(from Latin, concussus, derived from con: together, quatere: to shake) Concussion is a term indicating disturbance or shaking. It has various meanings depending on the context in which it is used, but in neurological terms it refers to a disturbance in brain function, typically following a vigorous blow to the head, which may or may not be associated with a period of unconsciousness. It is associated with two conditions: (1) POST-TRAUMATIC AMNESIA, a loss of memory following trauma, the degree of impairment providing a rough-and-ready index of the degree of brain injury, and (2) POST-CONCUSSION SYNDROME. This is a condition typically associated with the later effects of CLOSED HEAD INJURY and can involve a variety of disturbances.
Early signs include such generalized effects as headache, nausea, somnolence and disturbances in the visual system (such as blurred vision). Later signs include continued headache, anxiety, depression, insomnia, fatigue, memory impairments and disorders in vision and auditory perception. These can persist for several weeks or, in some cases, over a year. There is a belief that while the early symptoms might be related to disturbances in physical processes the later disturbances might be more psychological in origin (as is the case with post-traumatic stress disorder). Repeated concussions can produce more lasting impairments, based on cumulative physical damage to the brain—the so-called PUNCH DRUNK SYNDROME.
