Longitudinal assessment of post-concussion driving reaction time.

Abstract

Objectives: Concussed patients present multiple neurocognitive and motor impairments including slowed reaction time (RT), a function essential to driving. We compared driving RT between concussed and non-concussed individuals across their concussion recovery (aim 1) and explored whether clinical concussion outcomes were correlated with driving RT uniquely in the concussion group (aim 2).

Methods: We recruited collegiate athletes (26 concussed and 23 age- and sex-matched controls) to complete the sport concussion assessment tool (SCAT5), a computerized neurocognitive test (CNS Vital Signs), and a driving simulation across 3 timepoints: ≤72 h, asymptomatic, and unrestricted medical clearance. RTs were recorded in response to 4 unanticipated driving events. CNSVS included 10 measures of cognitive function. General linear mixed models assessed interaction between group and time for aim 1 and group and concussion assessment outcome for aim 2 (α = 0.05). Pairwise comparisons with Cohen's d values were used following significant interactions and main effects.

Results: There was a significant main effect for timepoint, such that pedestrian RT was slower at the ≤72-h timepoint relative to both the asymptomatic (p value = 0.023) and unrestricted medical clearance (p- value = 0.022). There were no other significant group-by-timepoint interaction or timepoint main effects for yellow stoplight RT (p-value range = 0.334-0.798), vehicle incursion RT (p-value range = 0.234-0.925) or vehicle cross RT (p-value range = 0.177-0.364). There was no significant group main effect (p-value range = 0.077-0.955), assessment outcome main effect (p-value range = 0.099-0.999) or interaction (p-value range = 0.103-0.998) for predicting any of the RTs, except for executive function (p = 0.046), motor speed (p = 0.006), and psychomotor speed (p = 0.027) predicting vehicle cross RT regardless of group.

Conclusion: This study demonstrates that driving RT may not differ between acutely concussed and healthy individuals or may not be detected on a short, simulated drive. Current clinical concussion outcomes poorly relate to driving RT. More research is needed to determine when it is safe to return to driving post-concussion.