Non-concussed Athletes Research Articles

Conservative Concussion Management in Youth Athletes Can Avoid Increased Injury Rates After Return to Sport: Initial Evidence

Objective: To evaluate whether injury rates are elevated after return to sport after concussion clearance in youth athletes and examine differences between concussed athletes who sustain injury after return to play and those who remain uninjured. Design: Prospective cohort study. Setting: Large metropolitan hospital. Participants: Twenty-four youth athletes cleared for return to play after a concussion and 84 pediatric athletes without concussion. Independent Variables/Interventions: Concussion (with return to play clearance) versus no concussion; age, sex, hours of sleep, and sports participation. Main Outcome Measures: Injury for a 12-week period. Results: Injury rates were similar between the concussed (5/24 = 21%) and nonconcussed (15/84 = 18%) athletes (P = 0.77). Within the concussion group, there was no significant difference between the noninjured and injured participants in time to return to play, time from concussion to initial evaluation, age, sex, hours of sleep per night, or hours of sports participation per week (P ≥ 0.19). The median time to clearance for the concussed athletes was 34 (range: 18–61) days. Conclusions: This study provides preliminary evidence suggesting that when current guidelines for return to play are followed, concussed pediatric athletes can resume activity without facing an elevated risk of injury. Time to achieve clearance in pediatric and adolescent athletes can be expected to be longer than the 7 to 14 days typical for older athletes.

Injury Characteristics and Risk Factors of Sport-Related Concussion Among High School Athletes in School-Sponsored Sports.

Over a million sport-related concussions (SRC) affect children annually in the United States, posing a significant public health concern. Limited data exist on the premorbid risk factors and injury characteristics of SRCs in high school athletes. This study aims to understand acute SRC injury characteristics and describe premorbid risk factors in high school athletes. Athletes (aged 14-19 years) from 19 central Illinois high schools participating in school-sponsored sports from 2009 to 2023 were included. Sports Concussion Assessment Tool evaluations were performed as part of preseason and postinjury evaluations. Injury characteristics, such as mechanism, setting, and symptoms, were described using all SRCs in the study period. Odds ratios (OR) were computed to determine risk factors using athletes with a baseline Sports Concussion Assessment Tool before SRC and nonconcussed athletes. In total, 4360 athletes were included (3953 without SRC; 407 with ≥1 SRC of whom 168 had a previous baseline). Overall, 24.2% of SRCs occurred in female athletes, and most SRCs occurred in competitions while playing American football (52.3%), soccer (20.4%), and basketball (7.6%). Blow/hit to the head was the most common mechanism. Headache was the most severe symptom (2.55 ± 1.51 [SD]), and symptoms of emotionality and nervousness/anxiety were significantly more severe in female athletes (P < .05). Students with previous concussions (OR 2.64 95% CI [1.81, 3.78]), previous hospitalization for head injury (OR 3.19 95% CI [1.9, 5.14]), headache/migraine disorders (OR 2.23 95% CI [1.29, 3.66]), and learning disabilities (OR 2.69 95% CI [1.47, 4.61]) had greater odds of SRC (P < .05). Lower odds of SRC were seen in athletes identifying as Black or African American (vs White) (OR 0.54 95% CI [0.32, 0.86]) and those attending larger (vs smaller) schools (OR 0.64 95% CI [0.46, 0.88]). Understanding SRC risk factors and characteristics in high school athletes is critical for developing prevention and management programs, guiding neurosurgeons in mitigating SRC risk, and informing return-to-play decisions.

Uncovering the hidden effects of repetitive subconcussive head impact exposure: A mega-analytic approach characterizing seasonal brain microstructural changes in contact and collision sports athletes.

Repetitive subconcussive head impacts (RSHI) are believed to induce sub-clinical brain injuries, potentially resulting in cumulative, long-term brain alterations. This study explores patterns of longitudinal brain white matter changes across sports with RSHI-exposure. A systematic literature search identified 22 datasets with longitudinal diffusion magnetic resonance imaging data. Four datasets were centrally pooled to perform uniform quality control and data preprocessing. A total of 131 non-concussed active athletes (American football, rugby, ice hockey; mean age: 20.06 ± 2.06 years) with baseline and post-season data were included. Nonparametric permutation inference (one-sample t tests, one-sided) was applied to analyze the difference maps of multiple diffusion parameters. The analyses revealed widespread lateralized patterns of sports-season-related increases and decreases in mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) across spatially distinct white matter regions. Increases were shown across one MD-cluster (3195 voxels; mean change: 2.34%), one AD-cluster (5740 voxels; mean change: 1.75%), and three RD-clusters (817 total voxels; mean change: 3.11 to 4.70%). Decreases were shown across two MD-clusters (1637 total voxels; mean change: -1.43 to -1.48%), two RD-clusters (1240 total voxels; mean change: -1.92 to -1.93%), and one AD-cluster (724 voxels; mean change: -1.28%). The resulting pattern implies the presence of strain-induced injuries in central and brainstem regions, with comparatively milder physical exercise-induced effects across frontal and superior regions of the left hemisphere, which need further investigation. This article highlights key considerations that need to be addressed in future work to enhance our understanding of the nature of observed white matter changes, improve the comparability of findings across studies, and promote data pooling initiatives to allow more detailed investigations (e.g., exploring sex- and sport-specific effects).

Maintaining Cognitive Performance at the Expense of Gait Speed for Asymptomatic Concussed Athletes: A Novel Dual-Task and Post-Exercise Assessment.

Our goal was to evaluate persisting deficits in gait and executive functioning in asymptomatic athletes with a history of concussion using a novel approach combining a dual-task paradigm and post-exercise exertion. Thirty-eight athletes aged 17 to 25 years old participated in the study, including 18 with a history of concussion. The dual-task paradigm required walking continuously at a predetermined self-paced target speed of 6.5 km/h while executing a complex switch task. Athletes completed two conditions, each on separate days: (1) dual task alone and (2) dual task following 20 min of running on a non-motorized treadmill. The statistical analyses revealed a significant reduction in gait speed exclusively for athletes with a history of concussion and only following the post-exercise condition (p = 0.008). These findings suggest that although asymptomatic concussed athletes maintain a cognitive performance comparable to non-concussed athletes, this appears to be achieved at the expense of gait speed. Our results underscore the importance of incorporating gait assessments and post-exercise exertion into concussion evaluation protocols in both research and clinical settings.

A - 55 Pre- to Post-Season Reliability of Blink Reflex Parameters in Non-Concussed Athletes

Abstract Purpose Examining quantitative parameters of the blink reflex may improve sport-related concussion (SRC) diagnosis and management because it may serve as an objective measure of injury severity and recovery. However, the psychometric properties of several FDA-cleared devices assessing the blink reflex are understudied. The current study compared blink reflex parameters pre- and post-season using the BlinkTBI EyeStatTM device to assess its reliability in non-concussed athletes. Method A cohort of high school athletes underwent pre- and post-season BlinkTBI EyeStatTM testing. Statistical analysis included Spearman correlations, Wilcoxon signed-rank tests, and interclass correlations for ten blink parameters. Multivariable linear regressions assessed the influence of contact (i.e., soccer, football) vs. non-contact sports (i.e., baseball, softball, basketball) on changes in blink parameters. Results Among 32 athletes with pre- and post-season testing (age: mean = 15.3, SD = 1.1; 53.1% female), 19 played non-contact and 21 played contact sports. Most parameters were not statistically different between pre- and post-season, except for delta 30 (W = 229.5, p = 0.015), time under threshold (W = 191.0, p = 0.003), and oscillations (W = 667.0, p &amp;lt; 0.001). Parameters exhibited moderate to excellent reliability (interclass correlations = 0.575–0.872, p-values = 0.001–0.004). Spearman’s rho values ranged from 0.435 to 0.828 (p-values = 001–0.005). Participation in contact vs. non-contact sports was not associated with changes in blink parameters (all p-values&amp;gt;0.05). Conclusions Preliminary evidence suggest stable blink parameters across a sports season in non-concussed athletes when measured by the BlinkTBI EyeStatTM device. Contact sport participation was not significantly associated with changes in blink parameters. The findings add to the psychometric evidence that the blink reflex can be reliably measured, warranting further study on its utility in concussion.

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

ObjectivesTo 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 sourcesSystematic searches of seven databases...

Inversion position testing in concussed athletes

Context No prior study has examined inversion position testing in individuals who have experienced sports related concussions. Objective To investigate whether the inversion position testing (IPT) would un-mask symptoms in asymptomatic concussed collegiate athletes during the return to play progression assessment. Design Case-Control Study. Setting Athletic Training Room. Participants One hundred and thirty-nine collegiate student athletes were randomly recruited from 12 different sports belonging to National Collegiate Athletic Association Division I Conference. Main outcome measure(s) A baseline concussion symptom questionnaire was administered. Of the 139, 122 participants without any of the suspicious symptoms related to concussions were examined using the Concussion Symptom Inventory (CSI) in connection with IPT. Also, the 18 concussed athletes underwent the IPT when any symptom subsided. Results Eighteen of the 122 (16.2%) non-concussed athletes showed some post-IPT symptoms, while 5 of 12 (41.7%) concussed athletes showed some post-IPT symptoms in the baseline test. For the latter, neither the interaction ( P = 0.08) nor difference in the total CSI score was observed either from pre- to post-IPT ( P = 0.14) or between the baseline and post-concussion ( P = 0.96). Conclusion This study demonstrated that symptoms could be exacerbated by the IPT in concussed athletes even when their original symptoms had subsided prior to the testing. The IPT exacerbated post-concussive symptoms may depend on a number of days required for post-concussive symptoms to subside. The innovative instrument of IPT may prove effective in clarifying the degree to which post-concussive symptoms have subsided. Key words Concussion, College athletes, Inversion position, Symptoms.

Serum Amyloid Beta Precursor Protein, Neurofilament Light, and Visinin-like Protein-1 in Rugby Players: An Exploratory Study.

Concussion diagnosis is difficult and may be improved with the addition of a blood-based biomarker that indicates concussion. The purpose of this research was to investigate the capability of serum amyloid beta precursor protein (APP), neurofilament light (NfL), and visinin-like protein-1 (VILIP-1) to distinguish athletes who were diagnosed with a concussion pitch-side. An observational cross-sectional study design was used to replicate sideline concussion diagnosis. Subjects included mutually exclusive pre-match (n = 9), post-match (n = 15), and SRC (n = 7) groups. Six paired pre-and post-match subjects were analyzed for APP. APP increased significantly from pre-match (mean = 57.98 pg·mL-1, SD = 63.21 pg·mL-1) to post-match (mean = 111.37 pg·mL-1, SD = 106.89 pg·mL-1, p = 0.048) in the paired subjects. NfL was lower in the SRC group (median = 8.71 pg·mL-1, IQR = 6.09 pg·mL-1) compared to the post-match group (median = 29.60 pg·mL-1, IQR = 57.45 pg·mL-1, p &lt; 0.001). VILIP-1 was higher in the post-match group (median = 212.18 pg·mL-1, IQR = 345.00 pg·mL-1) compared to both the pre-match (median = 32.63 pg·mL-1, IQR = 52.24 pg·mL-1), p = 0.001) and SRC (median = 30.21 pg·mL-1, IQR = 47.20 pg·mL-1), p = 0.003) groups. APP, NfL, and VILIP-1 were all able to distinguish between pre-match and post-match groups (AUROC &gt; 0.700) but not from the SRC group (AUROC &lt; 0.660). Our results show that APP, NfL, and VILIP-1 were not helpful in differentiating concussed from non-concussed athletes pitch-side in this study.

Are EPB41 and alpha-synuclein diagnostic biomarkers of sport-related concussion? Findings from the NCAA and Department of Defense CARE Consortium

BackgroundCurrent protein biomarkers are only moderately predictive at identifying individuals with mild traumatic brain injury or concussion. Therefore, more accurate diagnostic markers are needed for sport-related concussion. MethodsThis was a multicenter, prospective, case-control study of athletes who provided blood samples and were diagnosed with a concussion or were a matched non-concussed control within the National Collegiate Athletic Association–Department of Defense Concussion Assessment, Research, and Education Consortium conducted between 2015 and 2019. The blood was collected within 48 h of injury to identify protein abnormalities at the acute and subacute timepoints. Athletes with concussion were divided into 6 h post-injury (0–6 h post-injury) and after 6 h post-injury (7–48 h post-injury) groups. We applied a highly multiplexed proteomic technique that used a DNA aptamers assay to target 1305 proteins in plasma samples from athletes with and without sport-related concussion. ResultsA total of 140 athletes with concussion (79.3% males; aged 18.71 ± 1.10 years, mean ± SD) and 21 non-concussed athletes (76.2% males; 19.14 ± 1.10 years) were included in this study. We identified 338 plasma proteins that significantly differed in abundance (319 upregulated and 19 downregulated) in concussed athletes compared to non-concussed athletes. The top 20 most differentially abundant proteins discriminated concussed athletes from non-concussed athletes with an area under the curve (AUC) of 0.954 (95% confidence interval: 0.922‒0.986). Specifically, after 6 h of injury, the individual AUC of plasma erythrocyte membrane protein band 4.1 (EPB41) and alpha-synuclein (SNCA) were 0.956 and 0.875, respectively. The combination of EPB41 and SNCA provided the best AUC (1.000), which suggests this combination of candidate plasma biomarkers is the best for diagnosing concussion in athletes after 6 h of injury. ConclusionOur data suggest that proteomic profiling may provide novel diagnostic protein markers and that a combination of EPB41 and SNCA is the most predictive biomarker of concussion after 6 h of injury.

Test-Retest Reliability and Efficacy of Individual Symptoms in Concussion Management.

(1) To determine test-retest reliability of individual Sport Concussion Assessment Tool-Third Edition (SCAT-3) symptom scores and symptom severity scores, (2) to examine the specificity/sensitivity of individual SCAT-3 symptom severity scores acutely (24-48 hours) postconcussion, and (3) to develop a model of symptoms best able to differentiate concussed from nonconcussed student athletes and cadets. Prospective, longitudinal, and cross-sectional. Twenty-six civilian schools and 3 US service academies. Collegiate student athletes (n = 5519) and cadets (n = 5359) from the National Collegiate Athletic Association-Department of Defense Grand Alliance: Concussion Assessment, Research and Education Consortium, including 290 student athletes and 205 cadets, assessed 24 to 48 hours postconcussion. Concussed and nonconcussed student athlete and cadet groups. Sport Concussion Assessment Tool-Third Edition individual symptom severity scores, total symptom scores, and symptom severity scores. Results indicated poor test-retest reliability across all symptom scores (intraclass correlation coefficient = 0.029-0.331), but several individual symptoms had excellent predictive capability in discriminating concussed from nonconcussed participants (eg, headache, pressure in the head, and don't feel right had area under the curve >0.8, sensitivity >70%, and specificity >85%) regardless of baseline testing. These symptoms were consistent with Chi-square Automatic Interaction Detector classification trees with the highest mean probability. Findings support the excellent diagnostic accuracy of honest symptom reporting, notwithstanding the known limitations in symptom underreporting, and suggest that there may be added value in examining individual symptoms rather than total symptom scores and symptom severity scores alone. Finally, findings suggest that baseline testing is not necessary for interpreting postconcussion symptom scores.

Altered Brain Functional Connectivity in Female Athletes Over the Course of a Season of Collision or Contact Sports.

University athletes are exposed to numerous impacts to the body and head, though the potential cumulative effects of such hits remain elusive. This study examined resting-state functional connectivity (rsFC) of brain networks in female varsity athletes over the course of a season. Nineteen female university athletes involved in collision (N = 12) and contact (N = 7) sports underwent functional magnetic resonance imaging scans at both pre- and post-season. A group-level independent component analysis (ICA) was used to investigate differences in rsFC over the course of a season and differences between contact and collision sport athletes. Decreased rsFC was observed over the course of the season between the default mode network (DMN) and regions in the frontal, parietal, and occipital lobe (p false discovery rate, ≤0.05) driven by differences in the contact group. There was also a main effect of group in the dorsal attention network (DAN) driven by differences between contact and collision groups at pre-season. Differences identified over the course of a season of play indicate largely decreased rsFC within the DMN, and level of contact was associated with differences in rsFC of the DAN. The association between exposure to repetitive head impacts (RHIs) and observed changes in network rsFC supplements the growing literature suggesting that even non-concussed athletes may be at risk for changes in brain functioning. However, the complexity of examining the direct effects of RHIs highlights the need to consider multiple factors, including mental health and sport-specific training and expertise, that may potentially be associated with neural changes.

A Comparative Analysis of Depressive Symptoms Following Sports-Related Concussion in Youth Athletes Versus Their Age-Matched Non-concussed Counterparts.

Background and objectiveAthletics is the leading cause of pediatric concussion, and depression is a major comorbidity associated with concussion in the pediatric population. Prior studies have described the risk of depression after concussion in high school-, collegiate-, and elite-level athletes, but there is scarce data on younger athletes. Interpretation of existing research on the association of depression with concussions in youth athletes is complicated by diverse study designs, varying measures of depression, differing timelines for symptom development, and a lack of control groups. Furthermore, limited research exists on sex-related differences in the development of depressive symptoms following sports-related concussions (SRC) in younger athletes. This study used the Seattle Pediatric Concussion Research Collaborative (SPCRC) Data Repository to compare depressive symptoms between youth athletes at one month post-SRC and non-concussed age-matched controls by using a standardized measure of depressive symptoms: the Patient Health Questionnaire-9 (PHQ-9). The secondary goal was to compare PHQ-9 scores between males and females for both concussed and non-concussed groups.MethodsThis study entailed a secondary analysis of data collected as part of the SPCRC Data Repository. We conducted a retrospective subgroup analysis of PHQ-9 scores at one month post-concussion for concussed youth athletes. We compared the PHQ9 scores of concussed youth athletes with PHQ-9 scores collected at the time of enrollment for non-concussed youth athletes.ResultsAfter random age-matching, a cohort of 266 patients (133 in the concussed group and 133 in the non-concussed control group) was included in the final analysis. The mean age was 13.8 years (range: 5-18 years). For the concussed group, a history of SRC was associated with a higher mean total PHQ-9 score at one month post-concussion compared with the control group at the time of enrollment (6.14 ±5.46 versus 1.53 ±1.81, respectively, p<0.0001). All nine subdomains of the PHQ-9 showed significantly higher scores in the concussion group compared with the control group (p<0.0001). Significantly higher scores were observed when comparing mean total PHQ-9 scores for male athletes in the concussion group with male athletes in the control group (7.03 ±5.72 versus 1.59 ±1.66, p<0.0001) and for female athletes in the concussion group compared with female controls (5.28 ±5.10 versus 1.49 ±1.92, p<0.0001). No significant differences were observed between sexes for total PHQ-9 scores or PHQ-9 subscores.ConclusionAt one month post concussion, youth with SRC demonstrated higher levels of depressive symptoms as measured by PHQ-9 compared with age-matched typically developing controls. No significant differences were identified in total PHQ-9 scores and subscores between male and female participants for either the concussion or control group. This study suggests that clinicians need to be vigilant and monitor for symptoms of depression in young athletes for at least one month post-concussion.

Blink duration is increased in concussed youth athletes: a validity study using eye tracking in male youth and adult athletes of selected contact sports

Objective. Diagnosing a sports-related concussion (SRC) remains challenging, and research into diagnostic tools is limited. This study investigated whether selected eye tracking variables would be a valid tool to diagnose and monitor SRC in adult and youth participants in selected contact sports, such as Rugby Union (rugby) and football (soccer). Methods. This prospective cohort study, with 70 concussed and 92 non-concussed adult and youth athletes, assessed the validity of five previously selected eye tracking variables for SRC diagnostics and management. The performance between concussed and age-matched control (non-concussed) athletes, as well as between three successive testing sessions in the concussed athletes were compared. Self-paced saccade count in adult group; blink duration in the memory-guided saccade and sinusoidal smooth pursuit tasks, proportion of antisaccade errors, and gain of diagonal smooth pursuit in the youth group were assessed. Results. The youth concussed group had higher blink duration in the fast memory-guided saccades task (p = 0.001, η 2 = 0.17) and a tendency for higher blink duration in the sinusoidal smooth pursuit task (p = 0.016, η 2 = 0.06) compared to the youth control group. In both tasks the blink duration in the concussed youth group decreased from session 1 to session 2 by 24% and 18%, accordingly, although statistical significance was not reached. The concussed adult group demonstrated a lower number of self-paced saccades compared to controls (p = 0.05, η 2 = 0.09), which gradually increased, with the largest difference between session 1 and session 3 (p = 0.02). Conclusions. Blink duration in youth athletes holds promise as a valid metric for concussion diagnostics and monitoring. It is recommended to focus future studies on comparing eye tracking performance within the same concussed athletes over time rather than comparing them to healthy controls.

A Preclinical Rodent Model for Repetitive Subconcussive Head Impact Exposure in Contact Sport Athletes.

Repetitive subconcussive head impact exposure has been associated with clinical and MRI changes in some non-concussed contact sport athletes over the course of a season. However, analysis of human tolerance for repeated head impacts is complicated by concussion and head impact exposure history, genetics, and other personal factors. Therefore, the objective of the current study was to develop a rodent model for repetitive subconcussive head impact exposure that can be used to understand injury mechanisms and tolerance in the human. This study incorporated the Medical College of Wisconsin Rotational Injury Model to expose rats to multiple low-level head accelerations per day over a 4-week period. The peak magnitude of head accelerations were scaled from our prior human studies of contact sport athletes and the number of exposures per day were based on the median (moderate exposure) and 95th percentile (high exposure) number of exposures per day across the human sample. Following the exposure protocol, rats were assessed for cognitive deficits, emotional changes, blood serum levels of axonal injury biomarkers, and histopathological evidence of injury. High exposure rats demonstrated cognitive deficits and evidence of anxiety-like behaviors relative to shams. Moderate exposure rats did not demonstrate either of those behaviors. Similarly, high exposure rats had histopathological evidence of gliosis [i.e., elevated Iba1 intensity and glial fibrillary acidic protein (GFAP) volume relative to shams] in the basolateral amygdala and other areas. Blood serum levels of neurofilament light (NFL) demonstrated a dose response relationship with increasing numbers of low-level head acceleration exposures with a higher week-to-week rate of NFL increase for the high exposure group compared to the moderate exposure group. These findings demonstrate a cumulative effect of repeated low-level head accelerations and provide a model that can be used in future studies to better understand mechanisms and tolerance for brain injury resulting from repeated low-level head accelerations, with scalable biomechanics between the rat and human.

Relation Between Repetitive Head Traumas and Academic Performance of Non-Concussed High School Athletes: A Comparison of High And Low Contact Sports

To assess the relation of repeated subconcussive head traumas and the academic performance and neuropsychological functioning of non-concussed high school athletes participating in high and low levels of contact sports.

Effects of Music Intervention on Stress in Concussed and Non-Concussed Athletes.

Sport-related concussion is a serious public health issue affecting millions of individuals each year. Among the many negative side effects, emotional symptoms, such as stress, are some of the most common. Stress management is repeatedly cited by expert groups as an important intervention for this population. It was shown that music has relaxing effects, reducing stress through the activation of brain areas involved in emotions and pleasure. The objective of this study was to explore the effects of a music-listening intervention compared with silence on experimentally induced stress in concussed and non-concussed athletes. To this aim, four groups of athletes (non-concussed music, non-concussed silence, concussed music, and concussed silence) performed the Trier Social Stress Test, for which both physiological (skin conductance level) and self-reported stress measurements were taken. No significant difference was found in the pattern of stress recovery for self-reported measurements. However, the skin conductance results showed greater and faster post-stress recovery after listening to music compared with silence for concussed athletes only. Taken together, these results suggest that music could be an efficient stress management tool to implement in the everyday life of concussed athletes to help them prevent stress accumulation.

Refinement of saliva microRNA biomarkers for sports-related concussion

BackgroundRecognizing sport-related concussion (SRC) is challenging and relies heavily on subjective symptom reports. An objective, biological marker could improve recognition and understanding of SRC. There is emerging evidence that salivary micro-ribonucleic acids (miRNAs) may serve as biomarkers of concussion; however, it remains unclear whether concussion-related miRNAs are impacted by exercise. We sought to determine whether 40 miRNAs previously implicated in concussion pathophysiology were affected by participation in a variety of contact and non-contact sports. Our goal was to refine a miRNA-based tool capable of identifying athletes with SRC without the confounding effects of exercise. MethodsThis case-control study harmonized data from concussed and non-concussed athletes recruited across 10 sites. Levels of salivary miRNAs within 455 samples from 314 individuals were measured with RNA sequencing. Within-subjects testing was used to identify and exclude miRNAs that changed with either (a) a single episode of exercise (166 samples from 83 individuals) or (b) season-long participation in contact sports (212 samples from 106 individuals). The miRNAs that were not impacted by exercise were interrogated for SRC diagnostic utility using logistic regression (172 samples from 75 concussed and 97 non-concussed individuals). ResultsTwo miRNAs (miR-532-5p and miR-182-5p) decreased (adjusted p < 0.05) after a single episode of exercise, and 1 miRNA (miR-4510) increased only after contact sports participation. Twenty-three miRNAs changed at the end of a contact sports season. Two of these miRNAs (miR-26b-3p and miR-29c-3p) were associated (R > 0.50; adjusted p < 0.05) with the number of head impacts sustained in a single football practice. Among the 15 miRNAs not confounded by exercise or season-long contact sports participation, 11 demonstrated a significant difference (adjusted p < 0.05) between concussed and non-concussed participants, and 6 displayed moderate ability (area under curve > 0.70) to identify concussion. A single ratio (miR-27a-5p/miR-30a-3p) displayed the highest accuracy (AUC = 0.810, sensitivity = 82.4%, specificity = 73.3%) for differentiating concussed and non-concussed participants. Accuracy did not differ between participants with SRC and non-SRC (z = 0.5, p = 0.60). ConclusionSalivary miRNA levels may accurately identify SRC when not confounded by exercise. Refinement of this approach in a large cohort of athletes could eventually lead to a non-invasive, sideline adjunct for SRC assessment.

Condition-specific health-related quality of life amongst amateur athletes six months and one-year following sport-related concussion: A prospective, follow-up

ObjectiveTo prospectively investigate the condition-specific health-related quality of life (HRQoL) of athletes six months and one-year following sport-related concussion. DesignProspective, longitudinal study. SettingClinical research centre at university school of public health. ParticipantsAmateur athletes who were diagnosed with sport-related concussion within one-week after presenting to a hospital emergency department were recruited along with sex-, age-, and activity-matched, non-concussed, control athletes. Concussion and control participants were assessed six months and one-year following sport-related concussion and study enrolment, respectively. Main outcome measuresParticipants completed the Post-Concussion Symptom Scale and five condition-specific HRQoL patient-reported outcome measures – Headache Impact Test-6, Fatigue Severity Scale, Neck Disability Index, Generalised Anxiety Disorder-7, and Dizziness Handicap Inventory. We performed Frequentist and Bayesian mixed-design analyses of variance to compare the concussion group and control group at both assessments and quantify whether there was greater evidence in favour of the null hypothesis compared with the alternative hypothesis. ResultsAt six-month and one-year assessments, the concussion group (n = 47; male = 72%; mean (SD) age = 22.68 (5.07)) and the control group (n = 47; male = 72%; mean (SD) age = 23.81 (4.60)) reported similar clinical symptom severity scores and condition-specific HRQoL. The proportion of athletes in the concussion group with clinically-impaired scores was similar to the proportion of non-concussed athletes with clinically-impaired scores. At six-month and one-year assessments, there was moderate-to-very strong evidence that there was no difference between concussion and control participants’ perceptions of the effects of headache, fatigue, neck pain, anxiety, and dizziness on HRQoL. ConclusionThere was moderate-to-very strong evidence in favour of no difference between the concussion and control groups on symptom severity scores and condition-specific HRQoL patient-reported outcome measures at six-month and one-year assessments. These results suggest that condition-specific HRQoL returns to the levels of non-concussed individuals within six months following sport-related concussion.

Recurrent neural network-based acute concussion classifier using raw resting state EEG data

Concussion is a global health concern. Despite its high prevalence, a sound understanding of the mechanisms underlying this type of diffuse brain injury remains elusive. It is, however, well established that concussions cause significant functional deficits; that children and youths are disproportionately affected and have longer recovery time than adults; and that individuals suffering from a concussion are more prone to experience additional concussions, with each successive injury increasing the risk of long term neurological and mental health complications. Currently, the most significant challenge in concussion management is the lack of objective, clinically- accepted, brain-based approaches for determining whether an athlete has suffered a concussion. Here, we report on our efforts to address this challenge. Specifically, we introduce a deep learning long short-term memory (LSTM)-based recurrent neural network that is able to distinguish between non-concussed and acute post-concussed adolescent athletes using only short (i.e. 90 s long) samples of resting state EEG data as input. The athletes were neither required to perform a specific task nor expected to respond to a stimulus during data collection. The acquired EEG data were neither filtered, cleaned of artefacts, nor subjected to explicit feature extraction. The LSTM network was trained and validated using data from 27 male, adolescent athletes with sports related concussion, benchmarked against 35 non-concussed adolescent athletes. During rigorous testing, the classifier consistently identified concussions with an accuracy of > 90% and achieved an ensemble median Area Under the Receiver Operating Characteristic Curve (ROC/AUC) equal to 0.971. This is the first instance of a high-performing classifier that relies only on easy-to-acquire resting state, raw EEG data. Our concussion classifier represents a promising first step towards the development of an easy-to-use, objective, brain-based, automatic classification of concussion at an individual level.

Diffusion Imaging Reveals Sex Differences in the White Matter Following Sports-Related Concussion.

Sports-related concussion (SRC) is a serious health concern. However, the temporal profile of neuropathophysiological changes after SRC and how these relate to biological sex are still poorly understood. This preliminary study investigated whether diffusion-weighted magnetic resonance imaging (dMRI) was sensitive to neuropathophysiological changes following SRC; whether these changes were sex-specific; and whether they persisted beyond the resolution of self-reported symptoms. Recently concussed athletes (n = 14), and age- and education-matched nonconcussed control athletes (n = 16), underwent MRI 24-48-h postinjury and again at 2-week postinjury (i.e., when cleared to return-to-play). Male athletes reported more symptoms and greater symptom severity compared with females. dMRI revealed white matter differences between athletes with SRC and their nonconcussed counterparts at 48-h postinjury. These differences were still present at 2-week postinjury, despite SRC athletes being cleared to return to play and may indicate increased cerebral vulnerability beyond the resolution of subjective symptoms. Furthermore, we identified sex-specific differences, with male SRC athletes having significantly greater white matter disruption compared with female SRC athletes. These results have important implications for the management of concussion, including guiding return-to-play decisions, and further improve our understanding regarding the role of sex in SRC outcomes.