Utility of multimodality evoked potentials in cerebral injury.

With technical rigor and a few modifications, reliable recordings of multimodality evoked potentials can be obtained in patients suffering head injury. The integrity or complexity of the EP waveform appears to be the best indicator of the reversibility of injury to the CNS. A multimodality approach is recommended in head trauma to enhance the sample of brain tissue evaluated, as a single pathway courses a very limited region of brain. In head injury, the EP and clinical findings do not correlate perfectly, although they are generally in agreement. In most cases, the EPs are accurate prognostic indicators and the rate of error of prediction is actually slightly lower than that of the clinical examination in head trauma. Serial evaluations are often necessary as a patient's course and prognosis may change. These changes may not be readily apparent on clinical examination. The information provided by MEP studies is quite helpful when the clinical examination is incomplete or inconsistent. Even when clinical data are available, the EP results, when combined with other indicators of neurologic integrity, afford a firmer basis for diagnostic and prognostic decisions.