Speaking English as a second language may alter results of sideline concussion testing

From youth to professional sports teams, concussions are a concern for athletes who participate in football, soccer, rugby, and a number of other high-impact sports. Many of these sports are turning to sideline concussion testing to determine if a player should be removed from a game and further evaluated for a concussion. One such sideline test is the King-Devick Test, which is a visual test that uses a series of cards and numbers to assess a player's ability to rapidly name numbers. The test is ideally initiated during a pre-season baseline and then it performed again on the sideline following a head impact. If there is an increase in the time it takes to complete the task or an increase in errors, the player is removed from play and directed to a medical professional. Tests of this nature assist in reducing the likelihood of second impact syndrome, which occurs when a second concussion is sustained before a first concussion has fully and properly healed and has an associated mortality.

To determine if a difference in primary language can affect the results of sideline concussion testing, researchers from New York University Langone Medical Center and Icahn School of Medicine at Mount Sinai used the King-Devick Test to evaluate 27 native English speakers and 27 non-native English speakers.

"As with any patient evaluation, the ability of that individual to verbally express himself or herself in the language utilized for the evaluation should be taken into account," explains Lead Investigator, Joel Birkemeier, MD and Primary Investigator John-Ross Rizzo, MD, both from NYU Langone Medical Center, when commenting on addressing language barriers in testing.

The participants were predominately female with an age range of 24 to 52 years. Those who were non-native English speakers represented a number of primary languages with Spanish and Chinese being the most common. The participants were all healthy and had no history of concussion. Each participant completed a survey to determine how dominant they were in their primary language versus English as well as King-Devick test, which was administered in a controlled, non-sporting environment.

"While we have multiple ways of moving our eyes (all controlled by different brain regions), the King-Devick Test mainly assesses one type -- the very rapid eye movements used to quickly dart the eyes between objects of interest," explains Drs. Birkemeier and Rizzo.

"These eye movements are called saccades. When we make a saccade, there are multiple components of the eye movement behavior that we can assess, such as how quickly the movement begins, how fast the movement progresses, and whether the movement lands the eye on the target accurately. We can also look at how long the eye has to rest before it makes a saccade to the next number in the test. In this study, we compare these components of saccades and rest periods between the two groups to look at the differences."

The researchers found the King-Devick test times for non-English speakers were significantly longer than English speakers. Additionally, the 'rest periods' or time interval between one fast saccadic eye movement and another was longer for non-English speakers, which the researchers say represents -- in part -- the time necessary to identify and speak each number in the King-Devick test. Finally, those who scored less dominant in their primary language were able to complete the test in a shorter time period.

"In this scenario, it is important to take linguistic background into account, because the average score of a non-native speaker was more similar to that of an individual who had suffered a concussion than to a non-concussed individual," explains Drs. Birkemeier and Rizzo of the findings. The King-Devick Test assesses ocular motor performance, but other things (such as concentration and linguistics) need to be taken into consideration when evaluating individuals with a suspected concussion. This study expands the knowledge of how to interpret King-Devick scores in individuals with a history of speaking English as their second language, and it provides another reason why there is a longer fixations or 'rest periods' and longer total test completion times, which is due to language rather than concussion."

While these findings are intriguing, if the test is administered according to the King-Devick instructions with a proper pre-season baseline, the linguistic delays would be factored into their initial scores, allowing for further deficits, following the potential head impact, to be secondary to the suspected concussive event itself. However, as more normative data is published, and clinicians interview patients who do not have the benefit of integrated pre-season testing, these linguistic factors must be accounted for and considered when comparing their performance to reference ranges.

In the future, Drs. Birkemeier and Rizzo would like to initiate a larger study to assess athletes who are non-native English speakers with pre-season baseline scores and study how well they perform on the King-Devick test in their native language, among several others.