Visual Performance of Non-Native Versus Native English Speakers on a Sideline Concussion Screen: Objective Look at Eye Movement Recordings

Objective: We performed a laboratory-based eye movement study during performance of the King-Devick (KD) test of rapid number naming. We sought to determine if having English as a second language results in slower KD reading times or changes in eye movements. Background: The KD test, a sensitive, rapid performance measure, adds a visual dimension to sideline testing for Methods: We tested 27 native English speakers (NES) (mean age 32) and 27 subjects for whom English was a second language (ESL) (mean age 34). Participants had no history of concussion. Participants performed a computerized version of the KD. Simultaneous infrared-based videooculographic (VOG) recordings were performed using the Eyelink1000+. A Bilingual Dominance Scale (BDS) survey, which quantifies primary versus secondary language dominance, was completed by all ESL subjects. Results: Digitized KD reading times were significantly prolonged for ESL participants, compared to NES (54.4 ± 15.4 sec vs. 42.8 ± 8.6 sec, p=0.001, Average intersaccadic intervals (ISI), a combined measure of saccade latency and fixation duration, were significantly longer for ESL participants (402 ± 116.9 msec vs. 317.7 ± 53.9 msec, p=0.002, The total number of saccades for ESL participants was significantly higher (149 ± 28 vs. 135 ± 18, p=0.03, t-test). Conclusions: This study highlights performance disparities that linguistics may impose on rapid number-naming tasks. Concussion screening is best implemented by establishment of pre-season baselines to allow for intra-subject comparisons after impact in sport. If pre-season baseline data are unavailable, caution should be taken in comparing non-native English speaker reading times to a NES normative control KD time database. Disclosure: Dr. Dempsey has nothing to disclose. Dr. Birkemeier has nothing to disclose. Dr. Hudson has nothing to disclose. Dr. Dai has nothing to disclose. Dr. Selesnick has nothing to disclose. Dr. Hasanaj has nothing to disclose. Dr. Balcer has received personal compensation for activities with Biogen Idec and Genzyme as a consultant. Dr. Galetta has received personal compensation for activities with Biogen Idec and Genzyme as a consultant. Dr. Rucker has received personal compensation in an editorial capacity for AAN Continuum. Dr. Rizzo has nothing to disclose.