Our goal is to preserve independence and mobility in patients with age-related decline. 

Age-related perceptual, cognitive, and motor declines impair patient mobility, increasing depression, social isolation, and caregiver burden. The Life Space Questionnaire (LSQ) indexes mobility and driving patterns through patient self-report and is linked to cognitive and depressive symptoms. The problem is that patients with age-related cognitive decline may lack self-awareness, resulting in inaccurate self-report and limiting the predictive utility of the LSQ. 

We developed a novel method to quantify real-world LS using reverse geocoded GPS driving data and home addresses of aging drivers (ages 65-90, μ=76). Drivers showed a range of cognitive abilities measured with standardized neuropsychological tools. Continuous data (3 months; 29,484 drives; 180,481 miles) were collected from drivers’ own vehicles and compared to LSQ items querying locations subjects drove to themselves. We tested the hypothesis that self-reported driving LS is related to objective, real-world LS from in-vehicle sensor data. 

Self-reported driver LS, based on the locations subjects drove to themselves, correlated with the all-item LSQ scores (r=0.45, p<0.001). Self-reported driving LS was similar to objective LS in only 32% of drivers. Differences between self-reported LS and objective LS were largest in drivers who self-reported the highest or lowest LS (over- and under-reporting; r=0.75, p<0.0001). 

Self-report may not accurately represent driver mobility and risk. Subjective reports of LS can differ widely from measurements of real-world mobility,underscoring the advantage of objective assessments of age-related decline in the real world. Driver behavior monitoring using in-vehicle sensor technology shows promise for early-detection of LS decline, which is common in patients with neurodegenerative diseases. These tools can be continuously deployed over extended time-frames, in remote and rural settings, and in patients who lack ready access to neurological care, in line with “my car the doctor”.