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02 Aug 2023

Are cognitive changes putting the brakes on driving?


Dr Andrew Budson from the United States Harvard Medical School shares some indicators. Driving, he says, requires many brain systems to work together.

Driving is a complicated skill involving a powerful machine, it is a dangerous activity. In New Zealand 378 people were killed in motor vehicle crashes in 2022, data is not available to confirm if cognitive impairment or dementia was a cause of any of those, but given dementia is frequently undiagnosed the data would not be accurate. The numbers of people with serious injuries from motor vehicle crashes is many times larger than the death rate.

In addition to good physical health, driving requires many brain systems to function together. The thinking part of your brain consists of four pairs of lobes in the left and right hemispheres of the brain, and all of them are active when you are driving, these lobes are: occipital, temporal, parietal, and frontal.

  • The visual-object system in your occipital and temporal lobes processes the images coming in from your eyes to enable you to distinguish cars, bicycles, and pedestrians.
  • The visual-spatial system in your occipital and parietal lobes determines where cars, bicycles, and pedestrians are in the road, how fast they are moving, and anticipates where they will be in a few seconds.
  • The attention system in your parietal lobes and the auditory system in your superior temporal lobe keeps you alert to 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 be going and whether you need to turn.
  • The motor system in your frontal lobes then translates these decisions into how hard your foot is pressing the pedals and whether your hands are turning the steering wheel.

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Date Published: August 2023

To be reviewed: October 2026

Driving combines conscious and unconscious brain activity. Once you've learned to drive, most of your routine driving occurs automatically and unconsciously. In fact, there's increasing evidence that you go through most of your daily routines automatically, without conscious effort controlling your actions. This is why, if you become distracted while you are driving, you may find yourself heading to work on autopilot when you meant to go to the supermarket.

Your conscious mind takes control, however, whenever the situation requires it. So if you are driving in a snowstorm, when it is raining, or on an icy road, your conscious mind will devote its attention to your driving.

Driving impairment

Alzheimer's disease and other forms of dementia affect a variety of different brain regions, including all four lobes of the brain. For this reason, people with Dementia often show impaired visual, auditory, attention, and decision-making abilities. That is why Doctors are becoming more focused on when someone with dementia must stop driving.

If you have been diagnosed with a memory disorder, ask an adult member of your family (or close friend) to ride in the car with you each month. One of your adult children would be best. If your adult children feel comfortable with your driving, that usually means you're driving safely. Another question a Doctor may ask you is will your adult children allow their children (your grandchildren) to be in your car while you are driving? If the answer to these types of question is no, don’t let false pride get in the way of being responsible and caring; stop driving and cancel your driver’s licence.