Answer:
A brain concussion
Explanation:
This is the effect when a person suffers a brain knock due to an accident or by playing contact sports like in this case.
Depending how hard was the hit, the brain can suffer different effects, this is due to the lost of the brain liquid that support it. The lost of memory is one of the effects, that can be due to the area that suffer the hit. Depending the are of the brain that was damage.
Hope this info is helpful.
