title: Factors influencing the duration of generalized tonic-clonic seizure.
abstract: OBJECTIVE
  This study investigated the duration of generalized tonic-clonic seizure (GTCS) and the factors that prolong GTCS duration.
  
  
  METHODS
  We retrospectively analyzed clinical data collected from a consecutive group of patients who underwent video-electroencephalography (EEG) and experienced at least one GTCS during monitoring. Each seizure was divided into seven phases. The duration of GTCS was defined as the comprehensive duration of each GTCS phase, particularly those of Phase 3 to Phase 7.
  
  
  RESULTS
  The mean GTCS duration per patient was 74.6s. The results indicated that patients with an age of seizure onset <2 years exhibited a significantly longer duration than those with an age of seizure onset >2 years (p=0.033). A significant difference was also observed in the duration of GTCS between wakefulness and sleep (wakefulness 76.2 ± 38.5, sleep 66.3 ± 27.8, p=0.017). Our data suggest no significant differences between primary and secondary GTCS. The correlations between the duration of GTCS and many risk factors were also analyzed, including gender, age, neurological examination, cognitive status, family history of epilepsy, location of MRI brain abnormalities, reported seizure frequency at time of admission, number of current AEDs, history of SE, and duration of epilepsy.
  
  
  CONCLUSIONS
  The mean duration of GTCS was<2 min. The age of seizure onset and the circadian pattern of seizure are the major factors influencing the duration of GTCS.
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Sipei
authors.initials: S
authors.lastname: Pan
authors.affiliation: Department of Neurology, First Hospital of Tsinghua University, Beijing, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Sanbo Brain Hospital, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.affiliation: Sanbo Brain Hospital, Beijing, China. Electronic address: liuxinclair@126.com.
authors.forename: Xingzhou
authors.initials: X
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D012640:Seizures; D012890:Sleep / Q000502:physiology; D013997:Time Factors; D014741:Video Recording / Q000379:methods; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult
keywords: Age at seizure onset; Generalized tonic–clonic seizure; Sleep and wakefulness; Video-EEG