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

Use of physical exertion to enhance objective testing following mild traumatic brain injury: a systematic review

Background

Assessment of recovery from mild traumatic brain injury (mTBI) is complex and challenging. Post-exertion testing, where individuals undergo objective testing following physical exercise, has shown promise in identifying mTBI-related impairments that may not be evident at rest, but could hinder a safe return to sport.

Objectives

To conduct a systematic review to determine if physical exertion affects objective physiological or sensorimotor tests differently in individuals with mTBI compared with healthy controls.

Methods

A systematic search of 11 databases and five trial registries on 30 May 2024 identified reports that: (i) compared individuals aged 12-65 years within 12 months of mTBI against healthy control participants, (ii) investigated the effects of a single session of physical exertion and (iii) collected before, during or after exertion, objective measures of physiological or sensorimotor function. Risk of bias was assessed with the Risk Of Bias In Non-randomized Studies of Interventions tool. Results were analysed descriptively.

Results

The review included 22 studies with 536 participants wih mTBI. Risk of bias was deemed high. At rest, 8/22 (36%) studies detected differences in physiological responses between participants wih mTBI and healthy control participants. During or after exertion, 21/22 (96%) studies detected differences in physiological responses, including cardiovascular, respiratory and cerebral autoregulation.

Conclusion

The findings indicate that objective testing during or after physical exertion can enhance the ability to detect mTBI-related impairments in various physiological parameters, and this concept could be considered when monitoring recovery and return to sport. Further studies are needed.

PROSPERO registration number

CRD42023411681.

Comparing the Impact of High-Intensity Exercise on Vestibular-Oculomotor Function Between Sex, Sport, and Activity Level

OBJECTIVE

To investigate the impact of high-intensity exercise on the vestibular and oculomotor systems in a group of sedentary and active males and females.

DESIGN

Prospective observational study.

SETTING

Performance laboratory; Institute of Sport, Exercise and Health, London.

PARTICIPANTS

Forty-five collegiate athletes and 30 age-matched sedentary participants.

INTERVENTIONS

A baseline Vestibular and Oculomotor Screening (VOMS) test was performed on all participants before undertaking a self-paced 5-minute treadmill run maintaining an intensity of 17/20 on the Borg scale. Post-run, participants were tested using the VOMS tool a further 3 times with each test 30 seconds apart.

MAIN OUTCOME MEASURES

Symptom provocation on testing of the VOMS tool.

RESULTS

At baseline testing, 25.3% of participants had 1 or more positive VOMS domains although there was no significant differences between sex, sport, or activity level. At postrun testing, 62.5% of participants had 1 or more positive VOMS domains; this was a significant change from baseline with large effect size (Z = 6.12, r = 0.72, P < 0.001).

CONCLUSIONS

High-intensity exercise has a deleterious impact on vestibular and oculomotor function. This change in function is consistent across all groups when considering activity level, sex, and sporting participation. These findings have implications when considering the timing of VOMS in relation to sporting participation and clinical testing that involves exercise.

Scoping review: Intervention for ocular motor disorders in children and adults with mild traumatic brain injury

SIGNIFICANCE

Intervention strategies for post-mild traumatic brain injury (mTBI) ocular motor disorders vary across disciplines and include watchful waiting, vestibular rehabilitation, vision rehabilitation/vision therapy, and optical intervention. However, evidence supporting their effectiveness is limited, highlighting the need for high-quality randomized controlled trials with standardized testing, diagnostic criteria, and reassessment of ocular motor function after intervention.

BACKGROUND

Ocular motor disorders occur frequently after mTBI.

OBJECTIVES

This study aimed to conduct a scoping review of interventions for mTBI-related ocular motor disorders in children and adults.

DATA SOURCES

The following electronic bibliographic databases were searched: PubMed, Embase, PEDro, OVID, Clinical Key, Google Scholar, and REHABDATA.

STUDY SELECTION

Intervention studies published in English between 2003 and 2024 involving mTBI participants who had an ocular motor assessment prior to intervention were included in this study.

DATA EXTRACTION AND SYNTHESIS

Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews guidelines were followed for reporting. Study population, intervention, and outcomes were extracted and synthesized in tabular and graphical formats.

RESULTS

Sixty-seven eligible studies were included, with only three (4%) judged as low risk of bias. Intervention strategies included watchful waiting (n = 31, 46%), vestibular rehabilitation (n = 13, 19%), vision rehabilitation/vision therapy (n = 10, 15%), optical intervention (n = 4, 6%), and alternative interventions or multifaceted interventions (n = 9, 14%). Among the studies providing statistically supported results, improvements in one or more ocular motor outcome domains were reported in nearly 80% of the studies on watchful waiting (19/24) and 100% of the studies on vestibular rehabilitation (4/4), vision rehabilitation/vision therapy (7/7), or optical intervention (1/1).

CONCLUSIONS AND IMPLICATIONS

Although post-mTBI ocular motor deficits improved with watchful waiting strategy, vestibular rehabilitation, vision rehabilitation/vision therapy, and optical interventions, most studies had significant risk of bias. This review emphasizes the necessity for high-quality randomized controlled trials with standardized testing protocols and diagnostic criteria and reassessment of ocular motor functions after intervention to evaluate the effectiveness of these interventions in different age groups and recovery stages.

Multimodal Assessment Battery and Heart Rate Variability Enhance Clinical Utility of Buffalo Concussion Treadmill Test

CONTEXT

The Buffalo Concussion Treadmill Test (BCTT) for exercise intolerance following concussion may highlight underlying autonomic dysfunction. Autonomic function at rest and with exertion may be predictive of neurocognitive performance for individuals with sports-related concussion. The purpose of this study is to explore the feasibility and utility of combining multimodal assessments with heart rate variability (HRV) measures during the BCTT for individuals with a remote history of concussion.

DESIGN

Prospective cohort study design, pretest/posttest.

METHODS

Participants included 5 males and 5 females (N = 10, age: 25.2 [3.3] y old, height: 173.2 [11.2] cm, mass: 73.4 [13.7] kg, body mass index: 24.5 [3.9], time since last concussion of 6.3 [4.5] y). All participants completed the multimodal assessment battery including: Concentration Reverse Digits (6 digits), Stroop Incongruent, and King-Devick Test under single- (seated) and dual-task conditions (walking on treadmill at 2.0 mph, 0% incline). Heart rate and HRV was collected at rest, during the BCTT, and during postexercise recovery. HRV data were processed and analyzed based on established protocols. Paired t tests were performed for pre- and postmeasurements separately for single- and dual-task tests of the multimodal assessment battery and HRV indices.

RESULTS

During the BCTT, HRV indices reflective of peripheral nervous system activity demonstrated a significant reduction with concomitant increase in HRV indices of sympathetic nervous system activity (P < .05). Recovery in these HRV indices toward baseline was observed during postexercise recovery. Neurocognitive performance on the Stroop task significantly improved with exercise (P < .05).

CONCLUSION

Implementation of multimodal assessments to evaluate physiological and neurocognitive responses to exercise in individuals with history of sports-related concussion is feasible. Addition of these objective measures may decrease reliance on self-reporting of exercise-induced symptom exacerbation, enabling clinicians to identify individuals whose neurocognitive performance or physiologic response to exercise on the BCTT deviates from the expected.

Assessing Brain Processing Deficits Using Neuropsychological and Vision-Specific Tests for Concussion

INTRODUCTION

Since verbal memory and visual processing transpire within analogous cerebral regions, this study assessed (i) if a visual function can predict verbal memory performance. It also hypothesized whether neurocognitive (e.g., ImPACT) tests focusing on the Visual Memory and Cognitive Efficacy Index will predict Verbal Memory scores and (ii) if vision metrics and age can identify individuals with a history of concussion. Finally, it also hypothesized that King-Devick and near point of convergence scores alongside age considerations will identify candidates with a prior reported history of concussion.

MATERIALS AND METHODS

This observational cohort assessed 25 collegiate ice hockey players prior to the competitive season considering age (19.76 ± 1.42 years) and BMI (25.9 ± 3.0 kg/cm2). Hypothesis 1 was assessed using a hierarchical (sequential) multiple regression analysis, assessing the predictive capacity of Visual Memory and Cognitive Efficacy Index scores in relation to Verbal Memory scores. Hypothesis 2 utilized a binomial logistic regression to determine if King-Devick and near point of convergence scores predict those with a prior history of concussion.

RESULTS

Hypothesis 1 developed two models, where Model 1 included Visual Memory as the predictor, while Model 2 added the Cognitive Efficacy Index as a predictor for verbal memory scores. Model 1 significantly explained 41% of the variance. Results from Model 2 suggest that the Cognitive Efficacy Index explained an additional 24.4%. Thus, Model 2 was interpreted where only the Cognitive Efficacy Index was a significant predictor (p = 0.001). For every 1 unit increase in the Cognitive Efficacy Index, Verbal Memory increased by 41.16. Hypothesis 2's model was significant, accounting for 37.9% of the variance in those with a history of concussion. However, there were no significant unique predictors within the model as age (Wald = 1.26, p = 0.261), King-Devick (Wald = 2.31, p = 0.128), and near point of convergence (Wald = 2.43, p = 0.119) were not significant predictors individually.

CONCLUSIONS

The conflicting findings of this study indicate that baseline data for those with a history of concussion greater than one year may not be comparable to the same metrics during acute concussion episodes. Young athletes who sustain a concussion may be able to overcompensate via the visual system. Future prospective studies with larger sample sizes are required using the proposed model's objective metrics.

Multisystem recovery after sport-related concussion in adolescent rugby players: a prospective study protocol

INTRODUCTION

Sport-related concussion is one of the most common injuries in adolescent rugby players with evidence of prolonged recovery in some concussed athletes. Concussion is a complex pathophysiological process that can affect a variety of subsystems with multifactorial presentation. Most research on adolescents recovery after concussion focuses on neurocognitive functioning and symptom outcomes over the short term. There is a need to explore concussion recovery over time across multiple subsystems in adolescent rugby players.

METHODS AND ANALYSIS

This prospective study will use sensorimotor and oculomotor outcomes in adolescent male and female rugby players aged 16-18 years. Players will be recruited from school or club rugby teams across the province of Ulster. Baseline assessment will be undertaken at the start of the playing season and will include questionnaires, Quantified Y Balance Test and Pupillary Light Reflex. Players who sustain a concussive event will be reassessed on all outcomes at 3 days, 7 days, 14 days, 23 days, 90 days, 180 days and 365 days postconcussion. For serial outcome data, we will examine response curves for each participant and make comparisons between known groups. We will use logistic regression to explore any association between demographic variables and recovery. The strength of the predictive model will be determined using R2, p values and ORs, with 95% CIs.

ETHICS AND DISSEMINATION

Ethical approval has been granted for this study from Ulster University Research Ethics Committee (REC/14/0060). This study will be published in an open-access research journal on completion.

TRIAL REGISTRATION NUMBER

ACTRN12622000931774p.

Exercise-Induced Vision Dysfunction Early After Sport-Related Concussion Is Associated With Persistent Postconcussive Symptoms

OBJECTIVE

The purpose of this study was to determine if exercise-induced vision dysfunction [reduced performance and/or symptom exacerbation on a post-exercise King-Devick (KD) test] in adolescents early after sport-related concussion was associated with increased risk of persistent post-concussive symptoms (PPCS, recovery >28 days). We used exercise as a provocative maneuver before the KD test, hypothesizing that concussed adolescents with exercise-induced vision dysfunction would be more likely to develop PPCS.

DESIGN

Secondary analysis of data from a multi-center, randomized clinical trial comparing KD test performance before and after the Buffalo Concussion Treadmill Test in adolescents within 10 days of sport-related concussion who were randomized to aerobic exercise or placebo stretching program.

SETTING

Three university-associated sports medicine clinical programs.

PARTICIPANTS

Ninety-nine adolescents with sport-related concussion (exercise group: n = 50, 15.3 ± 1 years, 60% M, 22% with PPCS; stretching group: n = 49, 15.9 ± 1 years, 65% M, 35% with PPCS) tested a mean of 6 ± 2 days from injury.

INDEPENDENT VARIABLE

King-Devick test performed immediately before and 2 minutes after Buffalo Concussion Treadmill Test.

MAIN OUTCOME MEASURE

Persistent post-concussive symptoms.

RESULTS

Adolescents who demonstrated exercise-induced vision dysfunction upon initial evaluation developed PPCS at a significantly greater rate when compared with adolescents who did not (71% vs 34%, P < 0.001). Exercise-induced vision dysfunction corresponded to a relative risk of 3.13 for PPCS.

CONCLUSIONS

Adolescents with exercise-induced vision dysfunction had a 3-fold greater relative risk of developing PPCS than those without exercise-induced vision dysfunction.

Norm-Based Cutoffs as Predictors of Prolonged Recovery After Adolescent Sport-Related Concussion

OBJECTIVES

To identify predictors of prolonged recovery (ie, >28 days) using patient demographic factors and healthy, norm-based cutoffs on a multimodal test battery in adolescents after sport-related concussions (SRCs).

DESIGN

Retrospective cohort. Patients were deemed recovered after successful completion of return-to-play/school protocols and received medical clearance.

SETTING

Community concussion clinic.

PATIENTS

Male and female adolescent student athletes diagnosed with a SRC and evaluated within 1 week of injury.

INDEPENDENT VARIABLES

Patient demographics, medical history, injury description, computerized neurocognitive testing, vestibular/ocular testing, and symptoms at initial clinical visit.

MAIN OUTCOME MEASURES

Performance on clinical testing to predict recovery duration, classified as normal (<28 days) or prolonged (>28 days).

RESULTS

A total of 201 adolescent student athletes (age = 15.3 ± 1.4 years) were included (female 35%). Average recovery duration for the entire cohort was 22.3 ± 13.3 days, with 22% (n = 45) of adolescent student athletes taking >28 days to recover. The final model was 88.3% accurate in classifying normal and prolonged recovery. Predictor variables included sex, loss of consciousness, history of ocular disorder, history of concussion, performance on visual motor speed composite, visual motion sensitivity symptom provocation and near point of convergence distance, number-naming total time, and symptom count.

CONCLUSIONS

These findings suggest that using norm-based cutoffs from cognitive, oculomotor, and vestibulo-ocular testing and symptom reporting, clinicians can accurately predict a prolonged recovery (sensitivity = 81%) and normal recovery (specificity = 83%) in an adolescent, SRC cohort.

Clinical Outcome Following Sport-Related Concussion Among Children and Adolescents with a History of Prior Concussion: A Systematic Review

Authoritative sources advise clinicians and parents that a history of prior concussion confers increased risk for worse outcome from a future concussion. However, the strength of the evidence supporting such pronouncements and thus the extent to which clinicians should incorporate this information into their care and management of pediatric concussion is unclear. This systematic review critically analyzed and synthesized the literature on the association between a history of prior concussion and prognosis/clinical outcome following a subsequent sport-related concussion among children and adolescents. The online databases PubMed, MEDLINE®, PsycINFO®, CINAHL, Cochrane Library, EMBASE, SPORTDiscus, Scopus, and Web of Science were searched from inception to May 15, 2021. From 5,118 total records screened, 51 studies (46 cohort studies and 5 case-control studies) met inclusion criteria, reporting concussion recovery or outcome for 26,643 youth. A median of 36% had a prior history of concussion. Across all studies and outcomes, the majority (k=37, 72.5%) did not find a statistically significant association between lifetime history of concussion and outcome from a subsequent concussion. Important methodological limitations in the literature were identified. Available studies do not provide consistent or compelling evidence that children and adolescents with a history of concussions are at increased risk for worse clinical outcome following a subsequent sport-related concussion-although methodological limitations temper the strength of this conclusion. Clinicians are cautioned against routinely treating children and adolescents with one or more prior injuries differently, and more conservatively, because doing so, in some cases, might be counterproductive.

Physical Activity Following Sport-Related Concussion in Adolescents: A Systematic Review

OBJECTIVE

To evaluate the evidence related to how physical activity (PA) affects recovery following a sport-related concussion (SRC) in adolescents.

DESIGN

Systematic review Data Source: PUBMED, MEDLINE, and SPORTDiscus Eligibility criteria for selecting study:(1) original research article (e.g., randomized controlled trials (RCT), quasi-experimental designs, cohort, case-control studies), (2) 66% or greater of the sample has to have a SRC diagnosed by a clinician, (4) human research, (5) evaluate the effect of a SRC on PA in adolescents only (<18 years). Participants were seen within 1-2 weeks post-SRC for acute studies and 4 weeks post-SRC for studies focused on prolonged recoveries.

RESULTS

Twenty-two studies met the inclusion criteria (i.e., 8 regarding PA (PA-daily aerobic activity including light-moderate intensities), 8 evaluating active rehabilitation/exercise programs (20 minutes of daily aerobic exercise below symptom threshold), 6 examining a single bout of exertion). The methodological quality of the literature was assessed using the Downs and Black risk of bias (ROB) checklist. The ROB scores ranged from 7-24, with only two RCTs included. Studies demonstrated single bouts of exertion testing were safe and feasible. Daily PA or active rehabilitation/exercise programs led to a reduction in symptoms present and a decrease in number of days to medical clearance.

CONCLUSION

Following a brief period of rest (24-48 hours), individuals can gradually and safely return to PA below their physical symptom exacerbation thresholds. Further research is warranted to delineate how to optimize the timing, intensity, duration, and modality of PA impacts symptom resolution and physiological recovery following SRC.

The acute, systemic effects of aerobic exercise in recently concussed adolescent student-athletes: preliminary findings

OBJECTIVES

Examine the acute effects (pre-, during, post-intervention) of two different intensities of aerobic exercise or rest on autonomic, oculomotor, and vestibular function and symptom burden in patients with a recent sport-related concussion (SRC) and compare their responses to sex-matched, age-stratified, non-concussed (HEALTHY) student-athletes.

METHODS

Student-athletes between the ages of 13 and 18 that presented to the sports medicine clinic within Day 3-7 post-SRC and from local schools were recruited for a randomized controlled trial (RCT). The participants were administered the Vestibular/Ocular Motor Screening (VOMS), King-Devick (K-D), and Post-Concussion Symptom Scale (PCSS) before and after the intervention. Heart rate variability (HRV) and mean arterial pressure (MAP) were collected before, during, and after the intervention. The intervention was either a single, 20-min session of treadmill walking at 40% (40HR) or 60% of age-predicted max heart rate (60HR), or seated, rest (NOEX).

RESULTS

30 participants completed the intervention with the SRC group treated 4.5 ± 1.3 days post-injury. Pre-exercise HRV and MAP were significantly different (p's < 0.001) during treatment but returned to pre-exercise values within 5 min of recovery in both the SRC and HEALTHY groups. Both the SRC and HEALTHY groups exhibited similar reductions pre- to post-intervention for symptom severity and count (p's < 0.05), three VOMS items (p's < 0.05) but not K-D time.

CONCLUSIONS

To date, this is the first adolescent RCT to report the acute, systemic effects of aerobic exercise on recently concussed adolescent athletes. The interventions appeared safe in SRC participants, were well-tolerated, and provided brief therapeutic benefit.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier NCT03575455.

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.

Spotlight on the Developmental Eye Movement (DEM) Test

The developmental eye movement (DEM) test is a practical and simple method for assessing and quantifying ocular motor skills in children. In this review, a summary of the literature relevant to the DEM test has been made, its psychometric properties and its pros and cons have also been considered. The DEM test provides clinicians with a simple method of measuring eye movement using a psychometric test. Over the years, many studies have enabled the identification of the strengthens and weaknesses of this test apart from outlining the psychometric properties. The validity of the test has been checked and expanded over time and studies have shown that the DEM test measures an aspect of eye movement related to reading, rather than purely parameters associated with eye-movement. Some reservations have emerged regarding the repeatability of the test because a degree of learning effect emerges over multiple sessions. Being aware of this point allows correct clinical application and interpretation of the test. Normative data in children were available for nine languages and countries. So far, DEM test could be applied clinically in each case when a rapid test of eye movement was required, such as in testing for vision-related visual problems.

Rehabilitation of Sport-Related Concussion

This article provides a summary of clinical assessment methods and nonpharmacologic rehabilitation techniques used for concussed patients. It describes concussion-relevant physical examination methods to identify underlying symptom generators. This approach allows practitioners to prescribe targeted rehabilitation therapies to treat postconcussion symptoms. Evidence-based rehabilitation approaches include cervical rehabilitation, vestibulo-ocular rehabilitation, and sub-symptom threshold aerobic exercise.

Postexercise Slowing on the King-Devick Test and Longer Recovery From Sport-Related Concussion in Adolescents: A Validation Study

CONTEXT

The King-Devick (KD) test is a rapid number-reading test that has emerging use in the assessment of sport-related concussion (SRC). Previous research suggested that healthy individuals and patients with acute concussions who had shorter recovery times (<3 weeks) demonstrated a learning effect on the KD test after mild to moderate exertion, whereas patients with longer recovery times did not.

OBJECTIVE

To assess if the absence of postexertional improvement on the KD test within 10 days of concussive head injury was associated with a longer duration of recovery.

DESIGN

Prospective cohort study.

SETTING

University concussion-management clinics.

PATIENTS OR OTHER PARTICIPANTS

Male and female adolescent athletes (n = 99, aged 13-18 years) presenting within 10 days of SRC.

MAIN OUTCOME MEASURE(S)

The KD test was administered before and after the Buffalo Concussion Treadmill Test (BCTT). Days from injury to recovery, with recovery defined as being asymptomatic, confirmed by the assessment of a physician who was blinded to the treatment group, and the return of normal exercise tolerance on the BCTT were recorded.

RESULTS

Participants with postexertional slowing (PES group, n = 33) had a longer duration of recovery (17 days versus 13.5 days, P = .033) than participants without PES (no-PES group, n = 66). At any clinic visit, PES was also associated with a relative risk of 2.36 (95% confidence interval = 1.55, 3.61; P < .001) of not recovering within the following week.

CONCLUSIONS

The current study validates our prior work showing that acutely concussed adolescents who did not display the typical learning effect on the KD test after the BCTT took longer to recover from SRC than those who exhibited the typical learning effect.

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.