Simple sideline test shown effective in diagnosing concussion in student athletes as young as 5 years old

The new study, published online in the Journal of Neuro-Ophthalmology, was conducted on 89 NCAA athletes and a younger subset of 243 youth athletes under age 17, and shows how the eye test, known as the King-Devick test, could help mitigate the problems that face concussion diagnosis in youth sports.

Study author Steven Galetta, MD, the Philip K. Moskowitz, MD Professor and Chair of Neurology at NYU Langone Medical Center, says the test can easily be administered on the sidelines by parents and non-health care professionals when athletic trainers and doctors are not available to monitor sidelines at youth sports games.

"Our findings in children and collegiate athletes show how a simple vision test can aid in diagnosis of concussion at all levels of sport," says Dr. Galetta, who is also a professor of ophthalmology at NYU Langone. "Adding the King-Devick test to the sideline assessment of student athletes following a head injury can eliminate the guesswork for coaches and parents when deciding whether or not a student should return to play."

As part of the King-Devick test, athletes read numbers off of three pieces of paper while being timed with a stopwatch. A worsened performance from a baseline reading suggests a concussion has occurred.

"Given that concussions may cause devastating short- and long-term cognitive effects, tools like vision testing that can objectively diagnose a concussion are critical," says Laura Balcer, MD, co-director of the NYU Langone Concussion Center, and a professor of neurology, ophthalmology and population health at NYU Langone.

Some sideline tests only measure cognition and balance, but visual testing is rarely performed, despite longstanding evidence that vision is commonly affected by concussion, according to a review article published by Dr. Galetta and Dr. Balcer in the March 3 print issue of Journal of Neuro-Ophthalmology. Previous research suggests about 50 percent of the brain's pathways are tied to vision.

The King-Devick test was developed in 1976 by optometrists Dr. Alan King and Steven Devick. Previous studies have looked at the test for neurological conditions that can affect vision like multiple sclerosis, before the researchers began testing it on athletes.

While earlier studies by the NYU Langone researchers looked at the King-Devick test on college athletes, this is the first to administer the test in children.

For the new study, researchers recruited 243 male and female athletes between the ages of 5 and 17 years old participating in a local youth hockey and lacrosse leagues, and 89 athletes who played these sports at the collegiate level. All of them underwent a baseline King-Devick test before the start of the sports season.

As part of the test, participants read numerical on cards from left to right as quickly as possible. Times for all three reading cards are added together, and then that number is compared with the baseline score: higher testing times suggest a worsening of performance consistent with a concussion.

All the student athletes were also given a brief cognitive test called the Standardized Assessment of Concussion (SAC) which measures memory, concentration and recall, and a Timed Tandem Gait Test, which is a timed walking trial.

Researchers determined 12 athletes sustained a concussion during the season. After matching them to control subjects of the same age and sport who did not experience a head injury, the study showed the King-Devick test outperformed the other two tests in distinguishing a concussed athlete versus an uninjured control subject with 92 percent accuracy (compared to 87 percent for Tandem Gait and 68 percent for SAC test).

Among concussed athletes, K-D scores worsened by an average of 5.2 seconds compared to baseline scores, while non-concussed athletes improved their times by 6.4 seconds compared with baseline.

Up to 3.9 million sports-related mild traumatic brain injuries, or concussions, occur annually in the United States, according to the Centers for Disease Control and Prevention, but researchers say that number is likely higher since the CDC only tracks emergency room visits.

Experiencing a concussion in a game increases an athlete's risk for sustaining a second condition in the same season by three times. Other complications include the dangerous second impact syndrome, or other short- and long-term side effects.

The group next plans to study the underlying mechanisms of the fast eye movements required for rapid number naming using electronic quantitative eye movement recordings in collaboration with Janet Rucker, MD, the Bernard A. and Charlotte Marden Associate Professor of Neurology and J.R. Rizzo, MD, director of the Visuomotor Integration Lab at Rusk Rehabilitation. According to Dr Balcer, these observations may permit more precise anatomical correlations of performance data and concussive symptoms.