REM sleep EEG records of the prehypsarrhythmic phase were identified. The prehypsarrhythmic phase encompassed 2 to 13 months (mean 4.5 months) after an initial insult. A classification system of three EEG types corresponding to the clinical states prior to West syndrome occurrence was developed. In addition, follow-up of all patients presenting with type 2 EEGs (n = 22) was evaluated.
  
  
  RESULTS
  Three clinical states and corresponding EEG types were classified. Clinical state 1 (weeks to months, silent phase) presented with (multi-)focal epileptic discharges <50% of the non-REM EEG recording time (type 1 EEG). Clinical state 2 (several weeks, beginning mental deterioration) was accompanied by type 2 EEG with bihemispheric epileptic discharges >50% of the non-REM EEG recording time within abnormal background activity (imminent hypsarrhythmia). Clinical state 3 (mental deterioration) was characterized by hypsarryhthmia. Interrater reliability of seven blinded raters was good (median weighted kappa 0.67). Out of 22 patients presenting with type 2 EEGs, two were lost for follow-up, and 16 developed West syndrome, whereas four were treated early with anti-epileptic drugs and remained stable.
  
  
  CONCLUSIONS
  Infants with West syndrome could be reliably identified several weeks before the occurrence of hypsarrhythmia by a typical EEG pattern (type 2), thereby opening the way for early intervention studies.
authors.affiliation: Center of Developmental Neurology and Epileptology, Frankfurt, Germany. hphilippi@vae-ev.de
authors.forename: Heike
authors.initials: H
authors.lastname: Philippi
authors.forename: Gabriele
authors.initials: G
authors.lastname: Wohlrab
authors.forename: Uli
authors.initials: U
authors.lastname: Bettendorf
authors.forename: Peter
authors.initials: P
authors.lastname: Borusiak
authors.forename: Gerhard
authors.initials: G
authors.lastname: Kluger
authors.forename: Karl
authors.initials: K
authors.lastname: Strobl
authors.forename: Thomas
authors.initials: T
authors.lastname: Bast
mesh_terms: D000927:Anticonvulsants / Q000627:therapeutic use*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012189:Retrospective Studies; D012894:Sleep Stages / Q000502:physiology; D013036:Spasms, Infantile / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology
chemical_list: D000927:Anticonvulsants