Driving is an important activity for older adults because it frequently relates to personal independence and wellbeing. This study compared the driving behaviors of older drivers with normal cognition and with MCI in unfamiliar driving situations and difficult maneuvers, and explored the practice effect on driving performance of drivers with MCI.

This study used an observational, cross-section research design.

Driving is an important activity for older adults because it is frequently related to personal independence, mobility, social interaction, wellbeing, and confidence. Dementia can impair older adults' driving. The current consensus is that people with moderate or severe dementia are too cognitively impaired to drive safely. Persons with Mild Cognitive Impairment (MCI), often considered a transitional state to dementia, and those with mild dementia can still potentially drive, although some require further evaluation to determine the driver's fitness to drive. Extensive research has been devoted to the development of fitness-to-drive assessments. However, very limited attention has been paid to whether the driving skills of drivers with MCI can improve and thus potentially prolong the driver's safe-driving years.

MCI is a common neurodegenerative disease in older adults, with a prevalence of 16-20%. It is estimated that 20-40% of the MCI population will progress to dementia. Despite the potential driving concerns, it should be noted that over 50% of people with MCI are considered safe drivers. Because un-warranted driving cessation may lead to depression, functional decline, and even increases in the family's care burden, researchers have guarded against the premature revocation of driving rights.

Recent studies exploring the driving behaviors of drivers with MCI have shown inconsistent results. For example, increasing difficulties and unsafe behaviors in driving can be considered early warning signs of possible cognitive impairment. There may be a connection between specific cognitive skills (such as flexibility of visual attention and executive functioning) and poorer driving performance on specific tasks, such as car-following and road-tracking. Drivers with MCI may encounter difficulties at intersections with stop signs or critical light changes, and with headway, driving speed, reaction time, and lateral control. However, the above studies were usually conducted with driving simulators.

Only a few studies have investigated the on-road driving performance of drivers with MCI. Wadley, et al. compared drivers with MCI to drivers with normal cognition on a standardized route with various driving maneuvers frequently encountered in daily life. The results showed "less than optimal" performance, such as statistically significant poor performances in overall driving skills, especially in lane control and left turns. Driving can become increasingly difficult, for the cognitive capacities of older drivers with MCI are likely to deteriorate over time.

Recent evidence has suggested that cognitive training can slow or even reverse the cognitive impairments associated with MCI. Cognition intervention have shown positive improvements in the immediate and delayed memory functions of persons with MCI after intervention. However, advances in cognitive training for persons with MCI have yet to be applied to driver rehabilitation.

Driving rehabilitation includes both screening for unsafe drivers and the provision of individually-tailored interventions for clients with disabilities or those with a recent health event. Older drivers with cognitive impairments, such as dementia, are frequently the focus of driver screening. The current literature on driving training or retraining, however, has focused on other client populations, such as stroke, traumatic head injuries, and spinal cord injuries, and excluded those with cognitive impairments or not included screening for cognitive impairments. Even though systematic reviews by Korner-Bitensky et al. (2009) and Unsworth et al. (2014) support that driver rehabilitation improves the on-road driving performance of older drivers, older drivers with MCI are rarely considered targets for driver re-training. This finding is surprising because the driving skills of drivers with MCI can be compromised. Drivers with MCI can potentially benefit most from driving re-education, yet few studies have discussed issues related to driving training of older drivers with MCI.

In short, it is imperative to maintain the independence of persons with cognitive impairments for as long as possible. Without intervention, the driving competence of persons with MCI is likely to deteriorate as the disease and age progress. This study is to explore this possibility by examining how drivers with MCI perform as compared to drivers with normal cognition when negotiating a new route and whether learning effects would manifest if the drivers were given opportunities to practice.

Inclusion criteria

• age of at least 50 years
• possession of a valid driving license and driving experience for at least 15 years
• regular driving habit, defined as at least once a week, and
• no reported significant driving issues

Exclusion Criteria

• reported health conditions that could potentially compromise driving competence, such as stroke, Parkinson's disease or other neuromuscular diseases
• visual impairments without correction, or
• physical impairments found in physical function assessments

the participant and the outcome assessor were both blind to the design.