A set of wheels represents freedom and independence. Giving up that autonomy can be a wrenching choice for older adults, who often hold fast to their keys long after their families have begun to worry that driving imperils their safety.
Now, a $5.9 million study at Washington University School of Medicine in St. Louis aims to learn more about how driving habits change with age and with the onset of Alzheimer’s disease, a form of dementia that affects one in 10 people over 65, stealing the ability to think, remember and, consequently, drive. The study is funded by the National Institute of Aging of the National Institutes of Health (NIH).
The findings will be used to develop strategies to help older adults stay behind the wheel without endangering themselves or others.
“There is an urgent need to better understand changes in daily driving behavior in older adults so that we can intervene to safely keep people on the road a little longer,” said the study’s principal investigator, Catherine Roe, PhD, an associate professor of neurology. “If we could give someone who’s 70 another 10 years of driving safely, that could really impact his or her autonomy and well-being.”
Many age-associated ailments can cause driving skills to deteriorate: problems with vision and hearing; conditions such as arthritis that limit movement; and cognitive impairments, such as Alzheimer’s, that weaken judgment.
Older adults often compensate for these changes by driving shorter distances and more slowly than younger motorists. They also avoid driving at night or in bad weather.
But even with these attempts to reduce risk, auto accidents are a leading cause of injury and death for people over 65. In 2014, more than 5,700 older Americans died, and another 236,000 were taken to emergency rooms due to vehicle accidents.
To learn more about why driving is so hazardous for older adults, postdoctoral researcher Ganesh Babulal led the Roe lab in the development of the Driving Real-World In-Vehicle Evaluation System (DRIVES) chip, which monitors how people drive in their own cars and their own neighborhoods. The chip plugs into a port, under the dashboard, that auto mechanics use to evaluate cars’ computer systems. It sends pulses of data every 30 seconds, stamped with the time and the car’s location. When a driver brakes hard, accelerates suddenly or collides with something, the chip shares that information with the researchers also.
The data will allow the researchers to paint a detailed picture of older motorists’ driving behaviors, including the number of trips taken, miles per trip, unique destinations visited and frequency of aggressive driving.
“When we were testing prototypes, I installed one of the chips in my car and quickly forgot it was there,” Roe said. “We believe people forget they have the chip and drive normally.”
About 50 people already have the chips installed in their cars, and Roe, Babulal and colleagues plan to enroll another 250. Participants are 65 or older and must not show any signs of mental decline at the time of enrollment. Each participant will drive with the chip for at least two years.
Participants also take yearly on-the-road driving assessments and fill out driving-related surveys and mood assessments. As Alzheimer’s disease is a major reason older adults stop driving, participants also will be tested for early signs of the disease.
Alzheimer’s is diagnosed when people start showing symptoms such as confusion, memory loss, and problems with thinking and reasoning. But scientists can detect molecular and cellular changes in the brain up to two decades before such symptoms appear.
To test for such changes, participants will undergo brain scans to detect plaques of the protein amyloid beta, one of the hallmarks of Alzheimer’s. They also will be given spinal taps once every three years to measure levels of amyloid beta and tau – another protein associated with Alzheimer’s – in the fluid surrounding the brain and spinal cord.
Roe and others have shown that driving skills decline in people who are still mentally sharp but on the path to Alzheimer’s disease.
“People with preclinical Alzheimer’s make more driving errors and are faster to fail a standardized road test compared with those with more normal levels of Alzheimer’s proteins,” Roe said. “So something’s already going on in people whose memory and thinking seem to be fine.”
Roe and Babulal already have begun mining data from the chips for insight into the behavior of older motorists.
“Driving is a really important thing for independence,” Roe said. “Until someone finds a cure for Alzheimer’s, people are going to have problems with driving, and we don’t fully understand what exactly those problems are. This study is designed to help us understand why people get in accidents, which is the first step toward preventing them.”