Concussion, or mild traumatic brain injury, happens when the head strikes something or is hit by a moving object. Inside the head, the brain moves quickly and then stops quickly against the inner wall of the skull. Typically a blow to the head, face or neck causes concussion. Less likely, it can be from a blow to the body with the force passed to the head. While concussions are often mild, they can have long-term effects that can be permanent and severe.

Concussion typically causes a short loss of brain function, which resolves naturally. Usually, there is no obvious structural problem in the brain or head. Results from an imaging test like a CT scan or an X-ray are often normal. A concussion can occur without any loss of consciousness. It can happen even with minor force or trauma. This is particularly true for people who have had one or more previous head injuries or concussions. More severe injuries can also happen along with the typical concussion symptoms and long-term effects.

How common is it?

Statistics suggest that concussion is more common now than in any other time in history. There is better understanding and awareness now, and better diagnosis. This increases the number of concussions reported, as previously people who experienced them were not properly diagnosed or were scared to admit their symptoms.

Changes in athletes themselves may be related. Athletes, whether professionals or young amateurs, are just plain bigger, faster and stronger. They hit objects and each other with more force than ever before.

In the U.S., it is estimated that 1.74 million people have a traumatic brain injury every year. About 75 to 95 per cent of these injuries are mild. The annual number of concussions related to sports is thought to be 1.6 to 3.8 million. The chance of an athlete in a contact sport having a concussion may be as high as 20 per cent, per season, per athlete.

As it is possible that most concussions are not reported, the number of actual injuries may be much higher. This may range from 100 to 600 injuries for every 100,000 people. Males are affected more often than females. Half of patients with a mild brain injury are between the ages of 15 and 34.

How does concussion happen?

The most common causes of concussion and traumatic brain injury are motor vehicle collisions, falls, injuries at work, and sporting events. For young people, motor vehicle collisions and recreational activities are more likely to be the cause. The most common contact sports associated with concussion are hockey, football, soccer, boxing and rugby. However, it can happen in any sport with contact or falls.

What are the symptoms of concussion?

The most common features of concussion are confusion and amnesia (memory loss or memory problems). Loss of consciousness can occur, but not always. These symptoms may appear right away or take several minutes to develop. Amnesia often involves loss of memory of the event itself, but may also include events just before or after the injury. Specific details about any loss of consciousness, confusion and amnesia are needed to decide the seriousness of the injury.

Symptoms may develop in minutes or hours, and include:

confusion
amnesia
headache
dizziness or vertigo (sensation of whirling and loss of balance)
a lack of awareness of surroundings
nausea and vomiting.

Later symptoms may include:

mood changes
difficulty with concentration or other higher thought processes
sensitivity to light and noise
sleep disturbance
fatigue.

Seizures are not common with a mild brain injury. They can occur in up to five per cent of more severe brain injuries.

How do we assess and diagnose concussion?

Anyone who has had a concussion or mild traumatic brain injury should see a doctor. The doctor will assess how the nervous system is functioning, and test mental function. Areas other than the head, including the neck and chest, will also be checked for injury. Plain X-rays of the skull are required only if there are concerns about fracture. CT scanning and MRI are generally not required for most concussions. If findings are worrisome or symptoms persist, then imaging may be of benefit.

Any prolonged loss of consciousness, or lasting change in awareness, nervous system symptoms, or difficulty staying conscious requires immediate assessment. In these situations, a CT scan or MRI likely is needed. However, CT scanning in particular does have risks related to radiation exposure. To limit this risk, the scan should only be done for certain symptoms and reasons.

Though an injury may seem minor or have mild symptoms to start, this does not always rule out more severe injury. Rarely, a mild brain injury or concussion can be associated with late changes including bleeding within the brain or a previously undetected fracture. A doctor should assess any change in symptoms.

Awareness of the frequency of concussions occurring among young athletes has grown. Along with this, tools have been developed to help evaluate injured athletes at the site of play. Sports medicine experts recommend a checklist and questionnaire exam (Sport Concussion Assessment Tool image/link at right) which determines the risk of concussion. This sideline test, known as the SCAT test, can be used for athletes as young as age 10. It assesses possible concussion and provides a timeline for return to activity.

When is it safe to return to activity?

In most cases, the outlook for full recovery from concussion is good. However, the risk of further concussion and long-term injury exists. It goes up when an athlete, who still has symptoms from an earlier concussion, returns to play too soon and is injured again. A second impact can be a significant risk for severe complications.

Athletes should not play again until they have had enough physical and mental rest to allow all symptoms to disappear, and they have been given medical clearance to return.

Are there long-term effects?

Returning to an activity too early can increase the risk of further concussions and chronic symptoms. Chronic symptoms include:

headache
dizziness
psychiatric symptoms
cognitive (thinking) problems
fatigue.

Frequent concussions over time may heighten the risk of long-term brain injury, including dementia. This is poorly understood, but is being studied more and more. We are starting to appreciate that untreated multiple head injuries may lead to depression, dementia, and premature death.

If concussion symptoms persist, more specific assessment and rehabilitation specific to concussion may be required. A doctor is needed for diagnosis, treatment and referral.

How do we prevent concussion?

The best approach to concussion is to prevent it in the first place.

Athletes, coaches, parents and training staff must be informed about concussions.
Everyone involved in an athlete’s care and well-being must follow the guidelines. The guidelines always apply, even if it means the athlete cannot participate. Symptoms must be strictly assessed, and return to play recommendations followed.
The culture of sports is an issue. A shift in thinking and attitude, and agreement from all levels, are needed. Parents, coaching staff and athletes must all be involved. For instance, someone who does not participate because of symptoms should not be made to feel weak, or that they are letting down the team.
To limit the number of head injuries in a particular sport, rules and education specific to that sport should be developed and followed. In hockey, this would include education about hits from behind and to the head.
Tougher regulation and penalties may change player behavior. It may be necessary to remove high-risk offenders.
Appropriate sport-specific helmets, equipment and training should be encouraged.
Safety equipment use in activities where it might not normally be worn should also be encouraged.

In this era of inactivity, video games, and obesity, it is in our children’s best interest to have an active and healthy lifestyle. It is our responsibility as parents and coaches to provide them with the opportunity to do so, in the safest manner possible. Education and training are available. When it comes to concussion, ‘playing through the pain’ is just plain wrong. Listening to one’s body does not make one weak or a quitter. We need to teach this to our children, our coaches and ourselves.

Keep Your Head in the Game Concussion in sport

Lately, television sports and newspapers have featured stories about concussions and their effects on famous athletes. However, this type of brain injury is not confined to professionals. Young amateurs and recreational athletes are at even higher risk.

What is a concussion?