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Commentary


Is clinical judgment enough to restrict driving?

Vol. 8, No. 2 / February 2009
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In “Driving with dementia: How to assess safety behind the wheel” (Current Psychiatry, December 2008) the authors provided helpful suggestions on how to implement driving restrictions. The algorithm, however, relies too heavily on costly driving evaluations at the expense of clinical judgment.

Although the American Medical Association and the National Highway Traffic Safety Administration may not feel that a dementia diagnosis is sufficient to restrict driving, this opinion is not unanimous. In 2000 the American Academy of Neurology issued a practice parameter standard that patients with a Clinical Dementia Rating of 1 should not drive. This rating is equivalent to probable Alzheimer’s disease (AD) with mild impairment.1

Furthermore, although the clockdrawing test, visuospatial copying tasks, and trail making test B might not have absolute utility in identifying those at risk of driving impairment, measures of attention and visuospatial skills have been found to correlate with on-road driving performance.2

Given that visuospatial testing evaluates an area of cognition that is necessary for driving and impairment of visuospatial functioning in AD is significantly correlated with anosognosia,3 a prudent clinician may choose to restrict driving privileges based on bedside examination and clinical impression alone.

Ben Schoenbachler, MD
Assistant professor
Director, Memory Disorders Program
University of Louisville
Louisville, KY

References

1. Dubinsky RM, Stein AC, Lyons K. Practice parameter: risk of driving and Alzheimer’s disease (an evidence-based review): report of the quality standards subcommittee of the American Academy of Neurology. Neurology. 2000;54(12):2205-2211.

2. Reger MA, Welsh RK, Watson GS, et al. The relationship between neuropsychological functioning and driving ability in dementia: a meta-analysis. Neuropsychology. 2004;18(1):85-93.

3. Auchus AP, Goldstein FC, Green J, et al. Unawareness of cognitive impairments in Alzheimer’s disease. Neuropsychiatry Neuropsychol Behav Neurol. 1994;7:25-29.

The authors respond

We agree with Dr. Schoenbachler’s comment that “a prudent clinician may choose to restrict driving privileges based on bedside examination and clinical impression alone,” and certainly do not wish readers to disregard the results of patient history, examination, or cognitive evaluation. Indeed, visuospatial testing has been shown to have moderate correlations with driving in the review that Dr. Schoenbachler cites. However, a recent systematic review1 highlighted the inconsistency of this evidence and reported that only 6 of 11 analyses of the relationship between visuospatial skills and driving showed significant associations.

Although our article emphasized the limitations of evidence on the predictive value of the clinical evaluation of driving fitness, we encourage physicians to use their clinical judgment to decide when a patient’s cognitive deficits or behavioral symptoms preclude safe driving. The algorithm emphasizes the role of on-road testing in cases when the clinician is uncertain. When impairment is so severe or obvious that the patient clearly is unsafe to drive, in-depth testing is not needed. For less severe cases, clinicians will need to determine if they have enough information to decide or if an on-road assessment is warranted.

Mark Rapoport, MD

Carla Zucchero Sarracini, BA

Nathan Herrmann, MD
Department of psychiatry
University of Toronto
Sunnybrook Health Sciences Centre
Toronto, Ontario, Canada

Frank Molnar, MD
University of Ottawa
Ottawa Health Research Institute
Ottawa, Ontario, Canada

Reference

1. Molnar FJ, Patel A, Marshall SC, et al. Clinical utility of office-based cognitive predictors of fitness to drive in persons with dementia: a systematic review. J Am Geriatr Soc. 2006;54(12):1809-1824.

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