More than five million people in the U.S. are afflicted with dementia, with Alzheimer's disease being the most common form. Deciding when to limit or stop driving can be a confusing issue for individuals diagnosed with dementia and their caregivers. Matthew Rizzo, MD, director of the Division of Neuroergonomics at University of Iowa Hospitals and Clinics, talks about what a diagnosis of Alzheimer's means to a driver:
We should start by explaining for those who do not know, what is Alzheimer's?
Alzheimer's disease is a progressive cognitive deterioration that primarily affects older people, say of retirement age (65 or older) and it typically shows up with difficulty in memory, with sometimes in spatial abilities. A person may have trouble recalling names, which actually most older people do, but this is more than usual. And they may do things like get lost and lose interest in their usual activities. There are progressive and subtle changes in behavior and abilities that sneak up on a person. They don't happen all at once. You don't wake up in the morning and suddenly have problems. But it's something that happens little by little by little until something occurs that raises the attention of everyone in the family and it becomes apparent that grandma or grandpa has a problem.
At what age does Alzheimer's commonly occur?
Mostly Alzheimer's is a disease of aging. Generally, it comes on in the sixth and seventh decades. In some people it can come on earlier. In the original case described by Alzheimer, I believe the woman who was afflicted was in her 50s when it first began. The way Alzheimer's starts is gradual. There are gradual changes in the brain and in the nerve cells in the brain which drop away. These changes may occur for years and maybe even decades before it becomes apparent that a person actually has the disease. The process that causes the disease is going on for several years. The year that the disease is actually presenting itself is generally around retirement age, as mentioned before.
Is there evidence to suggest that driving is a problem for someone with Alzheimer's?
Driving is a difficult thing to do. You have to be firing on all cylinders, as it were. You have to perceive, and attend, and decide, and act, remember the locations of cars that are around you. You have to do it all under the pressure of time. When you start to lose your powers and become slower and lose your attention and your spatial processing abilities, driving is inevitably a problem.
Do individuals in the early stages of the disease exhibit poor driving behavior?
Some do and some don't and this is the area where it's really difficult to say whether people should continue to drive. It's clear that people who don't recognize the environment around them, can't figure out how to get the key into the ignition, can't figure out where the foot pedals are, or even where they left their car shouldn't be driving. But when somebody starts to subtly lose their powers of thinking, it's not so obvious and it may even be that some people with early problems in Alzheimer's disease are safe drivers and should continue to be able to drive. And that's actually where the difficult policy decision is. When do you stop a person, where do you draw the line? This is the subject of a variety of research programs around the country.
Are there other warning signs that a person with Alzheimer's should stop driving?
I think perhaps the best thing is when family members notice that the driver is having difficulty, including things like missing exits, driving too slow, and having other drivers around the driver become angry or aggravated. Getting lost is especially a problem, not only do they not get where they're going and create an extra risk that way; but they get flustered. We've found that they actually make more mistakes when they're lost because their attention is divided with the extra task of geting back on track to get where they're going. They will make more lane errors and increase the potential for having a crash. So it's quite a problem.
For people in an early Alzheimer's stage, is it easier for them and their families if they stop driving immediately?
You know it would be easier, but then the question would be “Is it fair?” Driving is not a right, it's a privilege. We don't want to discriminate against an older person simply because there might be a problem. Probably the fairest thing to do is have a people come in when they're having thinking problems, be evaluated very carefully by a physician, usually a neurologist, and have a battery of tests called neuropsychological tests.
There's early evidence that certain kinds of neuropsychological attention and decision-making actually tests can be predictive of safe and unsafe driving. It may be useful to have people take a practical test like a road test. In a way this has become a sort of pass the buck thing. The Iowa Department of Transportation gives road tests to determine whether a person is a safe or unsafe driver. When they're not sure, they refer the driver to a physician to make the evaluation.
The physician, on the other hand, may say “I suspect there's a problem because of the diagnosis and refer back to the Iowa Department of Transportation or some other state department of transportation. So there's a lot of passing the buck and it's not because nobody wants to live up to their responsibilities; it's because these are very difficult decisions and sometimes it not clear whether a person should continue to drive or not. And fortunately, that is going on in Iowa.
I think that collaboration between the state department of transportation and physicians and other health care experts who know about the driving test and how it can fail can be useful and fruitful.
Will everybody with the disease eventually become an unsafe driver?
Eventually everyone who has the disease will be an unsafe driver, but many of them become timid and don't go out on the road, so they don't expose themselves to unsafe situations. Or they have family members who remind the person not to drive. Sometimes the person, because of pre-morbid personality characteristics, will continue to drive and not want to stop. Sometimes it's even necessary to hide the keys.
How do you distinguish between Alzheimer's driving and people that are normally aging?
There are tests that evaluate the cognitive abilities necessary for driving. These fall under the neuropsychological tests that I mentioned before. They include tests of attention like the field of view. This tests to see if people can perceive objects around them in the periphery which is very important, particularly at intersections when cars are whizzing back and forth and you have to decide whether to cross lanes of traffic.
Tests of decision making can be important. We've been using instrumented vehicles to make measurements of how people perform in the real world on the road. Driving simulation is used to put people in real-life situations where it would be unsafe to put them in on the road. We can measure their ability to evade crashes, which can be useful as well. We have a variety of techniques we use. We try to triangulate on the patient to get the best information on whether they're safe or unsafe drivers.
Is UI Hospitals and Clinics involved in any studies with regard to Alzheimer's and driving?
We've been studying older people who have cognitive impairments for some years at the university. We have a number of studies going on and we're still recruiting subjects for these research studies. |
