Effects of opioids on driving ability.

Driving has been regarded as an activity of daily living that is important in maintaining a person's independence in the community, access to employment, and social activities. Many patients, however, using opioid medications on a regular basis (Chronic Opioid Analgesic Therapy: COAT) to ameliorate their intractable pain have been restricted from driving out of concern that skills would be impaired and driving safety compromised by these medications. Yet there are no driving studies which have explored the effects of using opioid analgesics for an extended period of time. This pilot study was designed to determine the effects of medically prescribed, stable opioid use on the driving abilities of patients with persistent, nonmalignant pain. Sixteen patients with chronic nonmalignant pain on COAT, who met criteria for participation in the study, underwent a comprehensive off-road driving evaluation using measures which have been shown to be sensitive in predicting on-road driving performance. The evaluation consisted of a pre-driver evaluation (PDE), a simulator evaluation (SDE), and behavioral observation during simulator performance. Patients in the COAT group were compared to a historical control group of 327 cerebrally compromised patients (CComp) who had undergone the same evaluation and then passed an on-road, behind-the-wheel evaluation (BTW Pass; n = 162) or failed (BTW Fail; n = 165). Results revealed that COAT patients generally outperformed the CComp patients as a group by equaling or exceeding PDE and SDE scores of the BTW Fail patients as well as the BTW Pass patients on all measures that differentiated the groups. Notably, COAT patients had a relatively poorer performance than CComp patients on specific neuropsychometric tests in the PDE; however, the differences were not statistically significant and did not imply a systematic pattern of scores that reflected domain-specific deficits. Behaviorally, COAT patients were generally superior to CComp patients, also; however, COAT patients had greater difficulty in following instructions and as well as a tendency toward impulsivity, like the BTW fail group. While there was general support for the notion that COAT did not significantly impair the perception, cognition, coordination, and behavior measured in off-road tests that have been regarded as requisite for on-road driving, methodological problems may limit the generalizability of results and recommendations are made for research beyond a pilot study.

Evaluating fitness to drive after cerebral injury: basic issues and recommendations for medical and legal communities.

Specialists in rehabilitation are typically called upon to evaluate and render an opinion about whether or not a person can be entrusted to resume driving. And, because driving is an individual privilege to be balanced against the public's right to safety and protection from the dangers of a driver whose residual deficits may impede ability to drive safely, these specialists have developed a number of methods to assess fitness to drive. Unfortunately, many evaluators remain unfamiliar with research used as basis for evaluations or lack understanding of the strengths and weaknesses of tests in use. Therefore, there may be unquestioning trust in tests and methods that leads to errors of significant consequence in decisions about fitness to drive as well as unawareness of expanding risks of litigation that can emanate from inappropriate recommendations. This article intends to draw attention to issues, considerations, and problems underlying the conduct of driver evaluations, including focus on ways in which the legal and medical communities approach question of fitness, legal and medical definitions and terminology, responsibility for assessment as well as tests and methods used in evaluations. Conclusions are drawn from discussion of these matters and recommendations are outlined for addressing identified problems at the interface between medical and legal communities.

Estimates of driving abilities and skills in different conditions.

OBJECTIVES: This research was a preliminary effort to determine whether various driving situations seemed to require different driving skills and abilities and to identify the relative demands of specific physical, perceptual, cognitive, behavioral, and operational skills and abilities in different driving situations. METHOD: Experienced driver evaluators and trainers estimated the magnitude of driving abilities and skills for different photographed driving situations. Pictures of driving scenarios were counterbalanced for road type, traffic condition, and weather condition. RESULTS: A multifactorial analysis of variance of the total score for each scenario revealed significant main effects for road type and traffic condition but not for weather condition. Highway and city driving were rated as significantly more demanding overall than residential driving, but no difference was found between city and highway driving. Estimates of the overall demands for driving in heavy traffic were significantly greater than in light traffic. However, driving in inclement weather was not regarded as significantly more demanding than driving in sunny weather. Additionally, significant interaction effects were found for road type by weather condition and traffic by weather condition but not for road type by traffic condition. Through multivariate methods to evaluate the significance of individual abilities and skills across conditions, significant main and interactive effects were found for road type, traffic condition, and weather condition. Post hoc analyses showed the impact of these effects on such abilities and skills as scanning, attention and concentration, information-processing speed, and others. CONCLUSION: Evaluators' quantified estimates of driving demands showed driving as a complex task that (a) requires high levels of abilities and skills in all situations; (b) demands greater abilities in some situations than in others; and (c) involves different kinds and various degrees of abilities and skills, depending on the demand characteristics of the situation.

Off-road driving evaluations for persons with cerebral injury: a factor analytic study of predriver and simulator testing.

OBJECTIVES: Off-road evaluations composed of psychometric testing and simulator driving are commonly used in rehabilitation settings to assess a person's fitness to resume driving after a cerebral injury. Although the results of these evaluation methods separately provide information about ability to drive, there is no clear understanding about what is measured in comprehensive off-road evaluations as a whole. This study explored the interrelationship of perceptual, cognitive, behavioral, and operational variables that form the basis for off-road evaluations in order to determine whether there are basic dimensions underlying performance in these evaluations and to derive a small set of variables that could help in refining methods for evaluating persons with cerebral injuries. METHODS: One-hundred six persons with cerebral damage due to brain injury or cerebrovascular accident were administered a predriver evaluation that consisted of selected neuropsychometric tests. Subjects were also evaluated in a driving simulator that measured their operational responses to filmed driving situations and assessed their behaviors. Principal component analysis was used to identify manifest and latent variables contributing to the results of the evaluations. RESULTS: The analysis produced a model with five independent (orthogonal) eigenvectors, or factors, for this population: Higher Order Visuospatial Abilities, Basic Visual Recognition and Responding, Anticipatory Braking, Defensive Steering, and Behavioral Manifestations of Complex Attention. These factors accounted for 66.14% of the total variance in the subjects' responses to comprehensive off-road evaluations. CONCLUSION: These factors were useful in understanding driving performance and the role of predriver and simulator testing in driver evaluations.

Prediction of behind-the-wheel driving performance in patients with cerebral brain damage: a discriminant function analysis.

Rehabilitation specialists, particularly occupational therapists, are often involved in evaluating clients' fitness to resume driving after cerebral damage due to head injury or stroke. Their available methods include separate or combined administration of predriver, simulator, and behind-the-wheel evaluations. However, use of these methods without a theoretical model on which to base test selection has yielded some criticism and little research about the effectiveness of these methods in predicting driving performance. Using the authors' Cybernetic Model of Driving as the basis for assessing abilities and behaviors relevant to driving outcome, this study sought to determine the effectiveness of the evaluation methods by discriminant analysis and measurements of sensitivity in predicting behind-the-wheel failures. Comprehensive evaluations of 106 patients revealed that residual deficits in cognition per se did not render a person unfit to drive and underscored the importance of considering behaviors in determining fitness. The methods of evaluation were shown to be relatively sensitive in predicting outcome; off-road and on-road evaluation reached sensitivities of 90% and 92% with the inclusion of behavioral measures. Formulae for predicting outcome based on methods of evaluation are provided and reasons for failures in behind-the-wheel evaluations are discussed.

Driving after cerebral damage: a model with implications for evaluation.

Evaluation of the ability of cerebrally injured patients to return to driving is an important task for rehabilitation specialists. These evaluations require predictively valid methods of assessment based on identification of relevant skills and abilities. The present study tested a hypothetical model for driving after cerebral injury and determined its use in evaluating fitness to drive. Thirty-five patients with cerebral damage due to head injury or cerebrovascular accident participated in the study. All were administered (a) a predriver evaluation, that is, a battery of neuropsychological tests chosen a priori to test the model, (b) a simulator evaluation, and (c) a behind-the-wheel evaluation consisting of driving on a protected course and in traffic. The results showed that 93% of the driving outcome in traffic was explained cumulatively by findings from the predriver and simulator evaluations as well as from behavioral and operational measures during evaluation on the protected lot. These results supported the predictive validity of the model and are discussed in terms of methodology for evaluation of return to driving.

An assessment of measures to predict the outcome of driving evaluations in patients with cerebral damage.

The evaluation of the ability of patients to return to driving after cerebral damage stands out as one of the most important tasks confronted by rehabilitation professionals. The present study was designed to critically assess evaluations that were developed at one facility to determine fitness to drive: an offroad, predriver evaluation of skills regarded as important in driving and an on-road, behind-the-wheel evaluation of abilities needed to drive in actual traffic situations. The evaluation results of 3-patients with cerebral damage due to traumatic head injury or cerebrovascular accident were studied retrospectively. Only 4 out of 21 items on the predriver evaluation significantly predicted the outcome of the predriver evaluation and none of the predriver evaluation items predicted the outcome of the behind-the-wheel evaluation. Only 6 of the 26 tasks on the behind-the-wheel evaluation significantly predicted the outcome of the behind-the-wheel evaluation. None of the items on the predriver evaluation or the behind-the-wheel evaluation explained a significant portion of variance related to outcome. The lack of internal and predictive validity of driver evaluations is discussed in light of these findings, and recommendations are given for improving the predictive power of driving evaluations.