Concussion, traumatic brain injury, and chronic traumatic encephalopathy: lessons from the battlefield, ball field, and lab bench

Abstract

Concussion is defined as a mild traumatic brain injury reflecting brain dysfunction. In the United States, more than 1.5 million people experience some form of traumatic brain injury (TBI) per year. Most people with mild TBI have no long-term symptoms. One in six will have lingering or long-term symptoms. These include headache, dizziness, sleep changes, mood and behaviour changes and slow thinking. Common causes include motor vehicles accidents, falls and sport injuries. One fifth of soldiers involved in modern warfare are exposed to some form of TBI. Many people don’t realize they have sustained a mild TBI. Microscopic damage can affect the anatomy and function of brain cells. Repeated mild TBI particularly in sport can lead to long lasting symptoms. Moderate to severe TBI include brain contusions and more serious cerebral bleeds. It is more symptomatic and requires longer recovery. Short and long term sequalae of traumatic brain injury in civilian and military population are discussed.