Epilepsy in an elderly population: Classification, etiology and drug resistance

To characterize epilepsy in an elderly population and describe the prevalence of drug resistant epilepsy (DRE) using recently validated International League Against Epilepsy (ILAE) criteria.

Using a case-control design, 72 patients aged 60 years and older (cases) and 223 patients under age 60 (controls) were identified from the Saskatchewan Epilepsy Program database. Patients' charts were retrospectively reviewed. Bivariate and multiple logistic regression analyses were performed to identify variables that were associated with epilepsy in elderly patients.

Forty-seven elderly patients (65%) had focal epilepsy, while 9 (13%) had generalized epilepsy. The most common etiology in elderly patients with epilepsy was unknown in 30 (48%) patients. Other identified etiologies included brain tumors in 14 (19.4%), genetic in 6 (8%), degenerative disease in 4 (5%), stroke in 6 (8%) and head injury in 3 (4%). Significantly fewer elderly patients met criteria for DRE compared to non-elderly patients (26% vs. 51%, p = 0.001). In the multiple logistic regression analysis, elderly patients with epilepsy were more likely to have the presence of stroke, psychiatric comorbidity and to be on monotherapy.

In our sample, elderly patients with epilepsy were more likely to have seizures resulting from brain tumors and stroke, and less likely to have DRE than non-elderly patients. These unique features of elderly patients strongly suggest that clinical practice guidelines are needed to facilitate the highest quality of care in elderly patients with epilepsy.