Outcome prediction after severe closed head injury in adults.

Disability after severe closed head injury (CHI) differs from that of penetrating trauma or other causes of more focal cerebral damage, but its symptoms can be understood in terms of the pathophysiology and the usual pathology of CHI. Outcome can be quantified by means of specific, narrowly-defined measures, which may fail to reflect other serious sequelae, or by means of functional rating scales, which bear little logical relation to CHI pathophysiology and lump together patients with diverse deficits. The choice of appropriate intake measures of CHI severity in turn depends on which aspects of outcome are to be determined. As the cardinal symptom of CHI is altered consciousness, logical intake measures of CHI severity include measures of the depth and the duration of the abnormal state of consciousness. Confounding factors in outcome prediction include secondary complications of CHI, premorbid characteristics, and effects of acute and rehabilitative therapy. Most research has focused on functional outcome predictions based on simple intake measures obtained shortly after injury, but intake measures that permit accurate prediction of rehabilitation potential or of specific cognitive and behavioral outcomes are also needed.