Checking Alzheimer's Patients For Driving Safety
No one likes to make the tough decision to take away a person's right to drive, but as the number of aging drivers increases it will become more important. Especially as the number of people with Alzheimer's disease increases.
Dr Jeffrey D Dawson and colleagues may have found a way to make that difficult judgment call for those patients that suffer from Alzheimer's disease. In an article in the Feb 10 issue of Neurology they report that a battery of cognitive tests can be used to help decide who is safe to drive. The researchers found that patients who performed better on these tests made fewer errors during a supervised test drive.
The researches conducted a controlled trial using 40 patients with mild Alzheimer's disease and 115 patients without dementia. All participants were tested on a battery of cognitive, visual, and motor tasks. The results were used to calculate a composite measure of cognitive impairment (COGSTAT). Those who had higher overall cognitive function made fewer total safety errors on the driving exam.
Each person had to drive a supervised 35-mile test drive on roads within and surrounding Iowa City. The vehicle used was an ARGOS (Automobile for Research in Ergonomics and Safety), which has hidden instrumentation and sensors. The researchers had a certified safe driving instructor reviewed video tapes of each drive. The instructor assessed the number and type of safety errors made by the drivers.
Drivers with Alzheimer's disease made an average of 42 safety errors per drive while those without made with an average of 33.2 for controls. Alzheimer patients had more difficulty staying within their own lanes often straddling the center line.
Driving demands a diverse set of cognitive functions. The study is a nice place to start and suggests that a collection of off-road neuropsychological tests of cognition, vision, and motor abilities may be useful in predicting whether an aged or Alzheimer disease patient can safely drive a vehicle.
The study is limited as it failed to take into account other environmental factors, such as having family members in the vehicle and time of day. It is also limited by it's small number of participants.
The study was supported by the National Institute on Aging.
Source: neurology.org - Dawson JD, et al "Predictors of driving safety in early Alzheimer disease" Neurol 2009; 72: 521-527.