Winter 2008

Knowing When To Brake: Older Adults and Driving
By John R. Siberski, SJ, MD
Aging Well
Vol. 1 No. 1 P. 36

Driving, aging, and cognitive impairment is a hot-button topic for older adults, their families and caregivers, and geriatricians. Personal autonomy and the common good speed toward each other from opposite directions in the same freeway lane. You can help avoid a crash.

“And she had fun, fun, fun, ‘til her daddy took the T-bird away.”

For those who aren’t familiar with that line, it was the chorus of a huge 1964 hit by the Beach Boys. And that song was only one of many in which they and other groups extolled the thrills and joys of driving to a teenage generation—the baby boomers—that’s now approaching Social Security and Medicare. A generation that, even though most of its driving now involves taking the Corolla, SUV, or Saab to work, the supermarket, church, the kids’ soccer game, a doctor appointment, the garden shop, or even visiting the grandkids will more than likely continue to have fun, fun, fun while driving.

Until, that is, the Department of Motor Vehicles, perhaps on a physician’s recommendation, takes their T-bird (read: license) away.

The Demographics
Approximately 13% of the current U.S. population is 65 and older, with those over 80 composing the most rapidly increasing group. By 2030, 20% of the population will officially come under the category of older adult. More than 70% of current elders live in suburban or semirural settings where public transportation is scarce to nonexistent. Regarding elder city dwellers, only a relative fraction have access to safe, reliable, and affordable public transportation.

At the beginning of the 20th century, when folks such as Ransom Olds and Henry Ford were devising the manufacturing innovations that would make automobile ownership possible for the less wealthy, life expectancy in the country was approximately age 48. By the beginning of the 21st century, when a family or even individual may own two or three cars, life expectancy has increased to the age of 78. Even more significant is the current life expectancy for those of a particular age. A person aged 75 today can expect to live an average of 11 additional years, while a person aged 85 can expect approximately six.

But increased life expectancy is a mixed blessing at best. In the early 1900s, people died relatively young and healthy or of acute infectious diseases, the result of trauma, complications of childbirth, or the effects of then-untreatable diseases such as diabetes or coronary artery disease. For the most part, they died cognitively intact. By contrast, in the opening years of this century, most people die of an acute or semiacute illness that’s more often than not superimposed on a variety of chronic medical and neurological illnesses, including Alzheimer’s-related dementia.

Physiological Changes of Aging
All physiological parameters and characteristics change as a function of increasing age. Nobody can run as quickly at 50 as he or she could at 25. Few people can see as well in late middle age as in their 30s without using bifocals in good light. While few of the normal changes of aging are sufficient to prohibit driving, their cumulative effect, superimposed on medical illnesses and/or dementia, can take a significant toll on driving ability and safety. Medications can also contribute to poor driving performance. The most emotionally charged issue, however, is revoking driving privileges for an otherwise healthy individual in the early stages of a dementing disorder.

Dementia, as defined by neurologists Jeffery L. Cummings, MD, and D. Frank Benson, MD, in their book, Dementia: A Clinical Approach, is “an acquired persistent impairment of intellectual function with compromise in at least three of the following spheres of mental activity: language, memory, visuospatial skills, emotion or personality and cognition.” The prevalence of dementia of all kinds increases linearly with age. It’s fairly rare under the age of 65 and has only 1% prevalence between ages 65 and 70, but that doubles every five years. By 85, it’s close to 40%. The Cache County Study of Memory in Aging (2000) estimates that the prevalence of dementia for those 100 and older approaches 70% to 75%.

Memory, visuospatial skills, and the executive function component of cognition are of particular relevance in the problem of dementia and driving. While a diagnosis of Alzheimer’s—the most common dementia today—requires memory dysfunction, other forms of dementia in which memory is relatively preserved during the early stages may be as debilitating and can impair driving as much as Alzheimer’s.

Memory is a complex phenomenon that can be described in many ways. One is on a temporal continuum from immediate to short-term to long-term. Immediate memory allows one to hold, for example, a looked-up phone number in mind just long enough to order a pizza for delivery. By way of contrast, long-term memory, which is relatively spared in early Alzheimer’s, enables one to recall the driver’s test taken four or more decades earlier or a first car in exquisite detail. Skills such as how to start the car, the familiar route from point A to point B, and where the stop signs are along that route are also functions of long-term memory.

On the other hand, the memory demands one faces when confronting a detour from the usual route or while driving in unfamiliar territory may require holding on to new short-term information for a variable period of time—a difficult task even during the early stages of dementia. In general, a cognitively impaired individual is unable to drive safely long before he or she has forgotten how to drive.

Visuospatial skills include a component of memory, as well as depth perception, the ability to judge distance and speed, the ability to stay in one’s lane while driving, and the somewhat amorphous concept of sense of direction. Geriatric specialists frequently compare stories of lost patients found hours or days later and many miles, if not a few states, away from their destinations. Cognitively impaired drivers are also at particular risk for accidents while making a left turn across traffic, a maneuver that requires them to quickly process large amounts of rapidly changing spatial information.

Those forms of dementia that don’t initially affect memory (e.g., front temporal dementia, and Parkinson’s disease) may impair driving by affecting executive functions (EFs) which, unlike memory or visuospatial functions, aren’t intuitively obvious to most. EFs are higher-order cognitive functions needed to assimilate, manipulate, and apply information on the basis of shifting sensory input from the environment. They respond to what’s happening at the moment and integrate it with what happened in the remote or recent past and what one thinks will happen in the future. They include judgment, foresight, insight, abstract reasoning, self-governance, perspective taking, mental flexibility, context appropriate behavior, delay of gratification, planning/sequencing of complex behaviors, and inhibition of socially inappropriate responses.

One need not think about these functions for too long to realize the impact that loss of one or several could have on an individual’s ability to drive safely. Unlike memory, which is relatively easy to test, with abnormalities generally obvious to even the most casual observer, EF testing is time-consuming and requires a certain degree of expertise. The changes in behavior and personality resulting from impaired EF aren’t as easily noticed.

Driving/Age Specifics
For the average rural or suburban dweller, losing a driver’s license is akin to house arrest without the ankle bracelet. The nondriver becomes dependent on the kindness of family, friends, and neighbors, as well as strangers driving taxis. The impact on the individual’s family is significant. Shopping, doctor appointments, trips to the beauty salon, picking up some milk at the store, and so on may—and often does—entail inconvenience, often elaborate planning and timing, and sometimes annoyance, resentment, and argument. The impact of allowing cognitively impaired older drivers to remain on the road, however, is even more problematic.

Motor vehicle incidents are the leading cause of injury-related fatalities in the age group of 65 to 74 and the second-leading cause for those over 75. Thirteen percent of elders in the U.S. population are involved in 18% of road fatalities. In plotting the number of accidents or fatalities per million miles driven per age group—the only statistic permitting valid comparison across age groups—the U-shaped curve shows the highest risk of accident or death at two extremes: ages 16 to 19 and over the age of 80. The lowest incidence coincides with early to late middle age. Accidents and fatalities drop off sharply in one’s 20s and beyond, reflecting, among other things, learning, experience, and full brain maturation. The other end of the curve increasingly reflects impaired physical and cognitive function in elders, and it will continue to rise.

Those with dementia are 2.4 to 4.7 times more likely to be involved in an accident than age-matched noncognitively impaired individuals. The research data on driving and cognitive impairment is sobering. For subjects with mild Alzheimer’s dementia, the failure rate on a road test ranged from 24% to 60%. In a driving simulator study involving 21 subjects with Alzheimer’s, there was a 30% failure incidence (Rizzo, Reinach, & McGehee, 1997).

The Clinical Dementia Rating (CDR) scale rates the degree of impairment on six parameters important in daily life, including memory, orientation, and judgment/problem solving, on a five-point scale: 0, none; 0.5, questionable; 1.0, mild; 2.0, moderate; and 3.0, severe. By the time someone with dementia has reached a score of 1.0 on the CDR, he or she is most likely an unsafe driver or will soon become one. Neurologist Richard Dubinsky, MD, in Practice Parameter: Risk of Driving and AD puts the situation in stark terms: “The relative risk of crashes for drivers with Alzheimer’s Disease of CDR stage 1 is greater than our society tolerates for any group of drivers. Drivers with early Alzheimer’s at CDR 0.5 have an increased risk of accidents similar to that which society accepts for 16- to 19-year-old drivers and for those drivers intoxicated with alcohol at a blood alcohol level of 0.08.”

Unfortunately, unlike their unimpaired age-mates, those with CDR stage 1 dementia, like a drunk driver, may lack the insight to realize that they are driving poorly. Intact insight allows older drivers to set self-imposed limits such as driving fewer miles at slower speeds, restricting themselves to optimal driving conditions such as daylight, avoiding interstates at rush hour or altogether, and not driving in poor weather. Insight may be lost or impaired early in dementia, with the result that those individuals who most need to stop driving have the least awareness that they are incapable drivers.

Early Warnings
Among the red flags indicating that a cognitively impaired older driver is no longer competent to drive are getting lost in familiar territory, misjudging distances, inappropriate speed, missing signs or signals, moving violations, accidents or near-misses, and, what may be the most sensitive of signs, “passenger panic,” or the sudden realization that under no circumstances will grandma or grandpa be allowed to drive the grandchildren anywhere.

There are no easy answers. Limiting individuals to local driving typically isn’t a viable option. While they may remain able to get from home to the supermarket without difficulty, the challenges involved in processing incoming information and making a left turn across traffic are no less because the individual is staying closer to home. Pulling a driver’s license may be one of the most difficult and traumatic things a family or physician has to do.

Medical and Legal Considerations
Each state has variable reporting laws and protection for professionals or concerned citizens who report a cognitively impaired driver. In Washington, DC, for example, physician reporting is permitted, but not required. Nonphysician reporters cannot remain anonymous, and there is no immunity or legal protection for those who report. Maryland provides for “discretionary reporting” and offers a degree of legal protection to those who report. Pennsylvania requires reporting conditions that may impair driving ability, including Alzheimer’s, and grants immunity to those who report. More detailed information can be found in Physician’s Guide to Assessing and Counseling Older Drivers, available here. In addition to driving and reporting regulations for every state, the guide includes a section on “Medical Conditions and Medications That May Impair Driving,” as well as information on assessment, interventions, and legal or ethical responsibilities.

Practical Thoughts and a Personal Reflection
Generally speaking, it’s not a good idea for a close family member to assume the role of “bad cop,” telling an older individual that he or she must stop driving at a time when support and sympathy are most needed. If a physician or trusted caregiver is the one designated to break the news, it’s probably advisable to make at least tentative arrangements for another physician/caregiver to take over the individual’s care because he or she may refuse to return to that doctor or deal with that caregiver again.

At times, families have had to resort to disabling, hiding, or even selling the car to prevent a cognitively impaired older adult from driving. It’s never an easy situation, and it won’t be easy for most of us when our time comes. But there are some exceptions.

On October 1, 2007, Father Jimmy Martin, SJ, the oldest Jesuit priest in the world, died at Georgetown University Jesuit Community at the age of 105 years, 1 month, and 1 day. A terrific athlete, he played golf into his mid-90s and worked with weights until he was close to 100. One of the men in the community shared the following about him as we sat around reminiscing after his wake: “Jimmy loved to drive. When he was in his 80s, it wasn’t unusual for him to drive to Alexandria, VA, to celebrate Mass in the morning, return to Georgetown for lunch, go to Baltimore for an afternoon meeting, and return to Georgetown in time for dinner. No one knows what happened one day when he was 90. He returned the car from an errand, went to the superior’s office, dropped the keys on his desk, and said, ‘I’m through.’ And he was. He never discussed it again. He was simply through driving.”

I thought about Jimmy recently while making my monthly drive to visit my mother, aged 90—an excellent driver who quit at the age of 84 and sold the car—in northeastern Pennsylvania on a route that largely involves rural roads. The sun was just going down. Leaves were beginning to change. The smell of autumn was in the air. Classic 60s rock was playing on the radio.

In short, all was well. And then I wondered … Will I have the grace, courage, and insight to recognize when it’s time to stop driving? If not, I hope and pray that someone else will.

— John R. Siberski, SJ, MD, is assistant dean of students and associate professor of psychiatry at Georgetown University School of Medicine.

Reference
Rizzo, M., Reinach, S., McGehee, D., & Dawson, J. (1997) Simulated car crashes and crash predictors in drivers with Alzheimer’s disease. Archives of Neurology, 54(5), 545-551.

Resources
Breitner, J. (2006) Dementia—epidemiological considerations, nomenclature, and a tacit consensus definition. Journal of Geriatric Psychiatry and Neurology, 19(3), 129-136.

Fox, G.K., Bowden, S.C., Bashford, G.M., & Smith D.S. (1997) Alzheimer’s disease and driving: Prediction and assessment of driving performance. Journal of the American Geriatrics Society, 45(8), 949-953.

Hunt, L.A., Murphy, C.F., Carr, D., Duchek, J.M., Buckles, V., & Morris, J.C. (1997) Reliability of the Washington University Road Test. A performance-based assessment for drivers with dementia of the Alzheimer type. Archives of Neurology, 54(6), 707-712.

Morris, J.C. (1993) The Clinical Dementia Rating (CDR): Current version and scoring rules. Neurology, 43(11): 2412-2414.

Tallman, K. (1994) Driving performance in mild dementia. [unpublished doctoral dissertation]. Vancouver: University of British Columbia, Canada.