A new New Zealand study of rugby players provides additional evidence that the King-Devick Test, a simple two-minute test of rapid eye movement, is an accurate “remove-from-play” sideline concussion assessment tool, one which can accurately identify athletes with concussion, even when they neither display obvious concussion signs nor report any symptoms.
The rugby study, reported online in the Journal of Neurological Sciences, adds to a growing and impressive body of research, establishing the value of King-Devick as a sideline assessment tool to complement the many other diagnostic sport-related concussion assessment tools currently in use, such as SCAT2.
Researchers at the Sports Performance Research Institute (SPRI) in New Zealand recorded five witnessed concussions over the course of the season, while 17 were unrecognized and only identified with the KD.
The findings of five witnessed concussions was “not unexpected,” said lead author Doug King, Ph.D. of SPRI (no relation to the King of King-Devick), “but the number of unrecognized concussions is a concern. If the present finding is any indication that there is a ratio of 3.4 identified concussions for every witnessed concussion, then studies [are] under-estimating the incidence of concussions,” he said.
Such finding is consistent with numerous studies and anecdotal evidence suggesting that the number of concussions and hence concussion rate is far higher than actually reported based on a combination of factors, including the documented reluctance or complete unwillingness of many athletes – even those with detailed understanding of the signs and symptoms of and risks associated with concussion – to honestly self-report, their symptoms to sideline personnel, and the difficulty even trained sideline personnel experience in spotting the often subtle, sometimes even undetectable, signs of concussion.
The silver lining in the study’s finding is that the KD test was able to identify so many unwitnessed and unreported concussions so that such athletes could be removed from play and referred for a more complete assessment away from the sport sideline, and, in so doing, prevent the return of athletes with suspected concussion from returning to the playing field, where they run the risk of further injury to their brain, which evidence suggests, lengthens and complicates recovery, and, worse, increases the chance of catastrophic injury or even death from second impact syndrome.
The two-minute sideline test can be administered via an iPad app or with physical test-cards, players when they come off the field and can be applied to all contact sports including football, soccer, hockey, basketball, among others.
The test has shown such promise for sideline assessment of concussion that consumer advocate Ralph Nader is now calling for its mandatory use at all levels of sports, from the pros down to youth leagues.