Sport concussion assessment tool—fifth edition normative reference values for professional rugby union players

Objective: To describe distributions and establish normative ranges for new or changed subcomponents of the Sports Concussion Assessment Tool (SCAT)-5.

Design: Cross-sectional study.

Setting and Participants: Professional Rugby Union players performing 2017 preseason baseline SCAT-5 testing.

Independent Variables: Subcomponent tests newly introduced or changed in the SCAT-5.

Main Measurements: The 10-word immediate and delayed recall tests and the rapid neurological screen.

Results: Thousand two hundred three players were included in complete case analyses. The 10-word immediate recall test [median score 15, interquartile range (IQR) 15-22, range 3-30] showed an asymmetrical, bimodal distribution. The delayed recall test (median score 7, IQR 5-9, range 0-10) demonstrated a left skewed distribution. The diplopia and reading/following instruction tests of the neurological screen were performed normally by virtually all participants (98.5% and 99.6%, respectively). Normative classification ranges for each SCAT-5 subcomponents of interest were determined.

Conclusions: The increased spread of scores, with improved midrange centering, suggests that the increase to 10-word list lengths should improve the performance of immediate and delayed recall tests. Normative ranges will provide a distribution against which postinjury SCAT-5 scores can be compared and interpreted.