(note: I use “football” to mean “American football” as opposed to the game Americans call soccer).
Most people know playing football can be dangerous. But many may only associate the danger with injuries such as broken legs, torn ligaments and so on – the sort of injury that is easy to see and diagnose. However, there is increasing evidence that football may damage the brain.
In a study published in the Journal of the American Medical Association on May 14, 2014 and summarized in Science News on June 14, 2014, Patrick Bellgowan and his colleagues found that the hippocampus of college football players who had suffered a concussion were only three-quarters the size of age-matched controls. Players who had not suffered a concussion had hippocampi that were midway between the two groups – about five sixths the size of controls.
Bellgowan and his colleagues measured the hippocampi of 50 Division I football players and 25 age-matched volunteers. Of the players 25 had had concussions and 25 had not. They also recorded the number of years each player had played football, the size of the amygdalas (a brain region next to the hippocampus) and reaction times on a test.
They found that the three groups of people all had very similar sized amygdalas, However, the size of the hippocampi varied greatly, as noted above. In addition, players who had played football longer had slower reaction times.
Of course, correlation does not imply causation; but this is evidence that may explain some previous findings of memory problems in former football players. In addition, the fact that the amygdalas were similar in size is a partial control for natural brain size. Further evidence may come if researchers can detail the exact process that shrinks the hippocampus but not the amygdala. Another way to further strengthen the findings would be to associate position played or amount of physical contact with damage to the hippocampus.
What is the hippocampus?
The hippocampus is a seahorse-shaped region of the brain; it is part of the medial temporal lobe. It is located roughly between your two ears; there is one hippocampus on each side of the brain.
The hippocampus plays a key role in memory; in Alzheimer’s patients, it is one of the first regions to suffer damage. Damage to the hippocampus has also been linked to amnesia.(Squire ).