Explainer: What is a concussion?

22 June 2017

Dr Adrian Cohen from the University of Sydney explains what causes a concussion and how to best prevent them.

1. Causes of concussion

While it’s generally believed that concussions occur due to a direct impact to the head, anything that transmits force through to the brain such as a tackle in football can also cause concussion.

Concussion is thought of mainly in our high impact or contact sports. The highest incidence of concussion is seen in equestrian sports with roughly 30 concussions per 1,000 participants while it’s around 10 per 1,000 participants in football.

While concussions are definitely seen in people who are knocked unconscious, less than 10 per cent of concussions are from a knockout blow.

At the cellular level, the transmission of messages between cells is believed to be a major cause of concussion. It’s thought this is the result of the cells themselves not having enough energy due to a constriction of the blood supply preventing oxygen from getting to the cells.

2. Symptoms of concussion

A concussion can often be characterised by a range of symptoms including headaches, dizziness, sensitivity to light and the feeling of being in a fog. There are often auditory and hearing disturbances, visual disturbances and sometimes a person may not know where they are or what has happened to them.


Dr Cohen explains the different facets of concussion in a video, produced in association with the Sydney Morning Herald.

3. What do you do if you suspect a concussion?

The first step is to recognise a player could be concussed and remove them from the game. They should then be kept from the field and possibly future practice sessions until they are no longer displaying any symptoms.

4. Who is at risk?

We may think that only professional athletes are at high risk of concussion, but children and adolescents are actually at higher risk due to their brains still developing. As a result, their symptoms may be prolonged and more severe.

There is also a gender disparity with girls more affected than boys and women more so than men.

5. How can we prevent concussion?

We may wearing a hard helmet can protect the brain but that only protects against skull fractures and bleeding inside the skull, not against concussion. Similarly, soft headgear merely protects against superficial injuries such as cuts, abrasions and cauliflower ears.

We are however seeing a development in helmet technology where research is showing that the material of the headgear decreases the amount of impact going through the brain and therefore protects against concussion.

The University of Sydney is conducting research into this area in order to better diagnose, treat and prevent concussions.

Elliott Richardson

Assistant Media Advisor (Medicine, Dentistry, Nursing and Pharmacy)

Kobi Print

Media and PR Adviser (Medicine and Health)

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