Common symptoms of concussion include: headache, dizziness, fatigue, problems with vision, confusion and loss of consciousness. A person with a mild concussion may have nothing more than a headache or brief confusion. In more severe cases, symptoms tend to last longer, and may include loss of consciousness. Other associated symptoms are: worsening headache, inability to wake, dilation of the eyes, vomiting, nausea, loss of coordination and weakness of extremities. 