by Susan McFadden
One of the most robust findings about aging is that as we get older, we slow down not only in our motor responses, but also in the time it takes us to make decisions. This is especially true in situations (like roundabouts!) where a lot of information needs to be processed quickly. All of us know older people who have changed their driving habits because they no longer see well at night, or they no longer feel confident on crowded highways, using roundabouts, or driving in unfamiliar locations.
Often, families turn to physicians to determine when it is no longer safe for a person to drive. They assume that dad or mom will listen to the doctor more than to adult children. What happens when the doctor knows aperson has been diagnosed with Alzheimer’s disease or some other form of dementia? Will the doctor be morelikely to say the person should not be driving? How accurate is the doctor’s evaluation of the potential fordriving safely? Researchers in Belgium recently published a paper about a study that tried to answer these questions.
In Belgium, driving assessment experts evaluate people’s driving by using on-road tests at fitness-to-drive assessment centers. Doctors send their recommendations to the assessment centers for confirmation. The researchers wanted to know how much agreement there was between the physicians’ opinions about fitness- to-drive and the driving assessment experts.
All the drivers in this study had been diagnosed either with Alzheimer’s disease (AD) or with AD plus vasculardementia. Physicians were asked to make medical recommendations about the 68 participants by classifying them into one of three categories: favorable (no restrictions for low visibility, distance driven, or speed); reserved (driving allowed but with one or more restrictions); unfavorable (unfit to drive). All 68 persons then underwent testing by the on-road assessors who did not know what the physicians had recommended.
The physicians and the on-road assessors only agreed about 29 of the 68 persons, with the physicians overestimating the driving safety of 35% of the participants and underestimating the safety of 22%. Interestingly, when an individual had a high number of traffic violations, the physicians overestimated their driving safety! The researchers believe this occurred because the physicians did not take traffic violations into account when they made their recommendations. Another interesting finding was that there was higher agreement between family physicians and the on-road assessors (47%) than between specialists (neurologists, geriatricians, internal medicine specialists) and the on-road assessors (37%).
The researchers recommended that the decision about driving safety should come from a combination of standardized road tests, visual, and neuropsychological tests. They concluded the paper by stating that “regularstandardized on-road tests should be required for all individuals with mild dementia” so that physicians,families, and diagnosed persons can make good decisions about safe driving. This will be a challenge in the coming years for three reasons: (1) in the U.S. we do not have uniform requirements about on-road tests foradults with driver’s licenses; (2) about half of all persons with some form of dementia never receive a formaldiagnosis; and (3) we lack good transportation options for people who no longer can drive.
Ranchet, M., Tant, M., Akinwuntan, A. E., Morgan, J. C., & Devos, H. (2017). Fitness-to-drive disagreements in individuals with dementia. The Gerontologist, 57, 833-837.