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

Abstract

We investigated the acoustic startle reflex in recently concussed adolescent athletes compared to healthy controls and those with concussion history (>1 year prior) but no current symptoms. We hypothesized that individuals with recent concussion would have a suppressed startle response compared to healthy controls. We conducted a cross-sectional study on 49 adolescent athletes with a recent concussion (n=20; age: 14.6±1.6years; 60% female), a concussion history>1 year prior (n=16; age: 14.8±2.0years; 44% female), and healthy controls (n=13; age: 13.3±2.8years; 54% female). We measured the eyeblink of the general startle reflex via electromyography activity of the orbicularis oculi muscle using electrodes placed under the right eye. Measurement sessions included twelve 103 decibel acoustic startle probes~50 milliseconds in duration delivered~15-25seconds apart. The primary dependent variable was mean startle magnitude (µV), and group was the primary independent variable. We used a one-way analysis of variance followed by a Tukey post hoc test to compare mean startle magnitude between groups. Mean startle magnitude significantly differed (F=5.49, P =.007) among the groups. Mean startle magnitude was significantly suppressed for the concussion (P =.01) and concussion history groups (P =.02) compared to healthy controls. There was no significant difference between the recent concussion and concussion history groups (P =1.00). Our results provide novel evidence for startle suppression in adolescent athletes following concussion. The concussion history group had an attenuated startle response beyond resolution of their recovery, suggesting there may be lingering physiological dysfunction.