Concussion biomarkers (Eric Thelin episode 3)


Concussion biomarkers are needed. That is because the current imaging machines like MRI and CT more often than not can not visualize a concussion. This often results in doctors saying that there is nothing wrong with us, or that the symptoms we have are psychological. If a simple blood test can show you sustained a concussion and are at risk for lingering symptoms, concussion care would improve very much. Eric Thelin takes us on a deep dive into the realm of concussion biomarkers.

Table of contents

04:06 Finding brain injury biomarkers
05:10 Concussion biomarkers
07:47 Concussion and inflammation
10:08 Concussion awareness

Concussion Stories podcast introduction

[00:00 Melanie] If I say there is hope for complete recovery for people with a concussion, you say…?

[00:07 Professor McCrea] 100%!

[00:08 Professor Maas] And in fact, you didn’t only feel it you were outside the regular medical system, because they were not interested in you.

[00:16 Professor Sitskoorn] Neuroplasticity actually opens you up to the world. It makes it possible to develop; it makes it possible to rehabilitate.

[00:25 Professor Wilson] Traumatic brain injury has been called a silent epidemic for that reason, because it consists of changes and disabilities that are not obvious to other people.

[00:35 Dr. Zasler] If, as a physician, you felt you had nothing to offer a patient, then I think ethically, you need to say] “I don’t think there’s anything I can offer you. Maybe you should see Dr. M.”

[00:48 Professor Diaz-Arrastia] Historically, we have called these things mild traumatic brain injuries, which implies that, well… It may be a brain injury, but it’s not going to have great consequences, right? And that’s frankly not true.

About the Concussion Stories podcast

[01:05 Melanie] Welcome to Concussion Stories, a Lifeyana podcast series filled with hope. I’m here to let you know that you are not alone in your post-concussion recovery journey. My name is Melanie and I spent six and a half years learning, experimenting, and training in order to find a way to heal myself from post-concussion syndrome.

After making a full recovery by the end of 2018, I embarked on this mission to make the recovery journey easier for you. This is why I started this podcast, wrote detailed blog post and downloadable guides, offer coaching and also the course that I wish I had back when I was recovering — teaching you everything that I needed to know in order to make my recovery happen.

On Concussion Stories, we dig deep while discussing hopeful stories of recovery as well as the hard stuff in the messy middle. Let’s dive right in!

Eric Thelin

This is the third and last episode with Eric Thelin. If you haven’t read, listened to or watched the first two episodes, please find them right here:

Eric specializes in neurointensive care after brain injury at Karolinska University Hospital in Sweden.

Concussion biomarkers

In today’s episode, we are going to dive into the role of concussion biomarkers present in blood in both the acute and lingering concussion stages. We’re also going to learn about neuroinflammation. And where Eric thinks this comes from. This is Eric Thelin.

[02:31 Eric] What we need is more objective markers of chronic TBI pathology. 

‘Psychosomatic’ concussion symptoms

I don’t know how you have been handled by the health care system in the Netherlands, but there have probably been a few doctors that didn’t believe in your symptoms. Or perhaps they didn’t really understand and thought: “You’re probably suffering from some kind of psychiatric problem causing your somatic symptoms. That is probably the reason: it’s not your concussion, it’s other issues.”

Concussion biomarkers are needed

It would be good if there were a perfect blood sample or some sort of test that could actually indicate: this is a structural brain injury, and this is a psychiatric problem. If we could triangulate these patients, we could very much improve the sort of triage and the pathways in the healthcare system very early on for these patients. I think that will help tremendously.

[Timestamp needed Melanie] Yes, I think this is one of the coolest things that is emerging from CENTER-TBI, to be able to just pinpoint with a blood test: what is happening with patients? That would be so easy.

[Timestamp needed Eric] Yeah. Exactly! I did my PhD on traumatic brain injury  biomarkers. So I am very glad that CENTER-TBI has embraced this as well. 

Finding brain injury biomarkers

You need to follow-up these patients for a longer period of time: you need to sample them in more chronic stages. 

Severe TBI biomarkers

This is something that we do in patients with severe TBI, 10 to 15 years down the line. These patients have major lesions on MRI: half their brain is sometimes injured, and they are having severe problems today. Maybe they can’t move a hand or an arm, or they have severe cognitive problems and severe fatigue syndrome. So, they will probably show quite a strong signal in their TBI biomarkers.

Mild TBI biomarkers

However, in a mild TBI cohort, you need to have quite a sample size like CENTER-TBI has in order to actually see a signal in all the noise. That is because mild TBI is also a lot of noise, considering that the trauma can sometimes not even be visualized on the current imaging techniques.

Concussion biomarkers


[05:10 Melanie] How then–? I know there is one marker that everyone is focusing on now, right? Is it as close as that? Soon we know that one marker means mild TBI, so you have a concussion or you will be at risk for post-concussion syndrome? Or will this situation still take a while?

S100 calcium-binding protein B (S100B)

[05:33 Eric] I think there will be 2 markers that will come out of this. There might be 3. One will be the protein S100B, which is currently employed in the Scandinavian guidelines to screen for patients that have mild TBI in terms of hemorrhages. So, if a patient is below a certain cutoff level, you can send them home, and they don’t have to undergo a CT scan.

Neurofilament light polypeptide (NF-L)

However, one of the 2 proteins that I think will come out of all of this in terms of post-concussion syndrome, is the protein neurofilament light polypeptide (NF-L or Nfl). There have already been studies showing that if you have elevated levels 2 to 3 weeks after an injury, this is a protein that is released. It continues to be released because it has a very long half-life in serum (blood). If you sample it about three weeks or so after an injury, it has been associated with more post-concussion syndrome in boxers, for instance, or other close contact sport players. So, I think that is the blood concussion biomarker.

Glial fibrillary acidic protein (GFAP)

But another interesting protein that now emerged is glial fibrillary acidic protein, or as Americans say: GFAP. It is a protein that will probably replace S-100-B in the emergency room to screen if a patient has a hemorrhage in a mild TBI or concussion scenario. Recent study also shows that in long-term TBI patients, a year down the line, it is still elevated. So, I think that we have an ongoing inflammation-ish protein in GFAP, and we have the post-concussion protein in neurofilament light.

Concussion and inflammation

[07:47 Melanie] Okay. Let me ask a layman’s question.

[07:54 Eric] Shoot.

[07:56 Melanie] Where does this inflammation in post-concussion syndrome come from? Is it the brain? Is it somewhere else?

Where does the inflammation come from?

[08:04 Eric] That is a very good question, I must say. We don’t know today. We know that there is an interplay between the systemic, the blood, the body, and the brain. We know it exists in other pathologies, such as multiple sclerosis. The inflammatory cells come from the body and enter the brain.

Microglia, astrocytes and migrant inflammatory cells

In traumatic brain injury, it is probably very similar. There will be the microglia, which are the immune cells of the brain, and astrocytes, which are also immuno-competent cells in the brain that will activate and create an ongoing inflammation. However, if they activate, they will also recruit migrant inflammatory cells from the blood that will then migrate down the blood brain barrier and come into the injury.

Cytokines in the brain

I do believe that there is an interplay between the brain, the inflammatory cells and the body’s inflammatory cells. We published a paper on this a year ago. It concerned severe traumatic brain injury patients. Patients who had pneumonia in the intensive care unit, also had a device in their brain that measured cytokines, which are a measure of inflammation. 

Patients who suffered from pneumonia had different levels of certain cytokines in their brains. So there is definitely an interplay going on with regard to how the patient is doing, at least very early on. However, I think there is even an interplay in later stages as well.

[09:50 Melanie] This is super fascinating. I feel like this is the first time that I dug so deep with someone in the area of blood markers and inflammation markers. I hope that listeners are interested as well. 

Concussion awareness

I really want to thank you also on behalf of patients because I feel it is really important work that you are doing, even though it will take a long time for everything to translate all over the world.

[10:20 Eric] Oh yeah.

[10:21 Melanie] It is moving, and that is the most important part.

[10:24 Eric] It is. And thank you for creating awareness about this pathology and helping people. I think it is very important and your job needs to be acknowledged.

[10:36 Melanie] Thank you very much. I love doing it. That helps a lot.

Send us your questions

This concludes the three concussion stories episode with Eric Thelin. With all my heart, I hope that their contents may help you. Please know that you may always contact me to ask or tell Eric something and I will reply to your question or remark.

Share your thoughts with me?

Now, I would love to hear from you. What do you take away from this episode? Is there something that you can apply to your life right away? Head on over to and leave your comment now.

And if you want to hear and read more Concussion Stories, actionable steps and inspiration, be sure to subscribe to the Lifeyana email list while you’re there, so that you never miss out on new materials we constantly make for you.

If you want to support this podcast, head on over to Thank you for listening to this concussion stories episode by Lifeyana. May you be well and may you be happy.

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