Assessment Of Stimulated Blink Reflex And Symptoms Over Time In Collegiate Athletes With Sport-related Concussion

PURPOSE: Recovery times for collegiate athletes with sport-related concussion (SRC) range from 2 to 4 weeks. The stimulated blink reflex is abnormal after SRC. This study assessed the blink reflex daily from initial assessment (within 2 days of injury) to recovery and compared it with symptom recovery. METHODS:Prospective cohort. Blink reflex (EyeStat) and Post-Concussion Symptom Scale (max = 126) were assessed daily from injury to recovery. Blink reflex parameters: time to ipsilateral blink (latency), contralateral blink (differential latency), initial velocity, time to open, time to close, number of oscillations, and distance traveled (excursion). Associations over time were assessed using regression. RESULTS: 41 SRC (from 36 unique athletes, 20.46 ± 1.50 y/o, 79.5% male, 0.95 ± 1.2 days since injury) are included in analysis. Mean symptom severity at initial assessment was 25.00 ± 17.3 and mean time to symptom resolution was 10.87 ± 7.3 days. No significant correlation over time (i.e. p-value of interaction term of blink reflex parameter with days since injury) was observed between daily symptom severity and differential latency (p = 0.097), initial velocity (p = 0.150), time to open (p = 0.506) and number of oscillations (p = 0.228). However, a significant association was found for latency (p = 0.016), time to close (p = 0.017) and excursion (p = 0.012). In all three of these regression models, symptom severity significantly decreased over time (p = 0.013, 0.017 and 0.013, respectively) and correlated with individual blink reflex parameters throughout the recovery period (p = 0.002, <0.001 and < 0.001, respectively). CONCLUSIONS: Identifying patterns on how the blink reflex changes throughout recovery and identifying those that are associated with symptom recovery can help develop algorithms that can use change in blink reflex parameters to predict symptom recovery. Certain stimulated blink reflex parameters (latency, time to close and excursions) have a significant association with daily symptom reporting over time, meaning that they are abnormal when athletes report a high number of symptoms and return to baseline when athletes are asymptomatic. 1: UBMD Orthopaedics and Sports Medicine, University at Buffalo, Buffalo, NY 2: Department of Health and Human Performance, The Citadel, Charleston, SC