SOMERVILLE, Ma. – In advance of a sleep apnea testing requirement by U.S. regulators, Harvard researchers are investigating a new type of screening tool to identify drivers at a higher risk for obstructive sleep apnea (OSA).

The psychomotor vigilance test is a 10-minute test of attention, alertness, and reaction time (RT). It can be accomplished within a short office visit, requires only brief instruction, is performed on portable, hand-held computers, and its output can be easily and quickly read and interpreted.

“Our goal is to develop objective screening methods beyond obesity for obstructive sleep apnea to be used in occupational health settings," said the study’s senior author, Stefanos N. Kales, MD, MPH, Division Chief & Medical Director of Employee and Industrial Medicine at Cambridge Health Alliance. “Subjective reports of excessive daytime sleepiness are notoriously unreliable especially during fitness-for-work examinations, and obesity in isolation as a screen has generated resistance from many drivers.”

OSA is the most common medical cause of excessive daytime sleepiness (EDS) and is associated with a two- to seven-fold increase in the risk of motor vehicle crashes, according to the authors.

As the major predominant risk factor for OSA is obesity, the prevalence of OSA among commercial drivers (where as many as 40-50% are obese) is considerably higher than in the general population, researchers say.

The abnormal alertness and RT patterns detected by the system were found almost exclusively among obese men whose body composition puts them at high risk for OSA.

Moreover, the PVT seems to detect people likely to suffer from EDS based on other research which has suggested that longer lapses in reaction time are highly likely to identify drivers experiencing eye closure, as opposed to simple distraction from the test.

"This novel use of the PVT is extremely promising as a potential, 10-minute frontline check for sleepiness accomplished at professional drivers’ federally mandated licensing exams, similar to vision and hearing screens common in current use," added Dr. Kales.