Please be advised to check with your countries’ driving licence authorities for directive on driving following a Stroke and fitness to drive, since many countries have different guidelines.  

For example, in the UK you would refer to the Driver and Vehicle Licensing Agency (DVLA) guide ‘Assessing fitness to Drive’, a guide for medical professionals (1).

A stroke happens when the blood supply to part of the brain is cut off. This can be caused by either:

1.A blood clot, causing an ischaemic stroke.  This is the most common type of stroke, accounting for 85% of all strokes

OR

2.A weakened blood vessels bleeding into the brain, a haemorrhagic stroke.

If an individual experiences symptoms of stroke that self resolve within 24 hours of starting this is called a transient ischaemic attack (T.I.A.) or mini stroke.  Practitioners should always check with their relevant licensing authority how a T.I.A. or Stroke is defined in their country. 

Clinical Features

3.Changes in Muscle Tone

Muscle tone can be increased or decreased after a stroke.

If muscle tone is increased it causes Spasticity (muscle tightness) resulting in difficulty moving or Clonus (muscle spasm with repetitive uncontrollable movements).

If muscle tone is reduced, muscles appear floppy, called Flaccidity, which again reduces the persons ability to control their limb movements.

If there is a significant increase or decrease in the muscle tone of limbs then the ability to control the vehicle consistently must be considered, and as per the impact of hemiplegia alternative controls maybe needed.

If muscle tone is reduced in the muscles of the trunk, then seating position within the vehicle will also need to be considered to allow consistent access to the chosen vehicle controls.

4.Co-ordination Impairments

Co-ordination difficulties occur when the deep structures of the brain including the brainstem and cerebellum are damaged by the stroke.  

Seizure Risk 

• Having a stroke increases the risk of having a seizure which in turn creates driving licence issues that must be considered in the context of local legal frameworks.
• the risk of seizure after a stroke is greatest in the first day and continues for the first 12 months post stroke
• the risk for any individual is difficult to estimate with approximately 10% of all stoke patients experiencing one or more seizures, but the risk is biggest for those with the greatest impairments
• seizures can be partial or generalised and rarely (<2%) linked to epilepsy (7)
• in most countries seizures are notifiable to licensing agencies and result in fixed periods unlicensed.

Spasticity

• the increased muscle tone (spasticity) that can affect upper and lower limbs can prevent the use of standard vehicle controls or make using them effectively very difficult
• medication (e.g. Baclofen, Tizanidine) used to control spasticity can increase risk of seizures.

Relative inactivity causing Disuse Atrophy/Limb Contractures:

• people tend to favour use of non stroke limbs and over time the less used limbs become weaker and contractures (permanent tightening of tissues resulting in joint becoming immobile develop)
• if this is identified then change of vehicle control may be necessary, including less commonly used adaptations such as lightened steering.

Recent research reveals fairly consistent patterns in stroke outcomes. For instance:   

• in Scotland in 2019/20 84.9% of people admitted to hospital with their first stroke survived more than 30 days
• one in seven people with acute stroke died in hospital (RCP 2016)
• the risk of recurrent stroke within 90 days of a first stroke is around 5% (4) 
• longer term risk of recurrent stroke in those that survive their first stroke is
  • 11% in first year
  • 26% at 5 years
  • 39% at 10 years (5)
• disability is very common after stroke, at 90 days 10% of stroke patients under 65 years and 30% of stroke patients over 65 years are classified as moderate severity disability or above. At 6 months post stroke 40% of people still have difficulties with activities of daily living. (6)
  • the rate of functional improvement is specific to the individual. However, generally the lower limb function improves more quickly, and to a better level than upper limb function
  • the majority of functional recovery occurs most rapidly in the first 6 month after a stroke, with further improvements possible at a slower rate after this. If there are significant impairments at 1 year that prevent safe driving it is less likely that this will change positively in the future. 

1. Atrial fibrillation (AF) – increases the risk of further stroke, but rarely has symptoms and does not impact directly on driving task.
2. Hypertension – high blood pressure increases the risk of having a stroke by up to 4 times, but rarely impacts directly on the driving task.
   -Treatment of hypertension may lead to symptoms such as postural dizziness which should not be confused with dizziness that may impact on safe driving.  A clear history of the position that symptoms occur allows the assessor to decide this. 
3. Previous Strokes – multiple strokes tend to increase the overall impairments in patients. Careful assessment of physical and cognitive function is needed to identify how, and if, safe driving can be achieved.
4. Diabetes – diabetes increases the risk of stroke by 1.5 times, and approximately one third of people who have stokes also have diabetes.  Licensing rules in relation to diabetes must be considered, along with potential complications of diabetes that may also impact on the driving task e.g. reduction in visual acuity, peripheral neuropathy causing difficulties with proprioception etc (8)

Strokes usually result in physical symptoms affecting one side of the body, possibly causing:

• weakness
• increased muscle tone (spasticity) or reduced muscle tone (flaccidity)
• muscle atrophy from disuse+/- limb contractures
• reduced co-ordination
• sensation loss
• proprioception loss.

When assessing a potential driver after a stroke the physical examination should include:

• limb power
• muscle tone 
• sensation including proprioception.

This examination enables the assessor to determine the most effective control mechanisms to physically control the vehicle.

The physical control method recommended must reflect the physical capability of the person and also consider any cognitive impairments that may prevent/reduce new learning or adaptation to new control methods. If cognitive impairments are identified, then the assessor must be very cautious in recommending changes of control methods.

The most common recommendations when assessing for physical control of the car for people post stroke with physical weakness should include tests for:

• automatic transmission +/- steering wheel spinner +/- secondary control + for patients with right hemiparesis may need the addition of a left foot accelerator.

NB. The above may be altered to be relevant to your own countries on road driving position and car manufacturer.

A stroke can lead to a variety of visual changes that may prevent driving due to licensing issues.  It is essential to check local driving legislation before undertaking any on road assessment.

For all visual conditions, please always refer to an Ophthalmologist or other qualified expert.

Visual Impairments

As a stroke can cause damage to any part of the brain, it can impact on the complex working of the brain, so it is likely that people who have had a stroke will have cognitive changes. Please refer to a suitable expert for these cases: Further Reading

Post stroke physical impairments may lead to a requirement to review how the individual can:

• enter or exit a specific vehicle
• sit within a vehicle
• carrying walking aids including wheelchairs, or drive from wheelchair solutions
• control the vehicle. 

To control a manual geared vehicle, it usually requires all four limbs to be functional. If any limbs have reduced function e.g. hemiplegia, weakness, reduced proprioception, reduced coordination etc after a stroke then an automatic geared car allows for opportunities to consider modifications to control of accelerator, brake, steering and secondary controls to allow an individual to successfully control the vehicle.

The potential for cognitive impairment after a stroke may also impact on physical control of the car, as the individual cannot safely manage the competing cognitive tasks of attention to the road situation and control gear selection due to difficulties with divided attention or slowed cognitive processing. In these situations, trialling an automatic geared car can help to determine if reducing cognitive workload would help an individual to control a vehicle safely.

Vehicle and Adaptations

Driving automatic due to cognitive impairment

Adjusting to the combination of physical and cognitive impairments after stroke can be challenging and so the timing of a fitness to drive assessment can be crucial. Professionals involved in the fitness to drive assessment process need to balance somewhat competing aims of enabling a return to driving as soon as it is safe to do so, while recognising that ongoing recovery to reach that safe level, may take many months to complete. This includes the individuals insight into their impairments and therefore, their ability to make adjustments to their control methods and driving style.

The incidence of post stroke fatigue should not be underestimated with some studies suggesting >50% of people who have experienced stroke reporting ongoing fatigue. Timing of assessment, and potential to offer breaks should be considered.

If any changes to physical control, in a vehicle are indicated to support safe driving post stroke, then this must be advised to the relevant licensing authority for suitable licence coding to be implemented.