Soldiers may develop epilepsy from a head injury as many as 30 years down the road, hints a new study of Vietnam veterans.
Post-traumatic epilepsy, as the seizure disorder is known, is common after brain injuries sustained in battle.
"Soldiers have more severe injuries than what commonly occurs in the civilian populations," Dr. L. James Willmore, who was not involved in the new study, told Reuters Health.
"With severe injury, almost half develop epilepsy. It's difficult to treat and a persisting problem," added Willmore, an epilepsy expert at Saint Louis University in Missouri and a former medical officer in the U.S. Navy.
The new study, published Monday in the journal Neurology, is part of the National Naval Medical Center's long-term efforts to follow Vietnam vets with head injuries. It's the third evaluation of this group, performed 35 years after the original damage.
Most of the injuries involved penetration of the skull, for instance by shrapnel. Through interviews with the vets, a neurologist determined that 87 out of 199 (44 percent) suffered from post-traumatic epilepsy.
By comparison, less than four percent among a group of Vietnam vets without head injury had a history of seizures - about the rate seen in the general population, according to Willmore, who co-authored an editorial about the study.
Eleven vets reported that they had suffered seizures for the first time between their current evaluation and their prior evaluation 15 years ago. Willmore said recordings of their brain activity had confirmed the injury was the culprit.
It's unclear how head injuries cause epilepsy, however, especially so many years later.
The researchers, led by Jordan Grafman of the National Institute of Neurological Disorders and Stroke in Bethesda, Md., found little evidence that specific genes were to blame. But they did observe that seizures were more common in vets who had metal fragments lodged in their brains.
According to the researchers, their study is the first to follow vets over such a long time. Given how many injured soldiers survive today, they suggest screening those with penetrating brain injuries for post-traumatic epilepsy, as part of normal long-term care.
Since there isn't any way to reliably predict epilepsy today, said Willmore, "this is asking that all who are concerned about taking care of our injured soldiers be sensitive to the occurrence of seizures."
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