Study: Milder Head Blows May Affect Brain

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Harvard Medical School
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Study: Milder Head Blows May Affect Brain

News Review From Harvard Medical School

December 12, 2013

News Review From Harvard Medical School -- Study: Milder Head Blows May Affect Brain

A season of contact sports may affect memory and thinking, even if no concussion occurs, a new study suggests. The study included 80 college football and ice hockey players who did not have prior concussions. During a season of play in their sports, they wore helmets that recorded all blows to the head. These players were compared with 79 college athletes in non-contact sports such as track and crew. All players received brain scans and tests of memory and learning ability before and after the season. The 5 athletes who had concussions during the season were dropped from the study. Among the rest, about 20% of athletes in contact sports performed worse than expected on their tests after the season. About 11% of the non-contact athletes had such a result. Brain scans showed more abnormal areas among those who had lower test scores and more head impacts as recorded by their helmets. The journal Neurology published the study. HealthDay News wrote about it December 11.


By Robert H. Shmerling, M.D.
Harvard Medical School


What Is the Doctor's Reaction?

Have you noticed how often sports-related brain injuries have been in the news lately? 

High-profile athletes have been affected. And the National Football League agreed to pay $765 million to more than 4,500 players and their families to settle a lawsuit. The suit accused the NFL of withholding what it knew about the risks of repeated head injuries.

But the issue is even bigger than what is happening to elite athletes. Athletes involved in contact sports at all levels of competition are at risk. 

Concussions suffered during sports can lead to long-term brain damage. A concussion is a brain injury that follows trauma. The symptoms can include:

  • Loss of consciousness
  • Confusion
  • Impaired judgment
  • Poor coordination
  • Balance problems

Long-term problems that can follow repeated concussions include depression, dementia and changes in personality. Chronic traumatic encephalopathy is a newly defined condition related to head trauma. Autopsies have shown this condition in former athletes who had repeated concussions. The most dramatic findings have been among men who boxed or played football.

These concerns about brain injury have led to new precautions. In NFL games, a player who has a major head injury or displays signs of a possible concussion during a game must leave the game. He must pass a series of tests of brain function before returning. It's common now to see a trainer or doctor making sure an injured athlete is "oriented" (knows where he is, what day it is etc.). Checks also include the player's vision, memory and balance. If there is evidence of a possible concussion, the player must leave the game and have more tests.

But what are the effects of head injuries that don't cause a concussion?  A new study looks at this question. Eighty varsity football and ice hockey players from Dartmouth College wore helmets that recorded information about head impact.  They were compared with other athletes who took part in track, crew and other non-contact sports. Each player had a brain scan and tests of memory before and after a season of competition.  None of these athletes had concussions.

The results are cause for concern:

  • About 20% of those involved in contact sports had scores of memory and verbal learning that were lower than expected and lower than those in non-contact sports. Declines like this occur in less than 7% of a healthy population.
  • Abnormal areas in the brain scans were more common among those with low memory and verbal learning scores and those with more head injuries.
  • The affected areas of the brain included the white matter, which controls such vital functions as movement, language and vision. The corpus callosum was also affected. This area of the brain controls signals between the two sides of the brain.
  • These findings suggest that even without a concussion, a single season of head injuries can affect the brain. However, this study did not assess whether these injuries led to long-term problems.


What Changes Can I Make Now?

Learn what you need to know about head injuries in sports before signing up.  Then do what you can to limit risk. 

  • Understand the rules of the sport, especially ones that intended to protect athletes.
  • Learn about concussions. Know how to identify a concussion.
  • Know which types of injuries are most likely to cause a concussion.
  • Review the procedures for evaluation and the types of symptoms that should lead to a player's removal from a game.
  • Understand how safety equipment is supposed to be used. Wear it every time you play.
  • Let medical personnel know about any symptoms you have after a head injury.

If you or a loved one has played sports that could lead to chronic traumatic encephalopathy, recognize the symptoms. Symptoms begin years or even decades after the last brain trauma. They include:

  • Memory loss
  • Confusion
  • Impaired judgment
  • Impulse control problems
  • Aggression
  • Depression
  • Anxiety
  • Suicidal thoughts
  • Parkinson's disease
  • Dementia

These symptoms can mimic other common conditions. So it's important to be evaluated if you have symptoms that suggest CTE, especially they are new. Let your doctor know if you had concussions or other head injuries in the past.


What Can I Expect Looking to the Future?

Awareness of the connection between sports-related head injuries and long-term brain damage will increase. Efforts to make contact sports safer will also continue.  Research should lead to:

  • More reliable ways to identify head injuries
  • Better sports equipment
  • Changes in rules
  • Other changes to protect players

It may be impossible to guarantee that all contact sports are absolutely safe. But it is important that athletes (or their parents) understand the risks they may be facing when playing their chosen sport. To make informed decisions, we need more and better information. You can expect to hear about more research to identify:

  • Which sports are the riskiest
  • How to reduce the risk
  • What treatments might prevent or slow long-term problems
Last updated December 12, 2013

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