6.3.1 General assessment and management guidelines
The person with a neurological condition should be examined to determine the impact on the functions required for safe driving as listed below. If the health professional is concerned about a person’s ability to drive safely, the person may be referred for a driver assessment or for appropriate allied health assessment (Box 3) (refer also to Appendix 10: Specialist driver assessors).
Box 3: Checklist for neurological disorders
If the answer is YES to any of the following questions, the person may be unfit to drive and warrants further assessment.
Some neurological conditions are progressive, while others are static. In the case of static conditions in those who are fit to drive, the requirement for periodic review may be waived.
Aneurysms (unruptured intracranial aneurysms) and other vascular malformations
The risk of sudden severe haemorrhage from most unruptured intracranial aneurysms and vascular malformations is sufficiently low to allow unrestricted driving for private vehicle drivers. However, the person should not drive if they are at high risk of sudden symptomatic haemorrhage (e.g. giant (greater than 15 mm) aneurysms). Cavernomas frequently produce small asymptomatic haemorrhages that do not impair driving ability. However, if they produce a neurological deficit, the person should be assessed to determine if any of the functions listed above are impaired. Commercial vehicle drivers should be individually assessed for suitability for a conditional licence.
If treated surgically, the advice regarding intracranial surgery applies (refer below). If the person has had a seizure, the seizures and epilepsy standards also apply (refer to section 6.2 Seizures and epilepsy).
Cerebral palsy may impair driving ability because of difficulty with motor control or if it is associated with intellectual impairment. A practical driver assessment may be required (refer to Part A section 2.3.1 Practical driver assessments). As the disorder is usually static, periodic review is not normally required.
A head injury will only affect driver licensing if it results in chronic impairment or seizures. However, any person who has had a traumatic injury causing loss of consciousness should not drive for a minimum of 24 hours, and the effects on functions listed above should be monitored. This is advisory and not a licensing matter.
Minor head injuries involving a loss of consciousness of less than one minute with no complications do not usually result in any long-term impairment. Similarly, immediate seizures that occur within 24 hours of a head injury are not considered to be epilepsy but part of the acute process (refer to Acute symptomatic seizures).
More significant head injuries may impair any of the neurological functions listed in the checklist above and can impair long-term driving ability. There may be focal neurological injury affecting motor or sensory tracts as well as the cranial nerves. Also personality or behavioural changes may affect judgement and tolerance and be associated with a psychiatric disorder such as depression or post-traumatic stress disorder (PTSD). Clinical, neuropsychological or practical driver assessments may be helpful in determining fitness to drive (refer to Part A section 2.3.1 Practical driver assessments). Comorbidities such as drug or alcohol misuse and musculoskeletal injuries may also need to be considered (refer to section 9 Substance misuse (including alcohol, illicit drugs and prescription drug misuse) and section 5 Musculoskeletal conditions).
Neurological recovery from a traumatic brain injury may occur over a long period, and some people who are initially unfit may recover sufficiently over many months such that driving can eventually be resumed.
Risk of post-traumatic epilepsy (PTE): Persons with depressed skull fractures, traumatic intracranial haematoma or severe traumatic brain injury are at increased risk of epilepsy, especially in the first year. Commercial drivers therefore should not drive for 12 months after the injury and require a conditional licence. Private driving may continue, provided the person otherwise meets the standard to drive (refer to table – Head Injury). If one or more seizures have occurred, the symptomatic seizures standard applies. PTE should be distinguished from immediate post-traumatic (acute symptomatic) seizures occurring within 24 hours of a head injury, which are considered part of the acute process (refer to Acute symptomatic seizures).
Intracranial surgery (advisory only; non-driving periods may be varied by the neurosurgeon)
Non-driving periods are advised to allow for the risk of seizures occurring after certain types of intracranial surgery. Following supratentorial surgery or surgery requiring retraction of the cerebral hemispheres, the person generally should not drive a private vehicle for six months and a commercial vehicle for 12 months. Notification to the driver licensing authority is not required. There is no specific restriction after infratentorial or trans-sphenoidal surgery.
If one or more seizures occur, the standards for seizures and epilepsy apply (refer to section 6.2 Seizures and epilepsy. and the driver should notify the driver licensing authority. Similarly, if there is long-term impairment of any of the functions listed in Box 3, fitness to drive will need to be assessed (refer to section 6.3 Other neurological and neurodevelopmental conditions).
Ménière’s disease may be accompanied by acute vertigo, which can affect driving. However, attacks are usually accompanied by a prodrome of fullness in the ear, which gives sufficient warning to cease driving. Drivers, particularly commercial vehicle drivers, warrant individual assessment by an ENT specialist regarding their ability to respond in a timely manner to an attack. Such commercial drivers need also to meet the hearing standard (refer to section 4 Hearing loss and deafness).
Multiple sclerosis may produce a wide range of neurological deficits that may be temporary or permanent. Possible deficits that may impair safe driving include all of those listed in Box 3. Vehicle modifications may be made to assist with some of these impairments; the advice of an occupational therapist may be helpful in this regard (refer to Part A section 2.3.1 Practical driver assessments).
Neuromuscular disorders include diseases of the peripheral nerves, muscles or neuromuscular junction. Peripheral neuropathy may impair driving due to difficulties with sensation (particularly proprioception) or from severe weakness. Disorders of the muscles or neuromuscular junction may also interfere with the ability to control a vehicle. A practical driver assessment may be required (refer to Part A section 2.3.1 Practical driver assessments).
Parkinson’s disease is a common, progressive disease that may affect driving in advanced stages2 due to its motor manifestations (bradykinesia and rigidity) or cognitive impairments (deficits in executive function and memory and visuospatial difficulties).3 There may also be disturbances of sleep, with episodes of sleepiness when driving. When assessing the response to treatment, the response over the whole dose cycle should be taken into account (e.g. in patients with motor fluctuations, it would not be appropriate to assesses fitness to drive only on the basis of the best ‘on’ response). Most patients with severe fluctuations will be unfit to drive. A practical driver assessment may be required (refer to Part A section 2.3.1 Practical driver assessments).
Stroke (cerebral infarction or intracerebral haemorrhage)
Stroke may impair driving ability either because of the long-term neurological deficit it produces or because of risk of a recurrent stroke or transient ischaemic attack (TIA) at the wheel of a vehicle (refer below).
Stroke and TIA rarely produce loss of consciousness; it is very uncommon for undiagnosed strokes or TIA to result in motor vehicle crashes. When they do, it is usually due to an unrecognised visual field deficit.
The risk of recurrent stroke is probably highest in the first month after the initial stroke but is still sufficiently low (about 10 per cent in the first year) that it does not on its own require suspension of driving. However, fatigue and impairments in concentration and attention are common after stroke (even in those with no persisting neurological deficits) and may impair the ability to perform the driving task, particularly for commercial vehicle drivers. For this reason, there should be a non-driving period after stroke (four weeks for private drivers and three months for commercial drivers), even in those with no detectable persisting neurological deficit.
For those with a persistent neurological deficit, subsequent driving fitness will depend on the extent of impairment of the functions listed in Box 3. A practical driver assessment may be required (refer to Part A section 2.3.1 Practical driver assessments). While many people with mild stroke are independent in many activities of daily living, they may have ongoing aphasia (comprehension of written and spoken language) which may impact on fitness to drive. The vision standard may also apply (refer to section 10 Vision and eye disorders). If the person has had a seizure, the seizures and epilepsy standards also apply (refer to section 6.2 Seizures and epilepsy).
Private vehicle drivers who have made a full neurological recovery do not require a conditional licence. Patients should be encouraged to comply with stroke prevention therapy.
Treatable causes of stroke, such as high blood pressure, atrial fibrillation or carotid stenosis, should be managed with reference to this standard.
Transient ischaemic attack (TIA) (advisory)
TIAs can be single or recurrent and may be followed by stroke. They may impair driving ability if they occur at the wheel of a motor vehicle. However, as a TIA rarely produces loss of consciousness, it is an extremely uncommon cause of crashes. The risk of a further TIA or stroke is about 15 per cent in the first three months and about half of that risk occurs in the first week. In view of the low risk of TIA or stroke affecting driving, private vehicle drivers should not drive for two weeks, and commercial vehicle drivers should not drive for four weeks after a TIA. A conditional licence is not required because there is no long-term impairment (refer to Part A section 2.2.3 Temporary conditions).
Driving should be restricted if the person has had a subarachnoid haemorrhage. A conditional licence may be considered after a minimum three-month non-driving period for private vehicle drivers and after at least six months for commercial vehicle drivers, taking into account the presence of neurological disabilities as described in Box 3. The vision standard may also apply (refer to section 10 Vision and eye disorders). If the person has had one or more seizures, the seizures and epilepsy standards also apply (refer to section 6.2 Seizures and epilepsy). If a craniotomy has been performed, the advice for intracranial surgery also applies. A practical driver assessment may be considered (refer to Part A section 2.3.1 Practical driver assessments).
Space-occupying lesions including brain tumours
Brain tumours and other space-occupying lesions (e.g. abscesses, chronic subdural haematomas, cysticercosis) may cause diverse effects depending on their location and type. They may impair any of the neurological functions listed in Box 3. If the person has had one or more seizures, the seizures and epilepsy standards also apply (refer to section 6.2 Seizures and epilepsy). If a craniotomy has been performed, the advice regarding intracranial surgery also applies.
Other neurological conditions including developmental and intellectual disability
The impact of other neurological conditions including developmental and intellectual disability should be assessed individually. A practical driver assessment may be required. If the degree of impairment is static, periodic review is not usually required.