title: Serum neurofilament light as a biomarker for mild traumatic brain injury in contact sports.
abstract: OBJECTIVE
  To evaluate whether the axonal protein neurofilament light (NFL) in serum is a sensitive biomarker to detect subtle brain injury or concussion in contact sports athletes.
  
  
  METHODS
  Two prospective cohort studies involving (1) 14 Swedish amateur boxers who underwent fluid biomarker assessments at 7-10 days after bout and after 3 months of rest from boxing and (2) 35 Swedish professional hockey players who underwent blood biomarker assessment at 1, 12, 36, and 144 hours after concussion and when the players returned to play were performed. Fourteen healthy nonathletic controls and 12 athletic controls were also enrolled. Serum NFL was measured using ultrasensitive single molecule array technology.
  
  
  RESULTS
  Serum NFL concentrations were increased in boxers 7-10 days after bout as compared to the levels after 3 months rest as well as compared with controls (p= 0.0007 andp< 0.0001, respectively). NFL decreased following 3 months of rest, but was still higher than in controls (p< 0.0001). Boxers who received many (>15) hits to the head or were groggy after bout had higher concentrations of serum NFL as compared to those who received fewer hits to the head (p= 0.0023). Serum NFL increased over time in hockey players, and the levels returned to normal at return to play. Importantly, serum NFL could separate players with rapidly resolving postconcussion symptoms (PCS) from those with prolonged PCS.
  
  
  CONCLUSIONS
  The results from these 2 independent cohort studies suggest that serum NFL is a highly sensitive biomarker for concussion.
authors.affiliation: From the Institute of Neuroscience and Physiology (P.S., H.Z., K.B.), Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy at University of Gothenburg; Clinical Neurochemistry Laboratory (P.S., H.Z., K.B.), Sahlgrenska University Hospital, Mölndal, Sweden; Department of Molecular Neuroscience (H.Z.), UCL Institute of Neurology, Queen Square, London, UK; and the Division of Medical Sciences (Y.T.), Department of Health Sciences, Luleå University of Technology, Sweden. pashtun.shahim@neuro.gu.se.
authors.forename: Pashtun
authors.initials: P
authors.lastname: Shahim
authors.affiliation: From the Institute of Neuroscience and Physiology (P.S., H.Z., K.B.), Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy at University of Gothenburg; Clinical Neurochemistry Laboratory (P.S., H.Z., K.B.), Sahlgrenska University Hospital, Mölndal, Sweden; Department of Molecular Neuroscience (H.Z.), UCL Institute of Neurology, Queen Square, London, UK; and the Division of Medical Sciences (Y.T.), Department of Health Sciences, Luleå University of Technology, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Zetterberg
authors.affiliation: From the Institute of Neuroscience and Physiology (P.S., H.Z., K.B.), Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy at University of Gothenburg; Clinical Neurochemistry Laboratory (P.S., H.Z., K.B.), Sahlgrenska University Hospital, Mölndal, Sweden; Department of Molecular Neuroscience (H.Z.), UCL Institute of Neurology, Queen Square, London, UK; and the Division of Medical Sciences (Y.T.), Department of Health Sciences, Luleå University of Technology, Sweden.
authors.forename: Yelverton
authors.initials: Y
authors.lastname: Tegner
authors.affiliation: From the Institute of Neuroscience and Physiology (P.S., H.Z., K.B.), Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy at University of Gothenburg; Clinical Neurochemistry Laboratory (P.S., H.Z., K.B.), Sahlgrenska University Hospital, Mölndal, Sweden; Department of Molecular Neuroscience (H.Z.), UCL Institute of Neurology, Queen Square, London, UK; and the Division of Medical Sciences (Y.T.), Department of Health Sciences, Luleå University of Technology, Sweden.
authors.forename: Kaj
authors.initials: K
authors.lastname: Blennow
mesh_terms: D000293:Adolescent; D019540:Area Under Curve; D056352:Athletes; D001265:Athletic Injuries / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001774:Blood Chemical Analysis; D001914:Boxing / Q000293:injuries* / Q000502:physiology; D001924:Brain Concussion / Q000097:blood* / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006173:Gymnastics; D006688:Hockey / Q000293:injuries* / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016900:Neurofilament Proteins / Q000097:blood*; D011446:Prospective Studies; D012372:ROC Curve; D013548:Sweden; D013997:Time Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D016900:Neurofilament Proteins; C044882:neurofilament protein L