Long-term Effects of Concussion on Driving Behaviors: A Driving Simulator Evaluation
Concussive injuries have been hypothesized to result in a decline in motor performance that does not become clinically relevant until later in life. Despite injuries occurring at a young adulthood, subtle changes in motor functioning may be present, but not clinically apparent until later in life as younger individuals benefit from cognitive reserve. Cognitive reserve is known to decrease with age, but when coupled with concussion-related cell death, cognitive decline may be exacerbated and ultimately develop into clinically meaningful signs and symptoms at an earlier age. Research conducted by members of this team has documented changes in balance, gait, and upper and lower extremity motor control in cohorts of previously concussed young adults. It remains to be seen, however, if these changes are also present in a complex, everyday task such as driving. Thus, the aim of this investigation is to evaluate the influence of concussion history on driving performance. Hypothesis: We hypothesize that those with a concussion history will demonstrate worse driving performance and skill on a driving simulator compared to age-matched non-concussed individuals.
This study is the first to examine the long-term effects of concussion on driving safety. Although the research team has extensive independent experience with concussion and driving safety, this is the first investigation to ever combine the two in a single protocol. This approach to the issue of concussion and driving is innovative in using a high-fidelity driving simulator as a safe and controlled approach to measuring real-world safety critical behaviors. In addition to basic driving measures, i.e., vehicle handling measures, this study proposes the examination of higher-order skills such as planning and anticipation behaviors, as well as visual scanning behaviors to study concussed versus non-concussed drivers.
Concussion has traditionally been viewed as a transient injury with restoration of premorbid functioning typically occurring within 2 weeks. More recent work however, has demonstrated ongoing, sub-clinical changes in cognitive processes (eg attention allocation) and motor control (eg gait and balance) years after injury. Although these changes do not appear to affect activities of daily living, the influence they have on more complex tasks is unknown. Driving is a complex task that invokes continual cognitive processing (eg environmental updating and decision making) with motor control of the hands and feet. While complex in its own right, the ubiquitous presence of cellular phones adds a layer of complexity that may result in distracted driving and ultimately accidents. This investigation enrolled young adults with (n=16) and without (n=21) a concussion history to complete a driving simulation task with and without a secondary task (eg receiving a phone call, texting, GPS navigation) while evaluating variables associated with risky driving. We noted that those with a concussion history engaged in more risky behaviors, particularly when completing the secondary tasks. Indeed, concussed drivers were less likely to stop at a yellow dilemma light, more likely to be in an intersection when it was red, and had more tunnel vision, than drivers with no concussion history. There was also narrower horizontal scanning by concussed-drivers as compared to non-concussed drivers, regardless of whether engaged in a secondary task or not, indicating reduced lookout behavior and poorer hazard perception. Finally, even when not engaged in a secondary task, the concussed drivers looked away from the forward roadway more than the non-concussed driver, indicating increased distraction behaviors. Collectively, these findings support our previous works demonstrating on-going decrements in cognitive and motor performance years after concussion. How these findings related to real-world scenarios (eg traffic accidents) is unknown, but warrants further investigation.