By Dev Mishra, M.D.
President, Sideline Sports Doc
Clinical Assistant Professor of Orthopedic Surgery, Stanford University
- A recently published study shows that the addition of vision testing (the King-Devick test) to our standard testing with symptoms, cognition, and balance can improve diagnostic accuracy of concussion to 100% in young athletes. This testing should be done by athletic trainers or team physicians.
- For the medically untrained coach your priority is not to diagnose a concussion but only to suspect a concussion, remove the athlete from play, and send the athlete to a physician for proper diagnosis and management.
For healthcare professionals, it seems that we are starting to settle on four main areas to examine when evaluating athletes for concussion: their symptoms (how the athlete is feeling), cognitive testing (their thought process), balance testing, and now a fourth important component: rapid eye movement vision testing.
Before we go any further I’d like to point out that the medically untrained coach on the sideline needs to do one thing above all else: you only need to have a suspicion that the young athlete might possibly have a concussion and then you must remove the athlete from practice or the game. A physician skilled in sports concussion management should evaluate the athlete. Let the physician make the call as to the right time to start the gradual return to play progression. You can download a simple sideline concussion assessment guide from our website that can show you how to suspect a concussion.
The issues for certified athletic trainers and team physicians on the sidelines are a bit different than the issues faced by the medically untrained coach. We have to make a diagnosis with a strong measure of certainty and do it quickly. In the NFL there is literally an entire team of doctors and trainers specifically tasked with concussion evaluation but for high school and club sports it will have to be the trainers making the call, sometimes with a team physician present.
We typically rely on a simplified version of the Sport Concussion Assessment Tool version 3 (“SCAT3”) that allows us to rapidly but incompletely evaluate symptoms, simple memory, and a scaled-down balance test. The simplified version can be done in about 3 minutes; the full version requires about 15 minutes. The 3-minute screening is reasonable but still it’s possible to miss athletes who actually have a concussion. The full 15-minute test improves our diagnostic accuracy but it’s not perfect either, and we never have 15 minutes at a sports contest to do the whole test. Studies have shown that the full 15-minute test can miss 10% of athletes with a known concussion.
So we need to do better. Is there an objective, rapid test that can improve our diagnostic accuracy? This is where adding a vision function test called the King-Devick test comes in. A recently published study shows that adding the King-Devick test to the SCAT test increases diagnostic accuracy to 100% in young athletes. The beauty of the King-Devick test is that it can be done in 2 minutes or less and uses an iPad or computer with person to person reliability. Anyone can do it. The New York Times published recently on the King-Devick test. Please note that the NYT article shows illustrations of the test through cards but the King-Devick test is proprietary, with multiple patents and copyrights to its name so the proper legal access to the test is through the company website. The company has an online version that costs $15 and is produced in association with the Mayo Clinic, but I’m a bit skeptical about an online version for use at high school or club events because the right technology and connectivity doesn’t always exist.
To use the King-Devick test each athlete needs to have a preseason baseline test done when they are healthy. Essentially, the athlete reads a set of numbers on the test panels and is timed in seconds. The athlete with a suspected concussion can be given the King-Devick on the sideline and the results compared with the athlete’s baseline. If it takes longer to do the test it likely indicates a concussion. Combine the judgment of a skilled athletic trainer, the King-Devick test plus the simple SCAT and we now have a 5-minute set of tests that are highly accurate.
Simple. Inexpensive. Reasonably fast. Accurate. Published scientific evidence. This combination should make life quite a bit simpler for the trainer and physician tasked with sideline diagnosis of concussion.