What is concussion?

Concussion is a disturbance of brain functioning caused by direct or indirect force to the head. It is a mild form of traumatic brain injury (TBI) that results in the sudden onset of neurological symptoms that resolve spontaneously over a varying period of time.


Concussion symptoms

Many people believe loss of consciousness is the main symptom of concussion but concussion often occurs without this. Other concussion features may include:


  • headaches;
  • dizziness;
  • nausea and/or vomiting;
  • blurred vision;
  • sensitivity to light and noise.

Physical signs

  • unsteadiness, dazed look;
  • loss of balance and poor coordination;
  • slurred speech;
  • slowed reaction times.

Cognitive impairment (impairment to thinking or mental processes)

  • amnesia (memory loss);
  • difficulty concentrating, confusion;
  • feeling in a fog.

Behavioural and emotional changes

  • irritability, sadness, anxiety.

Sleep disturbances

  • sleeping more or less than usual;
  • insomnia.

Causes of concussion

Concussion is commonly caused by a head injury such as a blow to the head or face, including a fall where the head contacts a hard surface, as well as resulting from being shaken. Concussion is common in sport, particularly contact sports such as football.

How does concussion occur?

The brain is a firm 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, from a range of minutes to hours, or days to weeks. Occasionally the impact 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.

Concussion treatment

A person affected by concussion must have both physical and mental rest. A person who becomes concussed playing sport should leave the field immediately and be monitored closely. They should not return to the field of play on the day of the injury.

A person who suffers a mild concussion may not need emergency care, however it is strongly recommended that the person should be supervised until 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.

When to go to hospital

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.

A person who suffers a suspected concussion playing sport should have a medical assessment with a doctor within a day or 2 if they have had a head injury, even if they do not require emergency care, to check for complications and determine whether any investigations need to be performed.


Resting in the period after the injury while there are symptoms, is usually of benefit to the injured person. Most (80-90%) of concussions resolve in a short (7-10 day) period, although the timeframe for children may be longer.

Some symptoms of head injury may last for several weeks, such as headache, memory and concentration difficulties, and mood swings (‘post concussion’ syndrome), but the person will usually be back to normal within about a month. A gradual return to school and social activities should occur when the person is symptom free, before returning to sport.

It is dangerous for the brain to be injured again before it has recovered from the first injury, so it is important that a person is monitored if they have prolonged symptoms, and they must be cleared for a return to activity, before returning, in a gradual manner, to sport or vigorous exercise.

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