Cognitive changes with advancing age can affect driving safety.
You’ve just seen your doctor and been diagnosed with mild cognitive impairment or Alzheimer’s disease. Does this mean you shouldn’t drive?
Driving requires many brain systems to work together
Driving is a complex skill and a dangerous activity. Almost 43,000 people died in motor vehicle crashes in the US in 2021.
In addition to good physical health, driving requires many brain systems to work together. The thinking part of your brain consists of four pairs of lobes—occipital, temporal, parietal, and frontal—in the left and right hemispheres of the brain, and they’re all active when you’re driving:
- The visual-object system in your occipital and temporal lobes processes the images coming from your eyes to allow you to distinguish between cars, bicycles and pedestrians.
- The visuospatial system in your occipital and parietal lobes determines where cars, bicycles, and pedestrians are on the road, how fast they are moving, and predicts where they will be in a few seconds.
- The attention system in your parietal lobes and the auditory system in your superior temporal lobe keep you alert for car horns and other signs of danger.
- The decision-making system in your frontal lobes uses this visual, auditory, spatial, and motion information to determine how fast you should move and whether you should turn.
- The motor system in your frontal lobes then translates those decisions into how hard your foot presses the pedals and whether your hands turn the steering wheel.
Driving combines conscious and unconscious brain activity
“Wow,” you might think, “how can I do all these activities while driving and still sing along to the radio, listen to an audiobook, or talk to my friend sitting in the passenger seat?” The answer is that after when you learn to drive, most of your routine driving is done automatically and unconsciously. In fact, there is increasing evidence that you go through most of your daily routines automatically, with no conscious effort to control your actions. Therefore, if you become distracted while driving, you may find yourself going on autopilot when you want to go to the grocery store.
However, your conscious mind takes over when the situation calls for it. So if you’re driving in a snowstorm, when it’s raining, or on an icy road, your mind will focus on your driving. That’s why you’ll stop singing, pause the audiobook, and ask your friend to hold on for a minute during these situations.
Alzheimer’s disease and other dementias interfere with driving
Alzheimer’s disease and other forms of dementia affect different areas of the brain, including all four lobes of the brain. For this reason, people with Alzheimer’s disease often show impaired vision, hearing, attention and decision-making abilities. However, not everyone with Alzheimer’s needs to stop driving. It depends on both the overall severity of the disease and the specific cognitive abilities that are impaired.
Alzheimer’s begins quietly, with plaques and nodules building up in the brain, but without any symptoms. When the disease begins to affect thinking and memory, but function is normal, it has reached the stage of mild cognitive impairment. When the function is impaired, it has reached the stage of dementia. When only one or two complex activities are impaired (like paying bills), Alzheimer’s disease is in the very mild stage of dementia.
One study found that people with Alzheimer’s had an average of 0.09 car crashes per year, compared to 0.04 crashes in healthy adults of the same age. Another study found that individuals with Alzheimer’s disease in the mild cognitive impairment stage and very mild dementia had impairments similar to those of 16- to 20-year-old drivers. So, on the one hand, people with Alzheimer’s are at increased risk for driving. On the other hand, when Alzheimer’s disease is very mild, accident rates are like those of new drivers, a group that we as a society allow to drive with little or no restrictions.
Should people with Alzheimer’s drive?
The American Academy of Neurology has published guidelines to help clinicians know when people with Alzheimer’s and other dementias should stop driving. These guidelines were subsequently confirmed by a survey of caregivers. The guidelines suggest that clinicians consider the following factors, as the risk of accidents increases when more of these factors are present:
- Do caregivers report poor or unsafe driving skills?
- Is there a citation history?
- Is there a history of crashes?
- Do they drive less than 60 miles per week?
- Do they avoid driving in certain situations?
- Are they aggressive or impulsive in their driving?
- Is their cognitive ability impaired on a standardized test?
- Is there evidence of other factors that may interfere with their driving, such as alcohol use, drugs that cause cognitive impairment, sleep disorders, visual or motor impairments?
If you’ve been diagnosed with a memory disorder, ask a family member (or close friend) to ride in the car with you every month. One of your grown children would be best. If your kids feel comfortable with you driving, that usually means you’re driving safely.
Note that I’m not worried if you take a wrong turn or get lost. If you get lost, you can use GPS or a phone app, or ask someone for directions. I am only concerned about being a safe driver and not endangering yourself or others on the road.
What if your family thinks your driving is dangerous, but you believe you’re a good driver? Take a driving test at your local motor vehicle registry or rehab hospital. This will allow you to prove to your family that you are a safe driver. If you fail the test, be brave enough to hang up your keys. Take a taxi, use a ride-sharing app, or – even better – ride with a friend.