Driving Performance on the Descending Limb of Blood Alcohol Concentration (BAC) in Undergraduate Students: A Pilot Study

Young drivers are overrepresented in collisions resulting in fatalities. It is not uncommon for young drivers to socially binge drink and decide to drive a vehicle a few hours after consumption. To better understand the risks that may be associated with this behaviour, the present study has examined the effects of a social drinking bout followed by a simulated drive in undergraduate students on the descending limb of their BAC (blood alcohol concentration) curve. Two groups of eight undergraduate students (n = 16) took part in this study. Participants in the alcohol group were assessed before drinking, then at moderate and low BAC as well as 24 hours post-acute consumption. This group consumed an average of 5.3 ± 1.4 (mean ± SD) drinks in an hour in a social context and were then submitted to a driving and a predicted crash risk assessment. The control group was assessed at the same time points without alcohol intake or social context.; at 8 a.m., noon, 3 p.m. and 8 a.m. the next morning. These multiple time points were used to measure any potential learning effects from the assessment tools (i.e. driving simulator and useful field of view test (UFOV)). Diminished driving performance at moderate BAC was observed with no increases in predicted crash risk. Moderate correlations between driving variables were observed. No association exists between driving variables and UFOV variables. The control group improved measures of selective attention after the third asessement. No learning effect was observed from multiple sessions with the driving simulator. Our results show that a moderate BAC, although legal, increases the risky behaviour. Effects of alcohol expectancy could have been displayed by the experimental group. UFOV measures and predicted crash risk categories were not sentitive enough to predict crash risk for young drivers, even when intoxicated.     

The effects of a nap opportunity in quiet and noisy environments on driving performance

While napping has previously been shown to alleviate the effects of sleep loss, before advocating the use of naps in transport accident campaigns it is necessary to consider whether a nap opportunity in a noisy uncomfortable environment can produce the same benefits as a nap opportunity in conditions that are conducive to sleep. To examine this, eight participants drove a driving simulator for 50 min at 11:00 h on three different test days. The simulator used has previously been found to be sensitive to the effects of sleep loss, alcohol consumption, and time of day. All three sessions were conducted after one night of sleep loss. Prior to driving during each session the participants either had a 60 min nap opportunity in a quiet or noisy environment, or no nap opportunity. Driving performance and reaction time while driving were measured, as were subjective sleepiness and ratings of sleep quality. No significant benefits of nap opportunities on driving performance were found. Levels of subjective sleepiness were not affected by the nap opportunity condition; however, sleep was rated as more refreshing and restful after a nap in a quiet environment compared to noisy environment. The measures of effect size reported suggest further research is required to unequivocally test the effects of nap opportunities on driving ability.     

The Effects of a Nap Opportunity in Quiet and Noisy Environments on Driving Performance

While napping has previously been shown to alleviate the effects of sleep loss, before advocating the use of naps in transport accident campaigns it is necessary to consider whether a nap opportunity in a noisy uncomfortable environment can produce the same benefits as a nap opportunity in conditions that are conducive to sleep. To examine this, eight participants drove a driving simulator for 50 min at 11:00 h on three different test days. The simulator used has previously been found to be sensitive to the effects of sleep loss, alcohol consumption, and time of day. All three sessions were conducted after one night of sleep loss. Prior to driving during each session the participants either had a 60 min nap opportunity in a quiet or noisy environment, or no nap opportunity. Driving performance and reaction time while driving were measured, as were subjective sleepiness and ratings of sleep quality. No significant benefits of nap opportunities on driving performance were found. Levels of subjective sleepiness were not affected by the nap opportunity condition; however, sleep was rated as more refreshing and restful after a nap in a quiet environment compared to noisy environment. The measures of effect size reported suggest further research is required to unequivocally test the effects of nap opportunities on driving ability.     

Using Virtual Reality to Study Alcohol Intoxication Effects on the Neural Correlates of Simulated Driving

The use of virtual reality in the form of simulated tasks can provide a realistic environment in which to study complex naturalistic behaviors. Many of the behavioral effects of alcohol intoxication are well known, but there is relatively little imaging evidence examining how alcohol exposure might transiently modulate brain function, especially in the context of task performance. In this review, we provide a brief synopsis of previous work using functional magnetic resonance imaging (fMRI) to study the neural correlates of alcohol intoxication. We describe in detail two studies from our published work, the first involving a visual perception paradigm, and the second involving virtual reality through a naturalistic behavior; simulated driving. Participants received single-blind individualized doses of beverage alcohol designed to produce blood alcohol content (BAC) of 0.04 and 0.08 or placebo. Subjects were fMRI scanned after training to asymptote performance. In both studies we found specific circuits that were differentially modulated by alcohol, we revealed both global and local effects of alcohol, and we examined relationships between behavior, brain function, and alcohol blood levels.     

Self‐Awareness of Impairment and the Decision to Drive after an Extended Period of Wakefulness

Fatigue is an increasingly noted factor in road accidents. The ability to predict and be aware of impairment in terms of driving capability is important for potential legal liability and road safety. However, to date, there have been few studies that have investigated the accuracy of individuals in predicting how safely they could drive during conditions of sleep loss. Research has demonstrated that individuals rate themselves as better than the population average in a number of domains, including driving‐related skills. Therefore, this study also aimed to investigate self‐ratings of predicted driving ability during extended wakefulness and compare them to ratings made of a hypothetical other person under the same conditions. Thirty‐two participants remained awake for a period of 40 h. Every 2 h, they completed the Psychomotor Vigilance Task (PVT) and rated on a seven‐point scale how well they thought they could drive safely, react quickly in an emergency, and stay in their own lane. They were also asked to assess how they thought someone else in their own position could drive. The participants rated their driving ability as becoming significantly poorer at the same time that their PVT performance became significantly slower. Self‐ratings indicating a qualitative assessment of poorer than neutral driving occurred at 03:00 h for both the “drive safely” and “react quickly” questions, after 19 h of continuous wakefulness (starting at 08:00 h). This occurred at 05:00 h for the “keep in my lane” question. Previous studies with a similar protocol demonstrated that under these conditions, individuals exhibit a performance decrements equivalent to someone with a blood alcohol concentration of 0.05% (the legal driving limit in Australia). Participants consistently rated the ability of others to drive as poorer than their own. The main implication from this study for road safety and legal liability is that it is reasonable to focus on a person's perception of the situation, as it does align with objective reality to a certain extent. A concern in terms of road safety is potential overconfidence, indicated by rating others consistently poorer than themselves.     

Towards measuring brain function on groups of people in the real world

In three studies, EEGs from three groups of participants were recorded during progressively more real world situations after drinking alcoholic beverages that brought breath alcohol contents near the limit for driving in California 30 minutes after drinking. A simple equation that measured neurophysiological effects of alcohol in the first group of 15 participants performing repetitive cognitive tasks was applied to a second group of 15 operating an automobile driving simulator, and to a third group of 10 ambulatory people recorded simultaneously during a cocktail party. The equation derived from the first group quantified alcohol's effect by combining measures of higher frequency (beta) and lower frequency (theta) power into a single score. It produced an Area Under the Receiver Operator Characteristic Curve of .73 (p<.05; 67% sensitivity in recognizing alcohol and 87% specificity in recognizing placebo). Applying the same equation to the second group operating the driving simulator, AUC was .95, (p<.0001; 93% sensitivity and 73% specificity), while for the cocktail party group AUC was .87 (p<.01; 80% sensitivity and 80% specificity). EEG scores were significantly related to breath alcohol content in all studies. Some individuals differed markedly from the overall response evident in their respective groups. The feasibility of measuring the neurophysiological effect of a psychoactive substance from an entire group of ambulatory people at a cocktail party suggests that future studies may be able to fruitfully apply brain function measures derived under rigorously controlled laboratory conditions to assess drug effects on groups of people interacting in real world situations.     

Self-awareness of impairment and the decision to drive after an extended period of wakefulness

Fatigue is an increasingly noted factor in road accidents. The ability to predict and be aware of impairment in terms of driving capability is important for potential legal liability and road safety. However, to date, there have been few studies that have investigated the accuracy of individuals in predicting how safely they could drive during conditions of sleep loss. Research has demonstrated that individuals rate themselves as better than the population average in a number of domains, including driving-related skills. Therefore, this study also aimed to investigate self-ratings of predicted driving ability during extended wakefulness and compare them to ratings made of a hypothetical other person under the same conditions. Thirty-two participants remained awake for a period of 40 h. Every 2 h, they completed the Psychomotor Vigilance Task (PVT) and rated on a seven-point scale how well they thought they could drive safely, react quickly in an emergency, and stay in their own lane. They were also asked to assess how they thought someone else in their own position could drive. The participants rated their driving ability as becoming significantly poorer at the same time that their PVT performance became significantly slower. Self-ratings indicating a qualitative assessment of poorer than neutral driving occurred at 03:00 h for both the “drive safely” and “react quickly” questions, after 19 h of continuous wakefulness (starting at 08:00 h). This occurred at 05:00 h for the “keep in my lane” question. Previous studies with a similar protocol demonstrated that under these conditions, individuals exhibit a performance decrements equivalent to someone with a blood alcohol concentration of 0.05% (the legal driving limit in Australia). Participants consistently rated the ability of others to drive as poorer than their own. The main implication from this study for road safety and legal liability is that it is reasonable to focus on a person's perception of the situation, as it does align with objective reality to a certain extent. A concern in terms of road safety is potential overconfidence, indicated by rating others consistently poorer than themselves.     

Time-of-day mediates the influences of extended wake and sleep restriction on simulated driving

Although a nonlinear time-of-day and prior wake interaction on performance has been well documented, two recent studies have aimed to incorporate the influences of sleep restriction into this paradigm. Through the use of sleep-restricted forced desynchrony protocols, both studies reported a time-of-day × sleep restriction interaction, as well as a time-of-day × prior wake × sleep dose three-way interaction. The current study aimed to investigate these interactions on simulated driving performance, a more complex task with ecological validity for the problem of fatigued driving. The driving performance of 41 male participants (mean?±?SD: 22.8 ±2.2 yrs) was assessed on a 10-min simulated driving task with the standard deviation of lateral position (SDLAT) measured. Using a between-group design, participants were subjected to either a control condition of 9.33 h of sleep/18.66 h of wake, a moderate sleep-restriction (SR) condition of 7 h of sleep/21 h of wake, or a severe SR condition of 4.66 h of sleep/23.33 h of wake. In each condition, participants were tested at 2.5-h intervals after waking across 7 × 28-h d of forced desynchrony. Driving sessions occurred at nine doses of prior wake, within six divisions of the circadian cycle based on core body temperature (CBT). Mixed-models analyses of variance (ANOVAs) revealed significant main effects of time-of-day, prior wake, sleep debt, and sleep dose on SDLAT. Additionally, significant two-way interactions of time-of-day × prior wake and time-of-day × sleep debt, as well as significant three-way interactions of time-of-day × prior wake × sleep debt and time-of-day × sleep debt × sleep dose were observed. Although limitations such as the presence of practice effects and large standard errors are noted, the study concludes with three findings. The main effects demonstrate that extending wake, reducing sleep, and driving at poor times of day all significantly impair driving performance at an individual level. In addition to this, combining either extended wake or a sleep debt with the early morning hours greatly decreases driving performance. Finally, operating under the influence of a reduced sleep dose can greatly decrease performance at all times of the day.     

Positive alcohol expectancies mediate associations between ADHD behaviors and alcohol-related problems among college students

An increasing percentage of college students report being affected by ADHD behaviors, and this population is at increased risk of experiencing negative consequences associated with alcohol consumption. However, specific factors motivating alcohol consumption and contributing to negative outcomes among these individuals are not well understood. Recent work suggests alcohol expectancies may interact with ADHD behaviors to influence negative drinking-related outcomes among those with elevated inattention and/or hyperactivity-impulsivity. Seven-hundred-forty emerging adults (M age = 19.13 [SD = 2.25] years; 72.1% female; 85.8% Caucasian) enrolled in two public universities in the Southeast and Midwest USA completed the Brief Comprehensive Effects of Alcohol Survey (B-CEOA) and provided self-reports of ADHD symptoms and drinking-related outcomes. Multiple mediation analyses were conducted to evaluate effects of ADHD behaviors (i.e., hyperactivity-impulsivity, and inattention) and related impairment in major life domains (e.g., social interactions, occupational and educational activities, fulfillment of daily responsibilities) on drinking-related outcomes via positive and negative alcohol expectancies, controlling for sex, age, co-occurring oppositional behaviors, and data collection site. Inattention, hyperactivity-impulsivity, and impairment directly predicted both personal and social problems consequent to alcohol use. Effects of ADHD behaviors and impairment on drinking-related personal and social problems were partially mediated by positive expectancies. Findings are consistent with and extend prior work supporting a role of positive alcohol expectancies in alcohol-related negative outcomes among college students experiencing mild to moderate symptoms of ADHD.     

Morning Anaerobic Performance Is Not Altered by Vigilance Impairment

The aim of this study was to determine the role played by vigilance on the anaerobic performance recorded during a Wingate test performed at the bathyphase (nadir) of the circadian rhythmicity. Twenty active male participants performed a 60-s Wingate test at 6 a.m. during 3 test sessions in counter-balanced order the day after either (i) a normal reference night, (ii) a total sleep deprivation night, or (iii) a total sleep deprivation night associated with an extended simulated driving task from 9 p.m. to 5 a.m. During this task, the number of inappropriate line crossings (ILCs) was used to control and quantify the effective decrease in the level of vigilance. The main findings show that (i) vigilance of each participant was significantly altered (i.e., a drastic and progressive increase in ILCs is shown during the 7.5 hours of driving) by the sleep deprivation night associated with an extended driving task; (ii) the subjective evaluation of vigilance performed by self-rated scale revealed an increased impairment of the vigilance level between the normal reference night, the total sleep deprivation night and the total sleep deprivation night associated with an extended driving task; and (iii) the morning following this last condition, during the Wingate test, the recorded cycling biomechanical parameters (peak power, mean power and fatigue index values, power decrease, and cycling kinetic and kinematic patterns) were not significantly different from the two other conditions. Consequently, these results show that anaerobic performances recorded during a Wingate test performed at the bathyphase of the circadian rhythmicity are not altered by a drastic impairment in vigilance. These findings seem to indicate that vigilance is probably not a factor that contributes to circadian variations in anaerobic performance.     

The Effect of Low-Frequency Road Noise on Driver Sleepiness and Performance

It is a well-known fact today that driver sleepiness is a contributory factor in crashes. Factors considered as sleepiness contributor are mostly related to time of the day, hours being awake and hours slept. Factors contributing to active and passive fatigue are mostly focusing on the level of cognitive load. Less is known what role external factors, e.g. type of road, sound/noise, vibrations etc., have on the ability to stay awake both under conditions of sleepiness and under active or passive fatigue. The aim of this moving base driving simulator study with 19 drivers participating in a random order day and night time, was to evaluate the effect of low-frequency road noise on driver sleepiness and performance, including both long-term and short-term effects. The results support to some extent the hypothesis that road-induced interior vehicle sound affects driving performance and driver sleepiness. Increased low-frequency noise helps to reduce speed during both day- and night time driving, but also contributes to increase the number of lane crossings during night time.     

Alcohol consumption at midlife and successful ageing in women: a prospective cohort analysis in the nurses' health study

Background

Observational studies have documented inverse associations between moderate alcohol consumption and risk of premature death. It is largely unknown whether moderate alcohol intake is also associated with overall health and well-being among populations who have survived to older age. In this study, we prospectively examined alcohol use assessed at midlife in relation to successful ageing in a cohort of US women.

Methods and Findings

Alcohol consumption at midlife was assessed using a validated food frequency questionnaire. Subsequently, successful ageing was defined in 13,894 Nurses'' Health Study participants who survived to age 70 or older, and whose health status was continuously updated. “Successful ageing” was considered as being free of 11 major chronic diseases and having no major cognitive impairment, physical impairment, or mental health limitations. Analyses were restricted to the 98.1% of participants who were not heavier drinkers (>45 g/d) at midlife. Of all eligible study participants, 1,491 (10.7%) achieved successful ageing. After multivariable adjustment of potential confounders, light-to-moderate alcohol consumption at midlife was associated with modestly increased odds of successful ageing. The odds ratios (95% confidence interval) were 1.0 (referent) for nondrinkers, 1.11 (0.96–1.29) for ≤5.0 g/d, 1.19 (1.01–1.40) for 5.1–15.0 g/d, 1.28 (1.03–1.58) for 15.1–30.0 g/d, and 1.24 (0.87–1.76) for 30.1–45.0 g/d. Meanwhile, independent of total alcohol intake, participants who drank alcohol at regular patterns throughout the week, rather than on a single occasion, had somewhat better odds of successful ageing; for example, the odds ratios (95% confidence interval) were 1.29 (1.01–1.64) and 1.47 (1.14–1.90) for those drinking 3–4 days and 5–7 days per week in comparison with nondrinkers, respectively, whereas the odds ratio was 1.10 (0.94–1.30) for those drinking only 1–2 days per week.

Conclusions

These data suggest that regular, moderate consumption of alcohol at midlife may be related to a modest increase in overall health status among women who survive to older ages. Please see later in the article for the Editors'' Summary     

Adaptations to isolated shoulder fatigue during simulated repetitive work. Part II: Recovery

The shoulder allows kinematic and muscular changes to facilitate continued task performance during prolonged repetitive work. The purpose of this work was to examine changes during simulated repetitive work in response to a fatigue protocol. Participants performed 20 one-minute work cycles comprised of 4 shoulder centric tasks, a fatigue protocol, followed by 60 additional cycles. The fatigue protocol targeted the anterior deltoid and cycled between static and dynamic actions. EMG was collected from 14 upper extremity and back muscles and three-dimensional motion was captured during each work cycle. Participants completed post-fatigue work despite EMG manifestations of muscle fatigue, reduced flexion strength (by 28%), and increased perceived exertion (∼3 times). Throughout the post-fatigue work cycles, participants maintained performance via kinematic and muscular adaptations, such as reduced glenohumeral flexion and scapular rotation which were task specific and varied throughout the hour of simulated work. By the end of 60 post-fatigue work cycles, signs of fatigue persisted in the anterior deltoid and developed in the middle deltoid, yet perceived exertion and strength returned to pre-fatigue levels. Recovery from fatigue elicits changes in muscle activity and movement patterns that may not be perceived by the worker which has important implications for injury risk.     

The combined effect of heat and carbon monoxide on the performance of motorsport athletes

Two of the major stressors endured by a motorsport athlete (MSA) during a racing event are the effects of heat and carbon monoxide. To date, there has been little research into their combined effect on driving performance. Using an interactive racecar simulator located within an environmental chamber, subjects drove a simulated race (60 min) in environmental conditions similar to those that develop during a NASCAR Winston Cup oval track race (50 degrees C ambient temperature and 10-12% carboxyhaemoglobin levels). Subjects also completed cool (20 degrees C) and heat only (50 degrees C) race simulations. During the simulations, oxygen consumption, heart rate, core and skin temperatures and psychomotor performance were measured. The results demonstrated that exposure to a racecar micro-environment combining both heat and CO produced significantly greater (P<0.05) sweat loss and core temperature change (1.53 kg; 1.06 degrees C) when compared to the heat only (1.14 kg; 0.73 degrees C) and cool conditions (0.35 kg; 0.09 degrees C). Furthermore, a significant decrease (P<0.05) in psychomotor performance was also shown between the heat/CO condition (contact points=38), and both the heat only (25 points) and cool conditions (22 points). It follows that lengthy exposure to these two stressors could produce a substantial decrement in driving performance, thereby endangering the MSA and other race competitors.     

The Association between Alcohol Consumption Patterns and Health-Related Quality of Life in a Nationally Representative Sample of South Korean Adults

This study examined the relationship between alcohol consumption and health-related quality of life (HRQOL) in a nationally representative sample of middle-aged to older South Koreans. Data collected from 3,408 men and 3,361 women aged ≥ 40 years were obtained from the 2010 and 2011 Korea National Health and Nutrition Examination Survey. Based on the World Health Organization guidelines, the participants were categorized into zones I (0–7), II (8–15), III (16–19), or IV (20–40) according to their Alcohol Use Disorders Identification Test (AUDIT) scores, with a higher zone indicating a higher level of alcohol consumption. Data collected from the AUDIT and EuroQol 5-Dimension (EQ-5D) test were subjected to multiple regression analysis in order to examine the relationship between alcohol consumption patterns and health-related quality of life, and to identify intersex and interzone differences. Significant intersex differences were found for the mean total AUDIT and EQ-5D scores and the proportion of participants rating their pain/discomfort and impairment in mobility and usual activities as “moderate” or “severe” (p < 0.001). The analysis of the EQ-5D scores by alcohol consumption pattern and sex suggested the existence of an inverted U-shaped relationship between the total AUDIT and EQ-5D scores. The HRQOL of moderate alcohol drinkers was higher than that of non-drinkers and heavy drinkers. The results of this study will be valuable in designing appropriate interventions to increase the HRQOL impaired by the harmful use of alcohol, in comparing HRQOL among different countries, and in implementing alcohol-related health projects.     

Chronotype-dependent circadian rhythmicity of driving safety

Among the factors associated with driving safety, sleep-related variables constitute a leading cause of road accidents. Circadian fluctuations of driver’s somnolence has been previously linked to road safety. However, the role of chronotype in this relationship has been poorly investigated. Thus, the aim of the present work was to address whether driving performance is influenced by circadian patterns, in turn modulated by the driver’s chronotype and the time of day (i.e. synchrony effect). We assessed 47 healthy young adults with specific chronotypes in several simulated driving sessions, both in the morning and in the evening. We collected driving performance data, along with self-reported levels of activation prior to each driving session and other sleep-related variables. Participants drove less safely when testing times took place outside their optimal time of day, as determined by their chronotype and confirmed by self-reported levels of activation. These differences were more pronounced in the morning, when morning types shown a better driving performance. Our results suggest that chronotype plays an important role as a modulator of the relationship between the time of day and driving safety. Therefore, it is necessary to acknowledge this variable in theoretical models of driving behavior, and for the improvement of occupational accidents prevention programs.     

Time-of-Day Mediates the Influences of Extended Wake and Sleep Restriction on Simulated Driving

Although a nonlinear time-of-day and prior wake interaction on performance has been well documented, two recent studies have aimed to incorporate the influences of sleep restriction into this paradigm. Through the use of sleep-restricted forced desynchrony protocols, both studies reported a time-of-day?×?sleep restriction interaction, as well as a time-of-day?×?prior wake?×?sleep dose three-way interaction. The current study aimed to investigate these interactions on simulated driving performance, a more complex task with ecological validity for the problem of fatigued driving. The driving performance of 41 male participants (mean?±?SD: 22.8 ±2.2 yrs) was assessed on a 10-min simulated driving task with the standard deviation of lateral position (SDLAT) measured. Using a between-group design, participants were subjected to either a control condition of 9.33?h of sleep/18.66?h of wake, a moderate sleep-restriction (SR) condition of 7?h of sleep/21?h of wake, or a severe SR condition of 4.66?h of sleep/23.33?h of wake. In each condition, participants were tested at 2.5-h intervals after waking across 7?×?28-h d of forced desynchrony. Driving sessions occurred at nine doses of prior wake, within six divisions of the circadian cycle based on core body temperature (CBT). Mixed-models analyses of variance (ANOVAs) revealed significant main effects of time-of-day, prior wake, sleep debt, and sleep dose on SDLAT. Additionally, significant two-way interactions of time-of-day?×?prior wake and time-of-day?×?sleep debt, as well as significant three-way interactions of time-of-day?×?prior wake?×?sleep debt and time-of-day?×?sleep debt?×?sleep dose were observed. Although limitations such as the presence of practice effects and large standard errors are noted, the study concludes with three findings. The main effects demonstrate that extending wake, reducing sleep, and driving at poor times of day all significantly impair driving performance at an individual level. In addition to this, combining either extended wake or a sleep debt with the early morning hours greatly decreases driving performance. Finally, operating under the influence of a reduced sleep dose can greatly decrease performance at all times of the day. (Author correspondence: raymond.matthews@unisa.edu.au)     

Predicting Risk of Motor Vehicle Collisions in Patients with Glaucoma: A Longitudinal Study

Purpose

To evaluate the ability of longitudinal Useful Field of View (UFOV) and simulated driving measurements to predict future occurrence of motor vehicle collision (MVC) in drivers with glaucoma.

Design

Prospective observational cohort study.

Participants

117 drivers with glaucoma followed for an average of 2.1 ± 0.5 years.

Methods

All subjects had standard automated perimetry (SAP), UFOV, driving simulator, and cognitive assessment obtained at baseline and every 6 months during follow-up. The driving simulator evaluated reaction times to high and low contrast peripheral divided attention stimuli presented while negotiating a winding country road, with central driving task performance assessed as “curve coherence”. Drivers with MVC during follow-up were identified from Department of Motor Vehicle records.

Main Outcome Measures

Survival models were used to evaluate the ability of driving simulator and UFOV to predict MVC over time, adjusting for potential confounding factors.

Results

Mean age at baseline was 64.5 ± 12.6 years. 11 of 117 (9.4%) drivers had a MVC during follow-up. In the multivariable models, low contrast reaction time was significantly predictive of MVC, with a hazard ratio (HR) of 2.19 per 1 SD slower reaction time (95% CI, 1.30 to 3.69; P = 0.003). UFOV divided attention was also significantly predictive of MVC with a HR of 1.98 per 1 SD worse (95% CI, 1.10 to 3.57; P = 0.022). Global SAP visual field indices in the better or worse eye were not predictive of MVC. The longitudinal model including driving simulator performance was a better predictor of MVC compared to UFOV (R² = 0.41 vs R² = 0.18).

Conclusions

Longitudinal divided attention metrics on the UFOV test and during simulated driving were significantly predictive of risk of MVC in glaucoma patients. These findings may help improve the understanding of factors associated with driving impairment related to glaucoma.     

Low Cognitive Load and Reduced Arousal Impede Practice Effects on Executive Functioning,Metacognitive Confidence and Decision Making

The present study investigated the effects of low cognitive workload and the absence of arousal induced via external physical stimulation (motion) on practice-related improvements in executive (inhibitory) control, short-term memory, metacognitive monitoring and decision making. A total of 70 office workers performed low and moderately engaging passenger tasks in two successive 20-minute simulated drives and repeated a battery of decision making and inhibitory control tests three times – before, between and after these drives. For half the participants, visual simulation was synchronised with (moderately arousing) motion generated through LAnd Motion Platform, with vibration levels corresponding to a well-maintained unsealed road. The other half performed the same simulated drive without motion. Participants’ performance significantly improved over the three test blocks, which is indicative of typical practice effects. The magnitude of these improvements was the highest when both motion and moderate cognitive load were present. The same effects declined either in the absence of motion (low arousal) or following a low cognitive workload task, thus suggesting two distinct pathways through which practice-related improvements in cognitive performance may be hampered. Practice, however, degraded certain aspects of metacognitive performance, as participants became less likely to detect incorrect decisions in the decision-making test with each subsequent test block. Implications include consideration of low cognitive load and arousal as factors responsible for performance decline and targets for the development of interventions/strategies in low load/arousal conditions such as autonomous vehicle operations and highway driving.     

Alcohol abstinence and mortality in a general population sample of adults in Germany: A cohort study

BackgroundEvidence suggests that people who abstain from alcohol have a higher mortality rate than those who drink low to moderate amounts. However, little is known about factors that might be causal for this finding. The objective was to analyze former alcohol or drug use disorders, risky drinking, tobacco smoking, and fair to poor health among persons who reported abstinence from alcohol drinking in the last 12 months before baseline in relation to total, cardiovascular, and cancer mortality 20 years later.Methods and findingsA sample of residents aged 18 to 64 years had been drawn at random among the general population in northern Germany and a standardized interview conducted in the years 1996 to 1997. The baseline assessment included 4,093 persons (70.2% of those who had been eligible). Vital status and death certificate data were retrieved in the years 2017 and 2018.We found that among the alcohol-abstinent study participants at baseline (447), there were 405 (90.60%) former alcohol consumers. Of the abstainers, 322 (72.04%) had met one or more criteria for former alcohol or drug dependence or abuse, alcohol risky drinking, or had tried to cut down or to stop drinking, were daily smokers, or self-rated their health as fair to poor. Among the abstainers with one or more of these risk factors, 114 (35.40%) had an alcohol use disorder or risky alcohol consumption in their history. Another 161 (50.00%) did not have such an alcohol-related risk but were daily smokers. The 322 alcohol-abstinent study participants with one or more of the risk factors had a shorter time to death than those with low to moderate alcohol consumption. The Cox proportional hazard ratio (HR) was 2.44 (95% confidence interval (CI), 1.68 to 3.56) for persons who had one or more criteria for an alcohol or drug use disorder fulfilled in their history and after adjustment for age and sex. The 125 alcohol-abstinent persons without these risk factors (27.96% of the abstainers) did not show a statistically significant difference from low to moderate alcohol consumers in total, cardiovascular, and cancer mortality. Those who had stayed alcohol abstinent throughout their life before (42; 9.40% of the alcohol-abstinent study participants at baseline) had an HR 1.64 (CI 0.72 to 3.77) compared to low to moderate alcohol consumers after adjustment for age, sex, and tobacco smoking. Main limitations of this study include its reliance on self-reported data at baseline and the fact that only tobacco smoking was analyzed as a risky behavior alongside alcohol consumption.ConclusionsThe majority of the alcohol abstainers at baseline were former alcohol consumers and had risk factors that increased the likelihood of early death. Former alcohol use disorders, risky alcohol drinking, ever having smoked tobacco daily, and fair to poor health were associated with early death among alcohol abstainers. Those without an obvious history of these risk factors had a life expectancy similar to that of low to moderate alcohol consumers. The findings speak against recommendations to drink alcohol for health reasons.

In this cohort study conducted over 20 years, Ulrich John and colleagues examine the relationship between alcohol abstinence and mortality in a German adult population.