Sleep apnoea can hamper driving

People who suffer from sleep apnoea have longer reaction times while driving. They take longer to stop and are more likely to crash into obstacles. In sleep apnoea, a person wakes up repeatedly during the night due to a partial or complete airway collapse that obstructs breathing. The condition causes daytime sleepiness, and has been linked to impaired driving and greater accident risk. But to date, the only assessment of sleep apnea patients' driving skills has been through driving simulators. Researchers from the Grenoble University Hospital, France found that once the patients were treated for their sleep apnoea, their driving skills improved. To get a better sense of how sleep apnea affects driving skills in the real world, the researchers analysed 20 sleep apnea patients and 20 individuals without the condition perform a series of tests on a road safety platform consisting of two one-way tracks 150 meters long. Study participants drove onto the platform and had to brake to avoid a jet of water. Participants with sleep apnoea took a half-second longer, on average, than the controls to stop when the water jet appeared. This means a person travelling at 130 kilometers per hour (about 81 miles per hour), the top speed permitted on French highways, would take 18 meters or nearly 20 yards longer to stop. People with sleep apnea also collided with the water jet obstacle twice as often as those without the condition. While lab tests found that the sleep apnea patients were not sleepier than the controls, and did not have attention deficits, they did have a more difficult time dividing their attention between two tasks. Ten of the sleep apnea patients were then retested after three months of treatment with continuous positive airway pressure or CPAP, in which a mask delivers oxygen during sleep to keep the airways open. After treatment, their stopping distances and reaction times were no different from those of the healthy controls. Sleep experts have questioned whether treatment is necessary for sleep apnea patients who don't report daytime sleepiness. The findings show that, even without sleepiness, people with sleep apnea have impairments in attention that can significantly affect driving ability. Simple strategies could help identify attention problems and driving impairments in these patients, and should be investigated further. Public health policy should take into account the impact of obstructive sleep apnea syndrome on driving ability in order to reduce traffic accidents.