Hopkins PodBlog: Driving Miss Daisy

Older drivers can imperil all of us as their driving skills decline, often so incrementally it may be unapparent until a problem occurs, and this risk increases if cognitive impairment is present. The Journal of the American Medical Association took a look at this issue this week, in an article directed toward physicians entitled 'The Older Driver With Cognitive Impairment."

The article reviews literature related to cognitive assessments, aging, driving outcomes, computer simulations and related matters from 1994 to 2009. It reveals that about 4% of drivers older than age 75 have some sort of a dementia, and that these folks largely continue to drive well into the disease process.

Computer simulated driving experiences consistently find that drivers with dementia are more likely to drive off the road, brake more slowly, make slower left hand turns, and apply less brake pressure in order to stop as compared to their counterparts without dementia. Overall, they are about twice as likely to have an accident.

While computer simulations are revealing deficiencies, the paper also reports that as far as road driving tests go, 88% of folks with very mild dementia and 69% of those with mild dementia were able to pass such an exam. The average time to driving cessation for those with very mild dementia was 2 years, with those with mild dementia giving up the keys after 1 year. The clear conclusion seems to be that many cognitively impaired drivers remain on the road and that methods for assessing them may be inadequate.

In order to get a good picture of how well someone is driving, a caregiver or family member can be questioned, and objective evidence such as scratches or dents on the car, tickets or being pulled over by a policeman, getting lost, especially on familiar routes, and having other drivers honking or worse gathered. This may provide a clearer idea of how someone is doing behind the wheel.

As Rick and I discuss in the podcast, driving cessation here in the US is problematic at best. Our public transportation options are mostly limited, and cars are such a symbol of personal freedom and self-determination. This article suggests physicians step into the fray and begin such discussions with their patients early, to give them plenty of time to plan alternative transportation, and that they emphasize the need for personal and public safety.

Other topics this week include the benefits of sigmoidoscopy in reducing colon cancer deaths in the Lancet, deep brain stimulation for those with advanced Parkinson's disease in Lancet Neurology, and harm related to vitamin B supplementation in people with kidney disease related to diabetes in JAMA. Until next week, y'all live well.