driving and daytime sleepiness

Increased Driving Risk in Patients with Obstructive Sleep Apnea

A simulation study presented on 09/07/2016 at the European Respiratory Society (ERS) International Congress reported that patients with obstructive sleep apnea syndrome (OSA) may pose potential driving risks.  The study was done out of St. James’ University Hospital in Leeds, UK and led by Drs. Akshay Dwarakanath and Mark Elliott.

There is a higher risk of accidents in patients with OSA, as well as a significant difference in advice given by physicians about the issue.  To find the underlying cause of the issue, however, this study used standard deviation of lane position (SDLP) in a driving simulator to create a model for future studies, as well as try to identify the actual risk.

Data were collected from patients in the study.  This included two scores: Their Epworth Sleepiness Score (ESS) and their oxygen desaturation index (ODI).  The ESS looks at subjective sleepiness, while ODI measures the severity of their obstructive sleep apnea.  One hundred and twenty nine untreated OSAS patients participated in this part of the study.  Their mean age was 53 years, average ESS was 14, average ODI was 41, average BMI was 36, and they had an average of 31 years holding a driver’s license.  There were 79 people in the control study, who answered a questionnaire before going through the simulator.  Those in the control group performed the simulation once, while those with OSAS performed it twice.  Preset criteria helped determine simulator outcome using three potential results:

  1. Pass
  2. Intermediate
  3. Fail

When compared to the control group, the OSA patients had more episodes of nodding off and admitted to sleepiness during driving.  They were also less likely to get a passing score and more likely to fail than those in the control group.  About 53% of people in the control group passed, 47% intermediate, and none of them failed.  Only 31% of the patients in the OSA group passed, with 49% scoring at intermediate and 20% failing.  In those who failed, lane deviation was significantly worse.

The authors note that the worsened lane deviation is indicative of poor driving performance, which is much worse in patients with OSA who failed the simulator test, especially when they are compared to those in the control group.  This comparison is useful when giving advice to OSAS patients about their increased risk of accidents.  Finding a normal range through real time events, simulator performance, and the outcome allows researchers to stay ahead in the development of tests that would evaluate accident risk in patients with OSA.

Furthermore, the researchers note that OSA patients are on average 2-6 times more likely to have a traffic accident compared to those without the condition.  Nodding at the wheel and sleepiness are far more likely to be reported in patients with OSA than the patients in the control group, or without the condition.  Unfortunately, however, there are currently no tools to help validate this aspect.

Approximately 2-4% of the population has obstructive sleep apnea, so the authors state that objective tests are necessary to help ensure the safety of all drivers and road users.  While the Driver and Vehicle Licensing Agency does offer some advice for patients and providers, the information given is arbitrary and loosely based on past evidence and studies, which has the potential of preventing people from driving who are in fact able to drive.

There are major implications to the economy and society in general with regard to the advice given by DVLA.  For instance, OSA is most common in overweight individuals, and many drivers in developed countries are overweight.  If they are prevented from driving due to obesity, there could be issues with employment.  Additionally, there is the possibility that the problem could be driven underground.  An objective test will go a long way to helping identify actual accident risk so that clinicians can better advise their patients with obstructive sleep apnea.

 Reference:  http://www.eurekalert.org/pub_releases/2016-09/elf-ssh090516.php

 

Rachael Herman is a professional writer with an extensive background in medical writing, research, and language development. Her hobbies include hiking in the Rockies, cooking, and reading.

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