HOUSTON—Seizure duration and impaired consciousness may be important factors that affect driving performance, according to a study presented at the 70th Annual Meeting of the American Epilepsy Society. “With further work, we hope to … determine whether specific seizure types or localizations present a greater driving risk, with the goal of providing improved guidance to physicians and patients with epilepsy,” researchers said.
A lack of data about driving performance during ictal and postictal periods can make it difficult for physicians to determine whether patients can safely drive.
To study driving impairment during seizures, Hal Blumenfeld, MD, PhD, Director of the Yale Clinical Neuroscience Imaging Center in New Haven, Connecticut, and colleagues asked patients to perform a driving simulation test during inpatient video EEG monitoring. Dr. Blumenfeld, the study’s lead author, is the Mark Loughridge and Michele Williams Professor of Neurology and a Professor of Neuroscience and Neurosurgery at Yale University.
Hal Blumenfeld, MD, PhD
The study included 20 patients who were observed in the epilepsy monitoring unit at Yale New Haven Hospital. Investigators analyzed ictal and interictal driving data captured prospectively from the driving simulator. A total of 33 seizures were analyzed. The investigators compared interictal and ictal driving performance through quantitative analysis. Variables included car velocity, steering wheel movement, braking, and crash occurrence.
Patients drove between one and 10 hours, with an average driving duration of about three hours. Patients had variable impairment during ictal and postictal periods and during subclinical epileptiform discharges. Some seizures showed obvious impairment, and others showed no change in driving performance. Seizures with driving impairment had significantly greater duration and were more likely to involve impaired consciousness than seizures without driving impairment. Seven of the seizures resulted in crashes. Seizures lasted an average of 75 seconds in patients who crashed, compared with an average of 30 seconds in patients who did not crash.
Driving simulations during inpatient video-EEG monitoring may be a useful way to determine factors that influence driving safety, the researchers concluded.
“It is going to take a lot more data to come up with a reliable way of predicting which people with epilepsy should drive and which should not,” said Dr. Blumenfeld. “We want to unearth more detail to learn if there are people with epilepsy who are driving who shouldn’t be, as well those who are not driving who can safely drive.”