Abstracts

Rationale: Most of our knowledge with regard to pathophysiology, etiology and prognosis of epilepsy syndromes comes from advanced stages of epilepsy and cross-sectional studies. A paradigm shift is needed to extend this knowledge to a more dynamic longitudinal approach in early stages of epilepsy. Our First Seizure Clinic (FSC) had a particular interest in terms and classification, pathologies suggested by MRI, and treatment response. Methods: Since May 2008, an Adult FSC at QE II Health Sciences Center, Dalhousie University Halifax has been established with a strict First Seizure Assessment Approach (FSAA): 1) Coordinated by an epileptologist and a nurse practitioner, 2) Careful triaging, 3) maximum wait-time of 2- 4 weeks (often within few days), 4) Comprehensive clinical testing (early routine and sleep-deprived EEG, early MRI, screen for psychiatric comorbidity, social and cognitive issues), 5) Clinical research protocol, 6) Genetic blood sampling, 7) Comprehensive database 8) Follow-up visits 6, 12 and 24 months. Results: 391 new patients were seen from May 2008 to May 2012. 167 (42.7%) patients had to be excluded from the database due to the diagnoses other than first seizure (syncope, psychogenic non-epileptic seizures, cerebrovascular diseases or long-lasting epilepsy). We identified 3 subgroups of all drug-naïve FSC presentations (n=224): 1) Strictly first seizure (FS), n=113, 2), New-onset epilepsy (NOE = > 1 seizure within 1 year), n=85, and 3) Newly-diagnosed epilepsy (NDE = seizure history for more than 1 year), n=26. MRI images (epilepsy protocol) documented "pathologies" in 72% of the FS-, 58% of the NOE, and 82% of the NDE patients. CT showed significantly fewer abnormalities in all 3 groups. White matter hyperintensities (WMH) were found in 25% of the FS, 18% of the NOE, and 20% of the NDE-patients (age range 17-79 years, average 47.7 years). Congenital malformations were found in 8 out of 224 FSC patients (5 FS, 2 NOE, 1 NDE) including focal cortical dysplasia (FCD, n=4), heterotopia (HT, n=2), polymicrogyria (n=1). 87.5% (n=7) stayed seizure-free (n=3 without AED) over a mean follow-up of 93 weeks, n = 3 over follow-up greater > 160 weeks. Disease courses of patients with AED-treated NOE or NDE showed a highly variable pattern of developing pharmacoresistance with regard to primary response, initial seizure-free intervals, and secondary relapse. Conclusions: Our preliminary experience with systematically analyzing FSC patients is very promising. Our classification approach looking into 3 different subgroups of patients diagnosed either with FS only, NOE or NDE suggests new exciting insights. It questions current concepts and terms specifically with regard to "typical time courses" of early pharmacoresistance and epileptogenicity of MRI-proven "pathologies". The high rate of seizure-free patients with congenital malformations, even without AED, including focal cortical dysplasia puts the current perception of the role of FCDs in advanced stages of refractory focal epilepsy into a totally new perspective.