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Current Research

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Use of the King-Devick Test for sideline concussion screening in junior rugby league

Aim
To determine whether the King-Devick (K-D) test used as a sideline test in junior rugby league players over 12
matches in a domestic competition season could identify witnessed and incidentally identified episodes of concussion

Methods
A prospective observational cohort study of a club level junior rugby league team (n=19) during the 2014 New
Zealand competition season involved every player completing two pre-competition season baseline trials of the K-D test.
Players removed from match participation, or who reported any signs or symptoms of concussion were assessed on the
sideline with the K-D test and referred for further medical assessment. Players with a pre- to post-match K-D test
difference >3 s were referred for physician evaluation.

Results
The baseline test-retest reliability of the K-D test was high (rs=0.86; p<0.0001). Seven concussions were
medically identified in six players who recorded pre to post-match K-D test times greater than 3 s (mean change of 7.4 s).
Post-season testing of players demonstrated improvement of K-D time scores consistent with learning effects of using the
K-D test (67.7 s vs 62.2 s).

Discussion
Although no witnessed concussions occurred during rugby play, six players recorded pre to post-match
changes with a mean delay of 4 s resulting in seven concussions being subsequently confirmed post-match by health
practitioners. All players were medically managed for a return to sports participation.

Conclusions
The K-D test was quickly and easily administered making it a practical sideline tool as part of the continuum
of concussion assessment tools for junior rugby league players.

Further Reading: Read the whole study at Journal of the Neurological Sciences

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Evaluation of the King-Devick Test as a concussion screening tool in high school football players

Objective
Concussion is the most common type of traumatic brain injury, and results from impact or impulsive forces to
the head, neck or face. Due to the variability and subtlety of symptoms, concussions may go unrecognized or be ignored,
especially with the pressure placed on athletes to return to competition. The King-Devick (KD) test, an oculomotor test
originally designed for reading evaluation, was recently validated as a concussion screening tool in collegiate athletes. A
prospective study was performed using high school football players in an attempt to study the KD as a concussion
screening tool in this younger population.

Methods
343 athletes from four local high school football teams were recruited to participate. These athletes were given
baseline KD tests prior to competition. Individual demographic information was collected on the subjects. Standard team
protocol was employed to determine if a concussion had occurred during competition. Immediately after diagnosis, the
KD test was re-administered to the concussed athlete for comparison to baseline. Post-season testing was also performed
in non-concussed individuals.

Results
Of the 343 athletes, nine were diagnosed with concussions. In all concussed players, cumulative read times for
the KD test were significantly increased (p < 0.001). Post-season testing of non-concussed athletes revealed minimal
change in read times relative to baseline. Univariate analysis revealed that history of concussion was the only
demographic factor predictive of concussion in this cohort.

Conclusions
The KD test is an accurate and easily administered sideline screening tool for concussion in adolescent
football players.

Further Reading: Read the whole study at Journal of the Neurological Sciences

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Gender and age predict outcomes of cognitive, balance and vision testing in a multidisciplinary concussion center

Objective
This study examined components of the Sports Concussion Assessment Tool, 3rd Edition (SCAT3) and a vision-based test of rapid number naming (King–Devick [K-D]) to evaluate sports and non-sports concussion patients in an outpatient, multidisciplinary concussion center. While the Symptom Evaluation, Standardized Assessment of Concussion (SAC), modified Balance Error Scoring System (BESS), and K-D are used typically for sideline assessment, their use in an outpatient clinical setting following concussion has not been widely investigated.

Methods
K-D, BESS, SAC, and SCAT3 Symptom Evaluation scores were analyzed for 206 patients who received concussion care at the Concussion Center at NYU Langone Medical Center. Patient age, gender, referral data, mechanism of injury, time between concussive event and first concussion center appointment, and the first specialty service to evaluate each patient were also analyzed.

Results
In this cohort, Symptom Evaluation scores showed a higher severity and a greater number of symptoms to be associated with older age (r = 0.31, P = 0.002), female gender (P = 0.002, t-test), and longer time between the concussion event and first appointment at the concussion center (r = 0.34, P = 0.008). Performance measures of K-D and BESS also showed associations of worse scores with increasing patient age (r = 0.32–0.54, P ≤ 0.001), but were similar among males and females and across the spectrum of duration since the concussion event. Patients with greater Symptom Severity Scores also had the greatest numbers of referrals to specialty services in the concussion center (r = 0.33, P = 0.0008). Worse Immediate Memory scores on SAC testing correlated with slower K-D times, potentially implicating the dorsolateral prefrontal cortex as a commonly involved brain structure.

Conclusions
This study demonstrates a novel use of sideline concussion assessment tools for evaluation in the outpatient setting, and implicates age and gender as predictors of outcomes for these tests.

Further Reading: Read the whole study at Journal of the Neurological Sciences

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Adding vision to concussion testing: A prospective study of sideline testing in youth and collegiate athletes

Objective
Sports-related concussion commonly affects the visual pathways. Current sideline protocols test cognition and balance, but do not include assessments of visual performance. We investigated how adding a vision-based test of rapid number naming could increase our ability to identify concussed athletes on the sideline at youth and collegiate levels.

Methods
Participants in this prospective study included members of a youth ice hockey and lacrosse league and collegiate athletes from New York University (NYU) and Long Island University (LIU). Athletes underwent pre-season baseline assessments using 1) the King-Devick (K-D) test, a <2-minute visual performance measure of rapid number naming; 2) the Standardized Assessment of Concussion (SAC), a test of cognition; 3) a timed tandem-gait test of balance. The SAC and timed tandem-gait are components of the currently used Sport-Concussion Assessment Tool, 3rd Edition (SCAT3 and Child-SCAT3). In the event of a concussion during the athletic season, injured athletes were re-tested on the sideline/ rink-side. Non-concussed athletes were also assessed as control participants under the same testing conditions.

Results
Among 243 youth (mean age 11±3 years, range 5-17) and 89 collegiate athletes (age 20±1 years, range 18-23), baseline time scores for the K-D test were lower (better) with increasing participant age (p<0.001, linear regression models). Among 12 athletes who sustained concussions during their athletic season, K-D scores worsened from baseline by an average of 5.2 seconds; improvement by 6.4 seconds was noted for the non-concussed controls (n=14). The vision- based K-D test showed the greatest capacity to distinguish concussed vs. control athletes based on changes from pre- season baseline to post-injury (ROC curve areas from logistic regression models, accounting for age=0.92 for K-D, 0.87 for timed tandem gait, and 0.68 for SAC; p=0.0004 for comparison of ROC curve areas).

Conclusions
Adding a vision-based performance measure to cognitive and balance testing enhances the detection capabilities of current sideline concussion assessment. This observation in mild traumatic brain injury patients reflects the common involvement and widespread distribution of the brain pathways dedicated to vision.

Further Reading: Read the whole study at The Journal of Neuro-Ophthalmology

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The King-Devick test was useful in management of concussion in amateur rugby union and rugby league in New Zealand

Aim
To use the King-Devick (K-D) test in senior amateur rugby union and rugby league players over a domestic competition season to see if it could identify witnessed and unwitnessed episodes of concussion that occurred from participation in competition matches over three years.

Methods
A prospective observational cohort study was conducted on a club level senior amateur rugby union team (n=36 players in 2012 and 35 players in 2013) and a rugby league team (n=33 players in 2014) during competition seasons in New Zealand. All 104 players completed two trials 10 minutes apart of the K-D at the beginning of their competition season. Concussions (witnessed or unwitnessed) were only recorded if they were formally diagnosed by a health practitioner.

Results
A total of 52 (8 witnessed; 44 unwitnessed) concussive events were identified over the duration of the study resulting in a concussion injury incidence of 44 (95% CI: 32 to 56) per 1,000 match participation hours. There was a six-fold difference between witnessed and unwitnessed concussions recorded. There were observable learning effects observed between the first and second K-D test baseline testing (50 vs. 45 s; z=-8.81; p<0.001). For every 1 point reduction in each of the post-injury SAC components there was a corresponding increase (worsening) of K-D test times post-match for changes in orientation (2.9 s), immediate memory (1.8 s) concentration (2.8 s), delayed recall (2.0 s) and SAC total score (1.7 s).

Conclusions
The rate of undetected concussion was higher than detected concussions by using the K-D test routinely following matches. Worsening of the K-D test post-match was associated with reduction in components of the SAC. The appeal of the K-D test is in the rapid, easy manner of its administration and the reliable, objective results it provides to the administrator. The K-D test helped identify cognitive impairment in players without clinically observable symptoms.

Further Reading: Read the whole study at Journal of the Neurological Sciences

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Diagnostic tests for concussion: is vision part of the puzzle?

Background
Concussion, particularly in relation to sports and combat activities, is increasingly recognized as a potential cause of both short- and long-term neurologic sequelae. This review will focus on the neuro-ophthalmologic findings associated with concussion, the current tests for concussion, and the potential for visual performance measures to improve our detection and assessment of concussions.

Evidence Acquisition
A PubMed search using the specific key words "concussion," "mild traumatic brain injury," "neuro- ophthalmological findings," and "diagnostic and management tests" was performed. An emphasis was placed on articles published during the past 5 years, but additional articles referenced within recent publications were obtained.

Results
Concussion is frequently associated with abnormalities of saccades, pursuit eye movements, convergence, accommodation, and the vestibular-ocular reflex. Current sideline testing for athletes includes the Sports Concussion Assessment Tool, Third Edition (SCAT3) incorporates cognitive and balance testing. The King-Devick (K-D) test is a rapid visual performance measures that can be used on sidelines by nonmedical personnel, including parents of youth athletes. The K-D test complements components of the SCAT3 and improves the detection of concussions. Other vision-based tools for diagnosing and for managing concussion include eye movement tracking devices, pupillary assessment, computerized testing, imaging modalities, and eletrophysiologic testing. Many of the imaging modalities and electrophysiological studies have been combined with vision-based tests.

Conclusions
Concussion is associated with many neuro-ophthalmologic signs and symptoms. Visual performance measures enhance the detection and management of concussion, and future studies are under way to further incorporate vision-based testing into sideline diagnosis and long-term clinical assessments.

Further Reading: Read the whole study at The Journal of Neuro-Ophthalmology

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The Neuro-ophthalmology of Head Trauma

Lancet Neurol. 2014 Oct;13(10):1006-1016. doi: 10.1016/S1474-4422(14)70111-5.

Summary
Traumatic brain injury (TBI) is a major cause of morbidity and mortality. Concussion, a form of mild TBI, might be associated with long-term neurological symptoms. The effects of TBI and concussion are not restricted to cognition and balance. TBI can also affect multiple aspects of vision; mild TBI frequently leads to disruptions in visual functioning, while moderate or severe TBI often causes structural lesions. In patients with mild TBI, there might be abnormalities in saccades, pursuit, convergence, accommodation, and vestibulo-ocular reflex. Moderate and severe TBI might additionally lead to ocular motor palsies, optic neuropathies, and orbital pathologies. Vision-based testing is vital in the management of all forms of TBI and provides a sensitive approach for sideline or post-injury concussion screening. One sideline test, the King-Devick test, uses rapid number naming and has been tested in multiple athlete cohorts.

Further Reading:
Read the Whole Study at The Lancet Neurology

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Vision Testing Is Additive to the Sideline Assessment of Sports-Related Concussion

Neurol Clin Pract 10.1212/CPJ.0000000000000060

Objective
We examined the King-Devick (K-D) test, a vision-based test of rapid number naming that requires saccadic eye movements, as a complement to the Sport Concussion Assessment Tool, 3rd edition (SCAT3) for diagnosis of concussion.

Background
Visual signs and symptoms are common in concussion; adding a vision-based test may increase diagnostic power for clinicians and others evaluating athletes on the sidelines.

Design/Methods
Baseline and post-concussion data for the University of Florida men's football, women's soccer and women's lacrosse teams were collected, including K-D test, Standardized Assessment of Concussion (SAC) and Balance Error Scoring System (BESS). Post-Concussion Scale (PCS) was also used to assess symptom reporting. Analyses examined changes in scores from baseline to post-injury. The relation of changes in scores for K-D vs. SAC and BESS was determined, as was the relation of K-D scores to symptoms (PCS). Immediate Post-concussion and Cognitive Testing (ImPACT) scores, obtained as part of routine clinical practice for concussion management, but not diagnoses, were also correlated with K-D and SAC scores at baseline.

Results
Among 30 athletes with first concussion during their athletic season (n=217 total), differences from baseline to post-injury (witnessed event or time of reporting) showed worsening of K-D time scores in 79%, while SAC showed a ≥2-point worsening in 52%. Combining K-D and SAC captured abnormalities in 89%; adding the BESS identified 100% of concussions. Symptom severity scores on the PCS worsened from baseline with increases in K-D scores (p<0.001); among specific symptoms, light and noise sensitivities were particularly well correlated with K-D worsening. Baseline scores for the ImPACT testing visual motor speed sub-score were worse for athletes who required longer times to complete the K-D test at baseline (p<0.001, linear regression).

Conclusions
Adding a vision-based test may allow us to detect more athletes with concussion. This is particularly important since not all athletes reliably report symptoms of concussion, including those related to visual function.

Further Reading:
Read the Whole Study at Neurology: Clinical Practice

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The King-Devick Test as a Determinant of Head Trauma and Concussion in Boxers and MMA Fighters

Neurology. April 26, 2011; 76(17): 1456-62.

Objective

Sports-related concussion has received increasing attention as a cause of short- and long-term neurologic symptoms among athletes. The King-Devick Test is based on measurement of the speed of rapid number naming (reading aloud single digit numbers from three test cards), and captures impairment of eye movements, attention, language, and other correlates of suboptimal brain function. We investigated the King-Devick Test as a potential rapid sideline screening for concussion in a cohort of boxers and mixed martial arts (MMA) fighters.

Methods
The K-D test was administered prefight and postfight. The Military Acute Concussion Evaluation (MACE) was administered as a more comprehensive but longer test for concussion. Differences in postfight K-D scores and changes in scores from prefight to postfight were compared for athletes with head trauma during the fight vs those without.

Results
Postfight K-D scores (n=39 participants) were significantly higher (worse) for those with head trauma during the match (59.1+/- 7.4 vs 41.0 +/- 6.7 seconds, p<0.0001, Wilcoxon rank sum test). Those with loss of consciousness showed the greatest worsening from prefight to post fight. Worse post fight K-D scores (rs= -0.79, p=0.0001) and greater worsening of scores (rs= 0.90, p<0.0001) correlated well with post fight MACE scores. Worsening of K-D scores by >/= 5 seconds was a distinguishing characteristic noted only among participants with head trauma. High levels of test-retest reliability were observed (intraclass correlation coefficient 0.97 [95% confidence interval 0.90-1.0]).

Conclusions
The King-Devick Test is an accurate and reliable method for identifying athletes with head trauma, and is a strong candidate rapid sideline screening test for concussion.

Further Reading
Read the whole study at Neurology

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Saccades and Memory: Baseline associations of the King-Devick and SCAT2 SAC tests in professional ice hockey players

Journal of the Neurological Sciences. May15, 2013; 328(1-2): 28-31.

Objective
The Sports Concussion Assessment Tool 2 (SCAT2) and King-Devick (K-D) tests have both been proposed as sideline tools to detect sports-related concussion. We performed an exploratory analysis to determine the relation of SCAT2 components, particularly the Standardized Assessment of Concussion (SAC), to K-D test scores in a professional ice hockey team cohort during pre-season baseline testing. We also examined changes in scores for two athletes who developed concussion and had rinkside testing.

Methods
A modified SCAT2 (no balance testing) and the K-D test, a brief measure of rapid number naming, were administered to 27 members of a professional ice hockey team during the 2011-2012 pre-season. Athletes with concussion also underwent rinkside testing.

Results
Lower (worse) scores for the SCAT2 SAC Immediate Memory Score and the overall SAC score were associated with greater (worse) times required to complete the K-D test at baseline. On average, for every 1-point reduction in SAC Immediate Memory Score, we found a corresponding increase (worsening) of K-D time score of 7.3s (95% CI 4.9, 9.7 p < 0.001, R2 = 0.62, linear regression, accounting for age). For the overall SAC score, 1-point reductions were associated with K-D score worsening of 2.2s (95% CI 0.6, 3.8, p = 0.01, R2 = 0.25, linear regression). In two players tested rinkside immediately following concussion, K-D test scores worsened from baseline by 4.2 and 6.4s. These athletes had no differences found for SCAT2 SAC components, but reported symptoms of concussion.

Conclusion
In this study of professional athletes, scores for the K-D test, a measure for which saccadic (fast) eye movements are required for the task of rapid number naming, were associated with reductions in Immediate Memory at a pre-season baseline. Both working memory and saccadic eye movements share closely related anatomical structures, including the dorsolateral prefrontal cortex (DLPFC). A composite of brief rapid sideline tests, including SAC and K-D (and balance testing for non-ice hockey sports), is likely to provide an effective clinical tool to assess the athlete with suspected concussion.

Further Reading
Read the whole study at the Journal of the Neurological Sciences

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Use of a rapid visual screening tool for the assessment of concussion in amateur rugby league: A pilot study

Journal of the Neurological Sciences. September 15, 2012; 320(1-2): 16-21.

Aim
This study undertook to use the K-D sideline test with the SCAT2 to see if concussions could be identified in amateur rugby league players over a representative competition period.

Method
A prospective cohort study was conducted on two teams participating in an amateur rugby league. All players were tested for signs of concussion utilising the K-D test and players with longer times than their baseline scores undertook a further concussion assessment with the SCAT2.

Results
Five athletes with suspected concussion were evaluated by K-D testing. Three concussions were associated with witnessed events during the matches and two athletes were identified by the team medic as having longer K-D time scores incidentally post-match compared to baseline. Post-match K-D scores for all concussed athletes were worse than baseline for those with reported or witnessed concussion events (7 s; 5.0–7.1; p = 0.025) and for those identified incidentally (> 5 s; 8.9–9.1 s). Both groups also reported more symptoms on the PCSS (a part of the SCAT2) post-match.

Discussion
In this rugby cohort, the K-D test was not only useful in identifying changes in players with witnessed head trauma, but in identifying changes in players with an un-witnessed suspected concussion.

Further Reading
Read the whole study at the Journal of the Neurological Sciences

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The King–Devick Test and Sports-Related Concussion: Study of a Rapid Visual Screening Tool in a Collegiate Cohort

Journal of the Neurological Sciences. October 15, 2011; 309(1-2): 34-9.

Objective
Concussion, defined as an impulse blow to the head or body resulting in transient neurologic signs or symptoms, has received increasing attention in sports at all levels. The King–Devick (K–D) test is based on the time to perform rapid number naming and captures eye movements and other correlates of suboptimal brain function. In a study of boxers and mixed martial arts (MMA) fighters, the K–D test was shown to have high degrees of test–retest and inter-rater reliability and to be an accurate method for rapidly identifying boxers and mixed martial arts fighters with concussion. We performed a study of the K–D test as a rapid sideline screening tool in collegiate athletes to determine the effect of concussion on K–D scores compared to a pre-season baseline.

Methods
In this longitudinal study, athletes from the University of Pennsylvania varsity football, sprint football, and women's and men's soccer and basketball teams underwent baseline K–D testing prior to the start of the 2010–11 playing season. Post-season testing was also performed. For athletes who had concussions during the season, K–D testing was administered immediately on the sidelines and changes in score from baseline were determined.

Results
Among 219 athletes tested at baseline, post-season K–D scores were lower (better) than the best pre-season scores (35.1 vs. 37.9 s, P = 0.03, Wilcoxon signed-rank test), reflecting mild learning effects in the absence of concussion. For the 10 athletes who had concussions, K–D testing on the sidelines showed significant worsening from baseline (46.9 vs. 37.0 s, P = 0.009), with all except one athlete demonstrating worsening from baseline (median 5.9 s).

Conclusion
This study of collegiate athletes provides initial evidence in support of the K–D test as a strong candidate rapid sideline visual screening tool for concussion. Data show worsening of scores following concussion, and ongoing follow-up in this study with additional concussion events and different athlete populations will further examine the effectiveness of the K–D test.

Further Reading
Read the whole study at the Journal of the Neurological Sciences

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Concussions in amateur rugby union identified with the use of a rapid visual screening tool

Journal of the Neurological Sciences. January 29 2013. pii S0022-510X(13)00014-2. doi: 10.1016/j.jns.2013.01.012. [Epub ahead of print].

Aim
To use the King-Devick (KD) test and Sports Concussion Assessment Tool 2 (SCAT2) in amateur rugby union players to identify witnessed and unrecognized episodes of concussion that occurred from match participation.

Methods
A prospective observational cohort study was conducted on a premier club level amateur rugby union team during the 2012 competition in New Zealand. Every player completed a pre-competition questionnaire on concussion history, a baseline PCSS and two trials of the KD before the participated in any match activities.

Results
For players reporting a concussion in the previous three years there was an average of 4.0 +/- 2.8 concussions per player. There were 22 concussive incidents recorded over the duration of the competition (46 per 1000 match hours). Five concussive incidents were witnessed (11 per 1000 match hours) and 17 unrecognized concussive incidents were identified with the KD (37 per 1000 match hours). Witnessed concussions recorded, on average, a longer KD on the day of the injury (5.5 +/- 2.4 s) than unrecognized concussions (4.4 +/- 0.9 s) when compared with their baseline KD.

Discussion
The KD was able to identify players that had not shown, or reported, any signs or symptoms of a concussion but who had meaningful head injury. The current rate of concussion reported was a ten-fold increase in previously reported concussion injury rates. This makes the KD suitable for rapid assessment in a limited time frame on the sideline such as a five-minute window to assess and review suspected concussed players in rugby union.

Further Reading
Read the whole study at the Journal of the Neurological Sciences

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The King-Devick test as a concussion screening tool administered by sports parents

J Sports Med Phys Fitness

Background

Sports-related concussion has received increasing awareness due to short- and long-term neurologic sequelae seen among athletes. The King-Devick (K-D) test captures impairment of eye movements and other correlates of suboptimal brain function. We investigated the K-D test as a screening for concussion when administered by layperson sports parents in a cohort of amateur boxers.

Methods
The K-D test was administered pre-fight and post-fight by laypersons masked to the head trauma status of each athlete. Matches were watched over by a ringside physician and boxing trainer. Athletes with suspected head trauma received testing with the Military Acute Concussion Evaluation (MACE) by the ringside physician to determine concussion status. Athletes sustaining concussion were compared to the athletes screened using the K-D test.

Results
Post-fight K-D scores were lower (better) than the best baseline score (41.0 vs. 39.3 seconds, p = 0.34, Wilcoxon signed-rank test), in the absence of concussion. One boxer sustained a concussion as determined by the ringside physician. This boxer was accurately identified by the layperson K-D testers due to a worsening in K-D test compared to baseline (3.2 seconds) and an increased number of errors. High levels of test-retest reliability were observed (intraclass correlation coefficient 0.90 [95% CI 0.84 - 0.97]). Additionally, 6 boxers who participated in multiple bouts showed no worsening of their K-D times further supporting that scores are not affected by the fatigue associated with sparring.

Conclusion
The K-D test is a rapid sideline screening tool for concussion that can be effectively administered by non-medically trained laypersons.

Further Reading
Read the whole study at the Journal of Sports Medicine and Physical Fitness

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Comparison and utility of King-Devick and ImPACT® composite scores in adolescent concussion patients

Journal of the Neurological Sciences - 05 September 2013 (10.1016/j.jns.2013.08.015)

Purpose
To examine the diagnostic value of KD, by comparing KD with post-concussion symptom scale (PCSS) and ImPACT® composite scores. We hypothesized that KD would be correlated with visual motor speed/memory (VMS, VIS) and reaction time (RT), because all require cognitive visual processing. We also expected parallel changes in KD and PCSS across recovery.

Methods
Thirty-five concussed individuals (12–19y; 18 females, 17 males) were evaluated with PCSS, ImPACT® composite and KD scores over four clinical visits (V).

Results
KD times improved with each visit (ΔV1–V2: 7.86±11.82; ΔV2–V3: 9.17±11.07; ΔV3–V4: 5.30±7.87s) and paralleled improvements in PCSS (ΔV1–V2: 8.97±20.27; ΔV2–V3: 8.69±14.70; ΔV3–V4: 6.31±7.71), RT (ΔV1–V2: 0.05±0.21; ΔV2–V3: 0.09±0.19; ΔV3–V4 0.03±0.07) and VMS (ΔV1–V2: −5.27±6.98; ΔV2–V3: −2.61±6.48; ΔV3–V4: −2.35±5.22). Longer KD times were associated with slower RT (r=0.67; P<0.0001) and lower VMS (r=−0.70; P<0.0001), respectively.

Conclusion
Cognitive visual performance testing using KD has utility in concussion evaluation. Validation would further establish KD as an effective ancillary tool in longitudinal concussion management and research.

Further Reading
Read the whole study at the Journal of the Neurological Sciences

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The King-Devick test for Sideline Concussion Screening in Collegiate Football

J Optom. 2015 Jan 31. pii:S1888-4296(14)00116-2.
Danielle Leong, OD1, Greg Evans, MA, ATC2, Matthew Gimre, MD2, David Watt, MD2, Laura Balcer, MD, MSCE3, Steven Galetta, MD3
1 King-Devick Test, LLC, Oakbrook Terrace, IL, USA; 2 Wheaton College Sports Medicine, Wheaton, IL, USA; 3 Department of Neurology, New York University Langone Medical Center, New York, NY, USA


Purpose
Sports-related concussion has received increasing attention as a result of neurologic sequelae seen among athletes, highlighting the need for a validated, rapid screening tool. The King-Devick (K-D) test captures impairment of eye movements and other correlates of suboptimal brain function. We investigated the K-D test as a sideline screening tool in a collegiate cohort to determine the effect of concussion on K-D test performance and to determine the effect of physical exercise on K-D scores in the absence of concussion.

Methods
In this study, 127 athletes (mean age 20±1.2 years) from the Wheaton College football and men's and women's basketball teams underwent baseline K-D testing at pre-season physicals for the 2012-2013 season. K-D testing was administered immediately on the sidelines for football players with suspected head injury during the games and changes compared to baseline were determined. Post-season testing was also performed. Additionally, basketball players were tested immediately following an intense 2.5 hour work-out to test the effects of physical exercise on K-D performance.

Results
Sideline K-D scores of concussed athletes (n=11) were significantly higher (worse) than baseline (36.5±5.6s vs. 31.3±4.5s, p<0.005, Wilcoxon signed-rank test). While concussion resulted in worse K-D scores, there was no worsening after physical fatigue. In basketball players, K-D scores post-workout showed lower (improved) K-D scores (31.8±4.9 vs. 34.5±4.8, p<0.05, Wilcoxon signed-rank test). Additionally, post-season testing demonstrated improvement of scores likely consistent with learning effects. (35.1 ±5.2s vs. 34.4 ±5.0s, p<0.05, Wilcoxon signed-rank test). Test-retest reliability was analyzed between baseline and post-season administrations of the K-D test resulting in high levels of test-retest reliability (intraclass correlation coefficient (ICC)=0.95 [95% Confidence Interval 0.85 - 1.05]).

Conclusions
The data show worsening of K-D scores after concussion however no worsening following physical fatigue. This study supports the King-Devick test as an accurate, reliable and rapid sideline tool to identify athletes with concussion.

Further Reading: Read the Whole Study From The Journal of Optometry

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Sideline concussion testing in high school football on Guam

Surgical Neurology International 2014

Background

The risks of repeat concussions and returning to play (RTP) prior to the resolution of concussive symptoms are medically established. However, RTP guidelines for high school sports are varied and often notably absent. The island of Guam, a US territory, has a robust athletics program but lacks structure to reduce concussions or establish RTP protocols. Consequently, there is an opportunity to limit the incidence of "second-hit syndrome" and other harmful effects through education and testing.

Methods
We evaluated the feasibility of Sideline Concussion Testing SCT) as a novel feature of Guam high school athletics. Thirteen high school football players were observed over three consecutive football games. They were first given a questionnaire about concussion history, symptoms, medical evaluation, and RTP. Researchers used the King-Devick Test, a SCT tool, and baseline scores were recorded. If players were then observed to have significant head trauma or to show concussive symptoms, they were sidelined and tested.

Results
Five of 13 students had a previous concussion and limited awareness of RTP guidelines. Of those five, four received no medical consultation or stand down period before RTP. There was also a lack of understanding of what constitutes a concussion; five out of eight individuals who denied previous concussion confirmed having bell ringers, seeing stars, and other classic concussive symptoms. Over the course of the study the SCT identified three concussions, with significant deviations from baseline time on a test that measured visual and speech disturbances.

Conclusions
The feasibility of SCT use in Guam high school football was established and our pilot study identified areas for improvement. Established definitions of concussion and RTP guidelines were lacking. Therefore, an opportunity exists through public health efforts that involve the entire community to increase concussion awareness and reduce injuries in high school sports on Guam.

Further Reading
Read the whole study at Surgical Neurology International

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Effects of Youth Football on Selected Clinical Measures of Neurologic Function: A Pilot Study

J Child Neurol. 2013 Nov; DOI:10.1177/0883073813509887

Abstract
We assessed 10 youth football players (13.4 + 0.7 y) immediately before and after their season to explore the effects of football participation on selected clinical measures of neurologic function. Postseason postural stability in a closed-eye condition was improved compared to preseason (P 1⁄4 .017). Neurocognitive testing with the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery revealed that reaction time was significantly faster at postseason (P 1⁄4 .015). There were no significant preseason versus postseason differences in verbal memory (P 1⁄4 .507), visual memory (P 1⁄4 .750), or visual motor speed (P 1⁄4 .087). Oculomotor performance assessed by the King-Devick test was moderately to significantly improved (P 1⁄4 .047-.115). A 12-week season of youth football did not impair the postural stability, neurocognitive function, or oculomotor performance measures of the players evaluated. Though encouraging, continued and more comprehensive investigations of this at-risk population are warranted.

Further Reading
Read the whole study at the Journal of Child Neurology

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In the Clinic: Concussion

Ann Intern Med. 2014 Feb; 160(3):ITC2-1-1.

"For the oculomotor examination, an additional test that may be used is the King–Devick test, which is a tool that rapidly assesses eye movement and can be used in the office or on the sideline to determine impairment in eye movements associated with an acute concussion. This has been found to be potentially useful as a tool to determine removal from play. The 1-minute test involves reading single digits displayed on cards; any slowing of time to complete the test, ideally compared with the athlete’s baseline, is suggestive of concussion."

Further Reading
Read the whole study at Annals of Internal Medicine

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Visual Screening Test for Rapid Sideline Determination of Concussive and Sub-concussive Events

Neurosurgery. 2013 Oct; 73(4):N17-8

Overview

The need for sideline rapid assessment of mild head injury [like King-Devick] is fundamental to limiting the deleterious effects of repeated impacts to the head. The great majority of athletes are at the youth sports level and not in collegiate or professional sports, which leaves many important decisions to be made by parents and coaches on the sideline. This structural element of sport is unlikely to change since allocating medically trained people to youth sports will require unavailable financial resources. Accordingly, empowering adults to administer a simple, rapid, yet effective test is paramount to preventing repeated head injury. As increasing evidence suggests that even mild impact to the head can lead to accruing neuropathology, it may be prudent to routinely perform sideline testing for players involved in even modest collisions. This could help avoid return to play of athletes with sub-concussive impacts as knowledge about head injury continues to evolve.

Further Reading
Read the whole study at the Neurosurgery

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Assessment, Management and Knowledge of Sport-Related Concussion: Systematic Review

Sports Med. 2014 Jan; DOI: 10.1007/s40279-013-0134-x

Background

Sport-related concussions are a subset of mild traumatic brain injuries and are a concern for many sporting activities worldwide.

Objective
To review and update the literature in regard to the history, pathophysiology, recognition, assessment, management and knowledge of concussion.

Methods
Searches of electronic literature databases were performed to identify studies published up until April 2013.
RESULTS: 292 publications focusing on concussion met the inclusion criteria, and so they were quality rated and reviewed.

Conclusion
Concussion is hard to recognize and diagnose. Initial sideline assessment via the Sports Concussion Assessment Tool 3 (SCAT3), Child-SCAT3 or King-Devick test should be undertaken to identify athletes with concussion as part of a continuum of assessment modalities and athlete management. Sports medicine practitioners should be cognisant of the definition, extent and nature of concussion, and should work with coaches, athletes and trainers to identify and manage concussions. The most common reason for variations in management of concussion is lack of awareness of—and confusion about—the many available published guidelines for concussion. Future research should focus on better systems and tools for recognition, assessment and management of concussion. Sport participants’ knowledge of concussion should be evaluated more rigorously, with interventions for sports where there is little knowledge of recognition, assessment and appropriate management of concussion.

Further Reading
Read the whole study at Sports Medicine

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Sports-Related Concussion Testing

Current Neurology & Neuroscience Reports. October 2012, Volume 12, Issue 5, pp 547-559.

Abstract
Due to the recent focus on concussion in sports, a number of tests have been developed to diagnose and manage concussion. While each test measures different brain functions, no single test has been shown to quickly and reliably assess concussion in all cases. In addition, most of the current concussion tests have not been validated by scientific investigation. This review identifies the pros and cons of the most commonly used noninvasive tests for concussion in order to provide a more complete picture of the resources that are available for concussion testing. The potential utility of research tools such as the head impact telemetry system, advanced magnetic resonance imaging protocols, and biomarkers are discussed in the context of the currently employed tools.

Further Reading
Read the whole study at the Current Neurology & Neuroscience Reports

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Vision-Based Performance Testing as a Complement to SCAT3/Child-SCAT3 in Youth and Collegiate Athletes

Platform Presentation at the American Academy of Neurology 2014 Annual Meeting

Objective

We examined the King-Devick (K-D) test of rapid number naming as a complement to the SCAT3/Child-SCAT3 for sideline diagnosis in youth and collegiate athletes.

Background
Identification of rapid yet simple diagnostic tests is critical since athletes frequently under-report or do not recognize symptoms of concussion. SCAT3/Child-SCAT3 includes cognition and balance, but does not include a vision-based performance measure. Adding vision increases diagnostic power and performance measures are more practical than neurological exam- or technology-based tests since even parents of youth athletes can perform them.

Design/Methods
Members of a youth ice hockey and lacrosse league and collegiate athletes from NYU and Long Island University (LIU) participated in a prospective study to examine K-D, SAC (cognition) and timed tandem-gait (balance). K-D is a timed test for which athletes read numbers aloud from three test cards.

Results
Youth (n=242, mean age 11.0±2.8 years, range 5-17) and collegiate athletes (n=89, age 19.8±1.4 years, range 18-23) underwent baseline testing. Youth athletes completed K-D in 60.6±22.3 seconds, timed tandem-gait in 15.5±5.2 seconds; median SAC scores were 26 points (range 10-30). Baseline KD scores improved with increasing age in the youth cohort (p<0.001, linear regression). Among the 12 athletes with concussion during their season, K-D worsened from baseline by an average of 5.2 seconds; improvement by 6.4 seconds was noted for non-concussed controls (n=14). K-D showed the greatest capacity to distinguish concussed vs. control groups based on changes from baseline (ROC curve areas from logistic regression models, accounting for age= 0.92 for K- D, 0.87 for tandem, 0.68 for SAC, p=0.0004 for comparison of areas).

Conclusions
Rapid number naming is a useful visual performance tool to diagnose concussed athletes at youth and collegiate levels. Adding a rapid and simple vision-based test to the cognitive and balance performance measures of SCAT3/Child-SCAT3 enhances detection capabilities of current sideline testing.

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King-Devick Test Identifies Symptomatic Concussion in Real-time and Asymptomatic Concussion Over Time

Platform Presentation at the American Academy of Neurology 2014 Annual Meeting

Objective

To evaluate the effects of head injury in adolescents on long-term cognitive and visuospatial performance and determine if similar impairment (subclinical concussion) exists in athletes without obvious head injury.

Background
Sports concussion has an annual incidence of approximately 3.8 million. Over half go unreported and a substantial number may be asymptomatic. Repeat concussion is associated with serious consequences in long-term neurological function, to which adolescents may be more vulnerable. A rapid, cost-effective and reliable tool that facilitates diagnosis of concussion is needed. The King-Devick (K-D) test is a promising tool for real-time assessment of concussion. An increase in score from baseline suggests possible concussion. This is the first study to use K-D testing in adolescents for the detection of symptomatic and subclinical concussion.

Methods
High school hockey players underwent K-D testing pre-season, post-season and immediately after suspected concussion. All were assessed pre- and post-season with a computerized cognitive assessment test (Axon Sports®). Additional testing was performed in a subgroup of non-concussed athletes before and after a game to determine impacts of fatigue and subconcussive hits on KD scores.

Results
141 players were tested, of which 20 reported head injury. All 20 had immediate post-concussion K-D times >5s from baseline (average 7.3s) and all but 2 had worse post-season scores (46.4s vs. 52.4s p<0.05 Wilcoxon signed rank test). 11 non-concussed players had worse post-season times from baseline (37.6s vs. 43.8s). 110 players saw minimal improvement post-season (43.9s vs. 42.1s p<0.05) and 51 non-concussed players assessed before and after a game revealed no significant time change (43.4s vs. 42.0s post-game p<0.05). Pre- and post-season CCAT results will be correlated with K-D results and presented.

Conclusion
King-Devick testing accurately identifies real-time, symptomatic concussion in adolescents. Scores in concussed players may remain abnormal over time. The K-D test may additionally detect asymptomatic concussion. Athletes should undergo pre- and post-season K-D testing, with additional evaluation real-time to inform the assessment of suspected concussion.

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Vision-Based Concussion Testing in a Youth Ice Hockey Cohort: Effects of Age and Visual Crowding

Platform Presentation at the American Academy of Neurology 2014 Annual Meeting

Objective

We examined the King-Devick (K-D) test, a vision-based measure of rapid number naming, as a complement to the Sport Concussion Assessment Tool, 3rd edition (SCAT3/Child-SCAT3) for sideline diagnosis in youth athletes.

Background
Particularly in youth sports, identification of rapid yet simple diagnostic tests for concussion is critical. These rapid tests must be interpreted in the context of developmental status and age.

Design/Methods
Members of a suburban youth ice hockey league participated in a prospective study to examine three brief rink-side tests: K-D test, Standardized Assessment of Concussion (SAC, cognition) and timed tandem gait (balance). To perform the K-D test, athletes read numbers from three laminated test cards from left to right as quickly as possible. The cards become progressively more difficult due to changes in vertical spacing between lines; this is particularly notable for card 3.

Results
Ninety-nine athletes (mean age 10.8±3.0 years, range 6-17 years) underwent pre-season baseline testing for this study. Athletes completed the K-D test in an average of 56.5 seconds (best of two baseline trials, range 27.5-159.8 seconds). Average total SAC scores were 26/ maximum 30 points (range 17-30); average best of four trials for timed tandem gait was 15.9±6.0 seconds. All three tests showed better scores among older athletes (p<0.001 for all, linear regression). Time scores for K-D were significantly slower (worse) for younger athletes (p<0.001). This association of worse K-D scores with younger age was most evident for K-D card 3, the card with the greatest degree of vertical visual crowding (average of 3.9 seconds slower vs. card 1, p<0.001, linear regression).

Conclusions
Scores for rapid sideline concussion tests may vary with age and developmental status of youth athletes; better scores in this cohort were noted among older players. Visual crowding, an age-dependent inability to perceive objects due to clutter, may in part explain the more dramatic association of slower time scores on test card 3 with younger age for the K-D test.

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The King-Devick Test Is Vastly Superior To The Symbol Digit Modalities Test As A Sideline Determinant Of Concussion In Mixed Martial Arts Fighters

Platform Presentation at the American Academy of Neurology 2014 Annual Meeting

Objective

To compare the Symbol Digit Modalities Test (SDMT) to the King-Devick (K-D) test as potential rapid sideline screening for concussion.

Background
Sports-related concussion is increasingly recognized as a major public health problem due to potential for neurologic sequelae. Despite recent research that has suggested the potential role of the K-D test as a sideline screening tool for concussion, there remains a need for a rapid sideline test that requires less examiner attention. The K-D test screens for combined impairments in eye movements, attention and language by measuring the speed of rapid number naming from 3 test cards. The written version of the SDMT is based on measurement of the speed of conversion of geometric designs into number responses, and captures impairments of attention, processing speed, eye movements, writing, and other correlates of cerebral dysfunction.

Design/Methods
The SDMT and K-D test were administered pre- and postfight by a single examiner to 16 mixed martial arts fighters. Changes in SDMT and K-D scores from pre- to postfight were compared for those with head trauma during the fight vs those without.

Results
There was a modest correlation between head trauma during the match and whether there was worsening (increase) in K-D scores (r=0.54,p=0.015), the actual change (r=0.42,p=0.055) and the percentage change in K-D scores from pre- to postfight (r=0.50,p=0.025). Only 1 fighter without head trauma had a worsening of K-D score by ≥ 5 seconds. There was only small to medium correlation between worsening of SDMT score (decrease) and K-D score. Surprisingly there was no correlation between SDMT scores and concussion during the match.

Conclusions
This study confirms that the K-D test, but not the SDMT, is reliable in rapidly identifying athletes with head trauma. This suggests that further validation of the K-D test, but not the SDMT, may be valuable in the early detection of concussion.

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Baseline Concussion Testing in Different Environments: A Pilot Study

The Sport Journal

Purpose
Athletic trainers and sport medicine professionals have the responsibility of diagnosing and managing concussion in athletes. The King-Devick (K-D) Test provides athletic trainers and sport medicine professionals with an easy-to-use concussion screening tool that requires only two minutes to administer and has relevance to contact sports such as football, soccer, boxing, and mixed martial arts. The purpose of this pilot study was to examine the reliability of baseline testing with the K-D Test in different environments.

Methods
A total of nine participants (6 males, 3 females, mean age: 39 ± 14.49 yrs) participated in the three day investigation. Subjects reported to the human performance laboratory on three separate days. Participants were given standard instructions for the K-D Test. Participants were required to complete the K-D test under a quiet environment (with minimal to no noise) and under two loud (noisy) environments; one with speakers and the other with headphones.

Results
Results indicated K-D scores for baseline (BL) and speakers (SP) rendered group means of (BL: 40.54 ± 14.95 s, SP: 40.54 ± 15.92 s), while scores for HP signified slightly lower group means of 39.54 ± 14.39 s. No variables showed any statistical difference in K-D scores (P > 0.05).

Conclusion
Most participants were able to improve their K-D scores from Trial 1 (T1) to Trial 2 (T2) on baseline testing, signifying a slight learning effect within the study group.

Application to Sport
Athletic trainers, healthcare professionals, and those administering the K-D Test should be consistent in assessing pre and post K-D scores, although significant changes might not occur when performing the K-D Test under different environments (with crowd noise). Athletes should be treated on an individual basis when using the K-D Test to assess pre and post test scores.

Further Reading
Read the whole study at the The Sport Journal

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The King-Devick Test is Vastly Superior to the Symbol Digit Modalities Test as a Sideline Determinant of Concussion in Mixed Martial Arts Fighters

Poster Presentation at the European Neurological Society 2013 Annual Meeting
Daniel Kantor, MD Neurologique, Ponte Vedra, FL USA

Objective

To compare the Symbol Digit Modalities Test (SDMT) to the King-Devick (K-D) test as a potential rapid sideline screening for concussion

Background
Sports-related concussion is increasingly recognized as a major public health problem due to potential for neurologic sequelae. Despite recent research that has suggested the potential role of the K-D test as a sideline screening tool for concussion, there remains a need for a rapid sideline test that requires less examiner attention. The K-D test screens for combined impairments in eye movements, attention and language by measuring the speed of rapid number naming on 3 test cards. The written version of the SDMT is based on measurement of the speed of conversion of geometric designs into number responses, and captures impairments of attention, processing speed, eye movements, writing, and other correlates of cerebral dysfunction.

Methods
The SDMT and K-D test were administered pre- and postfight by a single examiner to 16 mixed martial arts fighters. Changes in SDMT and K-D scores from pre- to postfight were compared for those with head trauma during the fight vs. those without.

Results
There was a modest correlation between head trauma during the match and whether there was worsening (increase) in K-D scores (r=0.54, p=0.015), the actual change (r=0.42, p=0.055) and the percentage change in K-D scores from pre-to postfight (r=0.50, p=0.025). Only 1 fighter without head trauma had a worsening of K-D score by ≥ 5 seconds. There was only small to medium correlation between worsening of SDMT score (decrease) and K-D score. Surprisingly there was no correlation between SDMT scores and concussion during the match.

Conclusions
This study confirms that the K-D test, but not the SDMT, is reliable in rapidly identifying athletes with head trauma. This suggests that further validation of the K-D test, but not the SDMT, may be valuable in the early detection of concussion.

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Concussion Screening in High School Football Using the King Devick Test

Poster Presentation at the Association for Research in Vision and Ophthalmology 2013 Annual Meeting
Vladimir Yevseyenkov, Kirk Kaupke, Shawn Lebsock, Matthew Kaminsky
Vision Rehabilitation, Midwestern University, Glendale, AZ.

Purpose

To evaluate the effectiveness of the King-Devick (KD) test, a screening which evaluates saccadic eye movements, to identify football players who may have sustained a concussion during play. Secondary outcomes include evaluating whether performance of KD testing increases awareness of concussion in high School football players.

Methods
Forty seven high school football players ranging from freshmen to senior grade levels and all play levels were given a baseline KD test prior to beginning of the 2012 football season. Each student also filled out a survey gauging their level of awareness of concussion signs and symptoms. During the season, three varsity level players sustained concussions on-field. Each of these players had the KD test performed within thirty minutes of impact. The concussion diagnosis was confirmed by a neurologist within days of the on-field incident. At the end of the season, the KD test was again administered to all students. Students also took a post-season survey which was identical to the one they took prior to the start of the season to gauge their awareness of concussion.

Results
There was very little variance in athletes who did not have concussion when comparing pre- and post-season testing with LOA of 95% and confidence intervals of 95%. Test-retest reliability was analyzed using intraclass correlation coefficients (ICC) between baseline and end of the season data, showing correlation of 0.873 with significance of p < 0.05. The three football players whose concussion diagnosis was confirmed by a neurologist did in fact demonstrate diminished KD test performance times within thirty minutes of the on-field injury. Times were diminished by 41% in student 1, 100% in student 2, and 143% in student 3. Regarding the knowledge of concussions survey administered pre- and post-season, paired sample t-tests showed p > 0.05 significance for the question “I would say that my current knowledge level of concussions is very high.” Therefore, it is evident that the football students' level of awareness of concussion significantly increased throughout the season.

Conclusions
This study showed that the King-Devick Test can potentially be used as a rapid sideline tool to identify athletes who have potential concussion in a time period of under one minute.