Longitudinal white-matter abnormalities in sports-related concussion: A diffusion MRI study

Objective To study longitudinal recovery trajectories of white matter after sports-related concussion (SRC) by performing diffusion tensor imaging (DTI) on collegiate athletes who sustained SRC. Methods Collegiate athletes (n = 219, 82 concussed athletes, 68 contact-sport controls, and 69 non–contact-sport controls) were included from the Concussion Assessment, Research and Education Consortium. The participants completed clinical assessments and DTI at 4 time points: 24 to 48 hours after injury, asymptomatic state, 7 days after return-to-play, and 6 months after injury. Tract-based spatial statistics was used to investigate group differences in DTI metrics and to identify white-matter areas with persistent abnormalities. Generalized linear mixed models were used to study longitudinal changes and associations between outcome measures and DTI metrics. Cox proportional hazards model was used to study effects of white-matter abnormalities on recovery time. Results In the white matter of concussed athletes, DTI-derived mean diffusivity was significantly higher than in the controls at 24 to 48 hours after injury and beyond the point when the concussed athletes became asymptomatic. While the extent of affected white matter decreased over time, part of the corpus callosum had persistent group differences across all the time points. Furthermore, greater elevation of mean diffusivity at acute concussion was associated with worse clinical outcome measures (i.e., Brief Symptom Inventory scores and symptom severity scores) and prolonged recovery time. No significant differences in DTI metrics were observed between the contact-sport and non–contact-sport controls. Conclusions Changes in white matter were evident after SRC at 6 months after injury but were not observed in contact-sport exposure. Furthermore, the persistent white-matter abnormalities were associated with clinical outcomes and delayed recovery tim

Assessment of Blood Biomarker Profile After Acute Concussion During Combative Training Among US Military Cadets

Importance: Validation of protein biomarkers for concussion diagnosis and management in military combative training is important, as these injuries occur outside of traditional health care settings and are generally difficult to diagnose. Objective: To investigate acute blood protein levels in military cadets after combative training-associated concussions. Design, setting, and participants: This multicenter prospective case-control study was part of a larger cohort study conducted by the National Collegiate Athletic Association and the US Department of Defense Concussion Assessment Research and Education (CARE) Consortium from February 20, 2015, to May 31, 2018. The study was performed among cadets from 2 CARE Consortium Advanced Research Core sites: the US Military Academy at West Point and the US Air Force Academy. Cadets who incurred concussions during combative training (concussion group) were compared with cadets who participated in the same combative training exercises but did not incur concussions (contact-control group). Clinical measures and blood sample collection occurred at baseline, the acute postinjury point (<6 hours), the 24- to 48-hour postinjury point, the asymptomatic postinjury point (defined as the point at which the cadet reported being asymptomatic and began the return-to-activity protocol), and 7 days after return to activity. Biomarker levels and estimated mean differences in biomarker levels were natural log (ln) transformed to decrease the skewness of their distributions. Data were collected from August 1, 2016, to May 31, 2018, and analyses were conducted from March 1, 2019, to January 14, 2020. Exposure: Concussion incurred during combative training. Main outcomes and measures: Proteins examined included glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1, neurofilament light chain, and tau. Quantification was conducted using a multiplex assay (Simoa; Quanterix Corp). Clinical measures included the Sport Concussion Assessment Tool-Third Edition symptom severity evaluation, the Standardized Assessment of Concussion, the Balance Error Scoring System, and the 18-item Brief Symptom Inventory. Results: Among 103 military service academy cadets, 67 cadets incurred concussions during combative training, and 36 matched cadets who engaged in the same training exercises did not incur concussions. The mean (SD) age of cadets in the concussion group was 18.6 (1.3) years, and 40 cadets (59.7%) were male. The mean (SD) age of matched cadets in the contact-control group was 19.5 (1.3) years, and 25 cadets (69.4%) were male. Compared with cadets in the contact-control group, those in the concussion group had significant increases in glial fibrillary acidic protein (mean difference in ln values, 0.34; 95% CI, 0.18-0.50; P < .001) and ubiquitin C-terminal hydrolase-L1 (mean difference in ln values, 0.97; 95% CI, 0.44-1.50; P < .001) levels at the acute postinjury point. The glial fibrillary acidic protein level remained high in the concussion group compared with the contact-control group at the 24- to 48-hour postinjury point (mean difference in ln values, 0.22; 95% CI, 0.06-0.38; P = .007) and the asymptomatic postinjury point (mean difference in ln values, 0.21; 95% CI, 0.05-0.36; P = .01). The area under the curve for all biomarkers combined, which was used to differentiate cadets in the concussion and contact-control groups, was 0.80 (95% CI, 0.68-0.93; P < .001) at the acute postinjury point. Conclusions and relevance: This study's findings indicate that blood biomarkers have potential for use as research tools to better understand the pathobiological changes associated with concussion and to assist with injury identification and recovery from combative training-associated concussions among military service academy cadets. These results extend the previous findings of studies of collegiate athletes with sport-associated concussions

Musculoskeletal interventional ultrasound.

Ultrasound is a nonionizing, low-cost, portable imaging technique for the evaluation of tendons, muscles, joints, soft tissue masses, and cysts, especially in patients unable to tolerate computed tomography or magnetic resonance imaging. These advantages make ultrasound an ideal modality for guiding musculoskeletal interventions. Its real-time capabilities allow continuous observation of needle placement into the targeted area and direct visualization of interventions such as injection of medication while avoiding other soft tissue structures or nearby neurovascular bundles. After a brief overview of the technical factors involved in performing ultrasound-guided musculoskeletal interventions, this article reviews commonly performed percutaneous procedures in the musculoskeletal system

Musculoskeletal interventional ultrasound.

Ultrasound is a nonionizing, low-cost, portable imaging technique for the evaluation of tendons, muscles, joints, soft tissue masses, and cysts, especially in patients unable to tolerate computed tomography or magnetic resonance imaging. These advantages make ultrasound an ideal modality for guiding musculoskeletal interventions. Its real-time capabilities allow continuous observation of needle placement into the targeted area and direct visualization of interventions such as injection of medication while avoiding other soft tissue structures or nearby neurovascular bundles. After a brief overview of the technical factors involved in performing ultrasound-guided musculoskeletal interventions, this article reviews commonly performed percutaneous procedures in the musculoskeletal system

Early Single Sport Specialization in a High-Achieving US Athlete Population: Comparing National Collegiate Athletic Association Student-Athletes and Undergraduate Students.

CONTEXT: Early single-sport specialization and the relative age effect are often cited as improving the chances of sport success. Both concepts suggest that genetics and the environment have little influence on sport success. OBJECTIVE: To compare National Collegiate Athletic Association Division I student-athletes (SAs) with their undergraduate nonathlete peers (NAs) in terms of birth month, age of sport initiation, and age of single-sport specialization. A family history of sport participation was examined as a potential marker for genetic and social influences. DESIGN: Cross-sectional survey. SETTING: Large urban university. PATIENTS OR OTHER PARTICIPANTS: A total of 273 Division I SAs (138 women, 135 men) and 155 NAs (78 women, 77 men) participated. The NAs had been involved in competitive youth sports before entering the university. MAIN OUTCOME MEASURE(S): Participants were asked to complete a questionnaire that addressed the age of sport initiation, birth month, age of single-sport specialization, and parental and sibling sport achievement. MAIN RESULTS: Neither birth month nor the age of sport initiation differed between groups (age of sport initiation = 7.16 ± 2.6 years for the SAs versus 7.71 ± 3.5 for the NAs; CONCLUSIONS: The Division I SAs did not specialize in a single sport at a younger age than the NAs. No evidence of a relative age effect was present. Importantly, higher levels of sport achievement among the parents and siblings of SAs suggest that genetic endowment and family or other environmental dynamics play a large role in athletic performance. Overall, the results are not consistent with deliberate practice theory and point toward an alternative model that includes not only sport-specific skill development but also genetic and social factors as key elements of long-term sport achievement

Sport Specialization, Part I: Does Early Sports Specialization Increase Negative Outcomes and Reduce the Opportunity for Success in Young Athletes?

Context: There is increased growth in sports participation across the globe. Sports specialization patterns, which include year-round training, participation on multiple teams of the same sport, and focused participation in a single sport at a young age, are at high levels. The need for this type of early specialized training in young athletes is currently under debate. Evidence Acquisition: Nonsystematic review. Study Design: Clinical review. Level of Evidence: Level 4. Conclusion: Sports specialization is defined as year-round training (greater than 8 months per year), choosing a single main sport, and/or quitting all other sports to focus on 1 sport. Specialized training in young athletes has risks of injury and burnout, while the degree of specialization is positively correlated with increased serious overuse injury risk. Risk factors for injury in young athletes who specialize in a single sport include year-round single-sport training, participation in more competition, decreased age-appropriate play, and involvement in individual sports that require the early development of technical skills. Adults involved in instruction of youth sports may also put young athletes at risk for injury by encouraging increased intensity in organized practices and competition rather than self-directed unstructured free play. Strength-of-Recommendation Taxonomy (SORT): C

Acute White-Matter Abnormalities in Sports-Related Concussion: A Diffusion Tensor Imaging Study from the NCAA-DoD CARE Consortium

Sports-related concussion (SRC) is an important public health issue. Although standardized assessment tools are useful in the clinical management of acute concussion, the underlying pathophysiology of SRC and the time course of physiological recovery after injury remain unclear. In this study, we used diffusion tensor imaging (DTI) to detect white matter alterations in football players within 48 h after SRC. As part of the NCAA-DoD CARE Consortium study of SRC, 30 American football players diagnosed with acute concussion and 28 matched controls received clinical assessments and underwent advanced magnetic resonance imaging scans. To avoid selection bias and partial volume effects, whole-brain skeletonized white matter was examined by tract-based spatial statistics to investigate between-group differences in DTI metrics and their associations with clinical outcome measures. Mean diffusivity was significantly higher in brain white matter of concussed athletes, particularly in frontal and subfrontal long white matter tracts. In the concussed group, axial diffusivity was significantly correlated with the Brief Symptom Inventory and there was a similar trend with the symptom severity score of the Sport Concussion Assessment Tool. In addition, concussed athletes with higher fractional anisotropy performed better on the cognitive component of the Standardized Assessment of Concussion. Overall, the results of this study are consistent with the hypothesis that SRC is associated with changes in white matter tracts shortly after injury, and these differences are correlated clinically with acute symptoms and functional impairments

Repetitive Head Impact Exposure in College Football Following an NCAA Rule Change to Eliminate Two-A-Day Preseason Practices: A Study from the NCAA-DoD CARE Consortium

Repetitive head impact exposure sustained by athletes of contact sports has been hypothesized to be a mechanism for concussion and a possible explanation for the high degree of variability in sport-related concussion biomechanics. In an attempt to limit repetitive head impact exposure during the football preseason, the NCAA eliminated two-a-day practices in 2017, while maintaining the total number of team practice sessions. The objective of this study was to quantify head impact exposure during the preseason and regular season in Division I college football athletes to determine whether the 2017 NCAA ruling decreased head impact exposure. 342 unique athletes from five NCAA Division I Football Bowl Subdivision (FBS) programs were consented and enrolled. Head impacts were recorded using the Head Impact Telemetry (HIT) System during the entire fall preseasons and regular seasons in 2016 and 2017. Despite the elimination of two-a-day practices, the number of preseason contact days increased in 2017, with an increase in average hourly impact exposure (i.e., contact intensity), resulting in a significant increase in total head impact burden (+ 26%) for the 2017 preseason. This finding would indicate that the 2017 NCAA ruling was not effective at reducing the head impact burden during the football preseason. Additionally, athletes sustained a significantly higher number of recorded head impacts per week (+ 40%) during the preseason than the regular season, implicating the preseason as a time of elevated repetitive head impact burden. With increased recognition of a possible association between repetitive head impact exposure and concussion, increased preseason exposure may predispose certain athletes to a higher risk of concussion during the preseason and regular season. Accordingly, efforts at reducing concussion incidence in contact sports should include a reduction in overall head impact exposure

Comparison of Head Impact Exposure Between Concussed Football Athletes and Matched Controls: Evidence for a Possible Second Mechanism of Sport-Related Concussion

Studies of football athletes have implicated repetitive head impact exposure in the onset of cognitive and brain structural changes, even in the absence of diagnosed concussion. Those studies imply accumulating damage from successive head impacts reduces tolerance and increases risk for concussion. Support for this premise is that biomechanics of head impacts resulting in concussion are often not remarkable when compared to impacts sustained by athletes without diagnosed concussion. Accordingly, this analysis quantified repetitive head impact exposure in a cohort of 50 concussed NCAA Division I FBS college football athletes compared to controls that were matched for team and position group. The analysis quantified the number of head impacts and risk weighted exposure both on the day of injury and for the season to the date of injury. 43% of concussed athletes had the most severe head impact exposure on the day of injury compared to their matched control group and 46% of concussed athletes had the most severe head impact exposure for the season to the date of injury compared to their matched control group. When accounting for date of injury or season to date of injury, 72% of all concussed athletes had the most or second most severe head impact exposure compared to their matched control group. These trends associating cumulative head impact exposure with concussion onset were stronger for athletes that participated in a greater number of contact activities. For example, 77% of athletes that participated in ten or more days of contact activities had greater head impact exposure than their matched control group. This unique analysis provided further evidence for the role of repetitive head impact exposure as a predisposing factor for the onset of concussion. The clinical implication of these findings supports contemporary trends of limiting head impact exposure for college football athletes during practice activities in an effort to also reduce risk of concussive injury