title: Cognitive effects of one season of head impacts in a cohort of collegiate contact sport athletes.
abstract: OBJECTIVE
  To determine whether exposure to repetitive head impacts over a single season negatively affects cognitive performance in collegiate contact sport athletes.
  
  
  METHODS
  This is a prospective cohort study at 3 Division I National Collegiate Athletic Association athletic programs. Participants were 214 Division I college varsity football and ice hockey players who wore instrumented helmets that recorded the acceleration-time history of the head following impact, and 45 noncontact sport athletes. All athletes were assessed prior to and shortly after the season with a cognitive screening battery (ImPACT) and a subgroup of athletes also were assessed with 7 measures from a neuropsychological test battery.
  
  
  RESULTS
  Few cognitive differences were found between the athlete groups at the preseason or postseason assessments. However, a higher percentage of the contact sport athletes performed more poorly than predicted postseason on a measure of new learning (California Verbal Learning Test) compared to the noncontact athletes (24% vs 3.6%; p < 0.006). On 2 postseason cognitive measures (ImPACT Reaction Time and Trails 4/B), poorer performance was significantly associated with higher scores on several head impact exposure metrics.
  
  
  CONCLUSIONS
  Repetitive head impacts over the course of a single season may negatively impact learning in some collegiate athletes. Further work is needed to assess whether such effects are short term or persistent.
authors.affiliation: Department of Psychiatry, Dartmouth Medical School, Lebanon. thomas.w.mcallister@dartmouth.edu
authors.forename: T W
authors.initials: TW
authors.lastname: McAllister
authors.forename: L A
authors.initials: LA
authors.lastname: Flashman
authors.forename: A
authors.initials: A
authors.lastname: Maerlender
authors.forename: R M
authors.initials: RM
authors.lastname: Greenwald
authors.forename: J G
authors.initials: JG
authors.lastname: Beckwith
authors.forename: T D
authors.initials: TD
authors.lastname: Tosteson
authors.forename: J J
authors.initials: JJ
authors.lastname: Crisco
authors.forename: P G
authors.initials: PG
authors.lastname: Brolinson
authors.forename: S M
authors.initials: SM
authors.lastname: Duma
authors.forename: A-C
authors.initials: AC
authors.lastname: Duhaime
authors.forename: M R
authors.initials: MR
authors.lastname: Grove
authors.forename: J H
authors.initials: JH
authors.lastname: Turco
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001265:Athletic Injuries / Q000150:complications*; D001924:Brain Concussion / Q000150:complications* / Q000209:etiology / Q000523:psychology; D003071:Cognition; D003072:Cognition Disorders / Q000209:etiology; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D007858:Learning; D008297:Male; D008568:Memory; D009483:Neuropsychological Tests; D013177:Sports; D013334:Students / Q000706:statistics & numerical data*; D014495:Universities; D055815:Young Adult