BACKGROUND
Driver age and blood alcohol concentration are both important factors in predicting driving risk, however little is known regarding the joint import of these factors on neural activity following socially-relevant alcohol doses. We examined age and alcohol effects on brain oscillations during simulated driving, focusing on two region-specific frequency bands implicated in task performance and attention: posterior alpha power (PAP; 8–12 Hz) and frontal theta power (FTP; 4–7 Hz).
METHODS
Participants included 80 younger (25–35 years) and 40 older (55–70 years) community-dwelling, moderate drinkers. Participants consumed placebo, low, or moderate doses of alcohol designed to achieve target peak BrACs of 0, .04 or .065 g/dL, respectively. Electrophysiology was collected during engagement in a simulated driving task involving four scenarios of varied environmental complexity.
RESULTS
A main effect of age was detected in FTP, but neither an alcohol effect nor interactions were observed. For PAP, an age by alcohol interaction was detected. Relative to placebo controls, older and younger participants receiving low dose (.04 g/dL) alcohol evinced divergent PAP alterations, with a pattern of higher power among older participants and lower power among younger. This interaction was noted across the varied environmental contexts.
DISCUSSION
These findings are consistent with the hypothesis that compared to younger individuals, older drivers may be differentially susceptible to alcohol effects. While these age by alcohol interactions in neural activity are provocative, further investigation exploring the mechanisms and behavioral correlates of these effects will be crucial in determining their behavioral impact.