Losing Your Keys
“I don’t view advanced age as a criteria for decreased driving ability, but base it on the presence of medical diseases and functional decline. Driving impairment can affect individuals across all ages due to any of a number of diseases, ranging from glaucoma to arthritis. But many chronic diseases are significantly more common in older adults.”
DAVID B. CARR, MD
“SHE WAS CRYING, I was crying; it was terrible. That was the saddest day.”
Janice Gober will never forget the day her 73-year-old mother, Rosemary Ralls, relinquished her driver’s license. Despite the difficulty, Gober admits she also felt relieved.
“It was hard to take away my mother’s independence, but I couldn’t have lived with myself if she’d had a serious accident,” says Gober.
With the graying of America, millions of people across the nation are facing the same tough issue. Before the Missouri Department of Motor Vehicles revoked Ralls’ license, she had demonstrated erratic driving behavior and failed a driving assessment developed by Washington University researchers.
Not all older drivers are unsafe. It wasn’t Ralls’ age that flagged her as a potential driving threat, but her health: In December 2001, she became one of 4.5 million Americans diagnosed with Alzheimer’s disease (AD), a neurodegenerative disease characterized by a progressive worsening of attention, memory and other cognitive functions, all of which are necessary for driving.
“I don’t view advanced age as a criteria for decreased driving ability, but base it on the presence of medical diseases and functional decline,” explains David B. Carr, MD, clinical director of the division of geriatrics and nutritional science. “Driving impairment can affect individuals across all ages due to any of a number of diseases, ranging from glaucoma to arthritis. But many chronic diseases are significantly more common in older adults.”
Even some people with AD can drive safely, and driving performance declines at a different rate for every individual, says John C. Morris, MD, director of the Washington University Center for Aging and co-director of the university’s Alzheimer’s Disease Research Center (ADRC). It’s therefore impossible to predict driving performance based solely on whether a person has been diagnosed with dementia.
“We want to enable older adults to continue driving for as long as they are safe,” says Morris, the Harvey A. and Dorismae Hacker Friedman Distinguished Professor of Neurology. “Identifying and testing those at risk can be reassuring and help safe drivers remain independent. It also can help us deter the development of unsafe driving behaviors and intervene, before there is an actual crash or other problem.”
Researchers at the nationally renowned ADRC and its Memory and Aging Project have been studying the effects of dementia on driving for more than a decade.
Because AD is progressive and driving performance inevitably does worsen, the challenge is to figure out how to predict and evaluate dangerous declines in driving performance.
University researchers are investigating two key issues: how to confirm that an individual with dementia is in fact unsafe, and how to educate and empower physicians and families to recognize a potentially unsafe driver.
In a landmark 1997 study published in the journal Archives of Neurology, the ADRC team reported the first findings from the Washington University Road Test, one of the most comprehensive and extensively researched driving assessment tools for older adults. The 45-minute, in-traffic test is designed to measure driving behaviors commonly associated with dementia (see sidebar, below).
This was the test Ralls failed. Like her, more than 40 percent
of individuals in the study with mild AD and 19 percent with very mild
dementia also failed.
In the October 2003 issue of the Journal of the American Geriatrics Society, they reported that, as expected, the mild Alzheimer’s group declined the fastest, followed by the very mild dementia group.
“This is a preliminary study, but it suggests that testing currently safe drivers who have mild dementia every six months can be useful to identify those who become unsafe,” says study senior author Janet M. Duchek, PhD, associate professor of psychology and of occupational therapy.
To the researchers’ surprise, 3 percent of people without dementia failed the test the first time, and even those who passed declined over time, though at a slower rate than the mild and very mild dementia groups.
According to Morris, “The fact that driving ability
declined in nondemented participants implies that age-related changes
other than dementia likely contribute to driving performance and should
be further investigated in larger groups of
Despite its apparent effectiveness, the Washington University Road Test is expensive and time-consuming. So, while continuing to investigate the effectiveness of the road test, researchers also are exploring other options.
A team led by Morris and Duchek is collaborating with the Missouri Division of Motor Vehicles (DMV) to determine whether a five-minute cognitive screening test can predict a suspected impaired driver’s performance on the DMV’s driving test.
Based on a previous study the researchers published in the Journal of Gerontology in 1998, the DMV already has incorporated the use of five road signs in their written test that were found to help identify individuals with dementia.
Another project, led by Martha Storandt, PhD, professor of psychology and neurology, will examine data collected by the university’s Memory and Aging Project over the past 20 years.
Volunteers in the program return yearly for an extensive battery of psychometric tests that measure a wide range of cognitive abilities. By evaluating this longitudinal data, the team hopes to identify a “psychometric profile” associated with when a person decides to stop driving.
One of the biggest challenges in detecting unsafe drivers with AD is that, as part of the disease, patients often lose insight into their own health and mental acuity. It also can be difficult for families and physicians to identify those who are no longer safe to drive.
According to Morris, “We have an important task ahead of us: We must increase public awareness about driving issues in demented persons and empower families and health care professionals to intervene before a tragedy occurs.”
Morris’ concern is echoed by the American Medical Association (AMA). With the National Highway Traffic Safety Administration (NHTSA), the AMA instituted the Older Drivers Project in 2002, an effort aimed at helping physicians to assess the “driving fitness” of the millions of Americans over age 65.
“Online resources like the AMA’s guidelines will provide a fluid instrument for us to adjust as new research becomes available,” says Carr, who served as one of three appointed master trainers selected to teach others how to train physicians to use the AMA guidelines.
He and Thomas M. Meuser, PhD, research assistant professor of neurology and director of the ADRC’s education core, recently received a grant from the NHTSA to train Missouri physicians to specifically identify dementia and its potential effects on driving.
“We still don’t have enough information to recommend widespread screening for driving impairment in older adults,” Carr admits. “But, it is an exciting time for the field. We now have several useful screening methods that need to be studied further. Combined with increased education and awareness, these tools create an ideal situation for studying this problem and advancing the science in the area of driving control and cessation.”