[Significance of multimodality evoked potentials (MEPs) in severe head injuries]

Clinical significance of multimodality evoked potentials (MEPs) consisting of auditory evoked brainstem response (ABR), cortical somatosensory evoked potential (SEP) and visual evoked potential (VEP) was studied in 14 cases with severe head injuries. The cases in this series associated with cerebral contusion and/or intracranial mass lesions such as acute subdural, intracerebral and acute epidural hematomas and Glasgow Coma Scale (GCS) score was less than 8 in all instances. MEPs were recorded for 14 days after injury and evaluated by MEP grade modified from Greenberg, et al. Intracranial pressure (ICP) was monitored from the extradural space on main lesion side in all cases for 3 to 5 days. Transtentorial herniation on CT scan was also graded according to the status of subarachnoid cisterns around the tentorium. The outcome was assessed by Glasgow Outcome Scale at 3 months after injury and was classified into good, poor and dead. MEPs on admission showed mild to severe abnormalities determined by single or all modalities in all cases and they were fairly well correlated with GCS score on admission and initial ICP. In the cases with good outcome, initial MEPs showed mild to moderate abnormalities determined by single modality and improved within 3 days after injury. They returned to normal or remained at mild abnormality at 7 days. But abnormality on initial MEPs was more severe in the cases with poor outcome and they were deteriorated within 3 to 7 days when elevation of ICP above 25 mmHg was observed. MEPs remained at moderate abnormality even at 14 days after injury in these cases.(ABSTRACT TRUNCATED AT 250 WORDS)