John Williamson: The dementia driving test

There are several tests senior drivers need to do ensure they are fit to drive, including a dementia test. Photo / 123rf

OPINION

One of the curious things about writing a column like this is that you never really know who reads it and what they take from it. It is particularly gratifying when someone raises a point sufficient to have a discussion about a particular column.

I am a member of a bowling club that has its club day on the day this column is published. That means some members, who are early readers, have a ready-made greeting when I pay my match fee. Most club day players are of pensionable age and, as my previous column was about senior drivers, there was a veritable chorus from those wanting to tell me about their experiences.

One bowler gave a comment saying, ”I read your column, but you left out the dementia test when you get to 80.″ Another told me about a family member who had failed that so-called test, but who booked himself in for an on-road test, which he subsequently passed. That was much to his delight, and the chagrin of his more sceptical family members.

The test referred to is about cognitive ability, which is not specifically limited to a particular age, and which is pretty much left to the doctor’s judgment and family members’ suggestions. Family members may raise concerns if their loved one is showing increased confusion, loss of memory, social withdrawal, or decreased ability and motivation to complete usual activities. These may indicate early signs of dementia and raise questions about whether the person is safe to drive. Don’t expect, though, that the driver concerned will be particularly co-operative in that discussion.

Every two years after age 80, you need to pass a medical test in order to renew your driver’s licence. The doctor holds the whip hand and uses their judgment about your age, or how you come across to them, as well as family member feedback, in deciding to conduct a cognitive test, regarding your fitness to drive.

I was with my 92-year-old father when he went through this process about 15 years ago. I was astounded that he had to: remember a name he had never been confronted with and repeat it back five minutes later; recite the months of the year backwards; repeat back a list of 10 words; convert a series of numbers into letters (eg 5 = five); in a minute, name as many things as possible you can buy in a supermarket; and then repeat back the name he had been told five minutes earlier.

I was thankful that it wasn’t me who was being tested.

This is a traumatic experience to put any senior driver through, particularly with the pressure and anxiety of potentially losing the independence afforded by their driver’s licence. This particular test is called the SIMARD MD test, and is one of several such tests designed to screen cognitively-impaired, medically at-risk drivers.

You might wonder what all that has to do with the ability to drive.

Therein lies a conundrum. Many of these tests are poor predictors of our on-road driving, and that is why an on-road test must be part of any ceasing-to-drive decision. In fact, a study reported in the New Zealand Medical Journal in 2020 tested the ability of cognitive screening, to predict on-road driving performance in 34 drivers who had been diagnosed with dementia. Only six (17.5 per cent) of these drivers failed the on-road assessment, while 19 (56 per cent) retained their full driving privileges.

This was a small study that warrants further research, but what it really means is that the doctor should not be the sole arbiter, with only a paper-based desk assessment, in determining fitness to drive.

Driving is learned behaviour developed over 60-odd years of driving. The driving brain does not necessarily cease to function just because you can’t remember a name you were told five minutes earlier.

Any cognitive test should be complemented by an on-road assessment, before we are forced to give up the independence and pleasure we enjoy through driving.