title: Chronic traumatic brain injury in professional soccer players.
abstract: OBJECTIVE
  To determine the presence of chronic traumatic brain injury in professional soccer players.
  
  
  METHODS
  Fifty-three active professional soccer players from several professional Dutch soccer clubs were compared with a control group of 27 elite noncontact sport athletes. All participants underwent neuropsychological examination. The main outcome measures were neuropsychological tests proven to be sensitive to cognitive changes incurred during contact and collision sports.
  
  
  RESULTS
  The professional soccer players exhibited impaired performances in memory, planning, and visuoperceptual processing when compared with control subjects. Among professional soccer players, performance on memory, planning, and visuoperceptual tasks were inversely related to the number of concussions incurred in soccer and the frequency of "heading" the ball. Performance on neuropsychological testing also varied according to field position, with forward and defensive players exhibiting more impairment.
  
  
  CONCLUSIONS
  Participation in professional soccer may affect adversely some aspects of cognitive functioning (i.e., memory, planning, and visuoperceptual processing).
authors.affiliation: Department of Neuropsychology and Sportsneurology, St. Anna Hospital Geldrop, The Netherlands.
authors.forename: J T
authors.initials: JT
authors.lastname: Matser
authors.forename: A G
authors.initials: AG
authors.lastname: Kessels
authors.forename: B D
authors.initials: BD
authors.lastname: Jordan
authors.forename: M D
authors.initials: MD
authors.lastname: Lezak
authors.forename: J
authors.initials: J
authors.lastname: Troost
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000209:etiology / Q000503:physiopathology*; D003071:Cognition / Q000502:physiology; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology; D009483:Neuropsychological Tests; D012307:Risk Factors; D012916:Soccer / Q000293:injuries*; D014796:Visual Perception / Q000502:physiology