Elevated Autoantibodies to the GluA1 Subunit of the AMPA Receptor in Blood Indicate Risk of Cognitive Impairment in Contact Sports Athletes, Irrespective of Concussion.

To address the need for objective tests of concussion in athletes, we conducted a prospective clinical study in National Collegiate Athletic Association athletes of the relationship between neurocognitive performance and blood levels of the GluA1 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor peptides and autoantibodies to GluA1. Specifically, we compared 44 contact sport athletes to 16 noncontact sport athletes, with Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), as well as blood sample collection, before the start of the season and at the end of the season. Contact sport athletes exhibited significantly elevated serum GluA1 autoantibodies at the end of season, compared with preseason levels, irrespective of whether they sustained a concussion. Noncontact sport athletes showed no change in serum GluA1 autoantibodies, and neither group showed differences in GluA1 peptides. Amongst contact-sport athletes, the 'high GluA1 autoantibody group' (≥4 ng/mL) displayed impaired reaction time, a measure of cognitive impairment, while the 'low GluA1 autoantibody group' (<4 ng/mL) displayed normal reaction time. Our results reveal that contact sport athletes are at risk for developing cognitive impairment even without sustaining a diagnosed concussion and that serum GluA1 autoantibodies provide a blood-based biomarker of this risk. This could guide future studies on the differing susceptibility to cognitive impairment in contact sport athletes and facilitate efficient allocation of resources to contact sport athletes identified as having increased risk of developing cognitive impairment.

Retrospective analysis of whole-body cryotherapy adverse effects in Division I collegiate athletes.

CONTEXT: Although the physiological effects and the performance of athletes after utilizing whole-body cryotherapy (WBC) have been widely studied, there is a lack of data on its adverse effects. It is important to be aware of the adverse effects of any treatment for its use to be properly recommended. OBJECTIVES: This study aims to provide insight to any adverse effects that collegiate athletes experienced after utilizing WBC to better utilize this therapeutic modality. METHODS: After the Institutional Review Board (IRB) deemed exemption, all 457 Division 1-A varsity athletes were recruited via email to participate in a retrospective survey. Participants consented to the study by continuing to the questions. The inclusion criteria were that they must be 18 years of age or older, had completed WBC at that university, and were a student-athlete. The survey was six questions long, and if any of the inclusion criteria was not met, they were redirected to end the survey. The data were analyzed utilizing odds ratios. RESULTS: Of the 457 student-athletes, 11.2% (n=51) responded and 6.3% (n=29) met the inclusion criteria. Responses were obtained from women's lacrosse (27.6%; n=8), women's gymnastics (24.1%, n=7), field hockey (17.2%, n=5), wrestling (6.9%, n=2), football (6.9%, n=2), women's cross country (3.5%, n=1), men's basketball (3.5%, n=1), women's volleyball (3.5%, n=1), softball (3.5%, n=1), and baseball (3.5%, n=1). Among the responses, 79.3% (n=23) were females and 29.7% (n=6) were males. Within 1 h of WBC, the most frequently reported adverse effects were skin rash (27.6%, n=8), itching (13.8%, n=4), and fatigue (6.9%, n=2). More than 1 h after WBC, the most frequently reported adverse effects were skin rash (20.7%, n=6), itching (10.3%, n=3), and increased energy (6.9%, n=2). When stratified by female and male athletes, for both within 1 h and more than 1 h after WBC, there were increased odds for females reporting adverse effects; however, neither were statistically significant (OR 4.58, p=0.19, 95% CI 0.46 to 45.61) (OR 3.84, p=0.25, 95% CI 0.39 to 38.36). Within 1 h of WBC, 58.6% (n=17) of subjects reported no adverse effects, and more than 1 h after WBC, 65.5% (n=19) subjects reported no adverse effects. The mean satisfaction level rating was 6.34 (range 0-10, n=29). When asked if they would do WBC again, 65.5% (n=19) responded "yes" and 34.5% (n=10) responded "no." CONCLUSIONS: In this collegiate athlete population, negative adverse effects of WBC commonly included skin burns and itching while potentially proving a beneficial adverse effect of increased energy. Subjects commonly reported no adverse effects after WBC treatment as well.

SCAT5 Sex Differences: Normative Data, Clinical Thresholds, and Relevance for Identification of Concussion.

OBJECTIVE: This study evaluated sex differences in performance on the Sport Concussion Assessment Tool-5 (SCAT5) Standardized Assessment of Concussion (SAC) and in baseline SCAT5 symptom reporting. It established clinically relevant cut points for low performance on the SAC based on both reliable chance indices (RCIs) and normative performance. This study also evaluated the diagnostic utility of the sex-adjusted SCAT5 SAC for identification of suspected concussion in collegiate athletes. METHOD: In total, 671 uninjured collegiate athletes were administered the SCAT5 and 264 of these athletes also completed SCAT5 testing ~1 year later. Fifty-four athletes were administered the SCAT5 after being removed from play due to suspected concussion. Sex differences in cognitive performance and symptom reporting at baseline were evaluated and sex-specific clinically relevant cut points were provided. Chi square and logistic regression models were used to evaluate if SAC performance was a significant predictor of concussion status. RESULTS: Female athletes outperformed male athletes on the SCAT 5 SAC and showed minimally higher symptom endorsement. Use of sex-corrected normative data improved performance of the SAC in identification of suspected concussion when a low score cut point was used. Logistic regression models showed that sex-corrected SAC change from baseline (RCI) improved the predictive value of the model after first accounting for other elements of the SCAT5. CONCLUSIONS: Present results support the use of sex-specific normative data for the SCAT5 SAC, particularly if using low performance without comparison to a baseline; however, reliable change from a pre-injury baseline may have somewhat higher diagnostic utility.

Multidisciplinary Concussion Management: A Model for Outpatient Concussion Management in the Acute and Post-Acute Settings.

OBJECTIVE: To describe a model of multidisciplinary concussion management and explore management methods in the acute and post-acute settings. SETTING: A multidisciplinary concussion management program within a large health system. PARTICIPANTS: Patients with sports and non-sports-related concussions aged 14 to 18 years with persisting concussion symptoms at 4 weeks postinjury or beyond. DESIGN: Pilot randomized controlled trial comparing a subsymptom threshold exercise program with standard-of-care treatment in the post-acute setting. MAIN MEASURES: Beck Depression Inventory-II and the Post-Concussion Scale-Revised. RESULTS: Across groups, 60% improvement in concussion symptoms was noted. After removing the influence of depression, the intervention showed a large effect on symptom reduction, with participants in the intervention group improving more than those in the control group. There was no difference in response to the intervention by the sports and nonsports groups. CONCLUSION: Results demonstrate that exercise intervention is effective in reducing symptoms in adolescents with persisting symptoms. The finding that participants in the control group who underwent education, light activity, and sophisticated monitoring still had meaningful recovery supports the utility of active engagement in a multidisciplinary management program. Finally, depression had a clinically meaningful effect on recovery, highlighting the need for targeted intervention of noninjury factors relevant to persisting symptoms.