A concussion is a type of brain injury. It involves a short loss of normal brain function. It happens when a hit to the head or body causes your head and brain to move rapidly back and forth. This sudden movement can cause the brain to bounce around or twist in the skull, creating chemical changes in your brain. Sometimes it can also stretch and damage your brain cells.

Sometimes people call a concussion a "mild" brain injury. It is important to understand that while concussions may not be life-threatening, they can still be serious.

Concussions are a common type of sports injury. Other causes of concussions include blows to the head, bumping your head when you fall, being violently shaken, and car accidents.

Symptoms of a concussion may not start right away; they may start days or weeks after the injury. Symptoms may include a headache or neck pain. You may also have nausea, ringing in your ears, dizziness, or tiredness. You may feel dazed or not your normal self for several days or weeks after the injury. Consult your health care professional if any of your symptoms get worse, or if you have more serious symptoms such as:

• Convulsions or seizures
• Drowsiness or inability to wake up
• A headache that gets worse and does not go away
• Weakness, numbness, or decreased coordination
• Repeated vomiting or nausea
• Confusion
• Slurred speech
• Loss of consciousness

To diagnose a concussion, your health care provider will do a physical exam and will ask about your injury. You will most likely have a neurological exam, which checks your vision, balance, coordination, and reflexes. Your health care provider may also evaluate your memory and thinking. In some cases, you may also have a scan of the brain, such as a CT scan or an MRI. A scan can check for bleeding or inflammation in the brain, as well as a skull fracture (break in the skull).

Most people recover fully after a concussion, but it can take some time. Rest is very important after a concussion because it helps the brain to heal. In the very beginning, you may need to limit physical activities or activities that involve a lot of concentration, such as studying, working on the computer, or playing video games. Doing these may cause concussion symptoms (such as headache or tiredness) to come back or get worse. Then when your health care provider says that it is ok, you can start to return to your normal activities slowly.

Centers for Disease Control and Prevention