Accepted for Publication: February 10, 2014.
Published Online: March 13, 2014. doi:10.1001/jamaneurol.2014.367.
Study concept and design: Shahim, Tegner, Blennow, Zetterberg.
Acquisition of data: Shahim, Tegner, Wilson, Randall, Kallberg.
Analysis and interpretation of data: All authors.
Drafting of the manuscript: Shahim, Tegner, Blennow, Zetterberg.
Critical revision of the manuscript for important intellectual content: Tegner, Wilson, Randall, Skillbäck, Pazooki, Kallberg, Blennow, Zetterberg.
Statistical analysis: Shahim, Skillbäck, Blennow, Zetterberg.
Obtained funding: Tegner, Blennow, Zetterberg.
Administrative, technical, or material support: Tegner, Wilson, Randall, Skillbäck, Pazooki, Kallberg, Blennow.
Study supervision: Tegner, Blennow, Zetterberg.
Conflict of Interest Disclosures: Drs Wilson and Randall, who are employees of Quanterix Corp, and Drs Zetterberg and Blennow are listed as coinventors on a US patent application for plasma tau as a brain injury marker. Dr Blennow has served on advisory boards for Eli Lilly, Kyowa Kirin Pharma, Pfizer, and Roche. No other disclosures were reported.
Funding/Support: This study was supported by grants from the Swedish Medical Research Council.
Role of the Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Additional Contributions: We warmly acknowledge the participants and the Swedish Ice Hockey Association. Gisela Malmgård, BSc, Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden, provided skillful technical assistance. We thank the medical staff of the teams for their assistance in diagnosis, management, and blood sampling of the players: Bengt Gustafsson, MD, Djurgården Hockey; Torsten Johansson, MD, PhD, Frölunda HC; Örjan Fröjd, MD; Henrik Wrethling, MD, Brynäs IF; Karin Rundblad, MD, Skellefteå AIK; Göran Thoren, MD, Modo Hockey; Christer Andersson, MD, PhD, Linköpings HC; Ulf Nordström, MD, Örebro Hockey; Stefan Serenius, MD, AIK Hockey; Mattias Hell, BSc, Färjestad BK; Jonas Kalman, MD, HV 71; Stina Hedin, BSc, Frölunda HC; Patrik Johansson, MD, Växjö Lakers; and Billy Nilsson, BSc, Rögle BK. None of these individuals received compensation from the funding sponsor.