Objective Repeat concussion within the same athlete has been anecdotally associated with more severe symptom burden and prolonged recovery. This study sought to explore differences in symptom burden and recovery outcomes following an individual athlete’s initial vs. repeat sport-related concussion (SRC).

Design Retrospective within-subject cohort study.

Setting Regional Sport-Concussion Center.

Participants Athletes 12–23 years old diagnosed with two separate SRCs from 11/2017–10/2020 were included. Those with delayed presentation or missing symptom questionnaires were excluded.

Interventions (or Assessment of Risk Factors) The primary independent variable was whether this was the initial concussion treated by our center (i.e., initial concussion) vs. the second concussion treated by our center (i.e., repeat concussion).

Outcome Measures Primary outcomes were initial symptom severity and days to symptom resolution; secondary outcomes included days to return-to-learn (RTL) and return-to-play (RTP).

Main Results Of 868 unique patients, 47 presented with both initial and repeat concussions (5.4%). For those with repeat concussion, median time between concussions was 244 days (IQR=136–395). Comparing initial to repeat concussion, no differences were observed in time-to-clinic (4.3±7.3 vs. 3.7±4.6 days, p=.56) or initial symptom severity score (26±25.3 vs. 30.5±24.1, p=.32). While a difference was observed in time-to-symptom resolution between initial/repeat concussion (21.2±16.3 vs. 41.7±86.0 days), this did not reach statistical significance (p=.30). No significant differences were observed in time-to-RTL (17.8±60.6 vs. 6.0±8.3 days, p=.26) and RTP (33.2±44.1 vs. 29.4±39.1 days, p=.75). Repeat concussion was not associated with prolonged symptom resolution on univariate (HR=1.64, 95% CI=0.96–2.78, p=.07) and multivariable (HR=0.85, 95% CI=0.49–1.46 p=.55) Cox regression.

Conclusions No significant differences in initial symptoms or recovery were observed between an athlete’s initial vs. repeat concussions.