title: Tonic seizures of Lennox-Gastaut syndrome: periictal single-photon emission computed tomography suggests a corticopontine network.
abstract: OBJECTIVE
  Lennox-Gastaut syndrome (LGS) is a severe epileptic disorder with characteristic electroclinical features but diverse etiologies. The shared electroclinical characteristics suggest that common cerebral networks are involved in generating seizures. We sought to reveal these networks by comparing ictal and interictal single-photon emission computed tomography (SPECT).
  
  
  METHODS
  We identified 10 ictal-interictal SPECT pairs from seven patients with LGS (median age 11 years; range 1-38) who were studied during video electroencephalography (EEG)-confirmed tonic seizures. We performed a voxel-wise comparison of ictal and interictal SPECT studies across the group. The evolution of blood flow changes was explored by examining early and late injection groups.
  
  
  RESULTS
  Median duration of tonic seizures was 10 s (range 6-29 s), and injection latency from seizure offset was -8 to 48 s. In the early injection group (<10 s; three studies), there was hyperperfusion over pons and cerebellar hemispheres (p < 0.05 cluster corrected family wise error), and hypoperfusion bilaterally over the pericentral region, with a trend toward hyperperfusion over bilateral superior and middle frontal gyri, and lateral parietal cortex. In the late injection group, there was hyperperfusion over midline and lateral cerebellar regions, with hypoperfusion widely over bilateral frontal regions.
  
  
  CONCLUSIONS
  This study suggests that the tonic seizures of LGS result from activity in a network, containing bilateral frontal and parietal association areas and the pons. We postulate that tonic seizures recruit the corticoreticular system, which connects frontal attentional areas to the pontine reticular formation, and is normally responsible for postural tone and orienting behavior.
authors.affiliation: Pediatric Neurology Unit, Department of Paediatrics, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand; Department of Medicine, Austin Health, The University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Utcharee
authors.initials: U
authors.lastname: Intusoma
authors.forename: David F
authors.initials: DF
authors.lastname: Abbott
authors.forename: Richard A J
authors.initials: RA
authors.lastname: Masterton
authors.forename: Monique R
authors.initials: MR
authors.lastname: Stagnitti
authors.forename: Mark R
authors.initials: MR
authors.lastname: Newton
authors.forename: Graeme D
authors.initials: GD
authors.lastname: Jackson
authors.forename: Jeremy L
authors.initials: JL
authors.lastname: Freeman
authors.forename: A Simon
authors.initials: AS
authors.lastname: Harvey
authors.forename: John S
authors.initials: JS
authors.lastname: Archer
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D065768:Lennox Gastaut Syndrome; D008297:Male; D059906:Neuroimaging; D012640:Seizures / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D013036:Spasms, Infantile / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon; D055815:Young Adult
keywords: Epilepsy; Lennox-Gastaut syndrome; Single-photon emission computed tomography; Tonic seizure