This can be confusing as there is some controversy over which screens to use for cognitive abilities related to driving. There is no paper/pencil screening tool that will tell you definitively if your patient's cognitive abilities are impaired. And no screen should be used alone to make driver fitness determinations.
A screening tool or tools should be used to provide you with some objective information on whether your patient potentially has an impairment of the cognitive abilities related to driving. This can help you determine if further testing is needed e.g. an in-clinic or on-road functional assessment of cognitive abilities related to driving.
It is important that no single screening tool be used to make driver fitness determinations. As with any screen, they should be used, along with other information to identify those who would benefit from further testing or investigations. Most commonly used screens are impacted by education and language and therefor have false positives and false negatives that need to be considered.
Following are commonly used screening tools related to cognitive abilities:
Currently, the SIMARD-MD is the only validated screening tool specific to the cognitive abilities related to driving. There is some controversy related to it's use as since it's release, there have been some studies that question it's validity based on the methodology used. However, the quality and motivation of some of these studies have also been questioned. The bottom line is, if you use it as a screen and not to make driver fitness determinations, it can provide you with some objective information to help determine if further investigation is needed.
The Montreal Cognitive Assessment is not validated specifically for driving. A MoCA score within the range of normal does not rule out impairment of the cognitive abilities related to driving. However, if your patient has a MoCA score outside the range of normal it is an indicator for you to consider their ability to drive safely. As with other screens, it should not be used in isolation to determine driver fitness.
The Mini-Mental Status Exam has been the main cognitive screen for a long time to identify moderate cognitive impairment. Because it is not sensitive enough to mild impairments where driving can be impacted, it's correlation to driving is poor. However, that does not make it useless - if you are conducting an MMSE for other reasons and have a patient who scores outside the range of normal, driving safety should be questioned.
Trail Making Test A & B
Studies related to the reliability of these tests for driver fitness is somewhat mixed. However most agree that the correlation with driving is not strong and their use is better with healthy patients vs patients with known cognitive impairment. And as with other tools, they can be a useful tool to augment other information but not on it's own.
The Clock Drawing Test has shown some correlation with ability to drive safely. It actually requires a high level of brain functioning to draw a clock. Errors can show impairment with visual perception and short term memory which are both important to driving. As with all the screens, it should not be used in isolation but can be an indicator that more investigation is warranted.