Evoked potentials in severe head injury

Provided herein is a summary of findings by the authors and other investigators regarding the application of evoked potential studies to the assessment of neurologic function in severely head-injured patients in the acute and subacute stages postinjury. Multimodality Evoked Potentials (MEP's) are reportedly useful in three primary areas: 1) diagnosis; 2) prognosis; and 3) monitoring recovery. In diagnosis, the abnormalities in MEP's can be associated specifically with focal sensory/motor deficits such as hemiparesis and, generally, with the severity and extent of brain dysfunction. MEP abnormalities that are severe reflect irreversible damage while the mild abnormalities point to transient, reversible CNS dysfunction. Definition of the severity and extent of brain dysfunction by MEP's allows an accurate prediction of outcome, or the potential for recovery. Their accuracy is superior to many commonly used indices and MEP results add strength to clinical indicators of prognosis. Changes in MEP results obtained within a patient over time can be used to trace recovery and assess, for an individual, the functional consequences of secondary neurologic insult or medical complication. The authors conclude that MEP studies may serve a useful function as noninvasive indices of neurologic function in the management of severely head-injured patients.