Concussion is the sudden but short-lived loss of mental function that occurs after a blow or other injury to the head. Concussion is the most common but least serious type of brain injury.
The medical term for concussion is minor traumatic brain injury.
Symptoms of concussion include:
Most people with mild concussion do not require any treatment as they normally get better by themselves. However, if there are signs of a more serious injury, they may need emergency treatment.
Phone 999 for an ambulance immediately if the person:
Read about the symptoms of concussion for more information on when to seek emergency medical care or visit an accident and emergency (A&E) department.
There are a number of things you can do at home to relieve concussion symptoms, these include:
Read more about how concussion is treated including information on self care tips and when you can return to playing sport.
After experiencing concussion, a period of careful monitoring is needed. This can be for several days or weeks, depending on how serious the concussion was.
This is because the symptoms of concussion could also be symptoms of a more serious condition, such as:
Both of these conditions are medical emergencies. Go to your nearest accident and emergency (A&E) department as soon as possible if you or someone in your care shows any of the following signs:
While the medical term 'minor traumatic brain injury' can sound serious, the actual extent of damage to the brain is usually minimal and does not usually cause long-term problems or complications.
There is evidence that repeated episodes of concussion could cause long-term problems with mental abilities and trigger dementia. This type of dementia is known as chronic traumatic encephalopathy (CTE).
However, this seems to only be a significant risk for professional athletes who experience repeated episodes of severe concussion, such as boxers (CTE is sometime nicknamed 'boxer’s brain'.)
Post-concussion syndrome (PCS) is a poorly understood condition where symptoms of concussion can last for weeks or months afterwards.
Read more information about PCS as a complication of concussion.
Most cases of concussion occur in children and teenagers aged five to 14, with the two most common causes being sporting and cycling accidents.
Falls and motor vehicle accidents are a more common cause of concussion in older adults.
People who regularly play competitive team sports such as football and rugby have a higher risk of concussion.
Symptoms of concussion can be mild to severe and in some cases emergency treatment may be needed.
The most common symptoms of concussion are:
Difficulties with memory can take one of two forms, or possibly both forms:
Both retrograde and anterograde amnesia usually improve within a few hours.
Less common signs and symptoms of concussion include:
The following signs and symptoms suggest it is likely that the head injury has caused serious damage and you should phone 999 for an ambulance immediately:
As a precaution it is recommended that you visit your nearest accident and emergency (A&E) department if you or someone in your care has a head injury resulting in concussion and then develops any of the following signs and symptoms:
There are a number of factors that make you more vulnerable to the effects of a head injury:
It is also recommended that anyone who is drunk or high on recreational drugs is taken to A&E if they have a head injury resulting in concussion. It is often easy for others around them to miss signs and symptoms of a more severe injury.
Concussion occurs when a blow or impact to the head causes a sudden disruption to part of the brain known as the reticular activating system (RAS).
The RAS is located in the middle of your brain and helps regulate your sense of awareness and consciousness. It also acts as a filter that allows you to ignore unimportant information by focusing on details you need.
For example, your RAS helps you to:
During a head injury severe enough to cause concussion, your brain is moved out of its normal position for a short time. This rotation disrupts the electrical activities of brain cells that make up the RAS, which in turn triggers symptoms associated with concussion, such as:
The three main causes of concussion are:
Activities known to have a higher-than-average risk of concussion include:
Most doctors would argue that the physical benefits of regularly taking part in these sports outweigh potential risks associated with concussion. But this is only if you (or your child) wear appropriate equipment, such as a helmet, and are supervised by a suitably trained referee, umpire or trainer with experience in diagnosing and treating concussion.
The exception to this is boxing, as most doctors, especially those who treat head injuries, have stated that the risks of serious brain injury associated with boxing are unacceptably high and the sport should be made illegal.
Due to the nature of concussion, most diagnoses are either made in the accident and emergency (A&E) department, by a paramedic at the scene of an accident, or by a trained official at a sporting event.
The person making the diagnosis will make a careful physical examination to check if there are any noticeable signs and symptoms of a more serious brain injury, such as bleeding from the ears, while making sure breathing is unaffected.
If you are conscious, you will be questioned so your state of mind (particularly your memory) can be assessed.
Possible questions include:
You may be asked to try what is known as the 'finger-nose-finger' test. The person running the test will hold one of their fingers in front of you. You are asked to touch their finger and then touch the tip of your nose as quickly as possible.
This test is a good way of assessing what effect the concussion has had on your balance and co-ordination.
If you are unconscious, then as a precaution it is recommended to assume you have a serious neck or spinal injury until proved otherwise. Therefore it is recommended you are not moved until a specialist brace can be fitted around your neck and spine to protect it.
Similarly, if you see a person who is unconscious, make no attempt to move them unless they are in immediate physical danger. Instead, dial 999 for an ambulance and wait with them until paramedics arrive (dial 112 from elsewhere in Europe).
In some circumstances, further testing may be recommended if there are any signs or symptoms that suggest a more serious injury to your brain. The most widely used test for suspected brain injury is a computerised tomography (CT) scan.
However, if it is thought you may have damaged the bones in your neck an X-ray may be used to assess the damage quickly. CT scans are avoided on children under 10 where possible, but may be necessary in some cases (see below).
A CT scan takes a series of X-rays of the inside of your skull and puts them together using a computer. The image that is created forms a cross-section of the inside of your skull and brain.
A CT scan is usually recommended in adults who:
A CT scan is also recommended for adults who have experienced some loss of consciousness or memory since the injury and who:
A CT scan is usually recommended in children who:
A CT scan is also usually recommended for babies less than a year old who have a bruise, swelling or cut on the head bigger than 5cm (2 inches).
There are a number of self-care techniques you can use to relieve mild concussion symptoms. If more serious symptoms start to develop, seek immediate medical treatment.
Some self care techniques for mild symptoms of concussion are outlined below.
Sometimes the symptoms of a more serious brain injury do not occur for several hours or possibly days after the initial injury has taken place.
So it is important you remain alert for signs and symptoms that could suggest a more serious injury has occurred.
If you or someone in your care has any of the signs or symptoms listed below, go to your nearest accident and emergency (A&E) department as soon as possible:
Despite being one of the most common sport-related injuries, there is no internationally agreed consensus on advice about when it is safe to return to playing a contact sport, such as rugby, after a concussion.
Most national sporting federations and organisations recommend a 'step-wise' approach where you wait until you are free of symptoms and then resume a low level of physical activity. If the symptoms do not return, you can step up to a more intense level of activity.
If symptoms are still under control, continue to step up through the levels, eventually returning to playing the sport.
A 2008 conference of experts in sports medicine recommended these steps:
Each step should take 24 hours, so if you are symptom-free you should be able to return to play within a week.
If you do experience a return of symptoms, rest for 24 hours, drop down to a previous step, and then attempt to move up again.
There are a number of commonsense precautions you can take to reduce your risk of concussion.
These precautions include:
It is also easy to underestimate how many cases of concussion occur due to a fall or slip at home or in the garden, especially in older people. Following some or all of the suggestions below will help to keep your home and garden as safe as possible.
For more information, go to the website for the Royal Society for the Prevention of Accidents.
Post-concussion syndrome (PCS) is the term used to describe a collection of symptoms that can last for several weeks or months after the concussion.
PCS is not well understood and there is still controversy regarding the diagnosis. In particular, research has found rates of reported cases of PCS are much higher in countries where there is the possibility of obtaining financial compensation after an accident.
Experts cannot agree how many people with concussion will develop this complication. Estimates have ranged widely from 30% to up to 90%.
The exact cause of PCS is not known.
One theory is that PCS is the result of a chemical imbalance in the brain triggered by the initial injury that caused the concussion.
Another theory suggests that PCS may in fact be an emotional and psychological response to the initial injury; possibly a milder form of post-traumatic stress disorder (PTSD). This is mainly because there are several shared symptoms.
The symptoms of PCS fall into three main categories:
Physical symptoms of PCS include:
Psychological symptoms of PCS include:
Cognitive symptoms of PCS include:
There is no specific treatment for the symptoms of PCS, though many medications used to treat migraines have also proved effective in treating the headaches.
Most cases of PCS will resolve within three to six months and only one in 10 people will still have symptoms after a year.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.