A concussion is a type of brain injury. It's the most minor form. Technically, a concussion is a short loss of normal brain function in response to a head injury. But people often use it to describe any minor injury to the head or brain.

Concussions are a common type of sports injury. You can also have one if you suffer a blow to the head or hit your head after a fall.

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

• Seizures
• Trouble walking or sleeping
• Weakness, numbness, or decreased coordination
• Repeated vomiting or nausea
• Confusion
• Slurred speech

Doctors use a neurologic exam and imaging tests to diagnose a concussion. 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.

Centers for Disease Control and Prevention