Consistent topography and amplitude symmetry are more typical than morphology of epileptiform discharges in genetic generalized epilepsy

Udaya Seneviratne, Mark Cook, Wendyl D'Souza

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Objective: To provide a quantitative evaluation of typical electroencephalographic (EEG) abnormalities in genetic generalized epilepsy (GGE). Methods: We prospectively performed 24-ambulatory EEG recordings in a cohort of patients with GGE. The diagnosis was established according to the International League Against Epilepsy criteria. Details of all epileptiform discharges across the 24-time scale were entered into an electronic database. We carried out descriptive statistics to provide a quantitative breakdown of typical EEG abnormalities. 

Results: A total of 6923 epileptiform discharges from 105 abnormal 24-ambulatory EEGs were analyzed. 96% of discharges were symmetric in amplitude with fronto-central maximum topographically. Only 24% of the paroxysms had typical morphology while 43% were regular. Photoparoxysmal response, eye-closure sensitivity and hyperventilation-induced generalized paroxysms were less common in around 10%, whereas occipital intermittent rhythmic delta activity was very rare (2%). 

Conclusion: Our results indicate that generalized discharges with symmetric amplitude and fronto-central maxima are the most consistent findings in GGE, and other features are observed less frequently. Significance: Epileptiform discharges displaying highly consistent amplitude symmetry coupled with fronto-central topography should provoke consideration of GGE. Recognition of variations from typical abnormalities is important to avoid the risk of misdiagnosis and delayed diagnosis.

Original languageEnglish
Pages (from-to)1138-1146
Number of pages9
JournalClinical Neurophysiology
Issue number2
Publication statusPublished - 1 Feb 2016


  • EEG
  • Generalized epilepsy
  • Morphology
  • Seizure
  • Spike-wave
  • Topography

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