Abstract
Purpose :
This prospective observational cohort study aims to identify the incidence of SRC and related ocular manifestations in rugby union players using the King-Devick (K-D) test, while determining its utility in diagnosing concussion.
Methods :
Forty male rugby players (mean age 23.48±3.7 years; range 18-37 years) who played more than 50% of the season in the top two divisions at a semi-professional rugby club in Sydney participated in the study. During the 2017 pre-season, according to standardised baseline procedure players performed the K-D test, a rapid number-naming test eliciting predominantly saccadic eye movements. All athletes (22 forward and 18 defensive (back) players) were monitored throughout 18 rounds of the playing season and performed the K-D test following any suspected concussion. Twenty-eight were followed-up to repeat the K-D test during the season. A Wilcoxon signed-rank test was used to compare baseline to repeat and post-concussion K-D test scores. All injuries suffered were diagnosed and detailed by an experienced sports physician.
Results :
There were a total of 112 injuries across the playing season. Of these 6.25% (n=7) were diagnosed SRC, resulting in 9.72 concussions per 1000 match hours. In regards to playing position, 85.71% of the concussions occurred in forwards and 14.29% in backs. Due to 4 absentees during testing, baseline K-D test was conducted on 36 athletes resulting in an average completion time of 41.4±7.89 seconds. Players (n=28) that repeated the K-D test throughout the season demonstrated significant improvements (lower) to their original baseline scores (40.25±7.11 vs. 36.41±6.13 seconds, p<0.001). Concussed athletes displayed average K-D scores that were significantly worse (higher) than baseline (33.63±5.39 vs. 36.04±5.96 seconds, p=0.032) with a mean difference of 2.41. One player demonstrated a 2 second improvement post-concussion. The cohort also had 3 other direct ocular-related injuries, including one orbital fracture.
Conclusions :
Results from this cohort reflect over double the rate of SRC previously reported (4.73 concussions per 1000 match hours1). Baseline K-D scores are consistent with age-matched normal values. Inclusion of the K-D test may benefit sideline paradigms. Weekly tests are required to remove potential false negatives and identify any undiagnosed concussions.
1. Gardner et al. (2014) Sports Med 44:1717
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.