Stroke Patients a Highway Menace?

Surviving a stroke but driving too soon afterwards could mean a higher chance of causing a motor vehicle accident, two small Canadian studies have found.

In research presented at the American Heart Association/American Stroke Association’s International Stroke Conference in Nashville, Tenn, Megan Hird, B.Sc, a graduate student at St. Michael’s Hospital in Toronto, Canada, and colleagues reported on their study showing that a group of recovering ischemic stroke drivers were twice as likely as stroke-free peers to make errors during complex driving tasks. The patients were tested on driving simulators one month after their strokes.

The study, and a similar research project done by Kristin Vesely, also a graduate student at St. Michael’s involving testing patients who had aneurysmal subarachnoid hemorrhages, suggest that physicians need better guidelines on what advice to offer their patients.

The matter of when to resume driving is left up to the states in the US, but in Canada it is set at one month, Hird said. More research is needed to see whether the tests on driving simulators is as accurate as road testing, she said. But their work clearly showed non-stroke subjects did better at simulated driving tasks.

The two researchers agreed that the current Canadian post-stroke driving guideline may need updating and that a month is not enough recovery time for the brain to be able to resume some of the complicated mental tasks involved in driving. “The percentage of physicians who give patients advice on driving is as low as 9% we found,” Hird said.

Hird and colleagues tested a group of 10 patients who had mild ischemic strokes using simulated driving equipment. They were matched to a group who had not had a stroke. Both groups had more than 35 years of driving experience and fewer than 2 accidents during that time.

The study showed the stroke survivors had more difficulty making simulated left turns across oncoming traffic and were almost 4 times as likely to drive unsafely while simulating driving behind a bus. ggggggggggggggggg“Driving is a complex and multifaceted task,” Hird said.

In the second study, researchers looked at 9 patients who had subarachnoid hemorrhages, again using driving simulators to assess their performance compared to healthier controls. This group was aged 40 to 60.

The post-subarachnoid-stroke group using the simulators had difficulties that resulted in twice as many simulated collisions, and had a harder time than controls in making left turns in traffic, though right turns were not a problem.

Eventually it might be possible to develop standardized testing to better judge when post-stroke patients were not a road hazard, the two said. That would likely mean developing a combination of on-road testing and use of simulators.

For now, physicians should at least warn these patients that their driving skills may not be what they were before the stroke.