[Pupillography for the assessment of driver sleepiness].

BACKGROUND

Sleepiness behind the wheel is the second most frequent cause of fatal highway accidents when trucks are involved. Spontaneous pupillary oscillations provide objective and quantitative measures of the tonic central nervous activation which is a precondition for higher level mental performance. First experience with this method is now available from Germany and Upper Austria, with the aim to analyse the magnitude of the problem sleepiness behind the wheel.

METHODS

The pupillographic sleepiness test (PST) is a well established method in sleep research/medicine and consists of an 11-minute recording of pupil diameter by infrared video pupillography in the sitting subject, followed by automated data analysis. Parameter of analysis is the pupillary unrest index (PUI) for which a normal value data base is available. Car and truck drivers were examined with the mobile version of the device on a voluntary base during campaigns at German roadhouses and during traffic controls by the police in Upper Austria. All drivers were instructed about the hazards of daytime sleepiness and effective countermeasures.

RESULTS

First campaigns at German roadhouses found a percentage of excessive sleepiness values of up to 25%. Of 1180 truck and bus drivers controlled in Upper Austria 22.5% showed excessively sleepy results.

CONCLUSIONS

The pupillographic sleepiness test assesses daytime sleepiness and its mobile version is appropriate for application during pauses or traffic controls. Objective assessments of driver sleepiness offer important contributions to the prevention of sleepiness-related road-traffic accidents.