Neuroscientist criticises cognitive tests given to senior drivers, ‘outrageous’ doctors use them

By David Williams

NZ Herald·

20 Mar, 2024 12:27 AM3 mins to read

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A neuroscientist claims a cognitive test given to senior motorists to assess their fitness to drive is discredited, unreliable, and may put people behind the wheel who are not fit to drive.

Dr Kerry Spackman said the SIMARD MD test (Screen for the Identification of Cognitively Impaired Medically At-Risk Drivers, a Modification of the DemTect) did not test the cognitive skills required to drive safely such as motor control, perception skills, and reaction times.

It instead tests things such as word memory, number conversion and verbal fluency.

Spackman said these relate to general cognitive ability, not driving.

“It would be a bit like giving someone a music test to see if they are good at playing tennis.”

Cognitive neuroscientist Dr Kerry Spackman said a cognitive test is useful, but shouldn’t be the basis for deciding whether someone should drive or not.

He cited a Canadian study that found SIMARD MD could allow dangerous drivers to pass a test but rule out competent drivers who were fit to drive.

“The particular test referred to has been completely discredited by the US National Institute of Health as being totally unreliable,” he said.

“It is outrageous that NZ doctors are using a discredited test.”

Drivers must get a medical certificate to renew their licence at the ages of 75 and 80 and then every two years after that.

Bay of Plenty driver Eddie Bruce, 80, was asked to do a cognitive assessment at Katikati Medical Centre in January when he renewed his driver’s licence.

He failed both the initial SIMARD MD test and a follow-up Mini ACE (Mini-Addenbrooke’s Cognitive Examination) - a test that evaluates orientation, memory, language and visuospatial function, resulting in a one-year licence validity, instead of two.

Bruce and his wife Mavis rely on him to drive for all their needs. Mavis can no longer drive because she has an issue with her eyes.

“Not to sound like sour grapes, but at our stage of life what are we supposed to do, get people to come and pick us up each time? When realistically, I don’t believe my driving is impaired at all.”

Bruce said an on-the-road driving test would be preferable and should be the final word on whether people get their certificate, not a memory test.

David Speirs, the NZ Transport Agency Waka Kotahi director of regional relationships Bay of Plenty/Waikato, said it was up to individual medical centres how they managed the process. They relied on medical professionals to assess whether an individual was medically fit to drive.

Speirs said a low cognitive score was one of many reasons a doctor requested a driving test.

“A low cognitive score does not necessarily mean a person is unsafe to drive.

“If an occupational therapy driving assessment or on-road safety test is completed to a satisfactory standard, a licence is usually renewed.’’

Spackman said a cognitive test was useful, but shouldn’t be the basis for deciding whether someone should drive or not.

“Driving is not about mathematics or verbal reasoning. If you want to use a cognitive test, there would be better things to do such as visual processing, reaction times, motor control, and divided task attention,” he said.

“If someone fails that test, I wouldn’t say that is a definitive answer whether they should be road driving.

“You could imagine a where someone is good at verbal reasoning or memory for mass numbers and manipulation, but has very poor circuits for motor control.”