Turns and Downturns in Aging Drivers

Hardt, Marie; Basulto-Elias, Guillermo; Hofmann, Heike; Hallmark, Shauna; Sharma, Anuj; Dawson, Jeffrey D.; Rizzo, Matthew; Chang, Jun Ha · 2026 · OpenAlex-citations

DOI: 10.64898/2026.02.04.26345564

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Summary

This study investigates whether avoidance of left turns serves as a behavioral marker for early cognitive decline in older adults. While neuropsychological testing is the standard for detecting mild cognitive impairment (MCI) and Alzheimer’s disease, self-reported driving limitations often fail to capture subtle changes. Left turns are cognitively demanding and hazardous, yet older drivers rarely report avoiding them. The authors hypothesized that passive monitoring of naturalistic driving data could reveal these avoidance behaviors before formal diagnosis, offering a digital biomarker for functional decline. The researchers analyzed data from 106 older adults (aged 65–90) enrolled in a naturalistic driving study. Participants underwent baseline and one-year follow-up neuropsychological assessments to classify cognitive trajectories into four groups: stable normal, incident MCI, stable MCI, and progression to dementia. In-vehicle sensors, including gyroscopes and GPS, passively recorded driving behavior over 12 weeks. Turns were identified using gyroscopic heading changes exceeding ±10 degrees within one second, resulting in 295,112 detected turns. The study employed mixed-effects logistic regression to model the odds of making a left versus a right turn, treating cognitive prognosis as an ordinal predictor of increasing severity. The analysis revealed a statistically significant association between cognitive decline and left-turn avoidance. Greater cognitive impairment, indicated by progression to a more severe cognitive status category, was associated with reduced odds of turning left (odds ratio = 0.984, 95% confidence interval = 0.969–0.999; P = .037). Specifically, each unit increase in cognitive prognosis severity corresponded to a decrease in the likelihood of executing a left turn. Boxplot visualizations confirmed a decreasing trend in the percentage of left turns as cognitive impairment worsened. The study notes that while the effect size was subtle, the large volume of turning events per participant provided sufficient statistical power. These findings suggest that left-turn avoidance is a detectable digital behavioral marker of early cognitive decline. Passive driving data can identify functional changes that self-reports miss, potentially enabling earlier interventions to preserve mobility and independence. The authors conclude that further research is needed to establish clinical thresholds for concerning trends in left-turn frequency and to validate these findings in larger, more diverse cohorts. Limitations include the predominantly white, community-dwelling sample and the broad nature of the turn detection algorithm, which may have included non-intersection maneuvers.

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Topics

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• mci dementia driving
• cognitive impairment
• older drivers