Abstracts

Rationale: Juvenile myoclonic epilepsy (JME) is the most common age-related idiopathic generalized epilepsy, characterized by myoclonic jerks, generalized tonic-clonic seizures and absences. Generalized 4-6 Hz polyspike-wave complexes, on a normal background, are the typical EEG findings. Neuropsychological tasks during EEG to identify seizure provocative or inhibitory factors have been described, especially in patients with idiopathic generalized epileptic syndromes, particularly JME. Matsuoka et al. (2000) described inhibitory effect (IE) during a 10-20 minutes neuropsychological activation protocol in 63.9% (133/208) of patients with epilepsy who had paroxysms on the wake EEG (208/480), of whom 45 (9.37%) presented JME. The aim of this study was to analyze the IE during a video-EEG neuropsychological protocol (VNPP) in JME patients. Methods: Eighty JME patients underwent a VNPP including tasks such as reading, speaking, writting, spatial construction (praxis), and written/mental calculation and also eyes opening/closing, hyperventilation (HV), intermittent photic stimulation (IPS) and sleep. A discharge index (number of discharges per min/ number of discharges per min in wakefulness) was used according to Matsuoka et al. (2000) who considered rate above 2 for provocative effect, below 0.5 for inhibitory effect and between 0.5 and 2.0 for no effect. We considered an effect as inhibitory only when there was at least 3 discharges/10 minutes on resting EEG, since a shorter period of resting rate of discharges would not allow such analysis. Results: Fourteen (17.5%) patients had IE, of whom nine were females and 12 were under antiepileptic drug treatment (AED), eight with monotherapy and four with two AEDs. Exclusive IE was observed in four treated patients during the following tasks: reading (n=4), writing (n=2), mental calculation (n=2), spatial construction (n=2) and speaking (n=1). Eyes opening/closing, HV, IPS and sleep did not exert any effect on these patients. All the other 10 patients (8 treated and 2 non-treated) had activation of discharges besides IE. The IE was observed on praxis (9/10), reading (8/10), written calculation (6/10), speaking (5/10), mental calculation (4/10), writing (4/10), drawing (4/10) and sleep (2/10); none had IE during HV. In this group activation was observed during HV (7/10), IPS (7/10), eyes opening/closing (4/10), sleep (2/10), mental (1/10) and written calculation (1/10); none had language or praxis induction of discharges. Conclusions: VNPP is a useful instrument for characterization of provocative and inhibitory factors in JME. This study identified IE, observed in 17.5% of JME patients, which contrasts with the previously described 63.9% in general epilepsy during language and praxis tasks. Inhibitory effects coexisted with activation mainly induced by IPS and HV in most of the patients with JME.