Concussion is a mild form of traumatic brain injury (TBI) that affects the functioning of your brain. The effects are usually temporary. They can include loss of consciousness or awareness, headache, and problems with concentration, memory, judgement, balance and coordination.
Concussion is commonly caused by a head injury such as a blow to the head or face, but it can also result from being shaken. Concussion is common in sport, particularly contact sports such as football.
Your brain is a soft jelly-like organ that floats inside your skull in a clear liquid called the cerebrospinal fluid, which cushions it from bumps. However, a blow to your head can overwhelm this cushion and bounce your brain against the skull, leading to brain injury. This can also happen with a sudden acceleration or deceleration, as in a car accident or when your head and upper body are shaken.
This injury can affect brain function, usually for only a short time. But it may also lead to bleeding into the brain (intracerebral haemorrhage) or around the brain (subarachnoid or subdural haemorrhage). This bleeding can be fatal if not recognised and treated quickly.
Many people believe loss of consciousness is the main symptom of concussion but concussion often occurs without this. Other concussion symptoms may include headaches, amnesia (memory loss), confusion, nausea, dizziness or 'seeing stars', ringing in the ears, and slurred speech.
Physical and mental rest is the best way to recover from concussion. A person who becomes concussed playing sport should leave the field immediately and be monitored closely.
If a person with concussion has repeated vomiting, an increasingly painful headache or a seizure or fit, is unconscious, or their symptoms are getting worse, they should be taken to hospital immediately.
Even if you think you do not need emergency care, you should be supervised while concussion symptoms subside. Experts recommend you rest, and not drive or play sports for at least 24 hours after the injury, and not drink alcohol or take drugs for 1-2 days or while you still have symptoms. Paracetamol may be taken for headaches.
Experts also recommend that you see a doctor within a day or 2 if you have had a head injury, even if you do not require emergency care, to check for complications.
Some symptoms of head injury may last for several weeks, such as headache, memory and concentration difficulties, and mood swings ('post concussion' syndrome), but you will usually be back to normal within about a month. As it is dangerous for the brain to be injured again before it has recovered from the first injury, your doctor may suggest a graded return to sports or strenuous activity.
Last Reviewed: 19 August 2011