Research Letter: Concussion-Related General Startle Suppression in Adolescent Athletes

AbstractObjectives: We investigated the acoustic startle reflex in recently concussed adolescent athletescompared to healthy controls and those with concussion history (> 1 year prior) but no currentsymptoms. We hypothesized that individuals with recent concussion would have a suppressedstartle response compared to healthy controls.Methods: We conducted a cross-sectional study on 49 adolescent athletes with a recentconcussion (n=20; age: 14.6 ± 1.6 years; 60% female), a concussion history > 1 year prior (n=16;age: 14.8 ± 2.0 years; 44% female), and healthy controls (n=13; age: 13.3 ± 2.8 years; 54%female). We measured the eyeblink of the general startle reflex via electromyography activity ofthe orbicularis oculi muscle using electrodes placed under the right eye. Measurement sessionsincluded twelve 103 decibel acoustic startle probes ~50 milliseconds in duration delivered ~15-25 seconds apart. The primary dependent variable was mean startle magnitude (μV), and groupwas the primary independent variable. We used a one-way analysis of variance followed by aTukey post-hoc test to compare mean startle magnitude between groups.Results: Mean startle magnitude significantly differed (F=5.49, p=0.007) among the groups.Mean startle magnitude was significantly suppressed for the concussion (p=0.01) and concussionhistory groups (p=0.02) compared to healthy controls. There was no significant differencebetween the recent concussion and concussion history groups (p=1.00).Conclusion: Our results provide novel evidence for startle suppression in adolescent athletesfollowing concussion. The concussion history group had an attenuated startle response beyondresolution of their recovery, suggesting there may be lingering physiological dysfunction.