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Driving Restrictions for People With Epilepsy Still Debatable

WebMD Health News

Nov. 16, 1999 (New York) -- Patients with epilepsy who drive have the best chance of avoiding a seizure-related car crash if they have not had a seizure in at least 6-12 months, according to a report in the medical journal Neurology.

The research team, headed by Gregory L. Krauss, MD, of Johns Hopkins University in Baltimore, found that compared to patients with shorter intervals, those who had seizure-free intervals of 12 months or more had a 93% reduction in the risk of an accident, and those with seizure-free periods of 6 months or more had an accident-risk reduction of 85%.

Having reliable auras that served as warnings to stop driving also significantly reduced the risk of an accident; however, 26% of patients had crashes despite having auras.

Having few prior motor vehicle accidents not related to seizures also reduced the chances that people with epilepsy would be involved in a crash. Surprisingly, patients whose anti-epilepsy drugs were reduced or switched also had a lower risk of a seizure-related crash.

"[We had thought] that people whose medicines are switched or reduced will crash more, but in fact, it turned out to be the other way around," Krauss tells WebMD. "Some people did crash after changing medicine, but the bulk of the group seemed to have a protective effect from changing medication. Many of those people [had been] under-dosed, or their medication wasn't working properly, so the changes in medication most likely controlled their seizures better, protecting them from a seizure-related crash."

The 50 "cases" -- people with epilepsy who had car crashes during seizures -- and the 50 "controls" with epilepsy who did not, were matched by age and sex and were from the same clinic. There was no significant difference in the study findings based on seizure types, driving experience, or types of roads used.

Krauss and colleagues say a good approach to lowering the rate of seizure-related crashes may be to emphasize to physicians and patients the need to optimize anti-epilepsy drug therapy, with the goal of achieving longer seizure-free intervals.

An editorial in the same issue, commenting on the study, points out that other attempts to come up with appropriate driving restrictions for people with seizures and epilepsy have come to very different conclusions. For example, a recent workshop of the European Union Association of International Bureau for Epilepsy recommended a mandatory 1-year seizure-free period before driving, while a U.S. workshop conference recommended a minimum 3-month seizure-free interval.

Despite the differences, however, both panels stressed the importance of the physician's input and the need to consider other factors that may play a role in determining an individual's fitness to drive.

More than half of the patients in the current study who had crashes were driving despite seizure-free intervals shorter than those permitted in their states. According to Krauss and colleagues, only 27-54% of drivers with epilepsy register their condition with motor vehicle authorities, and requirements for physician reporting of patients with seizures to motor vehicle agencies vary from state to state, as do states' requirements for seizure-free intervals before resuming driving -- which range from 3 to 18 months.

Krauss says his group intends to continue gathering data on driving records of people with epilepsy from other areas of the country. "We are planning a larger, multicenter, population-based study to look at crash rates in different states," Krauss tells WebMD. "Obviously, the number of crashes in this population is not as great as the number of crashes due to alcohol or other problems, so we want to be able to put this into perspective and be more specific about what the rate of crashes is for specific intervals of driving after a seizure," Krauss says.

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