It’s Friday night, your team is playing and the scores are dead close. A player intercepts the ball, and bam! A player tackles his opponent to the ground. Trainers and doctors nervously gather as the commentators wait for confirmation: a concussion, mild traumatic brain injury, head knock, blow, tap, punch, smack… there are many terms for it.
How to prevent and treat such injuries is the subject of a Senate investigationwith public hearings this week.
But what exactly are these injuries? What happens in the brain?
Read more: Concussion risks aren’t limited to the AFL. We urgently need action to ensure that our children are also safe
What is a Concussion?
Concussion is a form of traumatic brain injury (TBI). Concussions usually fall on the milder end of the spectrum and are therefore often referred to as mild TBI.
Concussions are most common when the head directly collides with something. But it can also happen without head impact, when a blow to the body causes the head to move quickly.
The brain is a soft organ in a hard shell, floating in a thin layer cerebrospinal fluid. The brain can be damaged away from the site of impact for this reason, as it bounces into the skull with force.
Concussions that occur during sports can be complex because the head often rotates when the person falls. This “rotary gearcan cause more damage to the brain. This is especially the case for cells in the long stretches of white matter responsible for relaying signals around the brain.
In addition to causing initial damage to brain cells at the time of injury, a concussion causes a cascade of brain damage chemical and biological changes. These occur within minutes and can last for days or even weeks after a concussion.
Cell membranes become more permeable (more leaky), causing the brain chemicals inside and outside the cells to become unbalanced. Cellular functions go into overdrive to try to restore balance, using more fuel in the form of glucose. At the same time, blood flow to the brain is often reduced, resulting in a mismatch between energy supply and demand.
The structural structure of cells in the white matter can begin to weaken or break, preventing or reducing the ability of cells to communicate.
Sensing danger, cells of the immune system begin to migrate to the brain in an attempt to stop the damage, sending out chemical signals to recruit other inflammatory cells to the injury sites.
These initial reactions to a concussion usually go away over time, but the recovery period can be different for each person and may persist even after symptoms have resolved.
Read more: Repeated head injuries can cause degenerative brain disease in people who play sports, including juniors and amateurs
What are the symptoms?
Concussion symptoms may differ depending on the person and circumstances of the injury.
Some people have more obvious symptoms such as loss of consciousness, vomiting and confusion; others may have headaches, problems with their vision or thinking and concentration. Some people may have one symptom, while others may have many. Some people’s symptoms can be severe and others have only mild symptoms.
So diagnosing and managing a concussion can be difficult. Most people with a concussion find that their symptoms clear up within a few days or weeks. But round 20% of the people will have persistent symptoms for more than three months after their concussion.
Persistent symptoms can make it harder to perform at work or school, socialize with friends, and maintain relationships. Scientists don’t know why recovery is different for different people. We have no way to to predict who recovers from a concussion and who does not.
Read more: Having a brain injury does not mean you will get dementia
What about repeated blows to the head?
People who play contact sports are more likely to experience multiple concussions during a playing career. Higher concussion numbers tend to mean worse symptoms and slower recovery for subsequent concussions.
This indicates that the brain is not used to concussions and that any concussions are likely to cause additional damage.
Emerging evidence suggests that repeated concussions can lead to constant changes in the structure and function of human brain cells.
Inflammation can persist both inside and outside the brain. Inflammation is also possible cause or contribute to someone who develops symptoms, and long-term functional and structural changes in the brain.
Long-term symptoms and long-term brain changes may be worse in the long run for people who experience their concussions as Adolescents compared to people who had concussions as older adults.
Scientists are also starting to find differences in symptoms And changes in the brain in men and women. These may be related to renewed sex differences in the scaffold proteins of male and female brains, making female brains more susceptible.
Read more: Sports concussions affect men and women differently. Female athletes need more attention in brain research
We’ve known this for a long time
The long-term brain and behavioral changes associated with repeated sports concussions have been reported since at least the 1920. At the time, it was seen in boxers and was called dementia pugilistica, or punch drunk syndrome.
We now call this condition chronic traumatic encephalopathy (CTE). People who are found to have CTE do not always experience severe symptoms. Instead, symptoms tend to show up or worsen later in life, even decades after an injury or at the end of a playing career.
People have too varied symptoms which are sometimes difficult to measure, such as confusion, impaired judgment and aggression. This has made diagnosis difficult while people are still alive. We can only confirm CTE after someone has died by detecting altered structural proteins of the brain specific brain regions.
There is still much to learn about CTE, including the exact processes that cause it, and why some people will develop it and others will not.
Read more: Here’s what we know about CTE, the brain disorder that struck Danny Frawley
Concussions are common
A concussion is almost a common injury 30% of us will experience in our lifetime.
While we still have a lot to learn, current advice for people with concussions is to seek medical advice to help with initial treatment of symptoms and make decisions about returning to sports.
For coaches, trainers, parents, and others interested in learning more about coping with concussions, resources are available at Connectivity Traumatic Brain Injury Australia. These include his free concussion short courses to help you understand, recognize and treat a concussion when it occurs.