Abstracts

Rationale: The diagnosis of epilepsy is straightforward when we have a clear history of 2 or more unequivocal unprovoked seizures. However, it is not uncommon for physicians to be uncertain about the exact nature of the paroxysmal spells. For those patients as well as for those with single unprovoked seizures, the EEG and MRI can be very helpful in asserting the diagnosis or estimating the risk of recurrence. In this study we evaluated the relative contribution of EEG and brain MRI to the diagnosis of epilepsy. Methods: In this study, 28 neurologists from across Lebanon referred their patients (at least 6 month of age) with one or more suspected unprovoked seizures to the American University of Beirut where they underwent a full evaluation. This included a detailed description of the spells, full physical and neurological examinations, sleep deprived 3 hours video-EEG study, an epilepsy protocol MRI, bone densitometry, and quality of life questionnaire. Based on the history and physical examination alone, patients were stratified into one of four categories. Category 1: Patients with newly diagnosed epilepsy; category 2: Patients with a single unprovoked seizure; category 3: Patients with non-epileptic events; category 4: Unclear if the event(s) represented a seizure or a non-epileptic spell. The results of MRI and EEG of patients with a single seizure or unclear events were tabulated according to the presence or absence of epileptogenic lesion on brain MRI or epileptiform discharges on EEG. Results: In the first 6 months of the study, out of the 280 patients enrolled, a total of 66 patients were included in category 2 (41 patients) or 4 (25 patients). Following evaluation with EEG and brain MRI, 28 of those patients (42%) were switched to category 1. Thirteen (46%) did so because of epileptiform discharges on the EEG with absence of epileptogenic lesion on MRI, 12 (43%) because of an epileptogenic lesion on MRI with absence of epileptiform discharges on the EEG, and 3 (11%) because of epileptiform discharges on the EEG and an epileptogenic lesion on MRI. 16 patients (39%) were switched from category 2 to category 1 while 12 patients (48%) were switched from category 4 to category 1. This difference was not statistically significant. In addition, there was no significant difference between the contribution of MRI and EEG when stratified according to categories 2 or 4. Conclusions: The brain MRI and EEG were found to be highly valuable in patients presenting with a single unprovoked seizure and in those with paroxysmal spells of unclear nature. They have a complementary role, and when used together can establish the diagnosis of epilepsy in 42% of those patients. The study was partially funded by CNRS grant LCR 114110 522214.