Event-related potentials in professional city drivers: heightened sensitivity to cognitively relevant visual signals.

Event-related potentials to visual stimuli were recorded in 24 healthy, young subjects: 15 professional Belgrade city drivers and nine nondriver controls (no amateur driving experience) during a tacitly neutral GO:NOGO CNV paradigm and during one which explicitly mimicked heavy traffic conditions. In both paradigms GO S1 was a 30 ms red light, NOGO S1 a green light of equal duration; S2 was, in both cases, a yellow light presented 1.5 s post-S1. Overall, the early and late CNV for GO conditions were significantly larger (more negative) than for NOGO. This GO:NOGO difference was accentuated in drivers, as seen by a significant group-condition interaction using analysis of variance. The mean late CNV was significantly greater in drivers compared to controls: for GO at Cz during the neutral paradigm -12.9 vs. -5.0 microV, respectively, and for the traffic paradigm -14.4 vs. -6.0 microV. There were no significant differences in the CNV between the neutral and the traffic paradigms in either group. The pattern of CNV response seen in these professional Belgrade city drivers seems to suggest a heightened sensitivity to the cognitive significance of visual stimuli. To our knowledge, event-related potentials are applied here for the first time in professional drivers, a cohort known to have a high incidence of psychosomatic disorders, presumably related to the demands made upon them by their occupation. Further investigation using such objective electrophysiologic methods is clearly warranted in this high-risk group.