What are the warning signs for a possible concussion?

Concussion: A concussion occurs when a certain level of energy from an impact is transmitted directly to the brain. This results in a temporary stoppage of higher brain function resulting in loss of consciousness. The longer the time of unconsciousness or residual drowsiness, incoherance, dizziness, nausea, etc, the greater the potential for an underlying brain injury.

Concussion: Warning signs can include mental status changes, memory loss, headache, mood changes, sleep issues, difficulty concentrating, speech and slurring changes, dizziness, loss of balance.

Concussion warnings: symptomology is key.. What symptoms is one having? How did they occur? what kind of physical exam is presented.