A mild brain injury is an instance in which a person has had a physiological disruption in brain function due to trauma that presents as a loss of consciousness (usually no more than five minutes), loss of memory of events immediately following the injury, or an altered state of mental status at the time of injury. A mild brain injury can occur by the head being struck, an object striking the head, or whiplash to the brain without direct external trauma to the head. Physical indications of a mild brain injury may include nausea, vomiting, dizziness, headache, blurred vision, sleep disturbances, lethargy, and becoming easily fatigued. Cognitive indications may include lack of concentration, changes in perception or memory and speech that are not emotionally caused.