“Fitness-to-Drive in Neurologically Impaired Older Adults”  David B Carr MD

Project Overview
In elderly persons, neurological diseases (e.g., dementia or stroke) impair driving ability, which can result in a motor vehicle accident.  Moreover, older adult driver crashes tend to involve multiple vehicles, so the older driver and individuals of all ages are at risk of serious injury or death. Appropriate evaluations to determine fitness-to-drive in these patients often include performance-based road tests. However, there are many barriers to such tests, including cost, patient acceptability, and the availability of examination centers. There are also valid concerns regarding the safety of the driving instructor, the patient, and the public when administering such procedures in a real world setting.

The primary objectives of the proposed research are determining the feasibility and the clinical utility of assessing impaired driving behaviors and traffic safety knowledge along with novel functional abilities that are important when operating a motor vehicle.  The central hypothesis is that older adults with neurological disease will be able to perform these tests and demonstrate a wide range of impairments based on their disease severity, and that a combination of specific tests will predict who will fail a standardized road exam and/or experience a motor vehicle collision.

To test this hypothesis, 100 elderly (55+ years old) men and women with dementia and 100 with a history of a cerebrovascular accident will be evaluated using both interview/history questions and measurements of key driving abilities that will include both computerized and paper and pencil psychometric tests. A standard driving questionnaire that focuses on the presence of impaired driving behaviors will be administered to an informant or collateral source, while knowledge of traffic safety rules of the participant will be assessed.  Measures of visual function (far and near visual acuity, visual fields, color detection, phoria, etc), cognitive function (sustained and divided attention, visual processing speed, visuospatial skills, executive function, road sign recognition) and physical function (performance-based tests of strength, flexibility, balance, motor speed, and coordination) will be determined before administering a performance-based road test.

The results of the history (questionnaires) and physical examination (functional abilities) will be utilized to derive a model that will predict failure on a standardized road test and/or a motor vehicle collision.  Encouraging results from other pilot studies suggest the feasibility and utility of utilizing multiple predictors in creating fitness-to-drive models. The data generated from this pilot study will ultimately contribute toward establishing appropriate evaluation guidelines for physicians, occupational therapists, and highway patrol examiners who are faced with evaluating patients with neurological impairment. Making a decision to drive without an actual evaluation in a real traffic setting would allow additional patients to be examined across the country due to a decrease in cost for such testing, wider acceptance, and increased availability. This could have a major impact on reducing the number of unsafe drivers on the road and subsequently decrease the number of motor vehicle collisions and injuries on our roadways in an ever-expanding population of neurologically impaired drivers.

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