Seizures in the elderly; stroke and beyond

Virtual Special Editions are collections of targeted papers curated by a Guest Editor. Here, Dr Maria Stefanidou from the Boston University School of Medicine, author of the Editor’s Choice article in Volume 47, talks about Seizures in the elderly.

Epidemiological studies show that epilepsy incidence increases with advancing age. With an aging population, the incidence and prevalence of late-onset seizures is expected to rise. Seizures in the elderly increase morbidity due to higher risk of accidents, falls, and side effects related to antiepileptic drug use.

Cerebrovascular disease remains the most commonly identified cause of epilepsy in the elderly, but only a fraction of those with a cerebrovascular accident develop seizures. The recent study contacted as part of the Framingham Heart Study, a large, prospective, longitudinal community-based cohort, shows a 5% incidence of seizures after ischemic stroke over a 20-year follow-up period and an association between disability after stroke, a proxy measure of stroke size and severity, and risk of subsequent seizures1. Similar findings have previously been described by Heuts-Van Raak et al2 who reported an increased risk of seizures with large infarctions, especially those involving the anterior circulation and in particular the supramarginal or superior temporal gyrus, and Conrad et al3 who found that a higher NIH stroke scale at the time of either an ischemic or hemorrhagic vascular event was a major risk factor for subsequent development of epilepsy. Data published earlier this year from the Cardiovascular Heart Study4, another large, population-based cohort, offer further evidence that history of prior stroke is a significant predictor of incident epilepsy in the elderly, but black race was also identified as a potential, independent predictor of late-onset epilepsy.

Structural abnormalities secondary to stroke, dementia, infection, brain tumors and head trauma are responsible for only a moderate percentage of late-onset epilepsy and a large portion of seizures in this population remain cryptogenic. In the studies by Tanaka et al5 in Japan, and Huang et al6 in a Chinese elderly population no etiology was identified in 53% and 35% of cases, respectively. Therefore, there is need for vigorous, longitudinal, multiracial, epidemiologic studies to identify reliable predictors of late-onset epilepsy that go beyond the already identified clinical causes and may include the role of systemic inflammation, occult cerebrovascular and neurodegenerative processes and genetic predisposition.

Predictors of incident epilepsy in older adults: The Cardiovascular Health Study
Choi H et al.
Neurology. 2017 Feb 28;88(9):870-877. doi: 10.1212/WNL.0000000000003662. Epub 2017 Jan 27