The neurophysiology of brain injury.
OBJECTIVE
This article reviews the mechanisms and pathophysiology of traumatic brain injury (TBI).


METHODS
Research on the pathophysiology of diffuse and focal TBI is reviewed with an emphasis on damage that occurs at the cellular level. The mechanisms of injury are discussed in detail including the factors and time course associated with mild to severe diffuse injury as well as the pathophysiology of focal injuries. Examples of electrophysiologic procedures consistent with recent theory and research evidence are presented.


RESULTS
Acceleration/deceleration (A/D) forces rarely cause shearing of nervous tissue, but instead, initiate a pathophysiologic process with a well defined temporal progression. The injury foci are considered to be diffuse trauma to white matter with damage occurring at the superficial layers of the brain, and extending inward as A/D forces increase. Focal injuries result in primary injuries to neurons and the surrounding cerebrovasculature, with secondary damage occurring due to ischemia and a cytotoxic cascade. A subset of electrophysiologic procedures consistent with current TBI research is briefly reviewed.


CONCLUSIONS
The pathophysiology of TBI occurs over time, in a pattern consistent with the physics of injury. The development of electrophysiologic procedures designed to detect specific patterns of change related to TBI may be of most use to the neurophysiologist.


CONCLUSIONS
This article provides an up-to-date review of the mechanisms and pathophysiology of TBI and attempts to address misconceptions in the existing literature.
Gaetz
Michael
M
Aaken Laboratories, 216 F Street, Suite 76, Davis, CA 95616, USA. mbgaetz@telus.net
D000818:Animals; D001369:Axons / Q000473:pathology / Q000502:physiology; D001930:Brain Injuries / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D004569:Electroencephalography; D004594:Electrophysiology; D006801:Humans; D009474:Neurons / Q000473:pathology