Sports Concussion

Rugby is a team contact sport that is popular in many countries. Concussion remains one of the inherent risks of participation in rugby union with Certain facets of play, as well as specific tactics and strategies in contact and collision predispose athletes to a greater chance of sustaining a concussion. While other injuries incurred by rugby players have been well studied, less focus and attention has been directed towards concussion. The Third International Conference on Concussion in Sport defined concussion as a complex pathophysiologic process induced by traumatic biomechanical forces. World Rugby (previously known as the International Rugby Board or IRB) has acknowledged that there is a significant risk associated with concussions, and have subsequently implemented a risk management strategy [1]. This systematic review aims to evaluate the available evidence on concussion in Rugby Union (here- after referred to as ‘rugby’) and to conduct an analysis of findings regarding the ...

Background: Observational research has linked altitude to concussion risk, but the physiologic and epidemiologic bases for this association remain questionable. Methods: We performed a retrospective cohort study by analyzing four seasons of National Football League data from a widely used database (Concussion Watch) to determine if previous claims that altitude ≥196 m reduced concussion risk were replicable and whether an arbitrary predictor variable (animal vs. non-animal team logo) was related to concussion risk. Relative risk (RR) and 95% confidence intervals (95% CIs) were computed. Results: The previous association with altitude was reproduced for earlier seasons, but not replicable for recent seasons (RR = 0.92 [95% CI = 0.70, 1.22]). Across four combined seasons, " higher altitude " (RR = 0.78 [0.64, 0.96]) and animal logo (RR = 0.75 [0.63, 0.89]) were similarly associated with reduced concussion risk. Conclusions: Inconsistent epidemiologic effects, combined with weak physiologic rationale, suggest links between altitude and concussion are coincidental. Interdisciplinary critique of concussion research is necessary to ensure that marketing claims and clinical recommendations are scientifically justified. See video abstract at, http://links.lww.com/EDE/B234.

Open letters offer a unique focus for rhetorical analysis in sport communication, forming a message that is both interpersonal (the attempt to reflect dialogue through a letter writer and its recipients) and public (the “open” part of the open letter). The National Football League (NFL) attempted image repair when it used open letters to respond to accusations that it was not doing enough to protect athletes against devastating effects of concussions. Through the use of Benoit’s theory of image repair, the authors found that Commissioner Goodell’s open letters relied on 2 main image repair strategies: reducing offensiveness and corrective action. They consider the implications of these rhetorical choices for the complicated merging areas of sport, communication, and health in the NFL’s open letters.

Abstract
Background; about 25,000 people incurs annual commotio cerebri(mTBI) in Denmark. Almost
20% develops persistent symptoms, called post-concussion syndrome(PCS). Studies suggest as
many as 90% have vestibular dysfunction(Nuwer et al.). There is a growing consensus on the use
of vestibular rehabilitation (VR), and the purpose of this literature study is to determine the
effects of VR on people with MTBI or PCS and VD. Method; there was conducted a systematic
literature search on Cohcrane Library Central and CDSR, PubMed, CINAHL, EMBASE,
Scopus, Web of Science and Medline, limited to systematic reviews(SR) and randomized
controlled trials(RCT). Search completed with a broad definition of intervention and without
outcome for broader search. Results; 605 studies, 534 meets exclusion criteria, or didn’t have
access to fulltext, 72 studies excluded as: Diagnostic studies or not RCT/SR. Conclusion; there
is, with this search, not found evidence that VR has an effect on people with MTBI or PCS and
VD, measured on return to work, school or sports. This follows narrow search.

Chronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy caused by repetitive head injury.  Although it has chiefly been studied in contact sport participants,
anyone who experiences repetitive head injury is at risk of CTE. It is associated with a range of neuro-psychological problems, ranging from mood and behavioural symptoms to cognitive impairment and dementia.  Clinical diagnostic criteria have been proposed,3 but, as for many neurodegenerative disorders, a definitive diagnosis requires post mortem brain examination.

Concussions and Traumatic Brain Injury (TBI) have become one of the most prevalent and serious injuries a high school athlete can receive.  Due to the potential long-term effects these types of injuries have, there are now federal laws in place to help protect these athletes.  This theoretical paper will discuss the history of these laws and how the incidence of concussions has been affected since enactment.  Using data analysis from previous research, this paper will attempt to answer the following research questions.  First, has there been a reduction or increase in concussion injuries since the laws have been enacted?  And, secondly, has heightened awareness caused students, parents, and coaches to be more cautious?  Based on research analysis, it can be concluded that heightened awareness has brought concussion injuries to the forefront.  However, it appears that because the new rules and regulations are present that forces these types of injuries to be addressed, it seems that there have been more injuries since the laws have been enacted than less.  More longitudinal studies will need to be performed in order to get accurate data.

Abstract

Concussions have become a national epidemic. Millions of dollars have been spent to fund studies over the last 15 years. The majority of this research is focused on concussion causation and concussion management after the fact. The research continues, but the number of concussions in athletics increases each year.
No methodical approach to producing a specific protocol for strengthening the head and neck muscles exists, and no systematic study of increase in neck musculature attributed to such a protocol is documented. This study will produce a standardized methodology for the reduction of concussive and sub-concussive forces, laying the foundation for further research in this area.
The research participants were healthy male college students, ranging in age from 18-24 years old. There were 18 participants. Of the 18 subjects used for this study, 12 participants were randomly assigned to the experimental group and six participants were assigned to the control group. The participants followed a protocol consisting of 13 movements designed to sequentially train the musculature of the head, neck, and upper back.  The duration of the study was eight weeks.
The strength increases of participants in the active group were significant. The hypertrophy of the head and neck muscles for participants in the active group was equally as significant and even more impressive. Every active participant experienced strength increases during the eight week study; likewise, each active participant exhibited neck circumference increases. Participants in the control group experienced negligible strength or hypertrophy increases.

What is a concussion? Not too long ago, you were considered to have a concussion only if you lost consciousness from a head injury. In fact, not only do you not have to lose consciousness (research suggests only 10% of people do), 1 but you don't even have to hit your head. Many of the concussions in military personnel have occurred from the force of an explosion, not from a direct blow to the head. We also know that many concussions happen during whiplash injuries, like a car accident or in an infant that is violently shaken. Concussions are the most common type of traumatic brain injury and are often referred to as mTBI. Although the vast majority of research pertaining to nutrition and concussions has been done on animals, the potential for creatine and other nutrients to aid in the treatment and prevention of concussions is mounting. storage molecule called creatine phosphate. This molecule is an energy buffer for muscles 6 and for the brain in which the level of creatine phosphate is even higher than the level of ATP. 7 In the central nervous system, creatine operates by donating a phosphoryl group to ADP to make ATP thereby helping to replenish energy stores. 8 It has been shown with proton magnetic resonance spectroscopy that creatine levels in the brain decrease after sustaining a concussion. 9 It has also been shown that taking creatine-monohydrate orally is able to cause a significant increase of brain crea-tine levels. 10

Objective: The objective of the study was to determine the level of concussion knowledge and attitudes among sub-elite rugby union players in Western Kenya. Design: The study was a descriptive cross-sectional study and Quantitative methods were adopted. Setting: The study was carried out in Western Kenya Sample: The respondents were Sub elite rugby players who were randomly sampled from various rugby clubs in the region (n = 209) Analysis: Data was analyzed through descriptive statistics, confirmatory factor analysis and one-way analysis of variance (ANOVA). Main outcome measures: Concussion knowledge and attitude Results: Results from the Confirmatory factor analysis yielded a 22-item two-factor structure. The results showed a non-significant chi-square result, therefore, indicating good fit, the goodness of fit index (GFI), comparative fit index (CFI), and incremental fit index (IFI) had valued above .90 hence indicating a good fit. Root mean square error of approximation (RMSEA) that normally exceeds .1 warrants rejecting the model, however, our value was .05 indicating close fit. Cronbach's alpha for the 14-items Knowledge scale and 8-items attitude scale were α = .702 and α = .728. Deleting construct items did not increase the alpha. The mean concussion knowledge score was 20.94 out of 27 (95% CI 20.7 to 21.2, ± 2.02), 90% (n=188) correctly said that there was a possible risk of death if a second concussion occurred before the first one had healed. 49.3% (n=103) correctly answered that people who have had one concussion were more likely to have another concussion. In addition, 71.3% (n=149) correctly answered that, in order to be diagnosed with a concussion, a person didn't have to be knocked out. However, only 30% (n=63) answered correctly that after a concussion occurs, brain imaging (e.g., CAT Scan, MRI,

Objective: This study presents data using multimodal assessment via impact sensors and oculomotor function to quantify neurophysiological changes in the acute period following concussion.
Design: Cohort study.
Participants: Data on impact magnitude and frequency were collected with a wireless head impact sensor (XPatch1) worn by senior amateur rugby players participating in a domestic season. King-Devick Tests2 were performed pre- season and after significant impact scores (PLA > 100g, PRA > 10,000 rads/sec/sec). Following concussive episodes or significant head impacts (as measured by impact sensors), players were re-tested to elicit any differences and to assist in providing objective criteria for the return to play process.
Interventions: Any impact that resulted in a witnessed concussion or that was suspected on the basis of significant impact scores required post-match testing utilising the King-Devick test to help determine appropriate return to play readiness.
Outcome measures: Impact number, peak linear and peak rotational acceleration, risk weighted exposure. Time and errors completing the King- Devick test.
Main result: 20 concussions were detected in all, of which only 3 were witnessed (2 players unconscious on the field, one with balance disturbance resulting in removal from play).
Conclusions: A combination of regular impact monitoring and King-Devick Ocular testing provides a relatively simple process for objectively identifying and managing concussion in sports participants.

Background
Management of concussion remains a serious issue for professional sports, particularly with the growing knowledge on the consequences of repetitive concussion. One primary concern is the subjective assessment of recovery that dictates the time until a concussed athlete is returned to competition. In response to this concern, the Australian Football League (AFL) changed its policy in 2020 such that medical clearance for return-to-competition was extended from one day, to a minimum of five days, prior to the next scheduled match.
Objective
We sought to explore the impact of the AFL policy change by asking whether time to returnto-
competition after concussion was increased in the 2020 season relative to previous years.
Methods
Retrospective data on injury and return-to-competition were sourced from publicly available tables published by the AFL. Our primary exploration compared the number of matches missed and the number of days missed in concussed players across 2017 to 2020 inclusive, with secondary exploration analysing the proportion of players returning to play 12 days or longer.
Results
Analysis of data from 166 concussed players revealed no increase in the number of matches missed in 2020 relative to previous years as would have been expected from an extended recovery protocol. Comparing 2020 relative to 2017-19 we found that there was an overall moderate reduction in median time to return-to-competition (RTC) in 2020 (10 vs 13 days, respectively d=-0.345)) and a significant reduction in players taking more than 12 days to RTC (p=0.046).
Conclusion
This exploratory study demonstrates that clubs may not have followed policy change around concussion management designed to increase time to RTC. Ongoing auditing is required to ensure player clearance meets policy goals, highlighting the need for objective measures for RTC after concussion.

Key Points:
• In 2020, the Australian Football League (AFL) changed their concussion management policy to increase the time between when a player could be medically cleared prior to their next competitive match to five days. This should extend the number of days between concussion and return-to-competition to a minimum of 12 days.
• Using publicly available data, this study reports on the average number of matches missed and the number of day’s missed between a player’s reported concussion and their first competitive match.
• Comparison of matches and days missed between 2017-2019 (old policy) and 2020 (new policy) demonstrated that clubs weren't following the policy as carefully as they should. The data shows that players were rested for shorter periods in 2020.

ABSTRACT – Dating to Colonel John Paul Stapp MD in 1975, scientists have desired to measure live human head impacts with accuracy and precision.  But no instrument exists to accurately and precisely quantify single head impact events.  Our goal is to develop a practical single event head impact dosimeter known as “Intelligent Mouthguard” and quantify its performance on the benchtop, in vitro and in vivo. 
In the Intelligent Mouthguard hardware, limited gyroscope bandwidth requires an algorithm-based correction as a function of impact duration.  After we apply gyroscope correction algorithm, Intelligent Mouthguard results at time of CG linear acceleration peak correlate to the Reference Hybrid III within our tested range of pulse durations and impact acceleration profiles in American football and Boxing in vitro tests: American football, IMG=1.00REF-1.1g, R2=0.99; maximum time of peak XYZ component imprecision 3.6g and 370rad/s2; maximum time of peak azimuth and elevation imprecision 4.8° and 2.9°; maximum average XYZ component temporal imprecision 3.3g and 390rad/s2.  Boxing, IMG=1.00REF-0.9g, R2=0.99, R2=0.98;  maximum time of peak XYZ component imprecision 3.9g and 390rad/s2, maximum time of peak azimuth and elevation imprecision 2.9° and 2.1°; average XYZ component temporal imprecision 4.0g and 440rad/s2.  In vivo Intelligent Mouthguard true positive head impacts from American football players and amateur boxers have temporal characteristics (first harmonic frequency  from 35Hz to 79Hz) within our tested benchtop (first harmonic frequency <180Hz) and in vitro (first harmonic frequency <100Hz) ranges. 
Our conclusions apply only to situations where the rigid body assumption is valid, sensor-skull coupling is maintained and the ranges of tested parameters and harmonics fall within the boundaries of harmonics validated in vitro.  For these situations, Intelligent Mouthguard qualifies as a single event dosimeter in American football and Boxing.

Traumatic brain injury (TBI) continues to be a leading cause of morbidity and mortality throughout the world. Research has been undertaken in order to better understand the characteristics of the injury event and measure the risk of injury to develop more effective environmental, technological, and clinical management strategies. This research used methods that have limited applications to predicting human responses. This limits the current understanding of the mechanisms of TBI in humans. As a result, the purpose of this research was to examine the characteristics of impact and dynamic response that leads to a high risk of sustaining a TBI in a human population. Twenty TBI events collected from hospital reports and eyewitness accounts were reconstructed in the laboratory using a combination of computational mechanics models and Hybrid III anthropometric dummy systems. All cases were falls, with an average impact velocity of approximately 4.0m/s onto hard impact surfaces. The result...

Purpose of Review: Mild traumatic brain injury (mTBI) is a continuing healthcare concern worldwide contributing to significant cognitive and neurological impairment, consequently affecting activities of daily living. While mTBI recovery is becoming well studied, there are no interventions to reduce the known impairments of mTBI. Omega-3 fatty acids (N-3FA) are safe and beneficial for brain health, however their potential effects in a pathophysiological environment such as that seen post mTBI are unknown.

Recent Findings: Preclinical studies using rodent models are key to understanding molecular
mechanisms underlying improvements post injury. Studies to date have shown improved outcomes in rodent models following mTBI protocols, but these data have not been
quantified using a systematic review and meta-analysis approach.

Summary: Our systematic review assessed 291 studies identified from the literature. Of these studies, 18 studies met inclusion criteria. We conducted a meta-analysis examining the effect of high dose n-3FA vs placebo on neurological, cognitive and molecular changes following mTBI. Quality of studies were rated as moderate to high quality and while mostly compliant some areas of risk of bias were identified. Results showed that pre-clinical doses of 10 mg/kg/day – 370 mg/kg/day of n-3FA per day in rodents (equivalent to high clinical doses) resulted in improvements in neurological and cognitive performance (pooled effect sizes ranging between 1.52 – 3.55). Similarly, improvements in molecular and inflammatory markers were observed in treated rodents vs control (pooled effect sizes: 3.73 – 6.55). Overall, these findings highlight the potential for high dose n-3FA for human clinical studies following mTBI.

Depression is a common post-concussion symptom. The depressive symptoms and its effects seemingly appear to be more long term, with some patients still reporting three months to nine years' post-concussion. School apathy post head trauma can negatively influence prognosis and essentially make the condition worse. Student disruptions post head trauma will result in an inability to reason, problem-solve, set goals, self-monitor, initiate or inhibit response behavior, and effectively execute purposeful behavior. The current investigation examines the effects of traumatic brain injury (TBI) among school-aged athletes (ages 13-to 18-years-old) compared to same-aged athletes who did not have a diagnosis/history of TBI. A Multivariate analysis and t-test are utilized to address the self-reported data in relation to students' feelings, disruption, and school apathy with and without head trauma. It is expected that the results will show adverse effects in those student athletes who had reported head trauma when examining their feelings, disruptions, and school apathy when compared to those student athletes without head trauma.

BACKGROUND:
As recently dictated by the American Medical Society, balance testing is an important component in the clinical evaluation of concussion. Despite this, previous research on the efficacy of balance testing for concussion diagnosis suggests low sensitivity (∼30%), based primarily on the popular Balance Error Scoring System (BESS). The Balance Tracking System (BTrackS, Balance Tracking Systems Inc., San Diego, CA, USA) consists of a force plate (BTrackS Balance Plate) and software (BTrackS Sport Balance) which can quickly (<2 min) perform concussion balance testing with gold standard accuracy.
PURPOSE:
The present study aimed to determine the sensitivity of the BTrackS Balance Plate and Sports Balance Software for concussion diagnosis.
STUDY DESIGN:
Cross-Sectional Study.
METHODS:
Preseason baseline balance testing of 519 healthy Division I college athletes playing sports with a relatively high risk for concussions was performed with the BTrackS Balance Test. Testing was administered by certified athletic training staff using the BTrackS Balance Plate and Sport Balance software. Of the baselined athletes, 25 later experienced a concussion during the ensuing sport season. Post-injury balance testing was performed on these concussed athletes within 48 of injury and the sensitivity of the BTrackS Balance Plate and Sport Balance software was estimated based on the number of athletes showing a balance decline according to the criteria specified in the Sport Balance software. This criteria is based on the minimal detectable change statistic with a 90% confidence level (i.e. 90% specificity).
RESULTS:
Of 25 athletes who experienced concussions, 16 had balance declines relative to baseline testing results according to the BTrackS Sport Balance software criteria. This corresponds to an estimated concussion sensitivity of 64%, which is twice as great as that reported previously for the BESS.
CONCLUSIONS:
The BTrackS Balance Plate and Sport Balance software has the greatest concussion sensitivity of any balance testing instrument reported to date.

Objectives: The purpose of this study was to investigate the effectiveness of an isometric neck strengthening program to improve isometric neck strength in elite women's football-code athletes.
Design: Randomised controlled trial.
Method: Elite female soccer (n = 10) and Australian football (n = 30) players were randomised into either a control (n = 20) or experimental (n = 20) group for a 12-week intervention study during their respective seasons. While both groups undertook their prescribed strength and conditioning programs, the experimental group also performed isometric neck strengthening exercises three times per week prior to training. Isometric neck strength of the extensors, flexors, lateral flexors, and rotators were assessed pre, mid (Week 7), and post (Week 13) intervention with a hand-held dynamometer during early to mid-competition season. A mixed design analysis of variance was performed for statistical analysis.
Results: No significant group-by-time interactions in isometric neck strength were observed. All strength variables displayed a significant change over time throughout the 12-week period (p < 0.05). No significant between group differences in isometric neck strength variables were observed except for lateral left flexion (F(1, 38) =5.064, p = 0.030, η2p = 0.117).
Conclusion: The addition of isometric neck strengthening exercises did not improve neck strength beyond a standard strength and conditioning program for elite women's football-code athletes. While this specific program may not improve neck strength in elite women's football-code athletes, further investigation is needed to determine whether sport-specific neck strength exercises may improve neck strength or if lower-level competition athletes may still benefit from an isometric neck strengthening program.

Five international consensus statements on concussion in sports have been published. This commentary argues that there is a strong need for a new approach to them that foregrounds public health expertise and patient-centered guidance. Doing so will help players, parents and practitioners keep perspective about these potentially life-altering injuries especially when they recur.

Introduction:A Response to Statement by Interim University of North Carolina Chancellor Kevin Guskiewicz’s opinion of The Athletics’ article, Failure to Disclose: The mysterious absence of critical data from UNC’s renowned concussion research published October 8, 2019

There has been increasing growing public concern regarding the association of sports concussion on brain health in later life. Emerging evidence suggests that repetitive head impacts experienced in contact sports, may contribute to either chronic neurological impairments later in life, or neurodegenerative disease. While the majority of the research to date has focused or neuroimaging techniques, such as magnetic resonance imaging or computed tomography scanning; or functional outcomes, such as cognitive deficiencies, mood disorders, or neurodegenerative conditions, relatively less research has focused on neurophysiological abnormalities that may provide the mechanistic evidence for brain function decline and chronic neurological impairments. The aim of this chapter is to present recent research to illustrate chronic neurophysiological changes in those with a history of concussion. Specifically this chapter will summarize recent studies employing techniques such as electroencephalography (EEG), magnetoencephalography (MEG), and transcranial magnetic stimulation (TMS). These studies utilize event related potentials that have demonstrated good evidence of persistent functional injury. The chapter will discuss the advantages of using these techniques, and their ability to quantify functional decline in otherwise healthy retired athletes with a history of repeated head injury. Finally, the chapter will conclude on how these techniques can be utilized, co-registering with modalities such as advanced neuroimaging in the clinical assessment of older individuals with a history of concussion.

Concussions have reached epidemic levels. There is cure for concussions. Measures taken to reduce concussions have not been effective. The majority of research is focused on concussion causation and concussion management after the fact. The research continues but the number of concussions in athletics increases each year.
No methodical approach to producing a specific protocol to strengthen the head and neck muscles exists and no systematic study of increase in neck musculature attributed to such a protocol is documented. Thus, this study will produce a standardized methodology for the reduction of concussive and subconcussive forces, laying the foundation for further research in this area.
The research participants were healthy male and female college students, age range 18-24. There were 30 participants. Of the 30 subjects used for this study, 18 participants were randomly assigned to the experimental group and 12 participants in the control group. The participants followed a protocol consisting of 13 movements designed to sequentially train the musculature of the head, neck and upper back. The duration of the study was 8 weeks.
The strength increases were significant in the active participant group. The hypertrophy of the head and neck muscles was equally as significant and even more impressive in the male group. The females exhibited minimal muscle hypertrophy Every active participant experienced strength increases during the eight week study; likewise each active male participant exhibited neck circumference increases. The control group experienced negligible strength or hypertrophy increases.

Objective: Impacts to the head are the primary cause of concussive injuries in sport and can occur in a multitude of different environments. Each event is composed of combinations of impact characteristics (striking velocity, impact mass, and surface compliance) that present unique loading conditions on the head and brain. The purpose of this study was to compare falls, collisions, and punches from accident reconstructions of sports-related head impacts using linear, rotational accelerations and maximal principal strain of brain tissue from finite element simulation.
Methods: This study compared four types of head impact events through reconstruction. Seventy-two head impacts were taken from medical reports of accidental falls and game video of ice hockey, American football, and mixed-martial arts. These were reconstructed using physical impact systems to represent helmeted and unhelmeted falls, player-to-player collisions, and punches to the head. Head accelerations were collected using a Hybrid III headform and were input into a finite element brain model used to approximate strain in the cerebrum associated with the external loading conditions.
Results: Significant differences (p < 0.01) were found for peak linear and rotational accelerations magnitudes (30–300 g and 3.2–7.8 krad/s2) and pulse durations between all impact event types characterized by unique impact parameters. The only exception was found where punch impacts and helmeted falls had similar rotational durations. Regression analysis demonstrated that increases to strain from unhelmeted falls were significantly influenced by both linear and rotational accelerations, meanwhile helmeted falls, punches, and collisions were influenced by rotational accelerations alone.
Conclusion: This report illustrates that the four distinct impact events created unique peak head kinematics and brain tissue strain values. These distinct patterns of head acceleration characteristics suggest that it is important to keep in mind that head injury can occur from a range of low to high acceleration magnitudes and that impact parameters (surface compliance, striking velocity, and impact mass) play an important role on the duration-dependent tolerance to impact loading.

This article updates coaches and tennis sports scientists on recent changes to the consensus statement for sports-related
concussion. Specifically, the article provides new information that can be applied to tennis. While concussion in tennis is rare,
head injuries in tennis do occur. It is important that in-lieu of medical staff available at training or tournaments, coaches and sports
science practitioners are concussion aware.

Objective: The King-Devick (K-D) test is a rapid visual screening tool that can assess underlying brain trauma such as concussion via impairments in saccadic rhythm. A new tablet version of the K-D test using randomised numbers is now available, but reliability for this new version, as well as comparison to the traditional K-D test has not yet been reported. Known for learning effects in the test, the aim of this study was to determine test-retest reliability and to compare performance of the new ‘randomized’ version to the ‘traditional’ K-D test version. We hypothesized that the ‘traditional’ K-D test would show a greater rate of improvement with repeat application, compared to the ‘randomized’ K-D test.
Methods: Using a cross-sectional, repeated measures design in a healthy university student cohort (n=96; 21.6 ± 2.8 years; 49f: 47m), participants were required to complete the K-D test twice with a one-week break between testing sessions. Participants were randomly assigned into a ‘traditional’ group, where they completed a test-retest of the established K-D protocol, using the same numbers; or the ‘randomized’ group, where they completed test-retest protocol employing two different sets of numbers.
Results: Reliability testing showed strong intraclass correlation coefficient (ICC) for both the ‘traditional’ test group (Control group; 0.95 [CI: 0.91 – 0.97]) and the ‘randomized test group’ (0.97 [CI: 0.95 – 0.98]). However, contrary to our hypothesis, no differences were found between ‘traditional’ or ‘randomized’ groups for baseline (42.5 s [CI: 40.2 – 44.9 s] vs. 41.5 [38.7 – 44.4] respectively, p = 0.23) and repeated testing between groups (40.0 s [37.9 – 42.1 s] vs. 39.5 [36.9 – 42.0], p = 0.55), with both groups showing improved times with repeated testing (2.1 s [CI: 1.1 – 3.2 s] and 1.9 s CI: [0.9 – 2.9 s], p < 0.001, respectively).
Conclusions: The ‘randomized’ version of the K-D test, using different sets of numbers, demonstrates good reliability; comparable to the traditional K-D testing protocol that uses the same number sets. However, similar to the ‘traditional’ K-D test, learning effects were also observed in the ‘randomized’ test, suggesting that learning effects are not due to content memorization, but rather familiarity of the test. As a result, while either test format is suitable for sideline concussion screening or return to play decisions, comparison of data should be made to the individual’s baseline rather than to normative data sets.

Objective This study presents data using multimodal assessment
via impact sensors and oculomotor function to quantify neurophysiological
changes in the acute period following concussion.
Design Cohort study.
Participants Data on impact magnitude and frequency were collected
with a wireless head impact sensor (XPatch1) worn by
senior amateur rugby players participating in a domestic season.
King-Devick Tests2 were performed pre-season and after significant
impact scores (PLA>100 g, PRA>10,000 rads/sec/sec).). Participants
underwent a one hour baseline assessment of balance,
cognition and transcranial magnetic stimulation testing. Following
concussive episodes or significant head impacts (as measured
by impact sensors), players were re-tested to elicit any differences
and to assist in providing objective criteria for the return to play
process.
Interventions Any impact that resulted in a witnessed concussion
or that was suspected on the basis of significant impact scores
required post-match testing utilising the King-Devick test to help
determine appropriate return to play readiness.
Outcome measures Impact number, peak linear and peak rotational
acceleration, risk weighted exposure. Time and errors completing
the King-Devick test.
Main result 20 concussions were detected in all, of which only 3
were witnessed (2 players unconscious on the field, one with balance
disturbance resulting in removal from play).
Conclusions A combination of regular impact monitoring and
King-Devick Ocular testing provides a relatively simple process
for objectively identifying and managing concussion in sports
participants.