Time-course responses following sports-related concussion: a multi-modality study.

Abstract

Using a repeated-measures design, we investigated reported symptoms, oculomotor, and neurophysiological responses for up to 26 days following a sports-related concussion. Over the course of one season, 115 athletes (mean age 26.2 ± 5.4 years) from one football team (f = 28, <i>m</i> = 37) and one ice hockey team (f = 21, <i>m</i> = 29) were assessed for self-reported symptoms and severity of symptoms, cognitive testing for 10-word recall and digit backwards. Oculomotor performance was assessed using eye-pursuits. Neurophysiology was assessed using transcranial magnetic stimulation. Baseline data were collected during pre-season for all athletes and, when a concussion was identified during the season, additional data were collected at 2-, 12-, 19-, and 26-days post-injury. Twenty-two players suffered concussion injuries (f = 9, <i>m</i> = 13). Significant increases in symptoms were reported at 2 days (<i>p</i> < 0.001) and 12 days (<i>p</i> = 0.017). Severity of symptoms was significantly increased at 48 hours only (<i>p</i> = 0.002). Significant decrements in performance for 10-word recall (<i>p</i> = 0.003), digit backwards (<i>p</i> = 0.011), and eye-pursuit (<i>p</i> = 0.009) were observed at 48 hours in comparison to baseline. Transcranial magnetic stimulation revealed significantly increased cortical inhibition at 48 hours (<i>p</i> = 0.024), 12 days (<i>p</i> = 0.009), and 19 days (<i>p</i> = 0.028) compared to baseline. No differences were seen between females and males for any variables or timepoints. Players with SRC show acute changes in cortical inhibition, resolving by 26 days after injury, which follows a longer time-course for recovery compared to symptoms, cognitive tests, and oculomotor eye-pursuits. These results suggest that measuring the recovery of athletes with SRC warrants further investigation using physiological testing to accompany clinical measures in the determination of a player's readiness to return to play.