Huntington’s Disease and Driving: Is It Time to Stop?

Driving is about much more than getting from one place to another. For many people, it’s a way to stay engaged in work, relationships, and the community and — perhaps most importantly — remain independent.

Huntington’s disease (HD) is an inherited, progressive brain disorder that affects movement, thinking, and behavior, including many of the abilities driving requires. Motor symptoms may interfere with steering and pedal control, while changes in attention, processing speed, memory, judgment, and spatial awareness can make it harder to keep up with traffic signals, pedestrians, and directions, says Kathleen M. Shannon, MD, the director of the Huntington’s Disease Society of America Center of Excellence at the University of Wisconsin in Madison.

At some point, everyone with HD gives up driving, but a diagnosis doesn't automatically mean it's time to hand over the keys. The challenge is recognizing when driving has become unsafe and in planning early for other ways to get from here to there in order to maintain as much independence as possible, says Dr. Shannon.

How do you know if you’re still able to drive safely, or if it’s time to stop? And if you can’t drive, how can you continue to get where you need to go and stay connected to the people and activities that matter?

The driving problems associated with HD generally reflect changes in three areas: physical control, cognitive and visual processing, and behavior or mood.

Physical Changes

Chorea and other changes in movement control may make it difficult to steer steadily or move smoothly between the accelerator and brake. Huntington’s can also cause slow or jerky movements and may make it hard to maintain consistent pressure on the brake pedal, says Shannon.

Cognitive and Visual Changes

Driving requires you to divide and shift your attention repeatedly. At one intersection, for example, you may need to watch the light, scan for pedestrians, judge the speed and distance of approaching cars, choose the correct lane, and remember the next turn.

“HD can slow how quickly you take in that information and respond to it,” says David J. Moser, PhD, a neuropsychologist and a professor of psychiatry at the University of Iowa Carver College of Medicine and the Huntington’s Disease Center of Excellence in Iowa City. Changes in spatial awareness can also make it harder to judge where the car is within a lane or how much room you have when turning or parking, he says.

Reduced attention span and the loss of ability to shift attention from one thing to another can also negatively impact driving, says Dr. Moser. “Additionally, memory problems can make it difficult to recall where one is going while driving,” he says.

Behavioral and Emotional Changes

While behavioral and emotional changes may impact driving, motor control and cognitive function are usually the more important safety concerns, Moser says.

A crash is not the only sign that driving may be becoming unsafe. The following signs deserve attention, says Moser.

• You get disoriented or lost while driving, even on a familiar route.
• You take too long to apply the brakes or steer when a quick response is needed.
• You have trouble maintaining a straight line or a steady, appropriate speed, including veering toward oncoming traffic or the curb.
• You feel overwhelmed by everything you have to monitor, such as other cars, pedestrians, speed, changing weather, and traffic lights.

Missing traffic signals, following other cars too closely, or having difficulty parking, are indications of risky driving, says Shannon.

Keep in mind that you may not be the best person to evaluate your driving, says Moser.

“A person with HD might fully believe that their driving, or their thinking abilities, have not changed at all, while those around them can clearly see that serious changes are occurring,” he says.

“Driving concerns should be discussed with the healthcare team as soon as possible; they can help determine whether a formal driving evaluation is called for,” says Moser.

You or a family member can also arrange an evaluation independently if you notice significant changes in driving or cognitive testing that shows problems with abilities needed behind the wheel, he adds.

You may already want to stop driving because it makes you anxious or don’t think it’s safe anymore.

“The person with HD should be allowed to stop driving, rather than reassuring them that their driving is fine or that they should undergo a formal driving evaluation just to make sure they should stop,” says Moser.

The exact process varies, but an evaluation may include:

Office or Clinic Testing You may answer questions about your medical and driving history and complete vision, physical, and cognitive tests. These can assess reaction time, attention, processing speed, memory, spatial skills, decision-making, coordination, and motor control, says Shannon.

A Driving Simulator Some programs may have you “drive” in a simulator while an evaluator measures skills such as braking reaction time, visual scanning, and the ability to divide your attention in a safe, controlled setting.

When changes are very subtle and there have been no dangerous close calls, the care team or evaluator may recommend limits on driving instead of an immediate stop.

If driving changes are very subtle and have not led to dangerous close calls, Moser says precautions may include:

• Take only short trips in familiar areas.
• Drive during daylight, light traffic, and good weather.
• Drive only when you are rested and alert.
• Limit distractions, including conversations, caring for children or other passengers, and phone use.
• Keep a phone in the car so you can pull over and call for help if needed.

Driving is often a critically important aspect of a person’s independence and identity, says Moser. “We strive to strike the optimal balance between respecting a person’s freedom and independence while also protecting them, and others, from harm,” he says.

For example, “I see that you might be having difficulty with some driving tasks. Let’s talk to your doctor to see what [they] recommend,” says Shannon.

Keep the focus on protecting the person with HD, passengers, pedestrians, and other motorists. At the same time, acknowledge what stopping may cost emotionally and practically, and offer a transportation plan rather than simply asking for the keys, she says.

Moser recommends that a family member occasionally observe the person’s driving, either by riding along or following in another vehicle, and share any concerns with the healthcare team. “Some families assume everything is fine even though no one has actually seen the person drive in months or even longer,” he says.

Family members who are concerned should let the neurologist know before the next appointment so the issue is not missed, Shannon says.

“If I feel they (the person with HD) shouldn't drive, I tell them this, but if they are unwilling to stop, I order a professional driving assessment; if they fail the assessment, the DMV is informed and the license is canceled,” she says.

In many states, if the family knows the person shouldn't be driving, an anonymous call to the DMV will result in a notice to the patient that a doctor must complete a form about whether the person should continue to drive, says Shannon.

It’s important to find alternative strategies to maintain as much independence as possible, says Shannon.

A social worker can help you get access to services, she says.

Work with a family member or friend and list the trips that matter most, such as medical appointments, groceries, exercise, faith services, and time with other people.

Creative approaches may work for some people. “One of my most talented caregivers addressed the issue of transportation by negotiating with a young neighbor who needed a car to get to work, but could not afford one,” says Shannon.

She added the driver to her insurance policy and allowed him use of the patient’s car; when not working, this young driver became the patient’s chauffeur, she says.