Prognosis of juvenile myoclonic epilepsy is related to endophenotypes

Abstract

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.