OBJECTIVES: Mild cognitive impairment (MCI) and mild Alzheimer’s disease (AD) progressively compromise various aspects of cognitive function, which are essential for everyday functioning, and independence activities, such as driving. Reliable measures assessing the impact of cognitive deficits on driving ability can help to evaluate the real-world benefit of potential therapies targeted to improve cognitive function in the early stages of AD. This literature review summarizes the impact of MCI/AD on driving (measured by simulator) and the relationship between clinical outcome assessments (COAs) and driving outcomes.
METHODS: A targeted literature review identified publications, including driving outcomes and cognitive function assessments in MCI/AD. A meta-analysis was conducted to determine the relative sensitivity of outcomes and relationships. Standardized mean differences (Hedge’s g method) between MCI/AD and controls were calculated. Relationships between driving measures and COAs were assessed using Pearson’s correlation.
RESULTS: Five publications were identified. Poorer performance on driving measures (including accidents, attention, distance, driving errors, infractions, position, speed, and car control) was reported in the MCI/AD groups compared to controls; differences varied across studies. There was a consistent trend for the MCI/AD groups to have slower reaction times compared to controls. Pooled estimates of effect size were not calculated as most measures were only reported within a single study and studies reported on multiple measures. The strength of the correlations between COAs (cognitive tests, MoCA) and driving measures varied across categories: attention/reaction time (0.18), accidents (-0.65 to 0.98), general errors (-0.26 to 0.77) and across COA measures. The Trail Making Test, commonly used to clinically evaluate the fitness to drive, was low to moderately correlated with general errors (0.15 to 0.64).
CONCLUSIONS: Simulated driving performance measures can serve as an informative gauge to assess the potential functional impact of therapeutics targeting MCI or mild AD, wherein patients engage in complex everyday activities such as driving.
