A concussion is a traumatic injury to the brain caused by a sharp blow or sudden stop following an event. Ordinarily, the brain floats inside the skull in a protective pool of spinal fluid, but certain actions like a hard tackle or a car accident can literally slam the entire brain against the skull's interior walls. The resulting damage can be mild to severe, depending on the intensity of the blow and the brain's ability to realign itself afterwards. Many people recover from a mild concussion within hours, but others may exhibit symptoms for weeks after the event.
A typical concussion scenario may play out during a sporting event such as football. A defensive player may make a hard tackle on the quarterback after a pass, and the quarterback will fall down to the ground. Meanwhile, the quarterback's brain tries to remain focused in one direction while his body is violently thrown in another. When the quarterback strikes the ground, his brain is jolted from the momentum.
For a few minutes, the stricken player may experience dizziness, loss of consciousness, weakness in one side of his body or an uneven dilation of pupils. He may feel nauseated or break into convulsions. This is a classic example of a concussion.
The effects of a mild to moderate concussion usually resolve themselves after a few hours of rest. There may still be some problems with vision or orientation, but the brain should eventually recover from the injury over time. The most severe form, however, can be marked by an extended period of unconsciousness, mood swings, depression and bleeding inside the brain. This level of injury can usually be diagnosed through the use of MRI or CT scans soon after the incident. Not all bleeding or bruising of the brain is considered dangerous or life-threatening, but a concussion can aggravate existing conditions not previously diagnosed.
Some people who suffer a concussion may experience a condition known as postconcussion syndrome. Even after a few weeks have past, those suffering from this syndrome may still experience weakness on one side of the body, extreme mood swings and/or problems with basic cognitive functions, such as memory or orientation. This is why many physicians recommend that friends and family observe anyone who has suffered this injury in the past few months. Any significant changes in personality or cognitive ability should be noted for future reference.
A concussion is considered to be one of the mildest forms of brain injury, so most sufferers should recover fully and be able to resume their normal lifestyles. However, there are studies which suggest that a new injury can aggravate an older one and cause even more complications. Professional athletes such as football players, martial artists and boxers who regularly take sharp blows to their heads should always use proper headgear or consider retiring before permanent brain damage can occur.