You may be right if you're thinking that little old lady driving 35 miles per hour in the passing lane shouldn't be behind the wheel. Our driving abilities decline with age, and for those with cognitive issues such as dementia, it can be even worse shows studies at Rhode Island Hospital, and elsewhere.
A standardized road test - much like the one teenagers take to receive their learner's permit and driver's license - is often used to measure an individual's performance, including those of older adults. But researchers at the Rhode Island Hospital's Alzheimer's Disease and Memory Disorders Center went a step further, installing cameras in the personal vehicles of test subjects for two weeks, and then comparing their performance to the standardized test. The study is published in the November 2012 issue of the Journal of the American Geriatrics Society
"Many older people don't like to drive far from their homes, they like to stay in their comfort zone," said lead author Jennifer Davis, Ph.D., of the department of psychiatry at Rhode Island Hospital. "They don't drive many miles, and they often avoid driving at night. Taking them out of that comfort zone and placing them in an environment of formal test-taking - one which carries with it potentially life-altering consequences (loss of their driver's license) -- may lead to significant anxiety, which in itself could impair their driving abilities."
Davis and her colleagues worked with an independent driving instructor who completed the standardized tests with 103 older adults, some healthy and some with mild cognitive impairment. The researchers then observed the drivers in their natural driving state - in their own vehicles going about their daily routines. The driving instructor compared the videos to each participant's test results and found that the majority of the drivers fared better when driving their own vehicles.
Not surprisingly, the individuals with cognitive impairment had more errors on both the road test and naturalistic driving compared to cognitively healthy older adults. However, the cognitively impaired participants had a greater number of more severe errors on the standardized test than in their natural driving, suggesting that the standardized test may be more cognitively demanding than natural driving.
"It's natural to worry about older adults behind the wheel, even more so if they appear to have memory or cognitive issues, or have been formally diagnosed as such," Davis said. "But many of the people in our study drove safely".
"Receiving a diagnosis of Alzheimer's disease shouldn't result in an automatic revocation of an individual's driver's license," she said. "Rather, it should emphasize the importance of monitoring an older person's driving, so that he or she can safely maintain their mobility and independence for as long as possible."
Researchers note that this is the first study to compare standardized driving tests with natural driving, and requires further study.