Vision Test Could Help Diagnose Concussions on the Sidelines of Games

By ANTONIO BARBERA
Capital News Service

A vision test administered on the sidelines of sporting events could help identify athletes who’ve suffered a concussion, according to a study discussed this spring at the American Academy of Neurology's annual meeting.

Researchers, supported in part by the National Institutes of Health, determined that the King-Devick test detected 79 percent of concussions suffered by athletes of the University of Florida men’s football, women’s soccer and women’s lacrosse teams. The study followed 217 athletes, 30 of whom had a first concussion during the season the testing was taking place.

When combined with the test results of two other comprehensive concussion tests -- the Standardized Assessment of Concussion and the Balance Error Scoring System -- 100 percent of concussions were identified.

“I don’t think we’re ever going to have one comprehensive sideline test,” said study co-author Dr. James Clugston, team physician for the University of Florida Athletic Department, Gainesville. “But the King-Devick casts a wider net in diagnosing concussions.”

According to the Centers for Disease Control and Prevention, up to 3.8 million Americans sustain sports-related concussions each year. Most of these are not treated in a hospital or emergency department, according to the CDC, making diagnosis a challenge.

What makes the King-Devick test unique is that it is simple and fast, while increasing the accuracy in diagnosing concussions when used with other tests, according to the AAN.

“The King-Devick looks at a different area of brain function that we weren’t really focusing on,” said Clugston. “It’s really simple to administer and simple to interpret.”

A test-taker reads, as quickly and accurately as possible, rows of single-digit numbers that are unevenly spaced. A baseline test is established to determine time and accuracy to complete the test with a healthy brain. When an athlete is deemed to have a potential concussion, the test is administered again. Irregularities in time or accuracy indicate a concussion. 

The test takes about one minute to complete, and can be performed with charts or a tablet.

Current sideline concussion tests analyze balance and short-term memory, but the King-Devick test looks for vision-related problems.

“The visual pathways are commonly affected in concussion,” wrote Dr. Laura Balcer, author of the King-Devick study and a neurologist at the New York University Langone Medical Center, in a statement issued by the AAN. “Adding a vision-based test to evaluate athletes on the sidelines may allow us to better detect more athletes with concussion more quickly. This is particularly important since not all athletes reliably report their symptoms of concussion, including any vision problems.”

While the King-Devick should not be the only test administered to diagnose a concussion, it is effective in diagnosing athletes who hide their symptoms or aren’t aware they have a concussion, Clugston said. “All of the tests can be manipulated, and that’s a problem, but I think this may be a little more objective, and it’s an improvement because it’s testing a whole different function that we weren’t looking at before.”

Clugston said the King-Devick test has struggled to gain popularity on athletic sidelines, possibly because other concussion tests are free, while the King-Devick, with score sheets and a stopwatch, costs around $45. King-Devick also offers a test compatible for tablets, which integrates the stopwatch automatically and keeps records of scores.

“My ultimate desire would be that we have a truly objective test,” said Clugston. “And this helps get us there a little more.”