Practical Experience-Based Approaches to Assessing Fitness to Drive in Dementia

Frank J. Molnar, MSc, MDCM, FRCPC; Anna M. Byszewski, MD, FRCPC; Mark Rapoport, MD, FRCPC; William B. Dalziel, MD, FRCPC

Disclosures

Geriatrics and Aging. 2009;12(2):83-92. 

In This Article

Abstract and Introduction

Abstract

There may be up to 1.5 million persons with dementia who are driving in North America. In many jurisdictions, physicians are mandated to assess and report fitness to drive in such patients. Lack of knowledge of patients' driving status does not protect physicians from lawsuits. There is a paucity of research to aid physicians in the assessment of fitness to drive in persons with dementia. Guidelines recommend the Mini-Mental State Examination, the clock-drawing test, and Trails A and B but lack evidence-based instructions regarding how to interpret such tests. This article provides experience-based approaches to the assessment of fitness to drive in dementia as well as an approach to disclosure of the findings to patients.

Introduction

While the majority of older drivers remain safe drivers, a subset experience the cumulative functional effects of medical conditions (e.g., dementia, strokes, arthritis, Parkinson's disease) and medications (i.e., those with sedating properties) that impact on their fitness to drive.[1]

In North America, there are estimated to be 3.4 million people with dementia; if the published estimated proportion of persons with dementia who are driving[2] is correct, this suggests that there are more than 1.5 million drivers with dementia. In Canada, there are now an estimated 500,000 people with dementia, with an expected 250,000 new cases to be diagnosed over the next 5 years. As our population ages, the number of persons with dementia who are driving is also expected to escalate.[2]

In many jurisdictions front-line physicians are responsible for reporting patients who have medical conditions that may impact on fitness to drive. These legal reporting duties vary by province and territory and can be found in the Canadian Medical Association's driving guidelines (available at www.cma.ca/index.cfm/ci_id/18223/la_id/1.htm).[3] What is less clear is how to determine which patients are unsafe to drive during assessments in front-line clinical settings (e.g., physicians' offices).[4]

This is particularly true in the field of dementia. A recent systematic review revealed that no cognitive tests have cut-off scores that are validated to determine fitness to drive status in dementia.[5] Consequently, the Canadian Institutes of Health Research has funded a 5 year longitudinal prospective cohort study to develop and validate screening tools for fitness to drive that can be employed by physicians in their offices (www.candrive.ca). The study will begin recruiting this year and results can be expected in 5-7 years. When such validated screening tests are available they will still need to be employed within the framework of clinically sensible approaches such as those that will be presented in this article.

Pending the results of such research, we are left to refer to consensus guidelines that, due to a lack of evidence, are largely based on individual expert opinion or the consensus of small groups of experts.[3,6] Such guidelines tend to recommend tests such as the Mini-Mental State Examination (MMSE),[7,8,9,10,11,12,13,14,15,16] the clock-drawing test, and the Trail Making Test (Trails A and B),[7,16,17,18,19] none of which have well validated cut-off scores predicting fitness to drive in dementia, and some of which have conflicting published data.[5] Consequently, the guidelines cannot provide evidence-based information regarding how to interpret the cognitive tests recommended (i.e., what would represent fatal errors on these tests or which validated cut-off scores to employ).[5]

This article presents the practical approaches that we developed for the in-office screening and assessment of medical fitness to drive in persons with dementia.[4,20,21,22] The approaches presented in this article are based on a combination of clinical guidelines and clinical acumen and experience. They represent the attempts of seasoned clinicians to incorporate clinical guidelines into approaches that can be employed in busy clinical practices. The approaches have been refined via an ongoing iterative process of discussion and debate among us and our many clinical and research colleagues. The approaches represent our current opinions regarding the best approach to employ in this evidence-based vacuum. Consequently, readers must use their own judgment to decide how to use the approaches described in their own clinical practices.

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