Effect of Routine Sport Participation on Short-Term Clinical Neurological Outcomes: A Comparison of Non-Contact, Contact, and Collision Sport Athletes
To compare pre-season to post-season changes on a battery of clinical neurological outcome measures between non-contact, contact, and collision sport athletes over multiple seasons of play.
244 high school and collegiate athletes participating in multiple non-contact, contact, and collision sports completed standardized annual pre-season and post-season assessments over 1–4 years. Pre/post-season changes in 10 outcome measures assessing concussion symptoms, neurocognitive performance, and balance were compared between the groups using linear mixed models.
Small, but statistically significant overall pre/post-season change differences were present between the groups for Axon computerized neurocognitive test processing speed, attention, and working memory speed scores (Axon-PS, Axon-Att, Axon-WMS), as well as Balance Error Scoring System (BESS) total score. Small seasonal declines not exceeding reliable-change thresholds were observed in the collision sport group relative to the contact and non-contact groups for Axon-PS and Axon-Att scores. The collision and contact sport groups demonstrated less pre-/post-season improvement than the non-contact sport group for Axon-WMA and BESS, with less BESS improvement also observed in the collision sport group relative to the contact sport group. Overall, longitudinal performance on all 10 outcome measures remained stable in all 3 groups over 4 years.
Our findings do not necessarily support the notion that participation in sports associated with exposure to repetitive head impacts has clinically meaningful cumulative effects over the course of a season, nor over four consecutive seasons in high school and collegiate athletes.
The authors would like to thank Ms. Courtney McDonald, Ms. Ashley Rettmann, Ms. Lea Franco, and Mr. Max Bowen for their important contributions to this project, as well as all of the additional research and medical staff at the University of Michigan, Medical College of Wisconsin, University of California Los Angeles, and University of North Carolina. Primary funding for this work was provided through a research grant from the National Collegiate Athletic Association (NCAA). This project utilized a REDCap database housed at the Medical College of Wisconsin and supported by the Clinical & Translational Science Institute of Southeast Wisconsin (UL1TR001436). Dr. Eckner received effort support during the project period through career development awards from the Rehabilitation Medicine Scientist Training Program (RMSTP) and the National Institutes of Health (K23 HD078502-03). This publication was also made possible, in part, with support from the Grand Alliance CARE Consortium, funded by the NCAA and the DoD. The USAMRAA, Fort Detrick, MD, USA, is the awarding and administering acquisition office. This work was supported by the Office of the Assistant Secretary of Defense for Health Affairs through the Psychological Health and Traumatic Brain Injury Program under Award No. W81XWH-14-2-0151. Opinions, interpretations, conclusions and recommendations are those of the authors and are not necessarily endorsed by the DoD (DHP funds).
Compliance with Ethical Standards
This study was performed in accordance with the standards of ethics outlined in the Declaration of Helsinki. All participants provided informed written consent (or written assent with parental consent, for minors) prior to participation in this study. This research was approved by the Institutional Review Boards at the University of Michigan, Medical College of Wisconsin, University of California Los Angeles, and University of North Carolina. All sources of funding for this study are listed in the Acknowledgements.
Conflict of Interest:
In the previous 36 months and during the project period: Author Eckner has received unrelated research funding from the following: US Department of Health and Human Services, National Institutes of Health, NICHD; Rehabilitation Medicine Scientist Training Program; University of Michigan; Foundation for Physical Medicine and Rehabilitation; ElMindA Ltd; he is co-inventor of US patent 8,657,295 owned by employer University of Michigan; he was a paid grant reviewer for SRA International; he received speaker honoraria from the University of Utah and the American College of Oral and Maxillofacial Surgeons/Canadian Association of Oral and Maxillofacial Surgeons Joint Annual Conference. Author Nelson has received unrelated research funding from the NIH, Advancing a Healthier Wisconsin, Department of Defense, National Collegiate Athletic Association. Author Giza has received unrelated research funding from the following: NIH/NINDS, UCLA Brain Injury Research Center, UCLA Steve Tisch BrainSPORT Program, Easton Clinic for Brain Health; he has received consultant fees from Neural Analytics Inc.; he has been a paid advisory panel member for Highmark Interactive with stock/stock options and an unpaid advisory panel member for the MLS, NBA, US Soccer, and NCAA (travel reimbursement only for MLS and NCAA); he has been a Data Safety Monitoring Board member for LA Biomed Institute; he has received payment for providing expert medical-legal testimony; he receives book royalties from Wiley Publishing; he has received speaker honoraria for Sports Neurology lectures at multiple academic and medical institutions; he is a clinical consultant to the LA Lakers, NFL-Neurological Care Program, NHL Players Association. Author Guskiewicz has received unrelated research funding from the following: Centers for Disease Control and Prevention; Department of Defense; National Collegiate Athletic Association; National Football League. Authors Wang, Bancroft, Pohorence, Broglio, He, Kutcher, and McCrea declare no conflicts.
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