After reading about a study that recently concluded that individuals who have undiagnosed sleep apnea were more apt to be in a vehicular accident after a full nights sleep, than those with normal sleep patterns, I began to wonder about the thoroughness of the FMCSA sleep apnea questions. This study utilized patients who were known to have OSA (Obstructive Sleep Apnea) and subjects with normal sleep cycles.
Each subject had to complete 3 mid-afternoon driving tests on a simulator. The first test was performed after each of the individuals were well rested following a normal 8 hour period of sleep. This test served as a baseline for measuring the subjects in the future sessions.
On the second set of driving tests, each subject was restricted to only 4 hours of sleep and then had to drive the simulated course. The simulator was designed to experience night driving on an isolated road and navigate normal turns about every 10 minutes or so. Each subject had to navigate the turns and adjust back to 2 lane driving during the ongoing test.
On the third set of tests, both control groups were not only restricted to 4 hours of sleep, but were also provided the legal limit of alcohol that would normally be consumed within a 1 hour period. The study concluded the performance of the OSA patients was significantly worse than the non-OSA subjects.
Driving while tired, is well known to affect the reflexes and mental alertness of drivers. What this test data suggests, is that individuals who are also suffering from sleep disorders like Obstructive Sleep Apnea, are more likely to be in an accident under the same conditions. I believe the FMCSA sleep apnea questions asked of drivers in order to diagnose those at risk of OSA are not nearly thorough enough to fully sort out who is and isn’t at risk long term.