King-Devick concussion test performs poorly as a screening tool in elite rugby union players: a prospective cohort study of two screening tests versus a clinical reference standard

Acute evaluation of sport-related concussion and implications for the Sport Concussion Assessment Tool (SCAT6) for adults, adolescents and children: a systematic review

OBJECTIVES

To systematically review the scientific literature regarding the acute assessment of sport-related concussion (SRC) and provide recommendations for improving the Sport Concussion Assessment Tool (SCAT6).

DATA SOURCES

Systematic searches of seven databases from 2001 to 2022 using key words and controlled vocabulary relevant to concussion, sports, SCAT, and acute evaluation.

ELIGIBILITY CRITERIA

(1) Original research articles, cohort studies, case-control studies, and case series with a sample of >10; (2) ≥80% SRC; and (3) studies using a screening tool/technology to assess SRC acutely (<7 days), and/or studies containing psychometric/normative data for common tools used to assess SRC.

DATA EXTRACTION

Separate reviews were conducted involving six subdomains: Cognition, Balance/Postural Stability, Oculomotor/Cervical/Vestibular, Emerging Technologies, and Neurological Examination/Autonomic Dysfunction. Paediatric/Child studies were included in each subdomain. Risk of Bias and study quality were rated by coauthors using a modified SIGN (Scottish Intercollegiate Guidelines Network) tool.

RESULTS

Out of 12 192 articles screened, 612 were included (189 normative data and 423 SRC assessment studies). Of these, 183 focused on cognition, 126 balance/postural stability, 76 oculomotor/cervical/vestibular, 142 emerging technologies, 13 neurological examination/autonomic dysfunction, and 23 paediatric/child SCAT. The SCAT discriminates between concussed and non-concussed athletes within 72 hours of injury with diminishing utility up to 7 days post injury. Ceiling effects were apparent on the 5-word list learning and concentration subtests. More challenging tests, including the 10-word list, were recommended. Test-retest data revealed limitations in temporal stability. Studies primarily originated in North America with scant data on children.

CONCLUSION

Support exists for using the SCAT within the acute phase of injury. Maximal utility occurs within the first 72 hours and then diminishes up to 7 days after injury. The SCAT has limited utility as a return to play tool beyond 7 days. Empirical data are limited in pre-adolescents, women, sport type, geographical and culturally diverse populations and para athletes.

PROSPERO REGISTRATION NUMBER

CRD42020154787.

An assessment of current concussion identification and diagnosis methods in sports settings: a systematic review

Background

Concussion in sport is an ongoing global concern. The head injury assessment (HIA) by the field of play is acknowledged as the first step in recognising and identifying concussion. While previous systematic literature reviews have evaluated the sensitivity of side-line screening tools and assessment protocols, no systematic review has evaluated the research designs and assessments used in a field setting. This systematic review investigated existing screening and diagnostic tools used in research as part of the HIA protocol to identify concussion that are currently used in professional, semi-professional and amateur (club) sports settings.

Methods

A systematic searching of relevant databases was undertaken for peer-reviewed literature between 2015 and 2020.

Results

Twenty-six studies met the inclusion criteria. Studies were of moderate to good quality, reporting a variety of designs. The majority of studies were undertaken in professional/elite environments with medical doctors and allied health practitioners (e.g., physical therapists) involved in 88% of concussion assessments. While gender was reported in 24 of the 26 studies, the majority of participants were male (77%). There was also a variety of concussion assessments (n = 20) with the sports concussion assessment tool (SCAT) used in less than half of the included studies.

Conclusion

The majority of studies investigating concussion HIAs are focused on professional/elite sport. With concussion an issue at all levels of sport, future research should be directed at non-elite sport. Further, for research purposes, the SCAT assessment should also be used more widely to allow for consistency across studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13102-022-00514-1.

An investigation into the measurement properties of the King-Devick Eye Tracking system

Objectives

Eye tracking has been gaining increasing attention as a possible assessment and monitoring tool for concussion. The King-Devick test (K-DT) was expanded to include an infrared video-oculography-based eye tracker (K-D ET). Therefore, the aim was to provide evidence on the reliability of the K-D ET system under an exercise condition.

Methods

Participants (N = 61; 26 male, 35 female; age range 19-25) were allocated to an exercise or sedentary group. Both groups completed a baseline K-D ET measurement and then either two 10-min exercise or sedentary interventions with repeated K-D ET measurements between interventions.

Results

The test-retest reliability of the K-D ET ranged from good to excellent for the different variables measured. The mean ± SD of the differences for the total number of saccades was 1.04 ± 4.01 and there was an observable difference (p = 0.005) in the trial number. There were no observable differences for the intervention (p = 0.768), gender (p = 0.121) and trial (p = 0.777) for average saccade’s velocity. The mean ± SD of the difference of the total fixations before and after intervention across both trials was 1.04 ± 3.63 and there was an observable difference in the trial number (p = 0.025). The mean ± SD of the differences for the Inter-Saccadic Interval and the fixation polyarea before and after intervention across both trials were 1.86 ± 22.99 msec and 0.51 ± 59.11 mm2 and no observable differences for the intervention, gender and trial.

Conclusion

The results provide evidence on the reliability of the K-D ET, and the eye-tracking components and demonstrate the relationship between completion time and other variables of the K-D ET system. This is vital as the use of the K-DT may be increasing and the combination of the K-DT and eye tracking as one single package highlights the need to specifically measure the reliability of this combined unit.

Wearables in rugby union: A protocol for multimodal digital sports-related concussion assessment

Background

Pragmatic challenges remain in the monitoring and return to play (RTP) decisions following suspected Sports Related Concussion (SRC). Reliance on traditional approaches (pen and paper) means players readiness for RTP is often based on self-reported symptom recognition as a marker for full physiological recovery. Non-digital approaches also limit opportunity for robust data analysis which may hinder understanding of the interconnected nature and relationships in deficit recovery. Digital approaches may provide more objectivity to measure and monitor impairments in SRC. Crucially, there is dearth of protocols for SRC assessment and digital devices have yet to be tested concurrently (multimodal) in SRC rugby union assessment. Here we propose a multimodal protocol for digital assessment in SRC, which could be used to enhance traditional sports concussion assessment approaches.

Methods

We aim to use a repeated measures observational study utilising a battery of multimodal assessment tools (symptom, cognitive, visual, motor). We aim to recruit 200 rugby players (male n≈100 and female n≈100) from University Rugby Union teams and local amateur rugby clubs in the North East of England. The multimodal battery assessment used in this study will compare metrics between digital methods and against traditional assessment.

Conclusion

This paper outlines a protocol for a multimodal approach for the use of digital technologies to augment traditional approaches to SRC, which may better inform RTP in rugby union. Findings may shed light on new ways of working with digital tools in SRC. Multimodal approaches may enhance understanding of the interconnected nature of impairments and provide insightful, more objective assessment and RTP in SRC.

Clinical trial registration

NCT04938570. https://clinicaltrials.gov/ct2/results?cond=NCT04938570&term=&cntry=&state=&city=&dist=

Sports related concussion: an emerging era in digital sports technology

Sports-related concussion (SRC) is defined as a mild traumatic brain injury (mTBI) leading to complex impairment(s) in neurological function with many seemingly hidden or difficult to measure impairments that can deteriorate rapidly without any prior indication. Growing numbers of SRCs in professional and amateur contact sports have prompted closer dialog regarding player safety and welfare. Greater emphasis on awareness and education has improved SRC management, but also highlighted the difficulties of diagnosing SRC in a timely manner, particularly during matches or immediately after competition. Therefore, challenges exist in off-field assessment and return to play (RTP) protocols, with current traditional (subjective) approaches largely based on infrequent snapshot assessments. Low-cost digital technologies may provide more objective, integrated and personalized SRC assessment to better inform RTP protocols whilst also enhancing the efficiency and precision of healthcare assessment. To fully realize the potential of digital technologies in the diagnosis and management of SRC will require a significant paradigm shift in clinical practice and mindset. Here, we provide insights into SRC clinical assessment methods and the translational utility of digital approaches, with a focus on off-field digital techniques to detect key SRC metrics/biomarkers. We also provide insights and recommendations to the common benefits and challenges facing digital approaches as they aim to transition from novel technologies to an efficient, valid, reliable, and integrated clinical assessment tool for SRC. Finally, we highlight future opportunities that digital approaches have in SRC assessment and management including digital twinning and the "digital athlete".

The Current Status of Concussion Assessment Scales: A Critical Analysis Review

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Concussion is a complex pathophysiologic process that affects the brain; it is induced by biomechanical forces, with alteration in mental status with or without loss of consciousness.

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Concussion assessment tools may be broadly categorized into (1) screening tests such as the SAC (Standardized Assessment of Concussion), the BESS (Balance Error Scoring System), and the King-Devick (KD) test; (2) confirmatory tests including the SCAT (Sport Concussion Assessment Tool), the ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing), and the VOMS (Vestibular Oculomotor Screening); and (3) objective examinations such as brain network activation (BNA) analysis, imaging studies, and physiologic markers.

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The KD, child SCAT3 (cSCAT3), child ImPACT (cImPACT), and VOMS tests may be used to evaluate for concussion in the pediatric athlete.

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Future work with BNA, functional magnetic resonance imaging, diffusion tensor imaging, and serum biomarkers may provide more objective assessment of concussion, neurologic injury, and subsequent recovery.

The learning effect of the King-Devick test in semi-professional rugby union athletes

OBJECTIVE

Abnormalities of eye movement and visual processing are common in traumatic brain injury. The King-Devick test (KDT) has been widely used in the detection and recovery of concussion. Current recommendations propose performing the initial test at baseline and then repeating annually to account for potential learning effects. In practice, this may still account for large deviations. The aim of this study was to determine the number of trials needed for a player to achieve a ceiling effect and to determine the validity of the existing protocol requiring two tests at baseline.

METHODS

One hundred and eighty-three semi-professional male rugby union players (median age = 22.5 (21.0-25.3) years) were recruited. Over the duration, all athletes performed the KDT on an iPad, under standardised baseline procedures and then repeated the test based on availability during weekly in-season training.

RESULTS

The improvement through each repeated trial was 0.60 ± 0.1 s (P < 0.001). The ceiling effect was determined at 30 trials. A median difference of 4.2 s (range 0-14.9) was calculated between the initial and best trial overall, although the greatest difference occurred within the first eight attempts. There was a significant positive correlation between the initial test value and the difference between first and fastest time (P < 0.001, r = 0.455).

CONCLUSION

We have shown continuous improvement with repeated attempts which suggests that administrators ideally should continue to perform the KDT over the duration of the season to optimise the value of the test.

Lay of the land: narrative synthesis of tackle research in rugby union and rugby sevens

Objectives

The purpose of this review was to synthesise both injury prevention and performance tackle-related research to provide rugby stakeholders with information on tackle injury epidemiology, including tackle injury risk factors and performance determinants, and to discuss potential preventative measures.

Design

Systematic review and narrative synthesis.

Data sources

PubMed, Scopus and Web of Science.

Eligibility criteria

Limited to peer-reviewed English-only publications between January 1995 and October 2018.

Results

A total of 317 studies were identified, with 177 in rugby union and 13 were in rugby sevens. The tackle accounted for more than 50% of all injuries in rugby union and rugby sevens, both at the professional level and at the lower levels, with the rate of tackle injuries higher at the professional level (mean 32/1000 player-hours) compared with the lower levels (mean 17/1000 player-hours). A player’s tackle actions and technical ability were identified as major risk factors for injury and a key determinant of performance.

Summary/conclusion

Evidence-based education, progressive tackle technique training with a high potential to transfer and law changes have been proposed as key modifiers of player tackle actions and technical ability. Conceivably, all three modifiers working in unison (as opposed to separately) will have a higher potential at reducing tackle injury risk while enhancing performance. With the guidance of tackle injury and performance studies, as well as stakeholder engagement, experiential and explorative tackle research has the potential to inspire innovative injury prevention and performance strategies.

On-field assessment of concussion: clinical utility of the King-Devick test

Sport-related concussion (SRC) is an important public health concern with up to 3.8 million SRCs occurring each year. As the incidence and rate of SRC increases, reliable and valid tools for diagnosis and management are needed. The King-Devick (K-D) test assesses a patient’s visual function based on reading a series of numbers as well as counting both time to completion and errors. Its rapid administration time and simplicity make the K-D test a potentially useful SRC diagnostic tool, though limitations exist in baseline testing and what constitutes an abnormal score. Additionally, the K-D tests should never be used in isolation to diagnose a concussion, but rather as one test in conjunction with additional clinical measures, as part of an individualized approach to each patient. The current review examines the clinical utility of the K-D test.

American Medical Society for Sports Medicine position statement on concussion in sport

Sport-related concussion (SRC) is a common injury in recreational and organised sport. Over the past 30 years, there has been significant progress in our scientific understanding of SRC, which in turn has driven the development of clinical guidelines for diagnosis, assessment and management of SRC. In addition to a growing need for knowledgeable healthcare professionals to provide evidence-based care for athletes with SRC, media attention and legislation have created awareness and, in some cases, fear about many issues and unknowns surrounding SRC. The American Medical Society for Sports Medicine (AMSSM) formed a writing group to review the existing literature on SRC, update its previous position statement, and to address current evidence and knowledge gaps regarding SRC. The absence of definitive outcomes-based data is challenging and requires relying on the best available evidence integrated with clinical experience and patient values. This statement reviews the definition, pathophysiology and epidemiology of SRC, the diagnosis and management of both acute and persistent concussion symptoms, the short-term and long-term risks of SRC and repetitive head impact exposure, SRC prevention strategies, and potential future directions for SRC research. The AMSSM is committed to best clinical practices, evidence-based research and educational initiatives that positively impact the health and safety of athletes.

The King-Devick test is not sensitive to self-reported history of concussion but is affected by English language skill

OBJECTIVES

Head injuries, including concussion, are a concern in many sports. Current validated concussion assessment protocols such are problematic with suggestions that an oculomotor examination, such as the King-Devick (K-D) test, could be included. This research explores the role of the K-D test in snowsport concussion research.

DESIGN

Experienced snowsport participants were recruited through a western Canadian resort (n=75).

METHODS

Participants completed a questionnaire that included their history of prior serious head impacts and were assessed via the computer-based K-D test in English.

RESULTS

Of the 75 participants, 23 (69%) reported at least one previous serious head impact. English was the not primary language for seven participants. Independent sample t-tests revealed: significant differences in the K-D average saccade scores for those who had broken their helmets, with or without a serious head injury (̄x¯=171.23, SD=12.9) and those who had not broken a helmet (̄x¯=186.61, SD=20.18; t (70)=-2.53, p=.014, twotailed) and significant differences in the K-D time for those whose native language is English (̄x¯=47.9, SD=6.3) and those where English was not their first language (̄x¯=53.3, SD=7.4; t(73)=.48, p=.04), but no significant difference for their saccade velocities: English (̄x¯=183.64, SD=20.0) versus those where English is a second or third language (̄x¯=188.44, SD=20.1; t(70)=-.56, p=.576).

CONCLUSIONS

For subjects whose first language is not English, such as in many snowsport resorts, the K-D test may need to be conducted in a person's native language to provide a valid assessment based upon the time to complete the task.