Concussion symptoms remain for up to 6 months

Researchers at the University of Cambridge have found that even mild concussion causes long-lasting effects in the brain. The team - which analysed data from across Europe - say that for almost a half of all people who receive a knock to the head, there are changes in how regions of the brain communicate with each other. The researchers believe that this can cause long-term symptoms such as extreme fatigue, headaches and poor concentration. It comes as governments and sporting bodies around the world seek to address concerns around concussion. Emmanuel Stamatakis has been leading the new study…

Emmanuel - We looked at a kind of brain scan called functional MRI, which is a little bit like an MRI scan, but shows you how oxygen moves around the brain. And in other words, we understand how different parts of the brain activate. And we also looked at how different parts of the brain coordinate with each other. So this technique that has not been used widely in this category of patients, we decided to use it because we have expertise in this area. And we also decide to use it because routine scanning, such as CT or what we call structural MRI, which shows you the brain in its glorious detail, doesn't actually show much after concussion. It's almost nothing. The findings are nothing from that type of scan. So we used the technique we use daily in the lab, which is called functional MRI, and we looked at a specific part of the brain that's quite susceptible to injury and cold, the thalamus. Now the thalamus, we have two thalami, one in each hemisphere of the brain. They're roughly the size of two quail eggs. And they're sitting, give or take, a millimetre at the top of our spinal cord. We know from simulations that Willie mentioned earlier, that those are particularly susceptible to injury. Now we see no damage on the structural scans we mentioned earlier. So we decide to see whether, ask the question whether this part of the brain coordinates differently with other parts of the brain, whether the information, the exchange with other parts of the brain and the rate that they exchange, changes.

Chris - Who did you look at? Because obviously you are interested in people who have had some kind of traumatic brain injury. So were you comparing before and after or people who have and haven't had these sorts of injuries when you look at this part of the brain?

Emmanuel - The data came from a huge European study, which involved about 60 centers all across Europe. And we took a subset of that data. This was a study that tried to understand brain injury. We took a subset of patients that had functional MRI scans and had very little damage or no damage at all on structural MRI. So the subset we came up with was 107 patients and we compared those to near their healthy controls. So this connectivity that we talk about, the synchronization of different, of the thalamus with different parts of the brain, we compare between these two groups.

Chris - And did you see a difference in the people who had had brain injury?

Emmanuel - We did indeed. We did indeed. We saw that the thalamus in the people who had the injury was hyper synchronized with other parts of the brain. It was working harder if you want. It was making an extra effort. And in fact we found that the harder it worked, the harder the thalamus worked, the more likely it was to develop long-term problems such as the ones you mentioned earlier, fatigue, poor concentration, and headaches.

Chris - What's your interpretation of the fact that you see this association between head injury and the thalamus talking harder as it were to other brain areas?

Emmanuel - There are theories about that. The most prominent being that the thalamus works very hard. Eventually it gives up. And in the long term scans in six months and one year after the injury, we see the actual damage it gives up eventually.

Chris - So you're saying that in the short term it tries to compensate for the aftermath of the injury? But in the longer term, you lose that effect. So any compensation you had is gone and then the person may well have residual loss of function.

Emmanuel - Absolutely. Absolutely. That's what I'm saying. Yes.

Chris - And then superimposed on that maybe the additional effects of the injury that Willie was talking about with Alex with respect to possible progression towards dementia.

Emmanuel - Yes. And the next step of our study is to find another subset of patients that had repetitive mild injury, repetitive concussion, and see whether that makes them more likely to develop dementia.