Identifying "safe" drivers with dementia not easy

By Will Boggs, MD

NEW YORK (Reuters Health) - No available in-office test can reliably differentiate safe from unsafe drivers among individuals with dementia, Canadian researchers report. Currently available tests that assess cognitive ability, they say, cannot be used in a standardized fashion in doctor's offices.

"There is a reason why (physicians) are struggling with the evaluation of fitness-to-drive in their patients," Dr. Frank J. Molnar from University of Ottawa told Reuters Health. "There appears to be an unintentional gap between the analytic approaches that driving researchers are comfortable using and have been trained to do (e.g., multivariate analysis) and the needs of clinicians for short, rapidly interpretable assessment tools that the researchers' analytic approaches will never yield."

Molnar and colleagues performed a comprehensive search of published studies in an effort to review evidence regarding in-office cognitive tests that might identify dementia patients who can drive safely and those who cannot.

They found 16 studies that met their inclusion criteria, including six that used history of crash, four that used driving simulator test results, and six that used on-road assessments as measures of driving safety.

None of the studies reported cutoff scores, which is a real problem, the investigators explain. The researchers also found a great deal of inconsistency between the test results and driving outcome measures.

In his practice, Molnar said he uses screening tests recommended by medical associations like the American Medical Association and the Canadian Medical Association and then asks himself if he would want to be a passenger if this person was driving.

Next, he looks for other signs that may indicate the patient is unsafe to drive. For example, if a patient has difficulty with simple activities, such as shopping, banking, cooking or hobbies, there is cause for concern.

"If the person has dementia and I feel they are still safe to drive for a short period, I advise them to start planning for driving cessation in the future and then decide when I should retest them," Molnar continued. "Generally, 6 months is felt to be the upper limit of time for reevaluation."

"I advise family members to call me immediately if there are any concerning signs of significant cognitive change," he continued. When it is still not clear if a person is safe to drive, Molnar refers then for specialized testing.

SOURCE: Journal of the American Geriatrics Society, December 2006.