Sex differences in cognitive-motor components of braking in older adults

Fast and accurate braking is essential for safe driving and relies on efficient cognitive and motor processes. Despite the known sex differences in overall driving behavior, it is unclear whether sex differences exist in the objective assessment of driving-related tasks in older adults. Furthermore, it is unknown whether cognitive-motor processes are differentially affected in men and women with advancing age. We aimed to determine sex differences in the cognitive-motor components of the braking performance in older adults. Fourteen men (63.06 ± 8.53 years) and 14 women (67.89 ± 11.81 years) performed a braking task in a simulated driving environment. Participants followed a lead car and applied a quick and controlled braking force in response to the rear lights of the lead car. We quantified braking accuracy and response time. Importantly, we also decomposed response time in its cognitive (pre-motor response time) and motor (motor response time) components. Lastly, we examined whether sex differences in the activation and coordination of the involved muscles could explain differences in performance. We found sex differences in the cognitive-motor components of braking performance with advancing age. Specifically, the cognitive processing speed is 27.41% slower in women, while the motor execution speed is 24.31% slower in men during the braking task. The opposite directions of impairment in the cognitive and motor speeds contributed to comparable overall braking speed across sexes. The sex differences in the activation of the involved muscles did not relate to response time differences between men and women. The exponential increase in the number of older drivers raises concerns about potential effects on traffic and driver safety. We demonstrate the presence of sex differences in the cognitive-motor components of braking performance with advancing age. Driving rehabilitation should consider differential strategies for ameliorating sex-specific deficits in cognitive and motor speeds to enhance braking performance in older adults.