Concussed patients have impaired reaction time (RT) and cognition following injury that may linger and impair driving performance. Limited research has used direct methods to assess driving-RT post-concussion. Our study compared driving-RT during simulated scenarios between concussed and control individuals and examined driving-RT’s relationship with traditional computerized neurocognitive testing (CNT) domains.
We employed a cross-sectional study among 14 concussed (15.9 ± 9.8 days post-concussion) individuals and 14 healthy controls matched for age, sex, and driving experience. Participants completed a driving simulator and CNT (CNS-Vital Signs) assessment within 48 h of symptom resolution. A driving-RT composite (ms) was derived from 3 simulated driving scenarios: stoplight (green to yellow), evasion (avoiding approaching vehicle), and pedestrian (person running in front of vehicle). The CNT domains included verbal and visual memory; CNT-RT (simple-, complex-, Stroop-RT individually); simple and complex attention; motor, psychomotor, and processing speed; executive function; and cognitive flexibility. Independent t tests and Hedges’ d effect sizes assessed driving-RT differences between groups, Pearson correlations (r) examined driving-RT and CNT domain relationships among cohorts separately, and p values were controlled for false discovery rate via Benjamini-Hochberg procedures (α = 0.05).
Concussed participants demonstrated slower driving-RT composite scores than controls (mean difference = 292.86 ms; 95%CI: 70.18-515.54; p = 0.048; d = 0.99). Evasion-RT (p = 0.094; d = 0.81), pedestrian-RT (p = 0.292; d = 0.31), and stoplight-RT (p = 0.292; d = 0.59) outcomes were not statistically significant after false discovery rate corrections but demonstrated medium to large effect sizes for concussed deficits. Among concussed individuals, driving-RT outcomes did not significantly correlate with CNT domains (r-range = -0.51, 0.55; p > 0.050). No correlations existed between driving-RT outcomes and CNT domains among control participants either (r-range = -0.52, 0.72; p > 0.050).
Slowed driving-RT composite scores and large effect sizes among concussed individuals when asymptomatic signifies lingering impairment and raises driving safety concerns. Driving-RT and CNT-RT measures correlated moderately, but not statistically, which indicates that CNT-RT is not an optimal surrogate for driving RT.
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Slowed driving reaction time following concussion symptom resolution.
