A head scan, such as from an MRI, can show doctors where fluid is building up in the brain by using magnetism and a computer to create images of the structures inside the head. Doctors can also use an electroencephalogram (EEG) to measure the electrical activity of the brain.
If he survives this initial stage of his injury but remains in a coma, doctors will assess Bertolotti's brain injury by the responsiveness of different parts of his body. His ability to respond will give doctors an idea of his chances to recover.
Officials were trying to prevent further altercations between these players by ejecting Ferrigno, but they fought on their own, presumably on a surface much harder than a soccer field. Bertolotti may have been unconscious after being punched, so he would not have been able to protect his head as he fell.
Bertolotti still faces hurdles to survive. Doctors have to watch his circulation and keep the swelling down inside his head, while they are also mindful of possible complications like infection and blood clots. Then, it will take physical therapy and rehab to try to restore any function he has lost.
The next question is whether Bertolotti will regain consciousness. People can spend years in a coma, called a "persistent vegetative state." There are many levels of this state of unconsciousness, and the patient's state of awareness and ability to respond to people around him varies greatly. If he does awaken, his therapists can give him progressive treatments that can, depending on the extent of the brain injury he suffered, potentially rehabilitate him.