Medical Assessment of the Older Driver

Older adults are likely to have multiple comorbidities and may be taking several medications. A significant number of medications, typically those affecting the central nervous system (eg, causing confusion, sedation) can potentially impair driving. Many have been shown to impair driving performance during road tests or in driving simulators and have been associated with an increase in motor vehicle crash (MVC) risk. Despite these risks, many of these medications should not be stopped abruptly and may need to be tapered. Obtaining input from the prescribing physician or pharmacist is important before stopping them.

Some medications that have been shown to increase driving risk include

• Antihistamines, benzodiazepines, opioids, anticholinergics, hypnotics, antihypertensives, and tricyclic antidepressants, which can cause drowsiness, hypotension, or arrhythmias

• pramipexole, ropinirole), which can occasionally cause acute sleep attacks

• Antiemetics (eg, prochlorperazine) and muscle relaxants (eg, cyclobenzaprine), which can alter sensory perception

• Antiseizure medications, which can cause sedation (alternatives may need to be considered)

When starting a new medication that could affect visual, physical, or cognitive function, patients should refrain from driving for several days (depending on the time required to reach a steady state) to be sure no adverse effects occur. When a medication in a drug class with the potential to increase driving risk must be used, the patient should be given a medication in that class that is least likely to cause impairment and at the lowest possible effective dose.

Falls and MVCs share common causative factors (eg, impaired vision, muscle strength, cognition). A history of falls indicates increased risk of MVCs in older adults and should prompt further evaluation for intrinsic factors that can impair mobility and driving (eg, visual, cognitive, and motor skills).

(See Functional Assessment of the Older Driver.)

The presence of a cardiac disorder may increase driving risk, particularly disorders that may impair consciousness or cause syncope (eg, arrhythmias). Patients who have had cardiac procedures (eg, coronary artery stents or bypass grafts, placement of internal defibrillator/pacemakers) or certain acute events (eg, unstable angina, myocardial infarction) need to refrain from driving for a brief time during recovery; the length of time depends on the procedure and the patient's clinical condition. Cardiac disorders can cause chronic cognitive impairment or acute impairment in consciousness (eg, dizziness, syncope, drowsiness).

Patients with severe heart failure (eg, class IV heart failure, dyspnea at rest or while driving) should refrain from driving until they can be evaluated with on-road testing and have the approval of their clinicians.

Neurologic disorders also increase driving risk. Specific disorders include

• Stroke or transient ischemic attack (TIA): Drivers with a single TIA should wait 1 month before resuming driving; those with recurrent TIAs or a recent stroke should be event-free for at least 3 to 6 months before resuming driving and be cleared by their neurologist or primary care physician. Physical examination should be done to assess how residual disability due to stroke may affect driving ability. Consider referring those with persistent visual, motor, or cognitive deficits to an occupational therapist-based driving assessment clinic.

• Seizures: Regulations for drivers who have seizures are state-specific, but most states require a seizure-free interval (often 6 months) before they reinstate driving privileges. Antiseizure medications can adequately control seizures in approximately 70% of patients, although relapses may occur when these medications are withdrawn or during periods of nonadherence. State-specific information regarding driver's license eligibility for people who have seizures should be sought (see the Epilepsy Foundation's State Driving Laws Database) along with advice from a neurologist.

Alzheimer disease or other progressive dementias eventually impair key functional abilities, including those required for driving. Monitoring patients for new driving errors that can be attributed to changes in cognition or identifying significant impairments in psychometric tests may be useful in determining referrals for on-road evaluation and/or possibly driving cessation. The American Academy of Neurology has practice parameters on driving and dementia (1). Several states presently require physicians to report significant cognitive impairment to the state's Department of Motor Vehicles (2).

Many other neurologic disorders (eg, Parkinson disease, multiple sclerosis) cause disability and should be monitored by functional assessment and, when appropriate, an on-road evaluation.

Diabetes mellitus poses a risk because patients may become hypoglycemic while driving; however, well-controlled diabetes has not been shown to increase MVC risk (3). Patients who have had a recent hypoglycemic episode with reduced consciousness should not drive for 3 months or until factors contributing to the episode (eg, diet, activity, timing and dose of insulin or antihyperglycemic medication) have been assessed and managed. Sensory changes in the extremities due to neuropathy, retinopathy, or both caused by diabetes can also impair driving ability.

Severe hyperglycemia is associated with cognitive impairment, and patients should not drive until their blood glucose and symptoms are under better control.

Sleep disorders, most notably obstructive sleep apnea syndrome, can cause drowsiness leading to MVCs, and patients should refrain from driving until they are adequately treated.

Use of a continuous positive airway pressure (CPAP) device has been shown to improve performance in a driving simulator and reduce MVCs (4).

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

1. National Highway Traffic Safety Administration: Clinician's Guide to Assessing and Counseling Older Drivers, 4th edition

2. Austroads: Assessing Fitness to Drive: An Australian resource providing medical standards for driver licensing

3. Epilepsy Foundation: State Driving Laws Database: A United States resource providing information for drivers with epilepsy