Usefulness of a morning routine EEG recording in patients with juvenile myoclonic epilepsy.

OBJECTIVE: To evaluate if a standard awake EEG recording in the morning is superior to afternoon awake EEG session in detecting generalized epileptiform discharges (GEDs) in patients with juvenile myoclonic epilepsy (JME). METHODS: The study group included 29 consecutive patients (23 women; mean age 22.3+/-6.3 years; age at onset of JME 15.4+/-3.4 years) with JME. Out of 29 patients 5 were untreated, 9 patients were treated with valproate, 8 with lamotrigine, 6 with levetiracetam and 1 patient with valproate plus phenobarbital. Two routine consecutive interictal EEG recordings were performed at 9a.m. and at 3p.m., respectively, while the subject was awake, on the same day after a a regular nocturnal sleep at own home. RESULTS: The morning EEG recording showed GEDs (i.e., generalized polispike and waves, photoparoxysmal response, or both). in 20/29 patients. In 15 of these 20 patients, the afternoon recording was normal and this difference was statistically significant (p < or = 0.001). Moreover, there was a striking reduction of GEDs in three of the remaining five patients. Nine/29 patients had both morning and afternoon EEG recording normal. CONCLUSIONS: The results of this study have illustrated a significant greater rate of detection of generalized epileptiform abnormalities by performing standard awake EEG in the morning in comparison with an afternoon session.