Drug Resistance in Late-onset Epilepsy

The annual incidence of epilepsy increases with age, from nearly 28 per 100,000 by the age of 50 years to 139 per 100,000 by the age of 75 years. Late-onset epilepsy differs from epilepsy at a young age in the prevalence of structural-related epilepsy, types of seizures, duration of seizures, and presentation with status epilepticus.

To check the response to treatment in patients with epilepsy with age of onset of 50 years and older.

We conducted a retrospective study. The cohort included all patients referred to the Rambam epilepsy clinic between 1 November 2016 and 31 January 2018 with epilepsy onset at age 50 years or older and at least one year of follow-up at the recruitment time point and epilepsy not caused by a rapidly progressive disease.

At recruitment, most patients were being treated with a single antiseizure medication (ASM); 9 of 57 patients (15.7%) met the criteria for drug-resistant epilepsy (DRE). The mean duration of follow-up was 2.8 ± 1.3 years. In an intention-to-treat analysis, 7 of 57 patients (12.2%) had DRE at the last follow-up.

Late-onset epilepsy, which is defined as a first diagnosis in patients older than 50 years of age, is easy to control with monotherapy. The percentage of DRE in this group of patients is relatively low and stable over time.