How can you tell if you have a concussion?

Three ways: 1) you cannot account for a period of time following the event-even if your friends or other observers say you acted awake 2) you have difficulty concentrating, easily distracted, bit irritable, sleeping is off, mild headache 3) if you hop on one foot, trying to stay on a floor target, you find you cannot stay on the target for ten hops.

Depends: The effects of concussions can vary and be unpredictable. It depends on the severity of the injury. The symptoms can include headache, dizziness, vision change (blurred vision/ double vision), nausea/vomiting. If your symptoms or headache are severe, or if you have a loss of consciousness, you should get evaluated immediately.