Greater incidence, severity of head injuries linked to late-life epilepsy

Greater prevalence and severity of head injuries as one’s life span continues shows a correlation to an increased risk for late-onset epilepsy, according to a cohort study published in Neurology.

“Head injury has long been associated with post-traumatic epilepsy. However, associations of head injury with epilepsy among older populations (where the incidence of head injury and epilepsy is highest) and the impact of the number of head injuries and head injury severity was less well characterized,” Andrea Schneider, MD, PhD, department of neurology, University of Pennsylvania Perelman School of Medicine told Healio.

The study sought to determine any associations between head injuries and subsequent development and diagnosis of epilepsy in patients at least 67 years old. Although head injuries are a known risk factor for persons with epilepsy, the degree to which sustaining head injuries before diagnosis may contribute to late-onset epilepsy (LOE) is less well understood, Schneider added.

Included were 8,872 participants enrolled in the Atherosclerosis Risk in Communities study, which collected data from 1987 through 2018 from four separate communities located in Maryland, North Carolina, Mississippi and Minnesota.

Among the participants, 55.1% were women and 21.6% were Black.

Researchers identified head injuries through 2018 from linked Medicare fee-for-service (FFS) claims for inpatient/ED care, hospitalizations and reporting from participants themselves. LOE cases were identified solely from linked Medicare FFS claims.

Of the enrollees, 6,173 reported no history of head injuries, whereas 2,699 reported at least one occurrence before turning 67, or at any time during the study follow-up period. In addition, 249 participants received an LOE diagnosis at some point during study follow-up without previously sustaining a head injury.

Results showed that, in the 2,699 participants with head injury, 1,225 suffered a first occurrence at age 67 or later, whereas 1,474 had their first head injury before age 67. Analysis of participants in the former category revealed that the risk of LOE associated with head injury, compared with no prior head injury, was elevated.

Among the 50 participants with a first head injury occurring at age 67 or later who subsequently developed LOE, the average time frame from first incident to initial seizure was 2.3 years. In contrast, in the analyses involving only participants with first head injury before age 67, there was no significant correlation between head injury and LOE risk.

Data further revealed the median time from initial head injury to development of LOE was 36.4 years for the 39 participants who reported initial head injury before age 67.

Associations with LOE were significant for head injuries sustained at or beyond 67 years old, but not for head injuries sustained before age 67.

“We found that head injury was associated with late-onset epilepsy (here defined as occurring at age 67 years or older) in a dose-dependent manner where a higher number of prior head injuries and more severe prior injuries were more strongly associated with risk for late-onset epilepsy,” Schneider said.

“Taken together, our results suggest that an emphasis on both primary and secondary prevention of head injuries may help to decrease the burden of epilepsy in older populations,” Schneider added.