Section 7

Aging

Most of the health-related conditions that are listed in this guide are more prevalent in older age groups. Older drivers may be involved in crashes because of the accumulation of medical illnesses and/or medications that affect function.

Unfortunately, the standard physical examination does not directly assess functional skills such as the ability to drive. At best, it can be used to detect the presence of medical conditions and to evaluate their severity and related complications, which may allow the physician to make judgments regarding possible effects on functions, such as fitness to drive.

Despite these limitations of the standard physical examination, most Canadian provinces and territories require that physicians report patients who have medical conditions that may make it unsafe for them to drive (see Section 3, Reporting – when and why). Even where such reporting is not mandatory, physicians may still be found liable if they fail to report a patient who is later determined to have caused harm to others as a result of medical impairment affecting fitness to drive.

When involved in motor vehicle crashes, older drivers suffer higher rates of morbidity and mortality than younger drivers (Transport Canada, 2022). Accurate assessments of fitness to drive allow physicians to help their patients avoid disabling injury or death. Such assessments also help patients and their families avoid the grief and legal repercussions associated with contributing to the injuries or deaths of other road users or bystanders. Thus, assessing fitness to drive represents a form of preventive health care that benefits not only one’s patients, but also the public. The reality is that, although physicians cannot completely assess all aspects of fitness to drive, they can make significant contributions to this assessment that will prevent unnecessary trauma to their patients and to the general public. While physicians therefore represent a major part of the solution, it is unrealistic to expect them to be able to detect all issues affecting fitness to drive in all situations. It should also be noted that physicians do not determine licence status. Rather, physicians provide accurate, timely, and relevant data to allow licensing authorities to make the most appropriate licensure decisions.

The objective of this section is to optimize physicians’ ability to fulfill this important societal role by addressing complex situations specifically related to aging that are not covered by other sections in this guide.

The following red flags should trigger screening and evaluation of fitness to drive:

Record (family/caregiver history) — family members and caregivers’ reports of concerns regarding driving safety (ask them to be specific), unexplained damage to the patient’s vehicle, moving violations (e.g., speeding tickets), near crashes, or crashes. Discuss this information with the family/caregiver(s) in a location separate from the patient so that they will be comfortable providing full disclosure.

Recent crashes reported by patient (Joseph et al., 2014).

Restriction of driving to less complex situations (Classen et al., 2013).

A variety of age-related changes in sensory input (e.g., vision), cognition (e.g., speed of cognitive processing, attention, scanning), and motor output (e.g., reaction time, power, coordination) can affect driving safety. Fortunately, because of compensatory voluntary restrictions at both the strategic level (e.g., planning when and where to drive, such as restricting driving to optimal traffic and weather conditions) and the tactical level (e.g., defensive driving strategies, such as increasing following distance), as well as years of driving experience, healthy seniors remain the safest drivers on the road.

Nonetheless, when older drivers experience medical conditions, either the conditions themselves or the medications used to treat them may affect fitness to drive. This guide provides a wealth of information regarding how to address such situations.

There may, however, be situations in which physicians or family members, or both, feel that a problem with driving is developing, but they cannot identify the precise cause. As a result, the physician may have difficulty employing the recommendations provided in other sections of this guide. An example of such a concern would be a sudden change in driving habits (e.g., marked decrease in distances driven or new avoidance of challenging driving situations), which the American Academy of Neurology suggests is a marker of possible driving concerns (Iverson et al., 2010). Often, these concerns arise from changes related not to aging but rather to hidden, as-yet-undiagnosed medical conditions. In such situations, tools such as the CANDRIVE fitness-to-drive assessment mnemonic (Figure 1) can help physicians to structure their review of potential causes contributing to the concerns about fitness to drive. Identification of likely causes will in turn allow them to use the most relevant sections of this guide. The CANDRIVE mnemonic is similar to, but incorporates more detail (e.g., in-car experiences) than, the SAFEDRIVE mnemonic that appeared in the 7th edition of this guide. In particular, the CANDRIVE mnemonic captures reaction time as both speed of mentation and speed of movement.

For cases in which physicians and family members are concerned but the CANDRIVE fitness-to-drive assessment mnemonic does not yield any identifiable medical domains where physicians can focus their diagnostic skills and for cases in which the functional effects are too subtle to determine whether they represent a significant risk to fitness to drive, physicians should consider referral to specialized driving assessment programs, many of which provide on- road evaluation (Appendix B).

Often the issue is not that the medical conditions are hidden but, rather, that there are too many conditions to assess vis-à-vis fitness to drive. Again, it may be unreasonable to expect that a physician who has never been trained to assess function directly will be able to determine medical fitness to drive in the face of multiple comorbidities that may be interacting (at times in a synergistic fashion).

For complex cases of this nature, the physician may start with general lists, such as the CANDRIVE fitness-to-drive assessment mnemonic (Figure 1). In the setting of multiple comorbidities, the main limitation of such lists is that they do not provide guidance on sequencing complex assessments.

Molnar and Simpson (2010) described a complementary approach to assessing patients with multiple comorbidities, based on classifying the problems identified into acute intermittent and chronic persistent disorders. Acute intermittent disorders (called “episodic limitations” in Section 2, Functional assessment — emerging emphasis, and “acute or fluctuating illnesses” in the CANDRIVE mnemonic) are medical problems that can suddenly incapacitate an otherwise low-risk driver. These problems (e.g., syncope, seizures) can cause sudden changes in cognition or level of consciousness, or both, but are less likely to be detected by physical examination, because they are not present most of the time. Decisions regarding when patients can resume driving after the occurrence of one of these episodes are based on the probability of recurrence (see Appendix C, Canadian Cardiovascular Society’s risk of harm formula). Chronic persistent disorders (called “permanent limitations” in Section 2, Functional assessment — emerging emphasis) are medical problems that are present at all times and can be detected by examining and testing the patient. Specific acute intermittent and chronic persistent disorders are reviewed in greater detail in other sections of this guide.

An effective way to employ this categorical breakdown is to first decide when the patient might resume driving according to their acute intermittent disorders (e.g., myocardial infarction, arrhythmia treated with implantable cardioverter defibrillator, seizure). This will provide time for recovery from any apparently persistent features that may in fact have a degree of reversibility (e.g., delirium, postural hypotension, stroke, traumatic brain injury, sleep apnea). At that point, the physician can more accurately assess irreversible chronic persistent conditions (e.g., dementia). For an example of how to employ this approach, readers are directed to the article by Molnar and Simpson (2010).

As useful as the above approaches are, what is truly needed are provincially and territorially funded continuing professional development (CPD) programs focused on the assessment of fitness to drive, as suggested by Dow and Jacques (2012). For such CPD programs to attract large numbers of physicians, linking attendance to CPD credits issued by the College of Family Physicians of Canada and the Royal College of Physicians and Surgeons of Canada should be considered.

To learn more about assessing fitness to drive in older patients, see the Canadian Geriatrics Society Journal of CME (https://www.geriatricsjournal.ca/).