TABLE 1.

Clinical Indicators of Mild Traumatic Brain Injury^a

Indicator	Duration and Parameters	Comment
Credible event	Need force acting on brain	Must be of sufficient severity to plausibly result in at least an altered level of consciousness. Typical manifestations include incomplete memory for event, confusion, disorientation, and reduced arousal.
Loss of consciousness	0–30 minutes	If unwitnessed, must distinguish from posttraumatic amnesia. Difficult to assess when intubated, sedated, or intoxicated.
Disturbed consciousness	Momentary to several hours	Can fluctuate, wax, and wane. Individual may appear stunned, dazed, confused, or disoriented.
Retrograde amnesia	0 to several hours	Often absent or very brief.
Anterograde amnesia (posttraumatic amnesia)	None to 24 hours	Individual may report patchy recollections. Ends with return of continuous, sequential memory. Difficult to assess when intubated, sedated, or intoxicated.
Neurological signs	Typically transient	May have visual disturbance, language difficulty, or impact seizure. Often no signs evident other than disturbance of consciousness and cognition.
Glasgow Coma Scale	13–15, 30 minutes after the event	Difficult to assess when intubated, sedated, or intoxicated.
Clinical symptoms	Variable	Individual may report headache, nausea, dizziness, sensitivity to light or noise, and cognitive problems.

^aAdapted from McAllister (2).