Traumatic brain injury refers to an injury to the mind caused by a foreign object that is visible to the naked eye and can generally cause serious consequences. Traumatic brain injury often causes permanent functional impairment of varying degrees. This depends on whether the damage is in a specific area of brain tissue (focal) or is widespread (diffuse). Different areas of brain damage can cause different symptoms, with focal symptoms including motor, sensory, speech, visual, and auditory abnormalities. Diffuse brain damage, on the other hand, often affects memory, sleep or leads to confusion and coma.