VANCOUVER – In a study at New York University, it took 27 healthy, native English–speaking volunteers 42.8 seconds to complete the King-Devick concussion screening test, which is about average for nonconcussed subjects.
However, it took 27 other volunteers with English as a second language 54.4 seconds (P = .001). Had the test been given on the sidelines instead of in a laboratory, the extra 12 seconds might easily have been mistaken as a sign of serious concussion because concussions generally add about 5 seconds to the King-Devick score.
Katharine Dempsey
“A prolongation of 12 seconds in non-native English speakers has real clinical implications,” said lead investigator Katharine Dempsey, a medical student and member of the eye movement research team in the department of neurology at New York University.
King-Devick (KD) is an increasingly popular sideline screening tool used widely in professional sports. Subjects are timed on how long it takes to read out loud and in English three sets of 40 numbers, with each set progressively more difficult to read. It’s administered by flashcards or, as in the study, by computer screen.
All of the non-native speakers at NYU were largely proficient in English, but their native languages – 18 in total, most often Spanish or Chinese – were often dominant, meaning they were used at home and to work out mental arithmetic. Some subjects did not use Roman numerals or right-to-left reading in their native tongues.
KD instructions recommend testing subjects against their own preseason baseline scores; the NYU findings emphasize how important that is when subjects aren’t native English speakers. The investigators are concerned that when baseline scores are unavailable, non-native English speakers will be scored against reference ranges for native speakers.
“There’s incredible utility in using a sideline concussion screening test, but we definitely have to get out the message that the best practice is to take an athlete’s own preseason baseline. We have to be incredibly cautious when comparing test times of non-native English speakers to a normative database for native speakers,” Ms. Dempsey said at the annual meeting of the American Academy of Neurology.
The participants were in their early 30s, on average, and had no histories of concussion. The majority were women, and most were NYU employees or their friends.
The team also tracked eye movements during testing. Non-native speakers had more quick eye movement (149 vs. 135; P = .03), but also fixated longer on numbers before initiating eye movement (345.4 milliseconds vs. 288.0; P = .007). Lag time correlated with native language dominance and suggests longer processing time.
The next step is to test how well patients do with KD testing in their native language, Ms. Dempsey said.
Ms. Dempsey had no disclosures.