Neurological disorders can compromise a person’s driving fitness. However, the complexity of these disorders – and the subjective nature of evaluations – can make determining driving fitness difficult.

Patients with degenerative neurological disorders rarely have enough insight into their own visual, cognitive, or motor functions to self-determine their driving fitness levels.

In clear or extreme cases of bad health, assessments are black and white.

But trying to assess the driving ability of patients in the middle of the spectrum (and determining when they should stop driving altogether) is very much a gray area. It can leave patients, family members, and physicians confused and frustrated.

Who determines when a patient is unfit to drive if the patient can’t – or isn’t willing to – make the determination for himself or herself?

Clinicians lack the formal training, equipment, and objective tests needed to assess the driving fitness of patients. Yet, the final determination often falls on their shoulders.

Proper assessment equipment can help clinicians bear the weight of that responsibility.

Neuropsychiatric tests, visual acuity exams, virtual driving simulators, and on-road assessments can all be used to help develop an objective, standardized assessment of driving fitness in patients suffering neurological conditions.

A diagnosis alone cannot determine fitness. Each neurological condition presents its own set of complexities, including severity, location of injury, and individual patient history.

An article published by Clinical Medicine and Research, “Neurologic Conditions: Assessing Medical Fitness to Drive” reviewed the key components of neurological conditions that affect driving ability. Those conditions included stroke, traumatic brain injury, peripheral neuropathy, dementia, dyspraxia, Parkinson’s disease, and epilepsy.

The goal of the article was to help practicing physicians evaluate their patients for driving safety and automobile licensure.

Risk assessment

Driving is a complex task. Drivers must have adequate operational, cognitive, and higher executive functions.

Safe driving requires:

• Adequate motor strength
• Speed and coordination
• Concentration
• Attention
• Adequate visual perceptual skills
• Insight and memory
• Strategic and risk taking behavioral skills, including the ability to process multiple simultaneous environmental cues in order to make rapid, accurate, and safe decisions.

For patients, returning to driving means a return to independence and normal activities of daily living. This can be especially true for those who had full driving ability before the onset of a neurological condition.

The decision to recommend revocation of driving privileges after stroke, traumatic brain injury, or seizure is important.

“Risk assessment is the ability to assess if a patient is able to control a motor vehicle at all times,” the article stated. “To drive with a crash risk comparable to that of the healthy general population.”

The article highlighted three needs for this type of assessment to occur:

1. Information about the functional capability of the driver in addition to the medical diagnosis (or diagnoses).
2. Knowledge of the minimum functional requirements for safe driving.
3. Knowledge and ability to correlate the assessment of the driver’s functional level with his or her risk of crashes as a driver.

Primary and subspecialty physicians often lack knowledge and formal training to make a recommendation to licensing agencies on driving fitness.

Cognitive, visual, motor, and higher cortical functions, which are required for safe driving, can all be negatively affected by neurological conditions.

A subjective, standard assessment is not available due to the complexity of both driving and neurological conditions.

The article used the example of blood alcohol concentration and calculations to determine a person’s ability to safely operate a motor vehicle:

“Federal and state governments have set blood alcohol concentration levels that determine drunkenness. A comparable method to establish acceptable risk in most neurological disorders does not exist.”

A driver’s experience behind the wheel, familiarity with the road, road conditions, and driving environment can impact ability assessments. Final assessments may also be swayed by the subjective opinion or observations of the physician.

No single measurement tool can best predict driving performance. Thus, accurately measuring and predicting driving performance requires a combination of neuropsychiatric, visual, virtual simulation, and on-road assessments.

Assessment pros and cons

Neuropsychologic tests can serve as an objective means of measuring higher cognitive and perceptual abilities. Research indicates that several neuropsychologic measures are useful in identifying patients that would pose a risk behind the wheel.

Even if physicians are careful to select the most relevant tests to assess driving fitness, standardized tests are not considered fully reliable predictors of risk for traffic collisions or violations.

On-road assessments are often considered the gold standard for determining driving fitness, but are limited in their ability to detect and document subtle deficiencies in psychological and psychomotor skills. There are also inherent safety risks of on-road assessments.

Virtual driving simulators may be useful for screening functional ability before on-road assessments are utilized to determine final driving fitness. Virtual driving simulators can:

• Keep patients from being on the road, even in a controlled assessment
• Help patients feel more confident about driving
• Identify key areas where patients need additional training to improve driving fitness
• Begin the patient assessment process in a safe and comfortable environment

Diagnosis of neurological conditions (e.g., stroke, TBI, epilepsy) is not a clear indication of driving ability.

Degenerative conditions (e.g., dementia and Parkinson’s disease) will eventually lead to revocation of a driver’s license simply due to the progressive nature of the disease. But it’s difficult to determine when that should occur. This results in many patients continuing to drive beyond when they safely should.

It can also be difficult to distinguish Alzheimer’s disease from normal age-related decline in cognitive functioning.

“Therefore, early in the disease course when insight remains intact, it may be possible to set certain driving parameters or limit their driving distance in order to maintain driving privileges,” according to the article. “In the early stages of mild cognitive impairment, neuropsychiatric testing may be useful in determining those specific deficits that may affect the ability to drive safely, particularly the more subtle aspects of cognitive function. These tests are poor predictors of future risk for crashes or violations.”

While physicians are commonly required to make a recommendation about whether a patient is fit to drive, most lack objective screening tools and adequate training.

Driving fitness is determined through an examination documenting the presence and degree of impairment in core functions necessary for safe driving.

“…neuropsychological and off-road testing should be utilized by physicians to make valid decisions as to whether to refer patients to the appropriate legal authority for on-the-road fitness-to-drive evaluation,” according to the article.

DriveSafety certified trainers help clinicians start the assessment process with virtual driving simulators. Schedule a call to find out which clinical simulator can best support patients with neurological conditions.

Read what others have to say

“After having the simulator in our office for the past year and a half, I can honestly say I wish I’d had the product 30 years ago,” says Susan Pierce, Driving Rehabilitation Specialist with Adaptive Mobility Services. “It provides an entirely new level of evaluation and intervention that hasn’t existed before from my perspective. Because the DriveSafety simulator offers a wide range of realistic driving scenarios, it has helped our evaluation and training service, decreased our time in the car, and lowered our risk exposure.”