Current Research

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

Neurol Clin Pract. 2014- In Press

We examined the King-Devick (K-D) test, a vision-based test of rapid number naming, as a complement to components of the Sport Concussion Assessment Tool, 3rd edition (SCAT3) for diagnosis of concussion. 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). Among 30 athletes with first concussion during their athletic season (n=217 total), differences from baseline to post-injury 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. Adding a vision-based test may enhance the detection of athletes with concussion.

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Baseline Concussion Testing in Different Environments: A Pilot Study

The Sport Journal. March 12, 2014

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

Platform Presentation at the American Academy of Neurology 2014 Annual Meeting

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.

Study Supported by: NIH K24 EY 018136.

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

Poster Presentation at the American Academy of Optometry 2013 Annual Meeting
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.

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College and Elite Athletes Using the King-Devick Test iPad App

Poster Presentation at the National Athletic Trainers' Association 2013 Annual Meeting
Hunsaker A, Hamson-Utley J, Mossbarger G
Weber State University


Introduction

The cognitive impairments following a concussion most often affected are memory, attention, and information processing speed and efficiency (Livingston, 2011). Long-term symptoms associated with post-concussion syndrome include chronic headaches, fatigue, visual disturbances, sleep difficulties, personality changes, sensitivities to light and noise, dizziness when standing quickly, and deficits in short-term memory (Covassin et al., 2008; Daneshvar et al., 2011; Galetta et al., 2011a; Heitger et al., 2008). Oculomotor dysfunction has been shown to be one of the common symptoms of an athlete suffering from concussive symptoms (Heitger et al., 2009; Heitger, Jones, & Anderson, 2008). The King-Devick (K-D) sideline concussion test challenges athletes to process and recite numbers on three cards that become more difficult to read as the athlete progresses through the test. In previous research the K-D test has been an efficient way to detect athletes suffering from oculomotor dysfunction, delays in information processing, attention and language (Galetta et al., 2011; Galetta et al., 2011; King, Clark, & Gissane, 2012). The purpose of this study is to examine the differences in baseline test scores between genders and across collegiate and extreme sport professional athletes using the K-D sideline concussion test. Our first hypothesis was that athletes will have increases times compared to non-athletes. The second hypothesis was that there will be a difference between male and female test times.

Methods
Participants: 152 total participants (89 male, 58.6%; 64 female, 41.4%). 96 Collegiate Athletes (48 football, 26 women's soccer, 16 women's rugby, 6 men's hockey). 35 Elite extreme snow sport athletes. 21 University non-athletes.
Procedure:
Each participant was tested on the K-D sideline concussion test, which tests the time it takes to perform rapid number naming. Tests were administered using the King-Devick Test app on the iPad. Participants were instructed to tap the screen of the iPad to start the test and then read the numbers out loud as fast as possible without making any errors and then tap the screen to stop the time. The test was given twice to each participant. The fastest time between two tests with no errors was recorded as the baseline score. Collegiate athletes were administered the test in the athletic training room or weight room. Elite athletes were tested in a hotel lobby during registration or in the medical trailer at the event. Non-athletes were tested in a classroom setting.

Results
There was a significant difference [F(5, 146) =2.530, p=.031, η 2=.080] between sport types. Tukey HDS post-hoc expressed a significant pairwise comparison (P value range = 0.001- 0.015). Extreme-snow sports (M = 47.69, SD = 7.58) were significantly slower than university football (M = 42.85, SD = 8.19) and university men's hockey (M = 36.43, SD = 8.06). University women's soccer (M = 46.45, SD = 7.48) was significantly slower than university men's hockey (M = 35.43, SD = 8.06). There was no significant difference in test time-score between athletes and non-athletes [F(1,150) = 0.092, p = 0.762, η 2 =0.001]. No significant difference was found between male and female [F(1,150) = 1.10, p = 0.296, η2 =0.007].

Discussion & Future Directions
Results of this study provide initial evidence of a deficit of visual tracking between different sports using the K-D test. Elite extreme-snow-sport athletes performed the K-D test at a slower time than university men's hockey and university football athletes. This may be due to the repeated, sub-concussive blows that occur from falls during practice and recreational snowboarding or skiing (Wright). Without looking at the number of concussions experienced in each sport, university women's soccer athletes performed slower on the K-D test than university men's hockey athletes. This could have been explained by the difference in gender, however the results of the study showed there were no difference in testing times on the K-D test between males and females. Our findings contradict a previous study that showed gender differences exist in outcomes of traumatic brain injuries and concussions (Dick, 2009). An assumption for each test was that the participant was reading the numbers as fast as they possibly could. In conclusion our results show there are differences in time to perform the K-D test between sports. This could be due to the number of repeated, sub-concussive blows that are experienced by athletes in different sports. Our findings showed no differences in time between gender or athletes and non-athletes. Further research should compare the number of concussions athletes have experienced to their baseline time to determine if there are deficits between athletes with more concussions as compared to athletes with no concussion history.

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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.