Repeated intracranial surgery confers a high risk for late PTE, possibly because people who need more surgery are more likely to have factors associated with worse brain trauma such as large hematomas or cerebral swelling. In addition, the chances of developing PTE differ by the location of the brain lesion: brain contusion that occurs on in one or the other of the frontal lobes has been found to carry a 20% PTE risk, while a contusion in one of the parietal lobes carries a 19% risk and one in a temporal lobe carries a 16% chance. When contusions occur in both hemispheres, the risk is 26% for the frontal lobes, 66% for the parietal, and 31% for the temporal. Post-traumatic seizures
The risk that a person will develop PTE is heightened but not 100% if PTS occur. Because many of the risk factors for both PTE and early PTS are the same, it is unknown whether the occurrence of PTS is a risk factor in and of itself. However, even independent of other common risk factors, early PTS have been found to increase the risk of PTE to over 25% in most studies. A person who has one late seizure is at even greater risk for having another than one who has early PTS; epilepsy occurs in 80% of people who have a late seizure.
The increased need for drugs to treat PTE led to trials with antiepileptics; these early trials suggested that the drugs could prevent epileptogenesis (the development of epilepsy). It was still thought that antiepileptic drugs could prevent epileptogeneis in the 1970s; in 1973, 60% of physicians surveyed used them to prevent PTE. However, the clinical trials which had supported a protective effect of antiepileptics were uncontrolled; in later, controlled trials the drugs failed to demonstrate an antiepileptogenic effect. Studies did show that antiepileptics prevented seizures occurring within a week after injury, and in 1995 the task force of the Brain Trauma Foundation published a recommendation suggesting their use to protect against seizures early after trauma. However, recommendations were published against the prophylactic use of antiepileptic drugs more than a week after injury by the Brain Injury Special Interest group of the American Academy of Physical Medicine and Rehabilitation in 1998 and by the American Association of Neurological Surgeons in 2000. Research
How epilepsy develops after an injury to the brain is not fully understood, and gaining such understanding may help researchers find ways to prevent it, or make it less severe or easier to treat. Researchers hope to identify biomarkers, biological indications that epileptogenesis is occurring, as a means to find drugs that can target pathways by which epilepsy develops.