People with sleep apnoea are more likely to fail a driving simulator test and report nodding while driving, according to new research. For the sufferers of sleep apnoea, driving is highly dangerous for all on the roads.
Sleep apnoea may affect as many as 40 per cent of truck drivers, according to recent research in the USA, but a new study suggests they may be underreporting its effects.
The new study, which will be presented at the European Respiratory Society’s Annual Congress this week, shows that commercial vehicle drivers are more likely to understate their daytime sleepiness from the condition than people who don’t work in that field. The Congress was jointly organized by the European Respiratory Society, and the European Sleep Research Society.
Obstructive sleep apnoea is characterized by having pauses in breathing or shallow breathing while sleeping to create disrupted sleep and has previously been linked with an increased chance of being involved in road traffic accidents.
A research team from the University Hospital in Leeds, UK, carried out two separate studies looking at the effect sleep apnoea has on driving during a simulator test, carried out at the University of Leeds.
In the first study, 133 patients with untreated sleep apnoea and 89 people without the condition took part in the test. All participants completed a 90 km motorway driving simulation and were tested on a number of key criteria, including: The ability to complete the distance, time spent in the middle lane, an unprovoked crash or a veer event crash.
The results showed that patients with untreated sleep apnoea were more likely to fail the test. Twenty-four per cent of the sleep apnoea patients failed the test, compared to 12 per cent of the people without the condition. Many patients with sleep apnoea were unable to complete the test, had more unprovoked crashes and could not adhere to the clear driving instructions given at the beginning of the simulator test.
In the second study, 118 patients with untreated sleep apnoea and 69 people without the condition completed a questionnaire about their driving behaviour and undertook the 90 km driving test on the simulator.
Thirty-five per cent of patients with sleep apnoea admitted to nodding at the wheel and subsequently 38 per cent of this group failed the test. This compared to 11 per cent of people without the condition admitting to nodding and none of this group failing the test.
“In the first study, although some people in the control group also failed the test, there were several key differences in the reasons for failure,” said Dr. Mark Elliott, chief investigator. “For example 13 patients were unable to complete the test because they fell asleep, veered completely off the motorway and 5 patients because they spent more than 5 per cent of the study outside of the lane that they had been instructed to remain in. No controls failed for either of these reasons. Further investigation is needed to examine the reasons for failure of the simulator test.”
The public health implications of drowsy driving are clear: The AAA Foundation for Traffic Safety estimates that more than 16 per cent of fatal crashes involve a drowsy driver.
To promote awareness of drowsy driving, the AASM released a free online presentation describing the signs, causes and effects of driver fatigue and some strategies to manage it. SAFE-D: Sleep, Alertness and Fatigue Education for Drivers is available at www.aasmnet.org/safed.aspx. The presentation also is on YouTube and Vimeo to share or embed.
By John Redfern