Relationship between Walking and Driving, and Cognitive Functioning Common to Both Modes of Mobility, in Healthy Older Adults.

INTRODUCTION: Driving and walking, the two main modes of mobility, require numerous common skills in the motor, sensory, and cognitive domains that deteriorate with age. The objective of this study was to investigate the relationship between walking and driving in healthy older drivers and to determine whether certain cognitive processes are involved in both modes of mobility. METHOD: Seventy-six older drivers from the Safe Move cohort were assessed in the following three domains: (1) cognition, using parts A and B of the Trail Making Test (TMT), the digit symbol substitution test (DSST), the Stroop test, and the Digit span; (2) gait, using a dual-task (DT) paradigm with a counting task; and (3) driving, assessed via a 40-50 min on-road test. Analyses were also performed on 2 subgroups: young-old (70-74 years old; n = 43) and old-old (≥75 years; n = 33). RESULTS: Four significant correlations were found across the whole sample between gait performance under DT conditions and driving scores. One correlation was also found in old-old adults. None were found in young-old adults. Furthermore, several cognitive measures were significantly correlated to both modes of mobility: TMT-A and B completion time in the whole sample, and DSST performance in the whole sample and old-old adults. DISCUSSION/CONCLUSION: Walking in complex conditions and on-road driving performance are closely related in healthy older drivers. Visuospatial attention, processing speed, and executive function are crucial and common cognitive processes to both modes of mobility in this population. Impairment in these cognitive functions should thus alert health professionals as it can quickly lead to mobility disorders, loss of autonomy and social isolation. Developing specific preventive programs and mobility support systems for healthy older adults is also crucial.