Medical aspects of fitness to drive a guide for medical practitioners

Introduction
Neurological conditions or suspected neurological conditions are a major cause of
medical‐related crashes in New Zealand. From police crash reports, between 2003 and
2007, 533 crashes involved a driver who either had an epileptic seizure (116 crashes)
or blacked out (417 crashes). Another 10 crashes were suspected of being caused by
a driver who had or was suspected of having a neurological condition. These figures
do not estimate the likely numbers of drivers with neurological conditions such as
dementia, as these are often reported as an age‐related factor. There are likely to be
drivers who had a neurological condition that the Police were not aware of.
Driving a motor vehicle requires the ability to perform precise, complex actions
in response to an environment that is continually changing. Any disease process
or substance (such as a medicine or recreational drug) that affects perception,
judgement, alertness and responsiveness or the ability to carry out the necessary
actions required to control a vehicle will impair an individual’s fitness to drive.
Individuals with progressive conditions are likely to pose a greater risk unless the
condition is closely monitored in relation to the ability to drive a vehicle safely. Static
conditions and those that are reversible generally pose less of a problem, and mobility
may often be an important consideration for such individuals. The issue in these cases
is simply one of an individual’s ability to drive safely. In these circumstances, the
testing officer may well be a better arbiter of fitness to drive.
2.1
Severe disabling giddiness, vertigo or
Meniére’s disease
Meniére’s disease, labyrinthine disorders and brain stem conditions may induce
significant distracting giddiness. Where the attacks of giddiness are sufficiently
disabling that they may impair an individual’s ability to drive safely, the individual
should be advised not to drive until their condition has been sufficiently treated.
Vertigo occurs for many reasons, most of which are due to inner ear disturbances.
The most common form of paroxysmal relatively disabling vertigo is benign
paroxysmal positional vertigo, which can occur in relation to head movement.
Some individuals may feel sufficiently disabled by their vertigo that they should not
drive, while others who have attacks are able to pull over to the side of the road.
There is no general prohibition on driving with vertigo except where the attacks of
vertigo are sudden, or unpredictable, and are sufficiently disabling that they may
impair an individual’s ability to drive safely, eg where an individual is unable to
concentrate on driving because of disabling giddiness.
General advice to medical practitioners
Where an individual is subject to attacks of disabling giddiness, medical practitioners
should discuss with their patients the potential seriousness of their attacks on their
driving. For example, individuals who suffer attacks where there are some warning
signs should be advised to pull over to the side of the road if this is safe to do so, rather
than try to continue driving during the attack.
Medical standards for all licence classes and/or endorsement types
Where the attacks of giddiness or vertigo are sufficiently disabling that they may
impair an individual’s ability to drive safely, the individual should be advised not to
drive until it has been sufficiently treated.
18 2. Neurological and related disorders | Medical aspects of fitness to drive | NZTA July 2009
July 2009 NZTA | Medical aspects of fitness to drive | 2. Neurological and related disorders 19