Subtle changes in everyday driving habits may be early warning signs of brain changes and higher dementia risk, even before traditional memory and thinking symptoms appear, according to an American research team.
Greater white matter damage in the brain was linked to decreased driving, fewer trips, taking the same routes and making more motoring errors, especially in those who later developed dementia. In contrast, adults aged 65 and older who were taking blood pressure tablets were less likely to show risky driving habits, even when brain damage was present.
Study of 220 older drivers
The researchers followed 220 motorists with an average age of 73 for five years living in St. Louis, Missouri, who did not have dementia when they enrolled in the study. Data was collected over a nine-year period, from 2016 to 2024.
Participants were monitored for continuous in-vehicle driving metrics, such as trip frequency, distance and destination, as well as safety events, including time spent speeding, collisions, hard braking or hard cornering. The participants underwent MRI brain scans to measure white matter hyperintensities at the outset. Just under half had a second MRI scan at least 12 months after their first scan. Participants also underwent annual clinical and cognitive assessments.
Key findings on brain damage and driving
Study author Professor Chia-Ling Phuah, of the Barrow Neurological Institute in Phoenix, said: “Driving habits in older adults can reveal early changes in brain health. How often people drive, where they go, and how much they vary their routes may signal underlying damage to the brain’s white matter, which is linked to cognitive decline and dementia.
“These findings suggest that even small shifts in daily driving patterns can offer important clues about brain changes - sometimes before traditional memory and thinking symptoms are noticeable.”
Among the 17% of participants who developed cognitive impairment, higher white matter hyperintensity burden on brain imaging was linked to a greater likelihood of unsafe driving practices, such as hard braking, and to more crashes.
Blood pressure medication and driving safety
Participants taking medications to manage high blood pressure, especially ACE inhibitors, were less likely to exhibit risky driving when compared with those who were not taking any blood pressure medication. This effect was observed regardless of whether their blood pressure levels were at target levels.
Prof Phuah said: “One especially promising finding was that people taking blood pressure medications, particularly ACE inhibitors, tended to maintain safer driving habits even when their brain scans revealed more damage. This effect was observed regardless of whether their blood pressure levels were at target levels. This suggests that these medications may help support brain health as we age.”
She added: “Participants with white matter hyperintensities located in the back of the brain - a region responsible for processing what people see and how they move - were at even higher risk of crashes than those with changes in other brain areas, making them more likely to experience unsafe driving episodes and car accidents over time.”
Real-life impact and expert reaction
For Larry Duncan, a retired business owner from Pinehurst, North Carolina, driving was part of his independence. But subtle changes began to appear before his Alzheimer’s diagnosis in 2023. His wife, Pam, said: “Larry was fine driving in familiar areas. But in new places where he had to make quick decisions, he became anxious.”
As his cognitive challenges progressed, Duncan’s doctor advised him to stop driving, a decision she describes as heart-breaking but necessary. Pam, who now volunteers for the American Stroke Association, said: “In early-stage cognitive impairment, symptoms can be subtle, and driving is one of them. Don’t ignore these changes. As caregivers, our role is to support independence while having the courage to make tough decisions. You can live well with dementia, but it starts with awareness and action.”
The study findings are due to be presented at the American Stroke Association’s International Stroke Conference in New Orleans next week. Duke University Neurology Professor Nada El Husseini, who was not part of the study, welcomed the findings. She said: “What’s surprising about these findings is that people taking ACE inhibitors were less likely to have impairment in their driving despite the extent of white matter disease. The impact of ACE inhibitors on cognitive function and driving safety in people with white matter disease requires further investigation. Also, these results suggest cognitive screening and brain imaging might be considered for people with driving difficulties.”
