Sideline vision tests often used to detect immediate signs of concussion may give false results for athletes who speak English as a second language.
A new study showed significantly slower vision test times for healthy non-native English speaking participants compared with native English speakers. Further, the computerized eye tracker used in the study also showed that the number of rapid eye movements, known as saccades, were significantly higher in the ESL group than the native English speakers.
The findings could have important implications, particularly amid growing evidence of vision testing’s potential to positively detect concussions on sidelines and its increasing use at games and practices.
4 million concussions a year
“These results highlight important disparities that language has on results of sideline vision testing, which are becoming more utilized in sports,” says study coauthor Joel Birkemeier, a postdoctoral research fellow at New York University’s Rusk Rehabilitation. “When performing sideline vision tests, clinicians and trainers may need to first take into account how language may affect score results.”
“When there’s any doubt if an athlete sustained a concussion during play, take the athlete out.”
The researchers presented their findings at the annual meeting of the Association of Academic Pshysiatrists (AAP) Annual Meeting in Sacramento, California.
Approximately 4 million sports-related concussions occur each year in the United States, with longterm consequences on brain function a growing concern among those who play contact sports. From 2001 to 2009, the rate of emergency department visits for sports and recreation-related injuries with a diagnosis of concussion rose 57 percent among children younger than 19, according to the Centers for Disease Control and Prevention.
For the study, researchers evaluated 54 people—27 native English speakers and 27 ESL speakers—with a computerized version of a vision test known as the King-Devick (K-D) Test. Patients ranged in age from 24 to 52 years old, with Spanish and Chinese being the most common native languages in the ESL group.
In the K-D test, participants are asked to rapidly read numbers presented in irregular patterns from left to right and top to bottom on three test cards, displayed in serial fashion. Times for all three readings are added together, and then that number is compared with a baseline score taken before the season: slower testing times and more errors when reading the numbers may indicate that a concussion has occurred.
Previous studies suggest approximately 50 percent of the brain’s pathways are tied to vision, and K-D tests are used increasingly to provide coaches, trainers, and parents a clue that an athlete should be removed from play and seen by a medical professional. Further, previous research has also shown that the K-D test detects concussion 86 percent of the time among youth, collegiate, and professional athletes tested.
In the new study, researchers used a new infrared-based eye-tracking device called the EyeLink. The EyeLink tracks eye movements while the participants look at a computer interface that contains the number sequences used in the K-D test. The researchers are using the device to develop biomarkers for concussion and other neurological conditions.
The study participants also completed a Bilingual Dominance Scale survey, which measured how dominant they were in their primary, non-English language as opposed to their secondary, English language.
‘Take the athlete out’
In addition to slower test times among the ESL group, “rest” time between saccadic eye movements was significantly longer for the ESL group compared to the native English speaking group—results that might be reflective of the time needed to process and say each number. The total number of saccades for the ESL group was also significantly higher than the native English speaking group. Participants who were less dominant in their primary language performed the vision tests quicker.
Future research will look closer at whether sideline vision testing in other languages influences results, as well as how other demographic characteristics affect the results of the test.
“Regardless of native language, if vision testing is performed properly where an athlete is tested before the season and after a suspected head injury, a drop in score should still suggest that he or she should be removed from play, says lead authors John-Ross Rizzo, assistant professor of rehabilitation medicine and neurology.
“In situations where baselines are not available, and scores are judged against average sideline test results, the comparisons become more precarious. We hope this initiates dialogue on multilingualism in sideline concussion screening. Until the research answers these questions, the bottom line remains—when there’s any doubt if an athlete sustained a concussion during play, take the athlete out.”