• repetitive
  • Caused by repetitive blows to the head over a long period, the condition primarily affects career boxers and has recently been linked to other contact sports including American football and ice hockey as well as military service(see Ann McKee ). (wikipedia.org)
  • onset
  • Some evidence indicates that a head injury may interact with other factors to trigger the disease and may hasten the onset of the disease in individuals already at risk. (wikipedia.org)