The effect of Dual-Task modality on midfrontal theta power and driving performance across the adult lifespan

Abstract

Driving is a complex activity, entailing concurrent preparation and execution of motor behavior, and processing of cognitive information. Dual-tasking often leads to performance decrements, especially when the subtasks require similar neural resources, e.g., controlling the steering wheel, handling the pedals and shifting gears. With higher age, the ability to simultaneously perform different tasks deteriorates, as more mental resources are required for accurate coordination of movements. Therefore, using electroencephalography, we measured the neural correlates of dual-task driving in 81 healthy younger (n = 27), middle-aged (n = 25) and older adults (n = 29). A visuocognitive and a visuomotor dual-task were combined with a simulated lane-keeping task, with the latter dual-task requiring more similar resources. As expected, steering precision decreased to a higher extent when combined with a visuomotor dual-task in all participants, compared to no deterioration in the visuocognitive dual-task. Yet, this visuomotor dual-task performance decrease was more prominent with increasing age. Remarkably, although mid-frontal theta power increased in all groups when a visuomotor dual-task was added, indicating the recruitment of additional mental resources, this increase was less prominent for middle-aged and older adults. This could signify a plateau effect of theta power in which a saturation of mental resources is reached, leading to an increased dual-task cost. Therefore, reducing driver task demands by limiting the need for motor control processing, e.g., by switching to automatic gear shifting, could be beneficial for driving safety.