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

Objectives: Using a repeated-measures design, we investigated reported symptoms, oculomotor, and neurophysiological responses for up to 26 days following a sports-related concussion.

Methods: Over the course of one season, 115 athletes (mean age 26.2 ± 5.4 years) from one football team (f = 28, m = 37) and one ice hockey team (f = 21, m = 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.

Results: Twenty-two players suffered concussion injuries (f = 9, m = 13). Significant increases in symptoms were reported at 2 days (p < 0.001) and 12 days (p = 0.017). Severity of symptoms was significantly increased at 48 hours only (p = 0.002). Significant decrements in performance for 10-word recall (p = 0.003), digit backwards (p = 0.011), and eye-pursuit (p = 0.009) were observed at 48 hours in comparison to baseline. Transcranial magnetic stimulation revealed significantly increased cortical inhibition at 48 hours (p = 0.024), 12 days (p = 0.009), and 19 days (p = 0.028) compared to baseline. No differences were seen between females and males for any variables or timepoints.

Conclusion: 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.