title: Headache after concussion.
abstract: OBJECTIVE
  Chronic post-traumatic headache attributed to mild head injury is a somewhat disputed headache diagnosis. A main object of this study was to assess the validity of this diagnosis by studying the headache pattern of concussed patients that participated in one historic (n = 131) and one prospective cohort (n = 217) study.
  
  
  METHODS
  Head injury patients were recruited from two hospitals in Kaunas, Lithuania. Controls were recruited amongst patients with minor orthopaedic traumas not involving the head and neck.
  
  
  RESULTS
  When data from the two studies were pooled, no difference in any headache category (diagnosis, attack frequency, symptoms) was found one or more years after the trauma, except that photophobia was somewhat more prevalent amongst the concussed patients. In both injury groups, the existence of pre-traumatic headache was a predictor of post-traumatic headache, although pre-traumatic headache seems to have been underreported amongst the concussed patients. There was a significant negative correlation between the duration of unconsciousness and the headache.
  
  
  CONCLUSIONS
  This negative correlation, and the lack of specificity indicates that headache occurring 3 months or more after concussion is not caused by the head or brain injury. Rather it may represent an episode of one of the primary headaches, possibly induced by the stress of the situation.
authors.affiliation: Norwegian National Headache Centre, Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway. lars.stovner@ntnu.no
authors.forename: L J
authors.initials: LJ
authors.lastname: Stovner
authors.forename: H
authors.initials: H
authors.lastname: Schrader
authors.forename: D
authors.initials: D
authors.lastname: Mickeviciene
authors.forename: D
authors.initials: D
authors.lastname: Surkiene
authors.forename: T
authors.initials: T
authors.lastname: Sand
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001924:Brain Concussion / Q000175:diagnosis / Q000453:epidemiology*; D015331:Cohort Studies; D015897:Comorbidity / Q000639:trends; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051298:Post-Traumatic Headache / Q000175:diagnosis / Q000453:epidemiology*; D011446:Prospective Studies; D015203:Reproducibility of Results; D055815:Young Adult