The American Academy of Neurology issued new guidelines Monday to help determine when people with Alzheimer's or other forms of dementia should stop driving.

According to the guidelines, published in the online edition of the academy's medical journal of Neurology, doctors should use the Clinical Dementia Rating (CDR) to identify dementia patients who may be at an increased risk of unsafe driving.

The CDR calls for doctors to use information gleaned from examining the patient, as well as information from caregivers, to determine the severity of the dementia.

The new guidelines note that recent studies have shown that as many as 76 per cent of patients with mild dementia are, in fact, safe drivers and can still pass an on-road driving test.

That stands in contrast to previous guidance, which said doctors should tell patients newly diagnosed with mild dementia not to drive. These new recommendations suggest doctors have a talk with the patient and family members to remind them that the patient's driving days are numbered.

Lead guideline author Dr. Donald J. Iverson, who reviewed more than 6,000 studies on the topic, before issuing the guidelines, that faced with these facts, we needed to provide guidelines for doctors caring for these patients "to identify those people at higher risk of unsafe driving, without unnecessarily restricting those who are safe drivers," he said in a statement.

He added though that while some people with dementia can still drive safely for a time, "nearly all people with dementia will eventually have to give up driving."

"It's important for doctors to discuss this with patients and caregivers soon after the diagnosis since restricted driving will affect the patient's quality of life and may lead to other health concerns such as depression."

He said the group felt it should issue guidance that helps doctors identify those patients who should stop driving, without restricting those who can still drive.

The guidelines list warning signs that caregivers and family members can watch for that signal unsafe driving from a dementia patient, including:

  • Collisions
  • Fewer kilometres being driven
  • Moving violations
  • Avoiding certain driving situations, such as driving in the dark or in the rain
  • Aggressive or impulsive outbursts

According to the guidelines, information from caregivers is particularly important for determining a patient's driving skills, sine the patient's own assessment of his or her driving skills is usually not useful.

The academy cites a study in which caregivers who rated a patient's driving as "marginal" or "unsafe" were often proven correct when the patient took a driving test. In contrast, many patients who considered themselves to be safe drivers were not always accurate in their assessments.