Purpose: To evaluate how diagnostic criteria influence remission rates for patients with childhood absence epilepsy (CAE) and to assess clinical and EEG parameters as predictors of outcome.
Methods: One hundred nineteen patients were diagnosed with CAE, according to International League Against Epilepsy (ILAE) classification criteria. They were subsequently evaluated according to stricter diagnostic criteria. Sixty-two subjects fulfilled these criteria as group 2; 57 did not and constituted group 1. Diagnostic parameters that prevented patients of group 1 from entering group 2, and variables such as sex, familial history of generalized epilepsy, and personal history of febrile convulsions also were tested as prognostic factors for terminal remission.
Results: Compared with those in group 1, patients of group 2 had significantly higher rates of seizure control (95% vs. 77%), higher rates of terminal remission (82% vs. 51%), fewer generalized tonic-clonic seizures (8% vs. 30%), and shorter mean periods of treatment (2.2 vs. 3.8 years). Significantly fewer patients were receiving polytherapy in group 2 than in group 1 (11% vs. 47%), and fewer patients had seizure relapses at antiepileptic drug discontinuation (0 vs. 22%).
Conclusions: Remission rates of patients with CAE are greatly influenced by the classification criteria used for selection. Stricter diagnostic criteria allow the definition of a homogeneous group of patients with excellent prognosis. Factors predicting unfavorable prognosis were generalized tonic-clonic seizures in the active stage of absences, myoclonic jerks, eyelid myoclonia or perioral myoclonia, and EEG features atypical for CAE.