Rapid sideline performance meets outpatient clinic: Results from a multidisciplinary concussion center registry

Characteristics of Pediatric Concussion across Different Mechanisms of Injury in 5 through 12-Year-Olds

OBJECTIVE

To investigate characteristics of sport-related concussion (SRC), recreation-related concussion (RRC), and nonsport or recreation-related concussion (non-SRRC) in patients 5 through 12 years old, an understudied population in youth concussion.

STUDY DESIGN

This observational study included patients aged 5 through 12 years presenting to a specialty care concussion setting at ≤28 days postinjury from 2018 through 2022. The following characteristics were assessed: demographics, injury mechanism (SRC, RRC, or SRRC), point of healthcare entry, and clinical signs and symptoms. Kruskal-Wallis and chi-square tests were used to assess group differences. Posthoc pairwise comparisons were employed for all analyses (α = 0.017).

RESULTS

One thousand one hundred forty-one patients reported at ≤28 days of injury (female = 42.9%, median age = 11, interquartile range (IQR) = 9-12) with the most common mechanism being RRC (37.3%), followed by non-SRRC (31.9%). More non-SRRCs (39.6%) and RRC (35.7%) were first seen in the emergency department (P < .001) compared with SRC (27.9%). Patients with RRC and non-SRRC were first evaluated at specialists 2 and 3 days later than SRC (P < .001). Patients with non-SRRC reported with higher symptom burden, more frequent visio-vestibular abnormalities, and more changes to sleep and daily habits (P < .001) compared with RRC and SRC (P < .001).

CONCLUSIONS

In concussion patients 5 through 12 years, RRCs and non-SRRC were more prevalent than SRC, presenting first more commonly to the emergency department and taking longer to present to specialists. Non-SRRC had more severe clinical features. RRC and non-SRRC are distinct from SRC in potential for less supervision at time of injury and less direct access to established concussion health care following injury.

Postinjury Outcomes After Non-Sport-Related Concussion: A CARE Consortium Study

CONTEXT

Concussion research has primarily focused on sport-related mechanisms and excluded non-sport-related mechanisms. In adult populations, non-sport-related concussions (non-SRCs) demonstrated worse clinical outcomes compared with sport-related concussions (SRCs); however, investigations of non-SRCs in college-aged patients are limited.

OBJECTIVES

To examine clinical outcomes in collegiate athletes with non-SRCs compared with SRCs and explore sex differences in outcomes among collegiate athletes with non-SRCs.

DESIGN

Prospective cohort study.

SETTING

Clinical setting.

PATIENTS OR OTHER PARTICIPANTS

A total of 3500 athletes were included (n = 555 with non-SRCs, 42.5% female) from colleges or universities and service academies participating in the National Collegiate Athletic Association Department of Defense Concussion Assessment, Research and Education (CARE) Consortium.

MAIN OUTCOME MEASURE(S)

Dichotomous outcomes (yes or no) consisted of immediate reporting, mental status alterations, loss of consciousness, posttraumatic amnesia, retrograde amnesia, motor impairments, delayed symptom presentation, and required hospital transport. Continuous outcomes were symptom severity, days with concussion symptoms, and days lost to injury. Data were collected within 24 to 48 hours of injury and at return to play. Adjusted relative risks (ARRs) compared the likelihood of dichotomous outcomes by mechanism and by sex within patients with non-SRCs. Multivariate negative binomial regressions were used to assess group differences in continuous variables.

RESULTS

Athletes with non-SRCs were less likely to report immediately (ARR = 0.73, 95% CI = 0.65, 0.81) and more likely to report delayed symptom presentation (ARR = 1.17, 95% CI = 1.03, 1.32), loss of consciousness (ARR = 3.15, 95% CI = 2.32, 4.28), retrograde amnesia (ARR = 1.77, 95% CI = 1.22, 2.57), and motor impairment (ARR = 1.45, 95% CI = 1.14, 1.84). Athletes with non-SRCs described greater symptom severity, more symptomatic days, and more days lost to injury (P < .001) compared with those who had SRCs. Within the non-SRC group, female athletes indicated greater symptom severity, more symptomatic days, and more days lost to injury (P < .03) than male athletes.

CONCLUSIONS

Athletes with non-SRCs had worse postinjury outcomes compared with those who had SRCs, and female athletes with non-SRCs had worse recovery metrics than male athletes. Our findings suggest that further investigation of individuals with non-SRCs is needed to improve concussion reporting and management.

Vision as a piece of the head trauma puzzle

Approximately half of the brain's circuits are involved in vision and control of eye movements. Therefore, visual dysfunction is a common symptom of concussion, the mildest form of traumatic brain injury (TBI). Photosensitivity, vergence dysfunction, saccadic abnormalities, and distortions in visual perception have been reported as vision-related symptoms following concussion. Impaired visual function has also been reported in populations with a lifetime history of TBI. Consequently, vision-based tools have been developed to detect and diagnose concussion in the acute setting, and characterize visual and cognitive function in those with a lifetime history of TBI. Rapid automatized naming (RAN) tasks have provided widely accessible and quantitative measures of visual-cognitive function. Laboratory-based eye tracking approaches demonstrate promise in measuring visual function and validating results from RAN tasks in patients with concussion. Optical coherence tomography (OCT) has detected neurodegeneration in patients with Alzheimer's disease and multiple sclerosis and may provide critical insight into chronic conditions related to TBI, such as traumatic encephalopathy syndrome. Here, we review the literature and discuss the future directions of vision-based assessments of concussion and conditions related to TBI.

Where's the Vision? The Importance of Visual Outcomes in Neurologic Disorders: The 2021 H. Houston Merritt Lecture

Neurologists have long recognized the importance of the visual system in the diagnosis and monitoring of neurologic disorders. This is particularly true because approximately 50% of the brain's pathways subserve afferent and efferent aspects of vision. During the past 30 years, researchers and clinicians have further refined this concept to include investigation of the visual system for patients with specific neurologic diagnoses, including multiple sclerosis (MS), concussion, Parkinson disease (PD), and conditions along the spectrum of Alzheimer disease (AD, mild cognitive impairment, and subjective cognitive decline). This review highlights the visual "toolbox" that has been developed over the past 3 decades and beyond to capture both structural and functional aspects of vision in neurologic disease. Although the efforts to accelerate the emphasis on structure-function relationships in neurologic disorders began with MS during the early 2000s, such investigations have broadened to recognize the need for outcomes of visual pathway structure, function, and quality of life for clinical trials of therapies across the spectrum of neurologic disorders. This review begins with a patient case study highlighting the importance using the most modern technologies for visual pathway assessment, including optical coherence tomography. We emphasize that both structural and functional tools for vision testing can be used in parallel to detect what might otherwise be subclinical events or markers of visual and, perhaps, more global neurologic decline. Such measures will be critical because clinical trials and therapies become more available across the neurologic disease spectrum.

Eye tracking for classification of concussion in adults and pediatrics

Introduction

In order to obtain FDA Marketing Authorization for aid in the diagnosis of concussion, an eye tracking study in an intended use population was conducted.

Methods

Potentially concussed subjects recruited in emergency department and concussion clinic settings prospectively underwent eye tracking and a subset of the Sport Concussion Assessment Tool 3 at 6 sites. The results of an eye tracking-based classifier model were then validated against a pre-specified algorithm with a cutoff for concussed vs. non-concussed. The sensitivity and specificity of eye tracking were calculated after plotting of the receiver operating characteristic curve and calculation of the AUC (area under curve).

Results

When concussion is defined by SCAT3 subsets, the sensitivity and specificity of an eye tracking algorithm was 80.4 and 66.1%, The AUC was 0.718. The misclassification rate (n = 282) was 31.6%.

Conclusion

A pre-specified algorithm and cutoff for diagnosis of concussion vs. non-concussion has a sensitivity and specificity that is useful as a baseline-free aid in diagnosis of concussion. Eye tracking has potential to serve as an objective “gold-standard” for detection of neurophysiologic disruption due to brain injury.

Rapid Automatized Picture Naming in an Outpatient Concussion Center: Quantitative Eye Movements during the Mobile Universal Lexicon Evaluation System (MULES) Test

Number and picture rapid automatized naming (RAN) tests are useful sideline diagnostic tools. The main outcome measure of these RAN tests is the completion time, which is prolonged with a concussion, yet yields no information about eye movement behavior. We investigated eye movements during a digitized Mobile Universal Lexicon Evaluation System (MULES) test of rapid picture naming. A total of 23 participants with a history of concussion and 50 control participants performed MULES testing with simultaneous eye tracking. The test times were longer in participants with a concussion (32.4 s [95% CI 30.4, 35.8] vs. 26.9 s [95% CI 25.9, 28.0], t=6.1). The participants with a concussion made more saccades per picture than the controls (3.6 [95% CI 3.3, 4.1] vs. 2.7 [95% CI 2.5, 3.0]), and this increase was correlated with longer MULES times (r = 0.46, p = 0.026). The inter-saccadic intervals (ISI) did not differ between the groups, nor did they correlate with the test times. Following a concussion, eye movement behavior differs during number versus picture RAN performance. Prior studies have shown that ISI prolongation is the key finding for a number-based RAN test, whereas this study shows a primary finding of an increased saccade number per picture with a picture-based RAN test. Number-based and picture-based RAN tests may be complimentary in concussion detection, as they may detect different injury effects or compensatory strategies.

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.

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.

King-Devick Test Performance and Cognitive Dysfunction after Concussion: A Pilot Eye Movement Study

(1) Background: The King-Devick (KD) rapid number naming test is sensitive for concussion diagnosis, with increased test time from baseline as the outcome measure. Eye tracking during KD performance in concussed individuals shows an association between inter-saccadic interval (ISI) (the time between saccades) prolongation and prolonged testing time. This pilot study retrospectively assesses the relation between ISI prolongation during KD testing and cognitive performance in persistently-symptomatic individuals post-concussion. (2) Results: Fourteen participants (median age 34 years; 6 women) with prior neuropsychological assessment and KD testing with eye tracking were included. KD test times (72.6 ± 20.7 s) and median ISI (379.1 ± 199.1 msec) were prolonged compared to published normative values. Greater ISI prolongation was associated with lower scores for processing speed (WAIS-IV Coding, r = 0.72, p = 0.0017), attention/working memory (Trails Making A, r = −0.65, p = 0.006) (Digit Span Forward, r = 0.57, p = −0.017) (Digit Span Backward, r= −0.55, p = 0.021) (Digit Span Total, r = −0.74, p = 0.001), and executive function (Stroop Color Word Interference, r = −0.8, p = 0.0003). (3) Conclusions: This pilot study provides preliminary evidence suggesting that cognitive dysfunction may be associated with prolonged ISI and KD test times in concussion.

Considering Biological Sex in Traumatic Brain Injury

Published epidemiological studies of traumatic brain injury (TBI) of all severities consistently report higher incidence in men. Recent increases in the participation of women in sports and active military service as well as increasing awareness of the very large number of women who sustain but do not report TBI as a result of intimate partner violence (IPV) suggest that the number of women with TBI is significantly larger than previously believed. Women are also grossly under-represented in clinical and natural history studies of TBI, most of which include relatively small numbers of women, ignore the role of sex- and age-related gonadal hormone levels, and report conflicting results. The emerging picture from recent studies powered to detect effects of biological sex as well as age (as a surrogate of hormonal status) suggest young (i.e., premenopausal) women are more likely to die from TBI relative to men of the same age group, but this is reversed in the 6th and 7th decades of life, coinciding with postmenopausal status in women. New data from concussion studies in young male and female athletes extend this finding to mild TBI, since female athletes who sustained mild TBI are significantly more likely to report more symptoms than males. Studies including information on gonadal hormone status at the time of injury are still too scarce and small to draw reliable conclusions, so there is an urgent need to include biological sex and gonadal hormone status in the design and analysis of future studies of TBI.

Tandem gait test performance in healthy, physically active adults: Clinical implications for concussion evaluation

OBJECTIVES

To identify factors affecting performance on the tandem gait test in healthy, physically active adults.

DESIGN

Cross-sectional.

METHODS

Participants completed the tandem gait test according to Sport Concussion Assessment Tool 3 (SCAT3) guidelines. Dependent variables included time for best trial (initial 3m, turn, final 3m and total) and whether the trial was "pass" or "fail". Independent variables included sex, concussion history, foot length, height and total number of trials.

RESULTS

55% (35/64) of participants passed the first trial of the tandem gait test; 19% (12/64) had a best time <14s. Sex and concussion history did not affect performance (p>0.05). There were no differences in turn times for those with and without a history of concussion (t=0.26, p=0.80). The number of trials was not significantly correlated with best time (þ=-0.04, p=0.74). There were low (þ=-0.31) to negligible (þ<0.30) correlations between foot length, height and all portions of the test. There was more variability in times for the turn (COV=27%) than during the straight portions (COV=18%).

CONCLUSIONS

Current recommendations for the tandem gait test led to a high false-positive rate in healthy, physically active adults. Sex, concussion history, number of trials and foot length had little to no influence on scores on the test. Turning times were more variable than times on the straight portions of the test. Clinicians may use these results as a guideline when interpreting performance on the tandem gait test in healthy physically active adults.

Neuromodulation for Mild Traumatic Brain Injury Rehabilitation: A Systematic Review

Background: Mild traumatic brain injury (mTBI) results from an external force to the head or body causing neurophysiological changes within the brain. The number and severity of symptoms can vary, with some individuals experiencing rapid recovery, and others having persistent symptoms for months to years, impacting their quality of life. Current rehabilitation is limited in its ability to treat persistent symptoms and novel approaches are being sought to improve outcomes following mTBI. Neuromodulation is one technique used to encourage adaptive neuroplasticity within the brain. Objective: To systematically review the literature on the efficacy of neuromodulation in the mTBI population. Method: A systematic review was conducted using Medline, Embase, PsycINFO, PsycARTICLES and EBM Review. Preferred Reporting Items for Systematic Reviews and the Synthesis Without Meta-analysis reporting guidelines were used and a narrative review of the selected studies was completed. Fourteen articles fulfilled the inclusion criteria which were published in English, investigating an adult sample and using a pre- and post-intervention design. Studies were excluded if they included non-mild TBI severities, pediatric or older adult populations. Results: Thirteen of fourteen studies reported positive reductions in mTBI symptomatology following neuromodulation. Specifically, improvements were reported in post-concussion symptom ratings, headaches, dizziness, depression, anxiety, sleep disturbance, general disability, cognition, return to work and quality of life. Normalization of working memory activation patterns, vestibular field potentials, hemodynamics of the dorsolateral prefrontal cortex and excessive delta wave activity were also seen. The studies reviewed had several methodological limitations including small, heterogenous samples and varied intervention protocols, limiting generalisability. Further research is required to understand the context in which neuromodulation may be beneficial. Conclusions: While these positive effects are observed, limitations included unequal representation of neuromodulation modalities in the literature, and lack of literature describing the efficacy of neuromodulation on the development or duration of persistent mTBI symptoms. Better clarity regarding neuromodulation efficacy could have a significant impact on mTBI patients, researchers, clinicians, and policy makers, facilitating a more productive post-mTBI population. Despite the limitations, the literature indicates that neuromodulation warrants further investigation. PROSPERO registration number: CRD42020161279.

Sports and non-sports-related concussions among Medicaid-insured children: health care utilization before and after Ohio's concussion law

Objective

To evaluate patterns of health care utilization for sports-related concussions (SRCs) and non-sports-related concussions (NSRCs) among Medicaid-insured children before and after the enactment of Ohio’s concussion law in April 2013.

Methods

We analyzed claim data from the Partners For Kids (PFK) Ohio Medicaid database. Concussion diagnoses were identified between April 1, 2008 and June 30, 2017. We compared frequency of concussions by age and sex across the law period. We evaluated type of health care utilization before and after law enactment using multinomial logistic regression.

Results

Over the 9 year study period, 6157 concussions were included, most of which (70.4%) were NSRCs. The proportion of SRCs increased with age. Among children younger than 5 years old, the majority (96.1%) of concussions were NSRCs. During the post-law period, greater odds of primary care visits than emergency department (ED) visits were observed for both SRCs (OR = 1.53; 95% CI 1.34, 1.75) and NSRCs (OR = 1.73; 95% CI 1.58, 1.90) compared to the pre-law period.

Conclusions

We observed higher proportions of health care utilization for NSRCs than SRCs in Medicaid insured children and a shift in health care utilization from the ED to primary care in the post-law period. SRCs and NSRCs are likely to have different patterns of health care utilization before and after the enactment of Ohio’s concussion law. Our results demonstrate that Ohio’s youth concussion law had a quantifiable impact on health care utilization.

A COMPARISON OF THE PAPER AND COMPUTERIZED TABLET VERSION OF THE KING-DEVICK TEST IN COLLEGIATE ATHLETES AND THE INFLUENCE OF AGE ON PERFORMANCE

Background

Sport-related concussion is a public concern with between 1.6 and 3.8 million sport- and recreation-related injuries occurring annually. An estimated 65% to 90% of concussed athletes show oculomotor disruption such as difficulty with saccades, accommodation, smooth pursuit, and fixation. A rapid number-naming saccade test, the King-Devick (K-D) test, has shown promising results as part of a multifaceted concussion assessment tool.

Purpose

The purpose of the current study was to evaluate the two versions of the K-D in collegiate aged (18-24) athletes to determine the agreement between versions. A secondary purpose was to investigate the association of K-D scores with sport, sex, use of glasses or contacts, and age of the athlete.

Study design

Descriptive laboratory study.

Methods

Division 1 NCAA collegiate athletes across ten sports were recruited to participate in baseline concussion assessments at the beginning of their respective athletic season. Correlations and multivariable logistic regression analyses were used to investigate the association of K-D scores with sex and age.

Results

One-hundred and nine athletes (69 males, 40 females; mean age = 20.40 ± 1.38 years) were baseline tested. There was excellent agreement (ICC=0.93, 95% CI: 0.90, 0.95) between the paper and computer version. Preseason K-D scores were statistically different (r²=0.873, p<0.05) with athletes scoring a mean of 37.58 seconds on the paper version (95% CI, 36.21, 38.96) and athletes scoring a mean of 41.48 seconds for the computerized tablet version (95% CI, 40.17, 42.91). There were no significant differences in sex, sport, or use of glasses noted for both versions. Age differences were identified; eighteen-year-old athletes took statistically longer than their peers for both K-D versions. Pairwise comparisons showed statistically significant differences between 18-year olds up to the age of 21-year-olds (p<0.05) for the computer version and statistically significant differences between 18-year olds up to 22-year-olds (p<0.05) for the paper version.

Conclusion

This study supports the use of either version of the K-D test as a potential part of a multifaceted concussion assessment. The age of the athlete influences scores and therefore a K-D baseline should be repeated annually for collegiate athletes. Clinicians should not substitute K-D versions (computer vs. paper) in comparing baseline to a post-concussion K-D score as the scores are quite different.

Level of evidence

Level 3.

Baseline Performance of High School Rugby Players on the Sport Concussion Assessment Tool 5

CONTEXT

Version 5 of the Sport Concussion Assessment Tool (SCAT5) was released in 2017 with an additional 10-word list option in the memory section and additional instructions for completing the symptom scale.

OBJECTIVE

To provide reference scores for high school rugby union players on the SCAT5, including immediate memory using the 10-word list, and examine how age, sex, and concussion history affected performance.

DESIGN

Cross-sectional study.

SETTING

Calgary, Alberta high schools.

PATIENTS OR OTHER PARTICIPANTS

High school rugby union players (ages 15-18 years) participating in a 2018 season cohort study (n = 380, males = 210, females = 170).

MAIN OUTCOME MEASURE(S)

Sport Concussion Assessment Tool 5 scores, including total number of symptoms (of 20), symptom severity (of 132), 10-word immediate memory (of 30), delayed memory (of 10), modified Standardized Assessment of Concussion (of 50), and balance examination (of 30).

RESULTS

The median number of symptoms reported at baseline ranged from 5 to 8 across sex and age stratifications. Median symptom severity was lowest in males with no concussion history (7; range, 0-28) and highest in females with a concussion history (13, range = 0-45). Median total scores on immediate memory were 2-3 (range = 0-4) for males and 21 (range = 9-29) for females. Median total scores were 3 (range = 0-4) on digits backward and 7 (range = 0-20) on delayed memory (all groups). Based on simultaneous quantile (q) regression at 0.50 and 0.75, adjusted for age and concussion history, being female was associated with a higher total symptoms score (q0.75 β_female = 2.85; 99% confidence interval [CI] = 0.33, 5.37), higher total symptom severity score (q0.75 β_female = 8.00; 99% CI = 2.83, 13.17), and lower number of errors on the balance examination (q0.75 β_female = -3.00; 99% CI = -4.85, -1.15). Age and concussion history were not associated with any summary measures.

CONCLUSIONS

The 10-word list option in the memory section reduced the likelihood of a ceiling effect. A player's sex may be an important consideration when interpreting the SCAT5 after concussion.

Treatment of Pediatric Concussion

Concussions have gained attention in medical literature, legal literature, and lay media over the past several years as a public health affecting children, particularly those who do not improve in the first few days after an injury. We discuss strategies for acute management immediately after a concussion and an introduction to medical and non-medical options for treatment of the complex symptoms that persist in some patients with concussions. We examine the role of rest and exercise during recovery. We briefly discuss the role of the multidisciplinary approach to concussion in a setting that engages multiple specialists. Finally, we address policy changes related to sport-concussions and their efficacy in improving long term outcomes.

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

OBJECTIVE

This study investigated the diagnostic and prognostic value of the King-Devick (K-D) test in conjunction with treadmill testing in adolescents after sport-related concussion (SRC) in an outpatient concussion management clinic without baseline measures.

DESIGN

Prospective cohort.

METHODS

The K-D test was administered pre- and post-exercise on a graded treadmill test to acutely concussed (AC, <10 days from injury, n = 46, 15.4 ± 2.1 years) participants for 2 clinic visits (1 week apart) and to matched controls (MC, n = 30, 15.8 ± 1.4 years) for 2 visits (1 week apart). Initial K-D test times were compared between MC and AC. Changes in times from pre- to post- exercise during a treadmill test were compared for MC and AC and from Visit 1 to Visit 2. Smooth pursuits and repetitive saccades were compared with initial visit K-D test performance.

RESULTS

Comparison of pre-exercise K-D test times at Visit 1 distinguished MC from AC (46.1 ± 9.2 s vs. 53.7 ± 13.0 s, p = .007). Comparison of pre- and post-exercise K-D test times revealed significant improvements for MC (46.1 ± 9.2 s vs. 43.1 ± 8.5 s, p < .001) and AC who recovered by Visit 2 (Fast Recovery Group [FRG], n = 23, 50.4 ± 10.0 s vs. 47.3 ± 9.8 s, p = .002). No significant difference was seen in pre- and post-exercise K-D test times on Visit 1 for AC who took longer than 2 weeks to recover (Slow Recovery Group [SRG], n = 23, 57.0 ± 15.0 s vs. 56.0 ± 16.3 s, p = .478). At Visit 1, AC had more abnormal smooth pursuits than MC (17% vs. 3%, non-significant, p = .064). AC, however, had significantly more abnormal repetitive saccades than MC (37% vs. 3%, p = .001) and AC with abnormal repetitive saccades took significantly longer to complete the Visit 1 pre-exercise K-D test than AC with normal repetitive saccades (58.6 ± 16.0 s vs 50.8 ± 10.2 s, p = .049).

CONCLUSION

The study supports utility of the K-D test as part of outpatient concussion assessment. Lack of improvement in K-D test performance after an exercise test may be an indicator of delayed recovery from SRC.

Neuro-ophthalmologic disorders following concussion

Visual symptoms, such as photophobia and blurred vision, are common in patients with concussion. Such symptoms may be accompanied by abnormalities of specific eye movements, such as saccades and convergence, or accommodation deficits. The high frequency of visual involvement in concussion is not surprising, since more than half of the brain's pathways are dedicated to vision and eye movement control. These areas include many that are most vulnerable to head trauma, including the frontal and temporal lobes. Vision and eye movement testing is important at the bedside and on the sidelines of athletic events, where brief performance measures that require eye movements, such as rapid number naming, are reliable and sensitive measures for concussion detection. Tests of vision and eye movements are also being explored clinically to identify and monitor patients with symptoms of both sport- and nonsport-related concussion. Evaluation of vision and eye movements can assist in making important decisions after concussion, including the prognosis for symptom recovery, and to direct further visual rehabilitation as necessary.