Table III. Classification of traumatic brain injury (TBI) severity used in the Department of Veterans Affairs and Department of Defense Clinical Practice Guideline: Management of Concussion/mild Traumatic Brain injury (April, 2009), modified to include complicated mild TBI. Use of this table to designate TBI severity requires consideration of as many variables as are available, and consideration of the differential diagnosis for eventrelated disturbances of consciousness and/or neuroimaging findings. LOC, loss of consciousness; PTA, post-traumatic amnesia (densely impaired new learning); AOC, alteration of consciousness (eg, confusion, disorientation, slowed thinking); GCS, Glasgow Coma Scale; CT, computed tomography of the brain; MRI, magnetic resonance imaging of the brain.

		Modified VA/DoD TBI Severity Classification System
	LOC (hours)	PTA (days)	AOC (days)	GCS score (best in first 24 hours)	CT or MRI
Mild TBI	≤ 0.5	≤ 1	≤ 1	13-15	Normal
Complicated mild TBI	≤ 0.5	≤ 1	≤ 1	13-15	Abnormal
Moderate TBI	> 0.5 to < 24	> 1 to < 7	> 1	9-12	Normal or abnormal
Severe TBI	≥ 24	≥ 7	> 1	3-8	Normal or abnormal