Which of the following are signs of a concussion?

The signs of a concussion primarily involve neurological symptoms resulting from a traumatic brain injury. Headache, confusion, dizziness, nausea, and changes in mood are classic indicators of a concussion, as these symptoms arise from the brain’s response to injury. They reflect both cognitive dysfunction and physical manifestations that may occur after the head experiences a forceful impact or jolt.

In contrast, while blurred vision and slurred speech can be associated with more severe brain injuries or other conditions, they do not encompass the general signs of a concussion as closely as the first set of symptoms. Also, while symptoms like ringing in the ears or fatigue can occur, they are less specific to concussions compared to the definitive signs listed in the correct answer. Lastly, signs such as a stiff neck, light sensitivity, and excessive thirst are more indicative of other medical conditions or complications and are not typical signs of a concussion.