Abstracts

Rationale: In this study, we investigated the correlation between different EEG abnormalities observed in patients with idiopathic generalized epilepsies (IGEs) and their seizure types. Methods: In this cross-sectional study, all patients with diagnosis of IGE, were recruited in the outpatient epilepsy clinic at Shiraz University of Medical Sciences, Iran, from 2008 through 2010. Demographic variables and relevant clinical and EEG variables were summarized descriptively. Statistical analyses were performed using independent samples T-test, Chi square and Fisher's Exact tests to determine potentially significant differences.Results: 336 patients were diagnosed as having IGEs. EEG findings in patients with GTCSs compared to patients without GTCSs were not different. Abnormal EEG findings in patients with myoclonic seizures compared to patients without these were not different. However, normal EEGs were more frequently observed in patients with history of myoclonic seizures (P = 0.0001). EEG findings in patients with absences compared to patients without absences were not different. Conclusions: Interictal EEG cannot differentiate the seizure types and therefore different syndromes of IGEs. Polyspikes, 3-Hz generalized spike-wave (GSW) complexes and 3.5 6 Hz GSW complexes, alone or in combinations, could be observed in various seizure types and syndromes of IGEs. The key element in making the correct diagnosis is a detailed clinical history.