Abstracts

Juvenile myoclonic epilepsy (JME) is a relatively benign idiopathic generalized epilepsy with well-described clinical and EEG features. Good response to treatment is considered one of its hallmarks with various cohorts reporting 82-97% of patients with good seizure control and only 10-15% as refractory. We examined the proportion of refractory JME patients in our clinic and hypothesized that there are clinical and EEG traits that are associated with refractoriness. Patients with JME were identified from the 1702 cases in the University of Virginia epilepsy database and presence of generalized poly-spike wave and generalized seizures were confirmed from medical records. Demographic, clinical and EEG data were collected. Patients were classified as non-refractory (NR) if they had been seizure free for at least one year at the time of their last visit and as refractory (R) if they continued to have seizures of any type despite having tried valproate. They were subdivided into those with a history of high versus low monthly seizure frequency. History of a maximum monthly seizure frequency [gt]10 was deemed high for myoclonic (MYO) and absence (ABS) seizures and [gt]3 for generalized tonic-clonic seizures (GTC). If a specific seizure type was not present they were deemed null. Other features analyzed were age of epilepsy onset, seizure types present, EEG features, psychiatric comorbidity, evolution from other syndromes, and family history of seizures. A diagnosis of JME was identified in 75 patients out of 239 with idiopathic generalized epilepsy (31% of all IGE). Mean age was 32 [plusmn] 12 and 40 (53%) were women. Mean age of onset was 14 [plusmn] 5. Despite AED use, 32 patients continued to report seizures. Questionable compliance or inadequate AED use was found in 8, leaving 23 (30%) who were truly refractory. Prior history of high monthly seizure frequency was more frequent in R than NR patients for MYO seizures (69.6% vs 36.5%, p= 0.017) and GTC seizures (52.2% vs 21.1%, p=0.03). Other features including photoconvulsive response, family history of seizures, psychiatric comorbidity and combinations of seizure types present were not statistically different between groups. We found a relatively high proportion of JME patients (30%) that continued to have seizures despite use of the most accepted drug for their syndrome. Although some referral bias is likely, this emphasizes that some patients with JME are refractory. A history of high frequency of MYO or GTC seizures increased the chances of being refractory later. In contrast to previous reports, we did not find that psychiatric comorbidity or seizure type combinations increased the chance of refractoriness. We did not find features that helped predict responsiveness to treatment. Further studies are warranted to investigate whether genetic or neurophysiologic factors account for a lack of response to treatment.