"In my practice, I recommend that family members and friends ask themselves a simple question," he said. "'Would you let your relative with Alzheimer's disease drive the grandchildren, or someone else's grandchildren, to an event?' If they answer to this is anything less than a simple 'Yes,' then it is sensible to consider at least a driving evaluation or even taking away the keys."
Surprisingly, some patients are relieved to stop driving, finding it a stressful activity, said Karlawish. For those who resist having their keys taken away, Karlawish requires a driver's evaluation as an unbiased and expert assessment. Patients and their families often resist the idea, citing the cost and hassle of arranging the evaluation.
"I simply ask them how much they would pay and the time they would take to maintain the car's mechanical function. Cast in this light, most families are willing to spend the time and money to make sure the driver is functioning," Karlawish said.
But the doctor's office or the family room is not the place where decisions on driving are to be made in some states.
California is one state where the law has set guidelines on when someone has to stop driving.
"In California, physicians are required to report when a patient is diagnosed with dementia, and the Department of Motor Vehicles retests their driving skills," said Dr. Gary Small, director of the UCLA Center on Aging. "Even though some patients with dementia are safe drivers, I advise caregivers to get an objective driving assessment for any family member with cognitive impairment whenever there is a doubt about driving safety."
Pennsylvania, Oregon and the province of Ontario, Canada, also have policies mandating this kind of reporting by physicians to the state.
So while guidelines may give more leniency to doctors when helping patients decide whether to take away a parent's car keys, the state may not.
"There are legal issues as well that can play a role," said Iverson. "A physician doesn't want the power or have the power to make a patient stop driving."
For AAA.com's advice and tools to help you decide if someone you know shouldn't be driving click here.
And for a list of local resources to help keep someone independent after their keys have been taken away click here.