Symptoms range from mild to severe and may appear right away or days or weeks after the injury. Physical symptoms include headache, unequal pupil size, dizziness, nausea and vomiting, fatigue, and sensitivity to noise or light. Symptoms can also affect mood, causing feelings of anxiety, sadness or irritability. Cognitive symptoms include a feeling of mental fog, difficulty concentrating, slowed response and difficulty remembering recent events or information. Concussions can also affect sleep, causing people to sleep either more or less than usual, feel drowsy, or have trouble falling asleep.
Behavior, mental ability and physical skills are all linked to specific areas of the brain. Each concussion is unique, making each individual demonstrate different combinations of signs and symptoms depending on which area of the brain was most affected.