Seizure outcome in 175 patients with juvenile myoclonic epilepsy – A long-term observational study

Summary Introduction Juvenile myoclonic epilepsy (JME) is a genetic generalized epilepsy syndrome. Under appropriate antiepileptic drugs (AED) up to 85% of patients become seizure-free, but many may have a relapse after AED withdrawal. Methods We retrospectively studied 242 patients with JME at the Department of Neurology, Medical University Innsbruck, Austria (1975–2006). We analyzed age at seizure onset, age at last follow up, seizure types, photosensitivity, seizure outcome and neuroimaging findings; inclusion criterion was a medical treatment period of >2 years; exclusion criteria were traumatic or infectious brain injury before the onset of JME and/or gross structural pathology on neuroimaging. Results We identified 175 patients (111 women) with a median age at seizure onset of 15 years, (range 3–46) and a median age at follow-up (FU) of 38 years (range 14–87; median FU 8 years, range 2–38). Fourteen percent showed (24/175) photosensitivity on routine EEG. Seizure outcome: 62% (109/175) were seizure-free of myoclonic seizures (MS), generalized tonic clonic seizures (GTCS) and absence seizures (AS) for >1 year, and 53% (94/175) for >2 years, including 16 patients (9%) without AEDs. Thirty-one percent (54/175) were seizure-free between 2and 5 years, 15% (26/175) between 6 and 10, and 8% (14/175) >10 years; 38% (66/175) were not seizure-free. Not seizure-free patients had more often MS, AS and GTCS within the first year of epilepsy than those who were seizure-free at last FU (11% vs. 3%, Chi 2 =4.679, df=1, p =0.043). Seizure-free patients had more often MS and GTCS as last seizure types in the year before becoming seizure-free (37% vs. 15%, p =0.003), whereas in not seizure-free group MS only and GTCS only persisted. Conclusions JME does not always need lifelong treatment, as a substantial minority of patients remain seizure-free without AEDs. AS, MS and GTCS at onset of the disease are indicators of poor long-term seizure control.