Prognosis of juvenile myoclonic epilepsy is related to endophenotypes

Purpose: To investigate if phenotypic variations have prognostic implications in juvenile myoclonic epilepsy (JME). Methods: Sixty-five consecutive JME patients had video-EEG recording and were followed for at least three years. Reflex traits were defined as seizures and/or EEG discharges induction by eye-closure, photic stimulation, language, praxis or calculation. Patients had psychiatric evaluation and answered to STAI (State-Trait Anxiety Inventory). Seizure control was classified according to Prasad et al. (2003).(24) Patients were divided into Group 1: good seizure control and Group 2: moderate or poor seizure control. Video-EEG/EEG evaluation was repeated in 21 patients. Results: Forty of 65 (61.5%) patients reached good seizure control, 25(38.5%) of whom became seizure free. Group 2 patients had longer epilepsy duration (13.9 +/- 9.0 vs. 8.7 +/- 8.2; p = 0.019); higher prevalence of the combination of all three seizure types (72.0% vs. 30.0%; p = 0.003); discharges in baseline EEG (56.0% vs. 22.5%; p = 0.008); seizure recording (68% vs. 20%; p < 0.001) and sensitivity to praxis (63.6% vs. 29.6%; p = 0.023). Compared to seizure-free patients, those with persistent seizures presented younger age at epilepsy onset (12.6 +/- 3.33 years vs. 15.4 +/- 5.47 years; p = 0.015); higher prevalence of personality disorders (25% vs. 4%; p = 0.029); higher scores in STAI-T (45.9 +/- 11.31 vs. 36.6 +/- 11.43; p = 0.011) and higher incidence of sensitivity to praxis (58.6% vs. 25.0%; p = 0.04) and to language (53.8 vs. 16.7%; p = 0.026) tasks. Repetition of EEG/video-EEG revealed a parallel evolution of reflex traits disappearance and seizure control. Discussion: Clinical features and reflex traits have prognosis implications in JME. (C) 2010 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.