EEG arousal and cardiovascular reactivity in professional drivers: the glare pressor test.

Patterns of electroencephalographic (EEG) and polygraphically recorded cardiovascular (CV) reactivity to the glare pressor test (GPT) were compared in 19 healthy, young male professional drivers and eight non-driver controls. After the first headlight impulse, 15 drivers showed persistent blockade of spontaneous alpha activity or complete desynchronization. This was accompanied by a significant fall in digital pulse amplitude and a significant rise in diastolic blood pressure (BP) (7.3 +/- 9.5 mmHg). Most drivers recovered baseline alpha activity and showed milder diastolic BP and digital pulse changes after the final (5th) glare impulse. However, in two drivers this last glare stimulus elicited the most pronounced changes: in one case a rapid onset of ventricular extrasystoles and in the other, maximal rise in diastolic BP, together with a persistently desynchronized EEG. No significant effects of the GPT upon central and CV indices were found in the control group. These results indicate that drivers show cardiovascular hyperreactivity to the GPT, with strong central arousal as expected during night driving when an on-coming headlight can represent impending danger and the need for accurate and timely responses to avoid a collision. Once optimal stimulus parameters for routine application are determined, the glare pressor test with EEG and polygraphic recording will offer a clinically useful, standardizable method for evaluating the connection between central mechanisms and CV reactivity in professional drivers, a cohort of patients whose occupational activity epitomizes mentally stressful work, and who are at high cardiac risk.