A concussion is a type of brain injury. It is a short loss of normal brain function in response to a head injury. Concussions are a common type of sports injury. You can also suffer from one if you suffer a blow to the head or hit your head after a fall. After a concussion, you may have a headache or neck pain. You may also experience 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 professional if you notice any of your symptoms getting worse, or if you have more serious symptoms such as seizures or trouble walking or sleeping.
A nonspecific term used to describe transient alterations or loss of consciousness following closed head injuries. The duration of unconsciousness generally lasts a few seconds, but may persist for several hours. Concussions may be classified as mild, intermediate, and severe. Prolonged periods of unconsciousness (often defined as greater than 6 hours in duration) may be referred to as post-traumatic coma (coma, post-head injury). (from rowland, merritt's textbook of neurology, 9th ed, p418)
A violent jar or shock, or the condition which results from such an injury.