ACUTE EFFECTS OF ALCOHOL ON SIMULATED DRIVING PERFORMANCE AND SELF-PERCEPTIONS OF IMPAIRMENT IN DUI OFFENDERS

Licensed drivers arrested for driving under the influence (DUI) of alcohol have increased rates of vehicle crashes, moving violations, and traffic tickets (Evans, 2004). To date, no research has examined specific self-regulatory mechanisms of the DUI driver under a dose of alcohol that might underlie risky driving behavior. The present study examined the degree to which DUI drivers display an increased sensitivity to the acute impairing effects of alcohol on driving performance and overestimate their driving fitness following alcohol consumption. Adult drivers with a history of DUI and a demographically-matched group of control drivers without a DUI were tested following a 0.65 g/kg dose of alcohol and a placebo. Results indicated that while alcohol impaired several measures of simulated driving performance, there were no differences between DUI offenders and controls on any of these measures. Compared with controls, intoxicated DUI drivers self-reported greater ability and willingness to drive as BAC declined despite no differences in levels of self-reported intoxication or BAC estimation. These findings provide evidence that DUI drivers might perceive themselves as more fit to drive after drinking despite clear evidence for their behavioral impairment. These findings could have important implications in the decisions to drink and drive

Alcohol responses, cognitive impairment, and alcohol-related negative consequences

textUnder frameworks such as Alcohol Myopia Theory, a body of literature has developed demonstrating how alcohol intoxication can increase behavioral risk-taking, potentially via impaired inhibition of prepotent behavioral responses. A separate area of research has shown that responses to alcohol intoxication are not homogenous across the population. Whereas most previous research has considered alcohol responses in relation to risk for alcohol use disorders, the present investigation tested whether they may additionally contribute to the acute effects of alcohol on drinking-episode-specific cognitive and behavioral consequences. We recruited 82 moderate-to-heavy drinking emerging adults to each complete 2 research protocols: a placebo-controlled, within-subject, counterbalanced alcohol challenge in a simulated bar laboratory and a 21-day, event-level self-monitoring follow-up. Replicating previous research, the alcohol challenge increased heart rate and subjective stimulant-like and sedative-like responses and impaired psychomotor performance and response inhibition. Individual differences in subjective stimulation but not sedation were significantly associated with inhibitory impairment. In the event-level follow-up, we found little evidence that alcohol responses elevated risk for adverse behavioral outcomes, although evidence was stronger that alcohol responses were associated with alcohol-induced memory blackout. Whether and how alcohol responses relate to the physiological, cognitive, and behavioral consequences of alcohol intoxication may depend on a) the quality of the response (e.g., stimulation vs. sedation), b) the type of outcome (e.g., response inhibition vs. blackout vs. behavioral risk-taking), and c) whether perceptions of alcohol-induced effects may contribute to emerging adults' evaluations of risk (e.g., driving after drinking and riding with a drinking driver).Psycholog

Alcohol Hangover and Multitasking: Effects on Mood, Cognitive Performance, Stress Reactivity, and Perceived Effort

The aim of this study was to examine the effects of hangover on mood, multitasking ability, and psychological stress reactivity to cognitive demand. Using a crossover design and semi-naturalistic methodology, 25 participants attended the laboratory in the morning following a night of (i) alcohol abstinence and (ii) alcohol self-administration during a typical night out (with order counterbalanced across participants). They completed a four-module multitasking framework (MTF, a widely used laboratory stressor) and a battery of questionnaires assessing mood, hangover symptom severity, and previous night’s sleep. The effects of the MTF on mood and perceived workload were also assessed. Participants in the hangover condition reported significantly lower alertness and contentment coupled with a higher mental fatigue and anxiety. Multitasking ability was also significantly impaired in the hangover condition. Completion of the cognitive stressor increased reported levels of mental demand, effort, and frustration, and decreased perceived level of performance. MTF completion did not differentially affect mood. Lastly, participants rated their sleep as significantly worse during the night prior to the hangover compared with the control condition. These findings confirm the negative cognitive and mood effects of hangover on mood. They also demonstrate that hangover is associated with greater perceived effort during task performance

Effects of alcohol intoxication on driving performance, confidence in driving ability, and psychomotor function: a randomized, double-blind, placebo-controlled study

Rationale: Alcohol-induced driving impairment can occur with any departure from a zero-blood alcohol concentration (BAC). Because intoxication is characterised by impaired judgement, drivers under the influence of alcohol may overestimate their capacity to safely operate a vehicle. Objectives: This study examined the effects of alcohol on driving performance, four-choice reaction time (FCRT), and self-rated confidence in driving ability. It specifically focused on alcohol doses equal to commonly enforced legal BAC limits (i.e. 0.05% and 0.08%). Methods: A randomized, double-blind, placebo-controlled design was utilised. Seventeen participants were tested in three conditions: placebo and two alcohol conditions aiming for BACs of 0.05% and 0.08%. Participants underwent a baseline FCRT task and a 1-h simulated highway driving task before completing another FCRT task and rated their confidence in their driving ability. Results: The high and low alcohol dose conditions resulted in a mean BAC of 0.07%, and 0.04%, respectively (n = 17). The high BAC treatment significantly increased standard deviation of lateral position (SDLP) by 4.06 ± 5.21 cm and standard deviation of speed (SDS) by 0.69 ± 0.17 km/h relative to placebo, while confidence in driving ability remained unchanged across treatments. FCRT performance was impaired by the high BAC treatment (all < 0.01), but there we no significant differences between placebo and low BAC conditions. Conclusions: The findings of this study show that driving performance and associated psychomotor functioning become significantly impaired below legally permissible driving limits in some jurisdictions. We identified a dissociation between driving performance and subjective awareness of impairment. Despite a significantly diminished driving ability at 0.07% BAC, drivers were unaware of their impairment

Alcohol intoxication progressively impairs drivers' capacity to detect important environmental stimuli

Rationale Alcohol intoxication impairs driving skills, leading to an increased frequency of accidents and crash fatalities. Inebriation may specifically impair environmental vigilance, reducing the driver's capacity for attention to stimuli that are relevant to successful navigation. Objectives We examined the separate and interactive effects of breath alcohol concentration (BrAC) and simulated driving scenario on the capacity to correctly identify visual stimuli embedded in the environment. Methods Ten healthy young adult drivers (6 males; 4 females) each performed 4 driving scenarios at each of 3 steady breath alcohol concentration levels (0, 60 and 100 mg/dl). Scenarios were based on speed or distance keeping while navigating a rural 2-lane road in daytime or nighttime conditions. Drivers pressed a button on the steering wheel corresponding to the direction of an arrow (up or down) which appeared briefly on road signs embedded in the environment, either overhead or on the roadside. Results Increasing level of BrAC and subjective scenario difficulty manifested significant, separate, but not interactive influences in association with the number of arrows correctly identified. Significant impairments could be detected at a level of BrAC below the current American limit for legal operation of a motor vehicle. Conclusions Environmental vigilance is subject to impairment by either/both alcohol intoxication and driving conditions

ALCOHOL-INDUCED IMPAIRMENT OF SIMULATED DRIVING PERFORMANCE AND BEHAVIORAL IMPULSIVITY IN DUI OFFENDERS

Licensed drivers arrested for driving under the influence (DUI) of alcohol have increased rates of vehicle crashes, moving violations, traffic tickets, and contribute to an estimated 120 million occurrences of impaired driving per year (Evans, 2004; Jewett et al., 2015). Survey research on DUI offenders indicates traits of impulsivity (e.g., sensation seeking). Together, these pieces of evidence suggest that DUI offenders display patterns of impulsive action and risk-taking while driving. However, to-date DUI offenders are rarely studied in a laboratory setting, and not much is known about how they respond to a dose of alcohol. The present study examined the degree to which DUI offenders display an increased sensitivity to the acute impairing effects of alcohol on mechanisms of behavioral impulsivity, skill and risk-based driving simulations, and subjective evaluations of driving fitness and perceived intoxication following alcohol consumption. A sample of 20 DUI offenders were compared to a demographically-matched sample of 20 control drivers. All participants attended two dose sessions in which they received either a 0.65 g/kg dose of alcohol or a placebo dose, counterbalanced, on separate days. Results indicated that alcohol affected all of the behavioral outcome measures. More specifically, alcohol increased impulsive choice responses and decreased response inhibition on the behavioral impulsivity tasks. Alcohol also increased risky driving behaviors and decreased driving-related skills. Furthermore, alcohol generally decreased participants’ self-reported willingness and ability to drive a motor vehicle, and increased levels of intoxication and BAC estimations relative to placebo. With regard to group differences, DUI offenders showed an increased sensitivity to the disrupting effects of alcohol on impulsive choices, such that DUI offenders showed a significantly greater preference for impulsive choices under alcohol relative to placebo than controls. Taken together, these findings provide some of the first pieces of evidence that compared to controls, DUI offenders display an increased tendency for impulsive decisions under alcohol, which likely contributes to risky decisions to drive after drinking, despite clear evidence for their behavioral impairment. These findings could have important implications for understanding the mechanisms underlying maladaptive behaviors in this high-risk population, and sheds light on possible targets for intervention to reduce DUI recidivism

The Effect of Low Dose Alcohol on Simulated Driving and Cognitive Performance

The current study investigated the effect of alcohol on simulated driving and cognitive performance across multiple blood alcohol levels (0.00, 0.02, 0.05 & 0.08%). The main objective was examine if the effect of alcohol was dose and task dependent and whether there was a mismatch in the development of acute tolerance across subjective and objective measures. Thirty participants (male & female) completed a simulated drive that comprised a rural highway which was divided into low and high traffic segments. In the driving scenario, a range of measures including speed maintenance, sign detection and hazard reaction were collected. Participants also completed a computer administered continuous performance test, a subjective measure of intoxication and had their breath alcohol level recorded. The experiment included a pre-alcohol, intoxicated and two post alcohol recovery conditions in which the measures were repeated at the same time intervals. Results showed no significant impairments in accelerator or brake reaction time but there was a significant increase in the number of crashes which increased in a dose dependent manner. There were no significant impairments in the sign detection task but traffic density was found to impair driving performance particularly in the heavy traffic segments. A significant Group*Density*Road interaction was also found, where the 0.05% group had a higher maximum speed on Road 4 than on Road 3 in the heavy traffic (70km/h) zone. There were no significant findings for the development of acute tolerance

Laboratory Analysis of Risky Driving at 0.05% and 0.08% Blood Alcohol Concentration

Background—The public health costs associated with alcohol-related traffic crashes are a continuing problem for society. One harm reduction strategy has been to employ per se limits for blood alcohol concentrations (BACs) at which drivers can legally operate motor vehicles. This limit is currently 0.08% in all 50 US states. Recently, the National Transportation Safety Board proposed lowering the legal limit to 0.05 % (NTSB, 2013). While research has well-validated the ability of alcohol to impair driving performance and heighten crash-risk at these BACs, relatively little is known about the degree to which alcohol might increase drivers’ risk-taking. Methods—Risk-taking was examined in 20 healthy adults who were each tested in a driving simulator following placebo and two doses of alcohol calculated to yield peak BACs of 0.08% and 0.05%, the respective current and proposed BAC limits. The drive test emphasized risk-taking by placing participants in a multiple-lane, high-traffic environment. The primary measure was how close drivers maneuvered relative to other vehicles on the road (i.e., time-to-collision, TTC). Results—Alcohol increased risk-taking by decreasing drivers’ TTC at the 0.08% target BAC relative to placebo. Moreover, risk-taking at the 0.05% target was less than risk-taking at 0.08% target BAC. Conclusions—These findings provide evidence that reducing the legal BAC limit in the USA to 0.05% would decrease risk-taking among drivers. A clearer understanding of the dose-response relationship between various aspects of driving behaviors, such as drivers’ accepted level of risk while driving, is an important step to improving traffic safety