In Patients With Cirrhosis, Driving Simulator Performance Is Associated With Real-life Driving

Abstract

Background & Aims Minimal hepatic encephalopathy (MHE) has been linked to higher real-life rates of automobile crashes and poor performance in driving simulation studies, but the link between driving simulator performance and real-life automobile crashes has not been clearly established. Further, not all patients with MHE are unsafe drivers, but it is unclear how to distinguish them from unsafe drivers. We investigated the link between performance on driving simulators and real-life automobile accidents and traffic violations. We also aimed to identify features of unsafe drivers with cirrhosis and evaluated changes in simulated driving skills and MHE status after 1 year. Methods We performed a study of outpatients with cirrhosis (n=205; median 55 years old; median model for end-stage liver disease score, 9.5; none with overt hepatic encephalopathy or alcohol or illicit drug use within previous 6 months) seen at the Virginia Commonwealth University and McGuire Veterans Administration Medical Center, from November 2008 through April 2014. All participants were given paper-pencil tests to diagnose MHE (98 had MHE, 48%), and 163 patients completed a standardized driving simulation. Data were collected on traffic violations and automobile accidents from the Virginia Department of Motor Vehicles and from participants’ self-assessments when they entered the study, and from 73 participants 1 year later. Participants also completed a questionnaire about alcohol use and cessation patterns. The driving simulator measured crashes, run-time, road center and edge excursions, and illegal turns during navigation; before and after each driving simulation session, patients were asked to rate their overall driving skills. Drivers were classified as safe or unsafe based on crashes and violations reported on official driving records; simulation results were compared with real-life driving records. Multivariable regression analyses of real-life crashes and violations was performed using data on demographics, cirrhosis details, MHE status, and alcohol cessation patterns, at baseline and at 1 year. Results Drivers categorized as unsafe had more crashes and made more illegal turns on the driving simulator than drivers categorized as safe; a higher proportion of subjects with MHE were categorized as unsafe drivers at baseline (16%) than subjects without MHE (7%, P=.02), and at 1 year follow up (18% vs 0%, P=.02). Alcohol cessation within less than 1 year and illegal turns during simulator navigation tasks were associated with real-life automobile crashes and MHE on in regression analysis; road edge excursions in the simulator were associated with real-life traffic violations. Personal assessment of driving skills improved after each simulation episode. Conclusions In a study of 205 patients with cirrhosis, we associated results from driving simulation tests with real-life driving records and MHE. Traffic safety counselling should focus on patients with cirrhosis who recently quit consuming alcohol and perform poorly on driving sim...

Covert Hepatic Encephalopathy

“…Paper- pencil tests for MHE diagnosis (48% of patients), driving simulation was completed by 163 patients, driving records were collected from the Virginia department of motor vehicles (DMV) and self-reported by patients at the study entry, also questions about alcohol usage/cessation was recorded[64]. Using the DMV records and comparing those to the simulation results the drivers were classified as either safe or unsafe.…”

“…On regression analysis, it was found that in MHE patients with recent alcohol cessation (less than a year) having illegal turns during simulator navigation tasks were associated with real-life automobile crashes. The authors concluded, “ Traffic safety counseling should focus on patients with cirrhosis who recently quit consuming alcohol and perform poorly on driving simulation[64]. ” In the discussion following these results, the authors write that these impaired simulator and real-life traffic outcomes are stable even when followed after a year.…”

“…Again, MHE patient with shorter history of alcohol cessation (<1yr but >6mo) performing poorly on simulation studies were the ones with the highest rates of real life traffic outcomes. Hence, the argument that “ it is not necessary to deem all the patients with MHE unfit to drive” and the focus of our counseling and restrictions should be directed at this subset of patients with MHE, poor real-driving histories and performance on the driving simulations studies and those who have recently quit alcohol[64]. …”

“…This history taking by the providers from CHE patients should be ongoing and a repeated dialogue at every visit with a particular focus on discussing their recent driving histories along with results of their driving simulation results if available. This is important as MHE patients tend to forget or lack insight in their problems and this will reinforce and hopefully foster openness to communication and reception of counseling on this sensitive issue by the CHE patients[40, 50, 64]. The overall approach by provider, leaving aside the legality of the issue, towards the driving history should be viewed as important aspect of overall health care and safety of such patients.…”

“…And this heightened approach may be helpful in reducing adverse outcomes related to this problem. This takes more importance in view of recent findings by Lauridsen et al who suggested that the traffic crashes in patients with MHE should be treated as a “potential public health issue” meriting openness in this problem basing this argument on the findings that crash rate in their study was higher than the 5% of the annual crash rate of average drivers[64]. …”