What is a "concussion"?

What is a "concussion"?

Les Weiner (Former Chair of the Department of Neurology, University of Southern California) gives expert video advice on: How long can a person be in a coma?; What is "persistent vegetative state"? and more...

A brain concussion is when you have a head injury, usually closed, in which you have jolted the neurons, essentially. Very often there is micro hemorrhages around areas of the brain where it's happened. A concussion, clinically, is that you momentarily lost awareness. Now, seeing stars from a concussion. So you don't have to be unconscious. But you should have some alteration of mental state. Most commonplace is when a prize fighter gets knocked down. He gets hemorrhages in his brain.