A heavy blow may cause long-term damage to the brain

, a blow to the head is enough to trigger progressive degeneration of the brain and long-term cognitive decline, according to a study published in Science-Translational Medicine.
people already know that repeated head impacts - like those that continue in boxing and rugby - can lead to personality changes, cognitive problems and depression years later. This condition, known as chronic traumatic encephalopathy (CTE), is associated with the gradual accumulation of tau proteins in the brain.
, of Imperial College London, wanted to know if similar brain changes could occur after a serious head injury.
to find out, they scanned the brains of 21 men and women. All suffered serious head injuries in a car accident, attack or fall between 18 and 51 years ago. They all experienced severe initial symptoms for more than 30 minutes, such as loss of consciousness, while many had problems thinking and remembering.
the results showed abnormally high levels of tau protein in the brains of 15 participants, especially in the outer part of the brain. Sharp's team says this may be because the outer layer of the brain is most susceptible to external influences.
the participants' brains appeared to have levels of tau protein that were not related to the severity of the symptoms, but the study may have been too small to detect the relationship, the researchers said.
also found high levels of tau protein in the outer layers of the brains of former athletes with CTE, especially those who suffered the most blows to the head. The team believes this is consistent with the idea that brain degeneration may come from several relatively small brain injuries, or from a particularly severe brain injury.
both types of head injuries can damage the brain structure known as micro tubes, which are stabilized by tau proteins. This, in turn, can cause the tau protein to get out of control and begin to form large lumps that gradually damage the rest of the brain.
there is no cure for brain degeneration after head injuries, but drugs such as antidepressants can sometimes help relieve CTE symptoms. (Source: Xu Xu, China Science Journal)
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