King-Devick Test Research Articles

Effects of Exercise on EEG Activity and Standard Tools Used to Assess Concussion.

A variety of cognitive assessment tools are used to determine the functional status of the brain before and after injury in athletes. Questionnaires, neuropsychological tests, and electroencephalographic (EEG) measures have been recently used to directly assess brain function on and near the playing field. However, exercise can affect cognitive performance and EEG measures of cortical activity. To date, little empirical evidence exists on the effects of acute exercise on these measures of neurological function. We therefore quantified athlete performance on a standardized battery of concussion assessment tools and EEG measurements immediately before and after acute exercise to simulate conditions of athletic competition. Heart rate and arterial oxygen levels were collected before and after the exercise challenge consisting of a 1-mile run. Together these data, from a gender-balanced cohort of collegiate athletes, demonstrated that moderate to hard levels of acute exercise improved performance on the King-Devick test (K-D test) and Standardized Assessment of Concussion (SAC) component of the Sport Concussion Assessment Tool (SCAT3). Gender played an important role in these effects, and performance was most affected by exercise in female athletes. EEG activity in the theta band (4–8 Hz) was decreased during periods of quiet resting with eyes open or eyes closed. Additionally, exercise produced a slowing of the EEG during the K-D test and a shift to higher frequencies during the balance assessment of the SCAT3. Together, these data indicate that exercise alone can influence outcome measures of cognitive assessment tools used to assess brain function in athletes. Finally, care must be taken to acquire postinjury measurements during a comparable physiologic state to that in which baseline assessment data were measured, and further research is needed into the factors influencing outcome measures of these tests.

VESTIBULAR AND OCULAR MOTOR FINDINGS IN ACUTELY INJURED 8-12-YEAR-OLD PATIENTS FOLLOWING CONCUSSION

Background:Vestibular and ocular motor deficits have been recognized as a key marker of the pathophysiology consistent with the diagnosis of concussion (Grady, 2010). Previous studies have been per...

History and Future Directions of Vision Testing in Head Trauma.

Concussion leads to neurophysiologic changes that may result in visual symptoms and changes in ocular motor function. Vision-based testing is used increasingly to improve detection and assess head injury. This review will focus on the historical aspects and emerging data for vision tests, emphasizing rapid automatized naming (RAN) tasks and objective recording techniques, including video-oculography (VOG), as applied to the evaluation of mild traumatic brain injury. Searches on PubMed were performed using combinations of the following key words: "concussion," "mild traumatic brain injury," "rapid automatized naming," "King-Devick," "mobile universal lexicon evaluation system," "video-oculography," and "eye-tracking." Additional information was referenced from web sites of vendors of commercial eye-tracking systems and services. Tests of rapid number, picture, or symbol naming, termed RAN tasks, have been used in neuropsychological studies since the early 20th century. The visual system contains widely distributed networks that are readily assessed by a variety of functionally distinct RAN tasks. The King-Devick test, a rapid number naming assessment, and several picture-naming tests, such as the Mobile Universal Lexicon Evaluation System (MULES) and the modified Snodgrass and Vanderwart image set, show capacity to identify athletes with concussion. VOG has gained widespread use in eye- and gaze-tracking studies of head trauma from which objective data have shown increased saccadic latencies, saccadic dysmetria, errors in predictive target tracking, and changes in vergence in concussed subjects. Performance impairments on RAN tasks and on tasks recorded with VOG are likely related to ocular motor dysfunction and to changes in cognition, specifically to attention, memory, and executive functioning. As research studies on ocular motor function after concussion have expanded, so too have commercialized eye-tracking systems and assessments. However, these commercial services are still investigational and all vision-based markers of concussion require further validation. RAN tasks and VOG assessments provide objective measures of ocular motor function. Changes in ocular motor performance after concussion reflect generalized neurophysiologic changes affecting a variety of cognitive processes. Although these tests are increasingly used in head injury assessments, further study is needed to validate them as adjunctive diagnostic aids and assessments of recovery.

Evaluation of the Commercial, Off-the-Shelf (COTS) King-Devick Eye Tracking System.

Concussion biomarkers are important guides for diagnosis and return-to-duty decisions. Recent literature describes the King-Devick (KD) test as a sensitive sports-related concussion screener. This test involves timing an individual reading aloud 120 digits printed on three test cards. The test is commonly considered to evaluate the effects of concussion and other factors on reading-related eye movements (EMs). However, the extent to which the KD test reflects EMs remains a matter of conjecture since the test reports only reading speed and number of errors. An off-the-shelf, computerized KD with eye tracking system recently became commercially available. Two early model KD with eye tracking systems were purchased in 2015 and evaluated before deploying them for research. The evaluation consisted of two studies; one with 20 volunteers assessing the comparability of the two systems and the other with 5 volunteers to quantify the systems' stability and repeatability over 5 successive days. The results showed that several of the systems' reported EM response parameters lacked face validity; consequently, the systems could not be used for scientific research. This conclusion emphasizes the importance of systematic test and evaluation of new equipment before it is used for research.

Assessment of vision in concussion.

To review emerging vision-based assessments in the evaluation of concussion. Involvement of the visual pathways is common following concussion, the mildest form of traumatic brain injury. The visual system contains widely distributed networks that are prone to neurophysiologic changes after a concussion, resulting in visual symptoms and ocular motor dysfunction. Vision-based testing is increasingly used to improve detection and assess head injury. Several rapid automatized naming (RAN) tasks, such as the King-Devick test and the Mobile Universal Lexicon Evaluation System, show capacity to identify athletes with concussion. Video-oculography (VOG) has gained widespread use in eye-tracking and gaze-tracking studies of head trauma from which objective data have shown increased saccadic latencies, saccadic dysmetria, errors in predictive target tracking, and changes in vergence in concussed individuals. RAN tasks demonstrate promise as rapid screening tools for concussion. Further investigation will involve assessment of the role for age, characterization of learning effects over repeated measurements, and identification of optimal thresholds for clinically significant performance decrements. Various RAN tasks are likely to be functionally distinct, engaging different neural networks according to the demands of each task. Measures of saccades, smooth pursuit eye-movements, the vestibulo-ocular reflex and, more recently, disparity vergence are candidate vision-based markers for concussion. Work to adopt these assessments to the sideline or clinical environments is ongoing.

Premorbid migraine history as a risk factor for vestibular and oculomotor baseline concussion assessment in pediatric athletes.

Migraine history has recently been identified as a risk factor for concussion and recovery. The authors performed a cross-sectional study examining baseline outcome measures on newly developed and implemented concussion assessment tools in pediatrics. The purpose of this study was to examine the effects of premorbid, diagnosed migraine headaches as a risk factor on vestibular and oculomotor baseline assessment in pediatric athletes. Pediatric athletes between the ages of 8 and 14 years with a diagnosed history of migraine headache (n = 28) and matched controls without a history of diagnosed migraine headache (n = 28) were administered a baseline concussion assessment battery, consisting of the Vestibular/Ocular Motor Screening (VOMS), near point of convergence (NPC), and the King-Devick (K-D) tests. Between-groups comparisons were performed for vestibular symptoms and provocation scores on the VOMS (smooth pursuit, saccades, convergence, vestibular/ocular reflex, visual motion sensitivity), NPC (average distance), and K-D (time). Individuals diagnosed with migraine headaches reported greater VOMS smooth pursuit scores (p = 0.02), convergence scores (p = 0.04), vestibular ocular reflex scores (p value range 0.002-0.04), and visual motion sensitivity scores (p = 0.009). Differences were also observed on K-D oculomotor performance with worse times in those diagnosed with migraine headache (p = 0.02). No differences were reported on NPC distance (p = 0.06) or headache symptom reporting (p = 0.07) prior to the VOMS assessment. Pediatric athletes diagnosed with migraine headaches reported higher baseline symptom provocation scores on the VOMS. Athletes with migraine headaches also performed worse on the K-D test, further illustrating the influence of premorbid migraine headaches as a risk factor for elevated concussion assessment outcomes at baseline. Special consideration may be warranted for post-concussion assessment in athletes with migraine headaches.

Examining the Utility of a Novel Neurologic Test in Patients With Obstructive Sleep Apnea: A Pilot Study.

Purpose: To test the association between participant King-Devick Test (KDT) times and obstructive sleep apnea (OSA) severity and evaluate for improvement after continuous positive airway pressure (CPAP) treatment. Methods: Study dates January 30 to July 31, 2018. Patients were referred for initial evaluation of sleep disordered breathing concerns. OSA severities were defined by Apnea Hypopnea Index (AHI) results, with ≥15 considered at least moderate OSA. The KDT is an objective physical measure of brain function. We estimated correlation between KDT time and AHI and compared mean KDT time between patients with and without moderate OSA. For the OSA subgroup, we evaluated for potential improvement in KDT after CPAP. Results: We enrolled 60 participants, of whom 35 (58.3%) had OSA with an AHI ≥15. Initial analyses noted no significant KDT time differences between patients based on OSA severity. However, after excluding 3 participants who had baseline neurologic illness, adjusted analyses demonstrated that mean KDT time was significantly prolonged for patients with moderate or greater OSA (AHI ≥15) as compared to those with mild or no sleep apnea (AHI <15); 63.4 seconds (95% CI 58.9-67.8) versus 55.7 seconds (95% CI 50.2-61.1), P = .03. CPAP-treated subjects demonstrated significantly improved KDT test times; 63.5 seconds mean pretreatment versus 55.6 posttreatment; −6.6 seconds mean difference, 95%CI (−12.0, −1.13), P = .02. Conclusion: Neurologic abnormalities in patients with OSA are potentially demonstrable utilizing this objective physical measure. Significant improvement is achieved in patients after CPAP treatment.

Measurement of resident fatigue using rapid number naming

ObjectiveSleep deprivation has a negative effect on neurocognitive performance. The King-Devick test (KDT), which tests speed and accuracy of number-reading, requires integrity of saccades, visual processing, and cognition. This study investigated effects of sleep deprivation in on-call residents using KDT. MethodsA prospective cohort study was conducted among 80 residents. KDT was performed at the beginning and end of an overnight call shift for the residents in the experimental group. A control group was tested at the beginning of 2 consecutive day shifts. Estimates of hours of sleep, Karolinska Sleepiness Scale (KSS)(1 = extremely alert, 9 = extremely sleepy), and time and accuracy of KDT were recorded. Results42 residents were tested before and after overnight call shifts and 38 served as controls. Change in test time differed between the groups, with the experimental group performing 0.54(SD = 4.0) seconds slower after their night on call and the control group performing 2.32(SD = 3.0) seconds faster on the second day, p < 0.001. This difference was larger in surgical compared to medical residents. ConclusionsSleep deprivation was inversely correlated with neurocognitive performance as measured by KDT, with more effect on surgical than medical residents. Further research could investigate whether this test could help determine fatigue level and ability to continue working after a long shift.

The King-Devick test in an outpatient concussion clinic: Assessing the diagnostic and prognostic value of a vision test in conjunction with exercise testing among acutely concussed adolescents

ObjectiveThis study investigated the diagnostic and prognostic value of the King-Devick (K-D) test in conjunction with treadmill testing in adolescents after sport-related concussion (SRC) in an outpatient concussion management clinic without baseline measures. DesignProspective cohort. MethodsThe K-D test was administered pre- and post-exercise on a graded treadmill test to acutely concussed (AC, <10 days from injury, n = 46, 15.4 ± 2.1 years) participants for 2 clinic visits (1 week apart) and to matched controls (MC, n = 30, 15.8 ± 1.4 years) for 2 visits (1 week apart). Initial K-D test times were compared between MC and AC. Changes in times from pre- to post- exercise during a treadmill test were compared for MC and AC and from Visit 1 to Visit 2. Smooth pursuits and repetitive saccades were compared with initial visit K-D test performance. ResultsComparison of pre-exercise K-D test times at Visit 1 distinguished MC from AC (46.1 ± 9.2 s vs. 53.7 ± 13.0 s, p = .007). Comparison of pre- and post-exercise K-D test times revealed significant improvements for MC (46.1 ± 9.2 s vs. 43.1 ± 8.5 s, p < .001) and AC who recovered by Visit 2 (Fast Recovery Group [FRG], n = 23, 50.4 ± 10.0 s vs. 47.3 ± 9.8 s, p = .002). No significant difference was seen in pre- and post-exercise K-D test times on Visit 1 for AC who took longer than 2 weeks to recover (Slow Recovery Group [SRG], n = 23, 57.0 ± 15.0 s vs. 56.0 ± 16.3 s, p = .478). At Visit 1, AC had more abnormal smooth pursuits than MC (17% vs. 3%, non-significant, p = .064). AC, however, had significantly more abnormal repetitive saccades than MC (37% vs. 3%, p = .001) and AC with abnormal repetitive saccades took significantly longer to complete the Visit 1 pre-exercise K-D test than AC with normal repetitive saccades (58.6 ± 16.0 s vs 50.8 ± 10.2 s, p = .049). ConclusionThe study supports utility of the K-D test as part of outpatient concussion assessment. Lack of improvement in K-D test performance after an exercise test may be an indicator of delayed recovery from SRC.

The King-Devick test in mixed martial arts: the immediate consequences of knock-outs, technical knock-outs, and chokes on brain functions

ABSTRACTThe aim of this prospective cohort study was to determine the effect of an ‘event,’ defined as a knock-out (KO), technical knock-out (TKO), choke, or submission, on King-Devick (K-D) test times in mixed martial arts (MMA) athletes. MMA athletes (28.3 ± 6.6 years, n = 92) underwent K-D testing prior to and following a workout or match. Comparison of baseline and post-workout/match K-D times to assess any significant change. K-D tests worsened (longer) in a majority of athletes following an ‘event’ (N = 21) (49.6 ± 7.8 s vs 46.6 ± 7.8 s, p = 0.0156, Wilcoxon signed-rank test). K-D tests improved (shorter) following a standard workout or match in which no ‘event’ occurred in a majority of cases (n = 69) (44.2 ± 7.2 s vs 49.2 ± 10.9 s, p = <0.0001, Wilcoxon signed-rank test). Longer duration (worsening) of post-match K-D tests occurred in most athletes sustaining an ‘event’; K-D tests shortened (improved) in a majority of athletes not sustaining an ‘event’. Our study suggests MMA athletes suffering an ‘event’ may have sustained a brain injury similar to a concussion.

Concussion in adolescent rugby union players: comprehensive acute assessment protocol and development of the SSC concussion passport to monitor long-term health

IntroductionSports-related concussion (SRC) can be challenging to diagnose, assess and manage. Much of the SRC research is conducted on adults. The assessment of SRC should aim to identify deficits using...

King-Devick Test Time Varies by Testing Modality.

To explore differences in baseline King-Devick Test (KD) completion time between 2 testing modalities: (1) spiral-bound paper cards (cards) and (2) iPad application (iPad). Cross-sectional cohort analysis. National Collegiate Athlete Association (NCAA) institutions. Student athletes from 13 women's and 11 men's collegiate sports who completed KD baseline testing as part of their first year in the Concussion Assessment, Research and Education (CARE) Consortium from 2014 to 2016 (n = 2003, 52.2% male). King-Devick Test modalities; cards or iPad. Baseline KD completion time (seconds). Mean baseline KD completion time of the iPad modality group [42.8 seconds, 95% confidence interval (CI), 42.1-43.3] was 2.8 seconds (95% CI, 2.1-3.4) greater than the cards group (40.0 seconds, 95% CI, 39.7-40.3) (t(1, 1010.7) = -8.0, P < 0.001, Cohen's d = 0.41). Baseline KD performance is slower when tested on an iPad than when tested on spiral-bound paper cards. The 2 KD modalities should not be used interchangeably in concussion assessments because differences in the modalities can lead to time differences similar in magnitude to those used to indicate concussion. From a research perspective, modality may influence interpretation and/or synthesis of findings across studies.

Pre-season concussion assessment utilizing the King-Devick Test

ABSTRACTThis study’s objectives were to assess the test-retest reliability and concurrent validity of the King-Devick Test (KDT) during concussion screening and to analyze potential sport-specific differences in test performance across two sports. Two hundred and sixty-six high school male American football and soccer players recruited from four area high schools participated prior to the fall sports season. Main outcome measures included the KDT and Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). KDT performance demonstrated significant correlations with the ImPACT visual motor speed composite scores, reaction time, Cognitive Efficiency Index and age. Significant baseline differences were noted on the KDT between football and soccer players. The KDT demonstrates concurrent validity with three neurocognitive domains on the ImPACT. Significant differences in baseline King-Devick Test scores were found between football and soccer players and may be related to the neurocognitive demands of the sport.

Impact of Factors that Affect Reading Skill Level on King-Devick Baseline Performance Time.

The King-Devick (K-D) test is often used as part of a multimodal assessment to screen for sport-related concussion. However, the test involves reading numbers, and little is known about variation in baseline performance on the K-D by reading skill level. We conducted a cross-sectional study analyzing data from the Concussion Assessment, Research and Education (CARE) Consortium to assess differences in baseline performance on the K-D associated with factors that impact reading skill level (learning disorder [LD] and primary home language other than English [PHLOTE]), while controlling for covariates (gender, type of sport, attentional issues, history of concussion and modality of administration). We had a sample of 2311 student-athletes (47% female), and multivariate regression indicated an average K-D performance time of 40.4s. Presence of LD was associated with a 3.3s slower K-D time (95% CI 1.9-4.7, p < 0.001), and PHLOTE was associated with a 2.6s slower K-D time (95% CI 1.2-4.0, p < 0.001), after controlling for other covariates. These results suggest caution in the use of normative data with the K-D. Future studies should explore the impact of factors associated with reading skill level on sensitivity of the K-D in detecting concussion.

The Self-Efficacy of Certified Athletic Trainers in Assessing and Managing Sport-Related Concussions.

Diagnostic and return-to-play assessments of athletes with sport-related concussions (SRCs) have changed dramatically over the past decade. Currently, SRC assessment and management has taken a multifaceted approach, with new SRC measures being developed yearly. However, to date, no researchers have examined certified athletic trainers' (ATs') self-efficacy in assessing and managing a patient with an SRC. To examine the self-efficacy of ATs in assessing and managing athletes with SRCs, with a secondary purpose of examining job setting (high school and college). Cross-sectional study. Web-based questionnaire. A total of 94 ATs (high school setting = 54.3%, n = 51; collegiate setting = 45.7%, n = 43) completed an online survey, for a response rate of 9.2%. The survey contained 3 primary subsections: demographics, self-efficacy in assessing SRCs, and self-efficacy in managing SRCs. Possible self-efficacy ratings for SRC assessment and management in the survey ranged from 0 to 100. Multivariate analyses of variance were performed to identify differences in the self-efficacy of high school and collegiate ATs in assessing and managing athletes with SRCs. The self-efficacy of all 94 participants in their assessment of SRCs was 60.34 ± 14.5 and in their management of SRCs was 55.30 ± 14.1. Collegiate ATs reported higher self-efficacy in the assessment of SRCs using balance ( P < .001) and the King-Devick test ( P = .04), and their responses approached significance for vestibular-ocular motor screening ( P = .05). Additionally, their self-efficacy in the management of SRCs was greater using balance ( P < .001) and vestibular-ocular therapy ( P = .01) compared with high school ATs. Athletic trainers had moderate self-efficacy regarding their assessment and management of SRCs. Collegiate ATs had higher self-efficacy in newer SRC assessment and management tools than high school ATs.

Use of the King-Devick test and Brain Gauge for the management of concussion

Use of the King-Devick test and Brain Gauge for the management of concussion

Traumatic brain injury results in altered physiologic, but not subjective responses to emotional stimuli

ABSTRACTBackground: While the cognitive sequelae of traumatic brain injury (TBI) are well known, emotional impairments after TBI are suboptimally characterized. Lack of awareness of emotional difficulties can make self-report unreliable. However, individuals with TBI demonstrate involuntary changes in heart rate variability which may enable objective quantification of emotional dysfunction.Methods: Sixteen subjects with chronic TBI and 10 age-matched controls were tested on an emotional function battery during which they watched a series of film clips normed to elicit specific positively and negatively valenced emotions: amusement, sexual amusement, sadness, fear and disgust. Subjective responses to the emotional stimuli were also obtained. Additionally, surface electrodes measured cardiac and respiratory signals to compute heart rate variability (HRV), from which measures of parasympathetic activity, the respiratory frequency area (RFA) and sympathetic activity, the low frequency area (LFA), of the HRV frequency spectrum were derived. The Neurobehavioral Rating Scale-Revised (NRS-R) and the King-Devick (KD) test were administered to assess neurobehavioral dysfunction.Results: The two groups showed no differences in subjective ratings of emotional intensity. Subjects with TBI showed significantly decreased sympathetic activity when viewing amusing stimuli and significantly increased sympathetic activity when viewing sad stimuli compared to controls. Most of the subjects did not show agitation, anxiety, depression, blunted affect, emotional withdrawal, decreased motivation or mental fatiguability on the NRS-R. However, 13/16 subjects with TBI demonstrated attention difficulty on the NRS-R which was positively correlated with the increased sympathetic activity during sad stimuli. Both attention difficulty and abnormal autonomic responses to sad stimuli were correlated with the timing on the KD test, which reflected difficulty with visual attention shifting.Conclusions: The HRV spectrum may be useful to identify subclinical emotional dysfunction in individuals with TBI. Attention difficulites, specifically impairment in visual attention shifting, may contribute to abnormal reactivity to sad stimuli that may be detected and potentially treated to improve emotional function.

In situ use of the King-Devick eye tracking test and changes seen with sport-related concussion: saccadic and blinks counts

ABSTRACTObjectives: Sport-related concussion (SRC) can result in impaired oculomotor function. Oculomotor performance, measured utilizing the King-Devick/Eye Tracking test (K-D/ET), is reported to be able to identify sub-optimal brain function. The objectives of the study were to determine the diagnostic accuracy of the K-D/ET in identifying SRC occurring from game participation and to perform a comparative analysis on saccade and blink counts for each K-D card individually and total counts between baseline and post-concussion.Methods: Nineteen male Australian Football players were assessed on the K-D/ET test. Those suspected of having SRC secondary to a head impact were also tested.Results: Participants recorded a slower time on the third (20.2 ± 4.6 s) screen when compared with the first (p = 0.0424) and second (p = 0.0150) screens. The number of blinks was higher on the third (2.9 ± 2.9) when compared with the second (p = 0.0057) screen. There was decrease of the K-D/ET total times between pre- and post-game (p = 0.1769). Participants who sustained a head impact recorded slower mean total K-D time (p = 0.7322), fewer mean total saccades (p = 0.0112), and more mean blinks (p = 0.8678) compared with their baseline scores. The assessment of blinks was the most sensitive measure for potential SRC (0.67). The K-D/ET duration was the most specific measure for potential SRC (0.88). An increase in the number of blinks had a fair specificity of 0.69.Conclusion: The rapid number-naming component of the K-D test is an assessment tool which quantifies impairment to oculomotor function and has been validated as a diagnostic tool for SRC. The clinical usefulness of the eye tracking component of the K-D/ET test is that it may be an effective method to assess concussions with the eye tracking component serving as a measure of progression and return to play. However, more research is required at the adult and youth level.

King-Devick test normative reference values and internal consistency in youth football and soccer athletes.

The King-Devick (K-D) test has gained popularity as a sideline concussion assessment tool, comprising of visual tracking and saccadic eye movements. However, limited normative data exist for youth athletes under the age of 13. The purpose of this study was to establish normative reference values and examine the internal consistency of the K-D test in youth athletes. The K-D test was administered to 422 youth football and soccer athletes prior to their respective season. The average K-D score was 54.29±11.5seconds. Across the two trials, 55% of participants committed at least one error. Overall, the K-D test demonstrated a high internal consistency (Cronbach α=0.92) when administered at baseline. Inter-item correlations revealed a moderate-to-strong relationship between test cards and trials (r range=0.71 to 0.95; P<0.001), along with test cards and baseline K-D time (r range=0.85 to 0.94; P<0.001). Although the K-D test was consistent during baseline testing, the high percentage of errors at baseline makes the K-D test questionable for post-concussion comparisons.

The effect of linguistic background on rapid number naming: implications for native versus non-native English speakers on sideline-focused concussion assessments

ABSTRACTObjective: To determine if native English speakers (NES) perform differently compared to non-native English speakers (NNES) on a sideline-focused rapid number naming task. A secondary aim was to characterize objective differences in eye movement behaviour between cohorts.Background: The King-Devick (KD) test is a rapid number-naming task in which numbers are read from left-to-right. This performance measure adds vision-based assessment to sideline concussion testing. Reading strategies differ by language. Concussion may also impact language and attention. Both factors may affect test performance.Methods: Twenty-seven healthy NNES and healthy NES performed a computerized KD test under high-resolution video-oculography. NNES also performed a Bilingual Dominance Scale (BDS) questionnaire to weight linguistic preferences (i.e., reliance on non-English language(s)).Results: Inter-saccadic intervals were significantly longer in NNES (346.3 ± 78.3 ms vs. 286.1 ± 49.7 ms, p = 0.001), as were KD test times (54.4 ± 15.1 s vs. 43.8 ± 8.6 s, p = 0.002). Higher BDS scores, reflecting higher native language dominance, were associated with longer inter-saccadic intervals in NNES.Conclusion: These findings have direct implications for the assessment of athlete performance on vision-based and other verbal sideline concussion tests; these results are particularly important given the international scope of sport. Pre-season baseline scores are essential to evaluation in the event of concussion, and performance of sideline tests in the athlete’s native language should be considered to optimize both baseline and post-injury test accuracy.