Neurovascular Coupling in Acutely Concussed Adolescent Patients

Neurovascular coupling (NVC) uniquely describes cerebrovascular response to neural activation and has demonstrated impairments following concussion in adult patients. It is currently unclear how adolescent patients experience impaired NVC acutely following concussion during this dynamic phase of physiological development. The purpose of this study was to investigate NVC in acutely concussed adolescent patients relative to controls. We recruited patients presenting to a sports medicine practice within 28 days of a concussion or a musculoskeletal injury (controls). Transcranial Doppler ultrasound was used to measure changes in patients' posterior cerebral artery (PCA) velocity in response to two progressively challenging visual tasks: (1) reading and (2) visual search. Each task was presented in five 1-min trials (20 sec eyes closed/40 sec eyes open). Resting PCA velocity data were derived by averaging PCA velocity across a 2-min baseline period that preceded the visual tasks. Filtered task data were converted to time-series curves representing 40 consecutive 1-sec averages for each trial. Curves were then averaged across the five trials and time-aligned to stimulus onset (eyes open) to generate a single ensemble-averaged 40-sec curve representing NVC response for each participant for each task. Independent t tests were used to assess group differences (concussion vs. control) in resting PCA velocity. Separate linear mixed-effects models were used to evaluate group differences (concussion vs. control) in NVC response profiles for both visual tasks and group-by-task interaction. Twenty-one concussion patients (female = 8 [38.1%]; age = 14.4 ± 1.9 years) and 20 controls (female = 7 [35.0%]; age = 14.4 ± 1.9 years) were included in our analysis. Average resting PCA velocity did not significantly differ between concussion patients (36.6 ± 8.0 cm/sec) and controls (39.3 ± 8.5 cm/sec) (t39 = 1.06; p = 0.30). There were no significant group differences in relative NVC response curves during the reading task (F1,1560 = 2.23; p = 0.14) or the visual search task (F1,1521 = 2.04; p = 0.15). In contrast, the differential response to task (e.g., increase from reading task to visual search task) was significantly greater in concussion patients than in controls (p < 0.0001). The NVC response to the visual search task was 7.1% higher than the response to reading in concussion patients relative to being 5.5% higher in controls. Our data indicate that concussed patients present with a significantly greater response to more difficult tasks than do controls, suggesting that concussed adolescents require increased neural resource allocation as task difficulty increases. The study provides insight into the neurophysiological consequences of concussion in adolescent patients.

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.

Sex Differences in Recovery Trajectories of Assessments for Sport-Related Concussion Among NCAA Athletes: A CARE Consortium Study

OBJECTIVES

The purpose of this study was to determine sex differences in recovery trajectories of assessments for sport-related concussion using Concussion Assessment, Research and Education (CARE) Consortium data.

METHODS

National Collegiate Athletic Association athletes (N = 906; 61% female) from sex-comparable sports completed a pre-season baseline assessment and post-sport-related concussion assessments within 6 h of injury, 24-48 h, when they initiated their return to play progression, when they were cleared for unrestricted return to play, and 6 months post-injury. Assessments included the Standardized Assessment of Concussion, Balance Error Scoring System, Brief Symptom Inventory-18, Immediate Post-concussion Assessment and Cognitive Testing (ImPACT), Sport Concussion Assessment Tool-3 symptom evaluation, Clinical Reaction Time, King-Devick test, Vestibular Ocular Motor Screen, 12-item Short-Form Health Survey, Hospital Anxiety and Depression Scale, and Satisfaction with Life Scale.

RESULTS

Only the Vestibular Ocular Motor Screen Total Symptom Score at the 24-48 h timepoint (p = 0.005) was statistically significantly different between sexes. Specifically, female athletes (mean = 60.2, 95% confidence interval [CI] 51.5-70.4) had higher Vestibular Ocular Motor Screen Total Symptom Scores than male athletes (mean = 36.9, 95% CI 27.6-49.3), but this difference resolved by the time of return-to-play initiation (female athletes, mean = 1.8, 95% CI 1.1-2.9; male athletes, mean = 4.1, 95% CI 1.5-10.9).

CONCLUSIONS

Sport-related concussion recovery trajectories for most assessments were similar for female and male National Collegiate Athletic Association athletes except for Vestibular Ocular Motor Screen symptoms within 48 h of sport-related concussion, which was greater in female athletes. Female athletes had a greater symptom burden across all timepoints, suggesting that cross-sectional observations may indicate sex differences despite similar recovery trajectories.

Menstrual Cycle Patterns After Concussion in Adolescent Patients

OBJECTIVE

To describe menstrual cycle patterns in adolescents with concussion and investigate whether menstrual cycle phase at injury influenced postconcussion cycle pattern changes or concussion symptoms.

STUDY DESIGN

Data were collected prospectively from patients aged 13-18 years presenting to a specialty care concussion clinic for an initial visit (≤28 days postconcussion) and, if clinically indicated, at a follow-up visit 3-4 months postinjury. Primary outcomes included menstrual cycle pattern change since injury (change/no change), menstrual cycle phase at time of injury (calculated using date of last period before injury), and symptom endorsement and severity, measured by Post-Concussion Symptom Inventory (PCSI). Fisher exact tests were used to determine the association between menstrual phase at injury and change in cycle pattern. Multiple linear regression was used to determine whether menstrual phase at injury was associated with PCSI endorsement and symptom severity, adjusting for age.

RESULTS

Five hundred twelve postmenarchal adolescents were enrolled (age 15.2 ± 1.4 years), with 111 (21.7%) returning for follow-up at 3-4 months. Menstrual pattern change was reported by 4% of patients at initial visit and 10.8% of patients at follow-up. At 3-4 months, menstrual phase at injury was not associated with menstrual cycle changes (P = .40) but was associated with endorsement of concussion symptoms on the PCSI (P = .01).

CONCLUSIONS

At 3-4 months' postconcussion, 1 in 10 adolescents experienced a change in menses. Menstrual cycle phase at injury was associated with postconcussion symptom endorsement. Leveraging a large sample of postconcussion menstrual patterns, this study represents foundational data regarding potential menstrual cycle effects of concussion in female adolescents.

Researcher degrees of freedom in statistical software contribute to unreliable results: A comparison of nonparametric analyses conducted in SPSS, SAS, Stata, and R

Researcher degrees of freedom can affect the results of hypothesis tests and consequently, the conclusions drawn from the data. Previous research has documented variability in accuracy, speed, and documentation of output across various statistical software packages. In the current investigation, we conducted Pearson's chi-square test of independence, Spearman's rank-ordered correlation, Kruskal-Wallis one-way analysis of variance, Wilcoxon Mann-Whitney U rank-sum tests, and Wilcoxon signed-rank tests, along with estimates of skewness and kurtosis, on large, medium, and small samples of real and simulated data in SPSS, SAS, Stata, and R and compared the results with those obtained through hand calculation using the raw computational formulas. Multiple inconsistencies were found in the results produced between statistical packages due to algorithmic variation, computational error, and statistical output. The most notable inconsistencies were due to algorithmic variations in the computation of Pearson's chi-square test conducted on 2 × 2 tables, where differences in p-values reported by different software packages ranged from .005 to .162, largely as a function of sample size. We discuss how such inconsistencies may influence the conclusions drawn from the results of statistical analyses depending on the statistical software used, and we urge researchers to analyze their data across multiple packages to check for inconsistencies and report details regarding the statistical procedure used for data analysis.

The effect of a home exercise program on visio-vestibular function in concussed pediatric patients

Background

A visio-vestibular home exercise program (VV-HEP) can provide an equitable and cost-effective method for therapy targeted towards visio-vestibular deficits that are common following concussion. The effects of a VV-HEP on improving concussion symptoms and visio-vestibular function are unclear.

Purpose

Determine the effect of VV-HEP on symptoms and visio-vestibular function in concussed pediatric patients.

Methods

This study included 527 patients [294 female (55.8%); age = 14.4 ± 2.1 years] reporting to a specialty care concussion center within 28 days of injury and for a first follow-up within 60 days of injury. Patients completed the Post-Concussion Symptom Inventory (PCSI) and Visio-Vestibular Examination (VVE). Patients were prescribed the VV-HEP at initial visit, with exercises including saccades, gaze stability, convergence, and balance, and instructed to complete these 1-2 times/day. At follow-up, patients self-reported their VV-HEP progress as (1) has not done, (2) in progress, or (3) completed. Primary outcomes included VV-HEP progress at follow-up, PCSI endorsement and severity, VVE subtests (normal/abnormal), and total VVE score (abnormal = 2 + abnormal subtests). Kruskal-Wallis tests and chi-square were used to determine if concussion symptoms or the proportion of abnormal VVE outcomes, respectively, were associated with VV-HEP status. Post-hoc pairwise comparisons with Bonferonni corrections were used to determine concussion symptom (α = 0.017 a priori) and VVE (α = 0.005 a priori) differences in VV-HEP status.

Results

At follow-up, patients who had completed the VV-HEP reported lower symptom endorsement (median = 1, IQR = 0-3) and lower symptom severity (median = 1, IQR = 0-4) relative to patients who had not started the VV-HEP (endorsement median = 7, IQR = 1-13, p < 0.0001; severity median = 15.5, IQR = 2-32.5, p < 0.0001) and those in progress (endorsement median = 8, IQR = 3-14, p < 0.0001; severity median = 15, IQR = 4-30, p < 0.0001). A lower proportion of patients who completed the VV-HEP reported with abnormal vestibular-ocular reflex (22.2%), tandem gait (0%), and total VVE score (22.2%) relative to those who had not started or those in progress (p < 0.005).

Conclusion

Our findings indicate that patients who completed the VV-HEP had lower symptom burden and improved visio-vestibular function relative to those who did not start or were in progress. This suggests that a VV-HEP can effectively reduce visio-vestibular dysfunction following concussion and may serve as a means to minimize inequities in access to care.

Pre- and post-season visio-vestibular function in healthy adolescent athletes

OBJECTIVE

To evaluate pre - to post-season differences in individual subtests of the Visio-Vestibular Examination (VVE) in healthy middle and high school athletes.

METHODS

This prospective cohort study recruited participants from a private suburban United States secondary school. Participants completed a demographic questionnaire prior to the start of their season. A proxy for head impact exposure was estimated by incorporating previously published head impact frequencies by team and sport. The VVE was completed pre - and post-season and consisted of 9 subtests: smooth pursuit, horizontal/vertical saccades and gaze stability, binocular convergence, left/right monocular accommodation, and complex tandem gait. Generalized estimating equations were employed to assess the relative risk of an abnormal VVE outcome based on testing session (pre - vs. post-season).

RESULTS

Participants included middle and high school athletes (n = 115; female = 59 (51.3%); median age at first assessment = 14.9 years, [IQR = 13.6, 16.0]) during 2017/18 - 2019/20 school years. During pre-season testing, accommodation (10.0%) and complex tandem gait (9.2%) had the largest proportion of abnormal outcomes, while smooth pursuits (10.6%) and convergence (9.5%) had the largest proportion of abnormal outcomes post-season. When assessing the effect of testing session on the relative risk of any abnormal VVE subtest, there were no significant findings (P ≥ 0.25). Additionally, there were no significant effects of testing session when adjusting for estimated head impact exposure for any VVE subtest (P ≥ 0.25).

CONCLUSIONS

Visio-vestibular function as measured by the VVE does not change from pre - to post-season in otherwise healthy adolescent athletes. Our findings suggest that the VVE may be stable and robust to typical neurodevelopment occurring in this dynamic age group and help inform post-injury interpretation of visio-vestibular impairments.

Influence of concussion history and age of first concussion on visio-vestibular function

OBJECTIVES

To assess if abnormalities on visio-vestibular examination (VVE) are associated with concussion history (first vs. repeat) or age of first concussion in acutely concussed adolescents.

DESIGN

Cross-sectional.

METHODS

Data were queried from the Children's Hospital of Philadelphia Minds Matter concussion registry. Patients aged 14-18 years old presenting for their initial visit to the specialty care concussion program within 28 days of injury were included. Demographics, including age, sex, concussion history, and age of first concussion, were collected before the exam. The VVE consisted of 9 subtests: smooth pursuit, horizontal/vertical saccades and vestibulo-ocular reflex (VOR), binocular convergence, left/right monocular accommodation, and complex tandem gait. Primary outcomes included VVE subtests (normal/abnormal), and total VVE score (abnormal = 2+ abnormal subtests).

RESULTS

Among 1051 patients included (female = 604(57.5 %); age = 15.6 ± 1.2; median lifetime concussions = 1 [IQR = 1,3]), 518 had repeat concussion. Controlling for age and sex, first vs. repeat concussion was not associated with any VVE subtest or total score (Total VVE Score RR = 1.35, 99.5%CI = 0.70,2.61). Of those with repeat concussion, 190 had valid age of first concussion data. Controlling for age, sex, and number of lifetime concussions, age of first concussion was not significantly associated with any VVE subtest or total score (Total VVE Score RR = 1.11, 99.5%CI = 0.78,1.57).

CONCLUSIONS

Adolescents with concussion history present with similar visio-vestibular function to those with no concussion history. Additionally, clinical effects of early age of first concussion may not be evident in children. This study provides foundational data regarding potential cumulative effects of concussion in younger athletes.

Epidemiology of Injuries in National Collegiate Athletic Association Women's Gymnastics: 2014-2015 Through 2018-2019

CONTEXT

Women's gymnastics athletes in the National Collegiate Athletic Association (NCAA) constitute a unique population of NCAA athletes given the nature and dynamics of the sport.

BACKGROUND

Routine examination of women's gymnastics injuries is important for identifying the evolving burden of injuries in this sport.

METHODS

Exposure and injury data collected in the NCAA Injury Surveillance Program during 2014-2015 through 2018-2019 were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics; injury rate ratios were used to examine differential injury rates.

RESULTS

The overall injury rate was 8.00 per 1000 athlete-exposures; injury incidence was greater in competitions than in practices (injury rate ratio = 1.84; 95% CI = 1.48, 2.29), though practice injury rates increased during 2015-2016 through 2018-2019. Most injuries were classified as strains (16.5%), sprains (16.4%), and inflammatory conditions (12.3%), with overuse injuries prevalent among practice injuries (22.5%). Concussions (8.4%) were the most commonly reported specific injury.

SUMMARY

The increasing trend in practice injury incidence is noteworthy although competition injury rates were higher overall. Findings also suggest that the etiologies of overuse injuries and inflammatory conditions as well as the biomechanical aspects of concussions warrant further attention.

Epidemiology of Injuries in National Collegiate Athletic Association Men's Track and Field: 2014-2015 Through 2018-2019

CONTEXT

College athletes have been competing in championship track and field events since 1921; the numbers of competing teams and participating athletes have expanded considerably.

BACKGROUND

Monitoring injuries of men's track and field athletes using surveillance systems is critical in identifying emerging injury-related patterns.

METHODS

Exposure and injury data collected in the National Collegiate Athletic Association Injury Surveillance Program during the 2014-2015 through 2018-2019 academic years were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics; injury rate ratios were used to examine differential injury rates.

RESULTS

Overall, men's track and field athletes were injured at a rate of 2.37 per 1000 athlete-exposures; injuries occurred at a higher rate during competition compared with practice. Most injuries were to the thigh (26.2%), lower leg (17.3%), or knee (10.7%) and were caused by noncontact (37.2%) or overuse (31.5%) mechanisms. The most reported injury was hamstring tear (14.9%).

SUMMARY

The etiologies of thigh and lower-leg injuries warrant further attention in this population. Future researchers should also separately examine injury incidence during indoor and outdoor track and field seasons.

Epidemiology of Injuries in National Collegiate Athletic Association Women's Track and Field: 2014-2015 Through 2018-2019

CONTEXT

Women's track and field events at the National Collegiate Athletic Association level have grown in popularity in recent years, and track and field athletes are vulnerable to a broad range of potential injuries.

BACKGROUND

Routine examination of track and field injuries is important for identifying emerging patterns in injury incidence.

METHODS

Exposure and injury data collected in the National Collegiate Athletic Association Injury Surveillance Program during the 2014-2015 to 2018-2019 academic years were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics, and injury rate ratios were used to examine differential injury rates.

RESULTS

The overall injury rate was 2.20 per 1000 athlete exposures; the competition injury rate was higher than the practice injury rate (injury rate ratio = 1.73; 95% confidence interval = 1.51, 1.97). Hamstring tears (8.9%), medial tibial stress syndrome (5.4%), and lateral ligament complex tears (4.2%) were the most reported injuries.

CONCLUSIONS

Given the results of this study, further attention may be directed toward factors associated with noncontact injury risk in the competitions. The changing injury rates of most reported injuries also warrant monitoring post 2018-2019.

The relationship between resilience and neurophysiological stress in Special Operations Forces combat service members

Military resilience research is increasing due to the growing literature associating resilience with stress adaptation. This study aimed to investigate which physiological stress adaptation components were associated with resilience in Special Operations Forces combat service members. Special Operations Forces combat service members (n = 117) self-reported resilience (ER89) and lifetime clinician-confirmed mild traumatic brain injury history. Participants also underwent transcranial Doppler ultrasonography to measure middle cerebral artery velocity during rest and a breath-holding task. Neither resilience nor mild traumatic brain injury history was significantly associated with middle cerebral artery velocity percent increase following breath-holding; younger Special Operations Forces combat service members had a higher percent increase in middle cerebral artery velocity following a breath-holding task. Resilience was negatively associated with time to return to baseline middle cerebral artery velocity following peak velocity; whereas, mild traumatic brain injury history did not have a significant association. The Special Operations Forces combat service members that scored higher in resilience tended to return to baseline middle cerebral artery velocity following peak velocity faster than their less resilient counterparts. More resilient Special Operations Forces combat service members recovered faster from physiological stress (breath-holding) than less resilient counterparts. This is the first study to investigate resilience and cerebrovascular stress response and recovery in this population. Our initial findings indicated that the Ego Resiliency Scale may be an optimal resilience psychometric and should be used to evaluate effective military resilience trainings, which aim to improve performance and mental health.

Repetitive Head Impact Exposure and Cerebrovascular Function in Adolescent Athletes

The purpose of this study was to determine how subconcussive head impact exposure in high school collision sport student-athletes influenced cerebrovascular function. Transcranial Doppler was used to assess pre- to post-season changes in: (1) resting middle (MCA) and posterior cerebral arteries (PCA), (2) cerebrovascular reactivity (CVR) via breath-holding index (BHI), vasomotor reactivity response (VMRr) and overall MCA response curve, and (3) neurovascular coupling (NVC) via NVC response magnitude and overall PCA response curve. Fifty-three high school-aged athletes (age = 15.8 ± 1.2years, height = 175.8 ± 8.1cm, mass = 69.4 ± 13.5kg) were recruited into two groups (collision vs. non-collision sport). All participants completed a pre-season cerebrovascular function assessment. Following a 4- to 5-month window (118.6 ± 12.2 days), 48 athletes from the original sample (age = 16.0 ± 1.2 years, height = 175.5 ± 8.1 cm, mass = 68.6 ± 4.0 kg) repeated the cerebrovascular assessment. There were no group differences in any cerebrovascular measures at pre-season testing (p > 0.05). At post-season testing, collision sport athletes demonstrated greater positive change in BHI (t₄₄ = -2.21, p = 0.03) while non-collision sport athletes demonstrated greater negative change in the NVC response magnitude to the reading task (t₄₄ = 1.98, p = 0.048), and lower overall PCA response curve to the reading task (F_1,2710 = 101.54, p < 0.001). All other pre- to post-season change values were non-significant (p > 0.05). Our data indicate that single-season changes in cerebrovascular outcomes may differ between collision and non-collision sport athletes. Although the clinical interpretation is still unclear, our study demonstrates that CVR and NVC assessments may be sensitive to the dynamic cerebrovascular changes occurring in adolescent athletes. Future research should continue to assess these outcomes following both subconcussive head impact exposure and throughout the recovery trajectory following concussion.

Concussion Symptom Characteristics and Resolution in 20 United States High School Sports, 2013/14-2017/18 Academic Years

BACKGROUND

High school (HS) sport-related concussions (SRCs) remain a public health concern in the United States.

OBJECTIVE

To describe patterns in symptom prevalence, symptom resolution time (SRT), and return-to-play time (RTP) for SRCs sustained in 20 HS sports during the 2013/14-2017/18 academic years.

METHODS

A convenience sample of athletic trainers reported concussion information to the HS RIOTM surveillance system. Symptom prevalence, average number of symptoms, and SRT and RTP distributions were examined and compared by event type (practice, competition), injury mechanism (person contact, nonperson contact), sex, and contact level (collision, high contact, and low contact) with chi-square tests and Wilcoxon rank-sum tests.

RESULTS

Among all SRCs (n = 9542), headache (94.5%), dizziness (73.8%), and difficulty concentrating (56.0%) were commonly reported symptoms. On average, 4.7 ± 2.4 symptoms were reported per SRC. Overall, 51.3% had symptoms resolve in <7 d, yet only 7.9% had RTP < 7 d. Differential prevalence of amnesia was seen between practice and competition-related SRCs (8.8% vs 13.0%; P < .001); nonperson-contact and person-contact SRCs (9.3% vs 12.7%; P < .001); and female and male SRCs in low-contact sports (5.8% vs 17.5%; P < .001). Differential prevalence of loss of consciousness was seen between practice and game-related SRCs (1.3% vs 3.2%; P < .001); and female and male SRCs in high contact sports (1.2% vs 4.0%; P < .001). Differential longer SRT (>21 d) was seen between new and recurrent SRCs (9.4% vs 15.9%; P < .001).

CONCLUSION

Headache was the most commonly reported symptom. Notable group differences in the prevalence of amnesia, loss of consciousness, and SRT may be associated with more severe SRCs, warranting further attention.