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THE ASSOCIATION OF HISTORY OF CONCUSSION WITH BASELINE SCORES ON THE SPORT CONCUSSION ASSESSMENT TOOL (SCAT5) IN HIGH SCHOOL RUGBY PLAYERS

Background: The Sport Concussion Assessment Tool 5 (SCAT5) is a standardized instrument designed to assist with the clinical and sideline assessment of concussion. Following the 5th International Conference on Concussion in Sport in 2016, the SCAT5 was released. Compared to the previous version (SCAT3), the SCAT5 includes more detailed instructions regarding the symptom checklist and a 10-word list in the immediate memory section to diminish ceiling effects. This study aims to examine the association between having a previous history of concussion and SCAT5 scores in high school rugby players. A second objective is to provide reference values for healthy rugby players for the SCAT5, including typical scores on immediate memory using the 10-word list. Methods: High school rugby players (ages 15-18) from Calgary, Alberta participating in the 2018 high school rugby season (n=388, male=212, female=176) were recruited to a cohort study and asked to complete a baseline SCAT5 assessment administered by trained research assistants at the beginning of the playing season. Outcome measures included baseline symptom evaluation (/22 symptoms)], self-reported rating of percentage of normal (100% perfectly normal) felt at time of testing, immediate memory score using a 10-word list [/30)], digits backward (/4), delayed word memory (/10), and modified Balance Error Scoring System [BESS (/30)]. Players also completed a preseason demographic questionnaire, which assessed their history of concussion. Results: A total of 237/388 (61.08%) rugby players reported no history of concussion (NC) and 151/388 (38.92%) reported at least 1 previous concussion (PC). Ninety of the 212 males (42.45%) and 61 of the 176 females (34.66%) reported a history of previous concussion. Median SCAT5 symptom score was 6 (range; 0-21) for NC and 7 (0-22) for PC groups. At the time of baseline testing, only 30.51% of NC players and 21.85% of PC players reported feeling 100% of normal. Median total scores on the immediate memory score (/30) were 21 (range; 9-28) for NC and 21 (range; 9-29) for PC. Median total score on digits backward (/4) was 3 (range; 0-4) and the delayed memory score (/10) was 7 (range; 0-20), for both NC and PC groups. Median total errors made on the BESS were 4 (range; 0-20) for NC players and 5 (range; 0-17) for PC players. Conclusions: Players with and without a previous history of concussion obtained similar scores on all components of the SCAT5 at baseline. Many high school rugby players did not report feeling 100% of normal during typical baseline testing sessions. The addition of the 10-word list option in the immediate and delayed memory section reduces the likelihood of a ceiling effect. This study informs the use and interpretation of the SCAT5 in high school rugby players.