Driving after Concussion: The Influence of Days since Concussion on Simulated Driving Performance Recovery

PURPOSE: The aim of this study was to determine whether simulated driving performance improves as the days since concussion increase. METHODS: This is a cross-sectional study. Forty-nine young-adult patients diagnosed with concussion (19.3 ± 1.5 yr, female 61.2%) completed a driving simulation assessment at an initial clinic visit between 0 and 12 d postconcussion. Primary outcome variables included the total number of collisions, speed exceedances, stop signs missed, lane excursions, total drive time, percent time over the speed limit, and percent time out of the lane. For each of the 11 drive segments, we examined the average speed, standard deviation of speed, average lateral lane position, and standard deviation of lateral lane position. Driving simulation outcomes were modeled using a negative binomial regression for count variables and linear regression for continuous variables, using the predictor of days since concussion. RESULTS: Fewer days since concussion was associated with more frequent centerline crossings ( P = 0.046); greater time spent out of the lane ( P = 0.045); a lateral lane position closer to the centerline while navigating a left residential curve ( P < 0.001) and while incurring a vehicle in the lane ( P = 0.026); and greater standard deviation of lateral lane position while navigating a crosswalk ( P < 0.001) and while navigating around a crash in the road ( P = 0.018). CONCLUSIONS: Clinicians should consider recommendations that support limited driving during the acute stages (24-72 h) of concussion followed by a gradual return to driving. A longitudinal study design in a larger sample is needed to better define driving performance recovery following concussion.