Patients with dementia and when they should stop driving

A common clinical problem in aging is when should driving a motor vehicle be discontinued. When does driving become a significant safety hazard as cognition and motor skills decline?

The American Academy of Neurology recently published a Practice Parameter update: Evaluation and management of driving risk in dementia. This important review provides clinicians and family members with assistance in making an accurate and timely decision.

The authors of the guideline review research evidence of a variety of markers for unsafe driving risk. Some markers have more research support than others.

A standard assessment of driving ability is the on-road driving test. Mild dementia may not cause significant driving impairment. On study found that among those with mild dementia, 76% were able to pass an on-road driving test.

The Clinical Dementia Rating Scale appears to have the most research support for predicting unsafe driving. This scale scores six variables: memory, orientation, judgement/problem solving, community affairs, home and hobby activity and personal care. Subjects with a score of 0 on this test are generally not at increase risk of driving problems. Scores of 0.5 and higher have been tied to increased risk of accidents and increased rates of failure to pass an on-road driving test.

The Mini-mental status score is less clear in predicting driving impairment. Nevertheless the authors support using a score of 24 out of 30 as a cutoff for examining the need to discontinue driving.

The guidelines list a variety of markers for risk that have various levels of research support from highest (level A to lowest level C). This list is:

* Clinical Dementia Rating Scale score 0.5 or higher (Level A)
* Caregiver rating of patient’s driving ability as marginal or unsafe (level B)
* Recent history of traffic citations (Level C)
* Recent history of accidents (Level C)
* Reduced driving mileage–less than 60 miles per week (Level C)
* Self-reported avoidance of driving situations (Level C)
* Minimental status scores of 24 or less (Level C)
* Aggressive/impulsive personality behaviors (Level C)

Interestingly, the patient’s self-rating of safe driving ability is not useful. A patient with dementia is unable to accurately report their driving ability.

More comprehensive neuropsychological testing does not appear to provide additional prognostic information. It can be helpful in estimating severity of dementia which does relate to risk.

For those with markers of risk, family should support alternate methods of transportation and urge voluntary surrender of driving privileges. For those at high-risk who refuse, referral to the local state Department of Motor Vehicles or a professional driving evaluation should be considered.

This guideline paper provides a patient and and a family/caregiver questionnaire that is helpful in assessing the at-risk driver. Other scales are also included.

William Yates is a family physician who blogs at Brain Posts.

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  • Steffan Lozinak

    This is an amazing article and gave me a good topic to blog about for today, thank you so much!!

  • Bill

    I am glad you enjoyed the post. I thought these guidelines were very helpful and important for those caring for geriatric populations.

  • soaringcanary

    Dr Yates, Thank you for this illuminating article. From a real-life perspective; “if only” the medical determination were more finite or less difficult to ascertain whether a person with ANY degree of dementia should continue to drive. With a [then 92] female family member who suffered a Stress-induced Cardiomyopathy event that almost killed her in 2008, the mini-status exam was conducted by her MD four months later and did prompt a Mandatory Referral to the DMV for her to stop driving. Unfortunately, after this willful [and cognitively compromised] woman fired not only the MD but me as the primary family advocate back then, it took her three months to prepare for and then successfully take a computerized [??] DMV test which negated the MD’s decision and since August 2009, she has been back on the road…while she is now 93 and by lunch, cannot tell you what happened at breakfast. Even at this age, the brain is so mysteriously astounding since she does have accurate long term recall, but this is not at all the same with the in-moment or new information since there is little to no functional ability to store short term memories…or, for that matter, the appropriate cognition processes, like with understanding, problem solving, and judgment. With such adverse combination of low blood sugar, deficiency of estrogen, and the grossly elevated stress hormones [adrenaline/cortisol/cathecholamines/epinephrine] during that event, I was the spontaneous stepdaughter/caregiver who, over a five week recovery, lived with her and did witness a worsening of short term memory soon after this brain injury. But while there have been no crashes, and a few scrapes/close calls as are evidenced by her vehicle…this lack of in-time memory status has NOT been enough for the DMV to deny her of her desire to continue driving [of course, for autonomy]…so as to ‘proactively protect the public [and her] BEFORE there is a crisis. Needless to say, over the last 18 months, her memory has continued to deteriorate and for family members, it is frustrating that she was allowed by an agency [and a new MD who by distraction defers to them] to continue driving after what I saw on a day to day basis was a biochemically-altering illness…which means I believe that every time she is behind the wheel in that car, it is unpredictably dangerous. Personally, I think an age cap, like 90, needs to be imposed by law to prohibit people who can’t make their own best decisions about driving…so as to better protect the unsuspecting citizenry. In our case, there is so much being left to chance or with a literal threatening of life by irresponsible default, not because of what the family tried to do [as she vehemently resists], but rather, via both an agency and the MD which, together, by their very mission statement and oath are supposed to be providing the adequate determination and oversight, not only for the individual, but also the common good.

  • Bill

    Soaringcanary presents a very interesting case. It raises the interesting issue of medical versus DMV assessment of safety to drive. One problem with dementia is not only the cognitive issue of impaired driving but the potential for lack of recognition of one’s deficit. Anosognosia can blind one from the ability to understand the extent of one’s deficits. I wonder if in the case presented above if the impairment is severe enough to consider a competency evaluation. If the patient is declared incompetent, the family or court-appointed guardian could remove access to the vehicle.

  • Jim Purdy

    Dementia is not the only reason to quit driving. I gave up driving several years ago when my diabetic neuropathy in my feet made it difficult to distinguish between the gas pedal and the brake.

    • Bill

      This is a good comment that adds something important to my post. There are many medical reasons to quit driving. Visual problems might be the most frequent and visual screening is incorporated in most states prior to license renewal. Many are like Jim and recognize when their ability to drive safely is medically compromised.

  • Robert Louis-Ferdinand

    Dr Yates. Thank you, a good article and it helps rate when people should not drive. I do see a lot of families going 1/2 way leaving keys around. This usually ends badly even if the license has been taken away. The keys need to be removed for the equation.

    I think a follow up should be how to handle it after the decision is made. We see this causes a lot of depression and confusion with our clients. I have heard ‘Just another thing they are taking away…” and “I don’t get it, I have a perfect driving record”. For some of our clients this is what causes them to be more home bound and if there is not an appropriate avenue to get them transportation will cause more issues. We try to schedule caregivers around busy times, and increase activities during this period.

    • Bill

      Thanks for your comment on an important issue. In the best case scenario, removing driving privileges is paired with substitution of another method of transportation. When we took away my mother’s car at 92, a friend took her for groceries once a week. Family members rotated taking her to church every Sunday. These were the only two places she was driving and tempered the loss of independence with giving up the keys.

  • Marie

    My 78 year old father, who is a dear and caring man, someone who would never deliberately hurt a fly, is a danger behind the wheel.

    My sister has POA and has verbally and in writing begged FOUR different physicians to please intervene and not one has. My dad puts on a charming front that hides his growing dementia well, so they still address all decisions and questions to him and ignore my sister, sitting right next to him! She will corner the doctor in the hall and say, didn’t you read my letter, don’t you know he is suffering from dementia? They all admit they hadn’t even read her letter, which they acknowledge was in the chart.

    I have advised her to keep trying to find a new doctor, but my father refuses to change, as the change to him is inexplicable. We all urge him not to drive, offer to drive him places ourselves, tell him we worry about him and others, but he does not believe he has any deficits. In the suburban area where he lives there is no public transport for the local trips you need to make the most often.

    Doctors are human and dislike confrontation as much as many. Until laws are changed, families will be in these untenable situations. And unless there is an emphasis placed on providing practical public transportation, these people will desperately cling to their car keys.

    • Bill Yates

      Marie: It looks like you have made a good effort to try to address your father’s driving issue. It can be frustrating. One other option would be to file a letter of concern directly with the Department of Motor Vehicles. It may not make any difference, but at least you have done all that you could.

      • Marie

        Thanks Dr. Yates. I will bring this up with my sister. But what a terrible betrayal it feels like. As though it is not a betrayal to unsuspecting people on the road.

        Old age sure isn’t for sissies (Bette Davis?). Neither is watching a loved one struggle with it.

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