[Clinical study of cortical and brainstem evoked potentials in head injury]

Three types of evoked potentials (EPs) auditory brainstem response (ABR), somatosensory evoked potential (SEP), and visual evoked potential (VEP) were recorded among 100 cases of head injuries within three days after the trauma had occurred. In order to assess these EPs, the normal wave patterns of 20 healthy subjects were used for comparison. For indices, wave I, III and V were used for ABR, N1, N2 and N3 for SEP, and N70, P100 and N125 for VEP. On this basis, five EP grades were constructed, from normal (grade I) to highly abnormal (grade V). Furthermore, an EP pattern classification was devised to integrate the respective EP grade. Namely, pattern A (PA), consisting of grade (G). I-III of the 3 types of EP; PB, composed of one type of EP or both ABR and VEP at G. IV-V; PC, consisting of both SEP and VEP at G. IV-V; PD, comprising both ABR and SEP at G. IV-V; and PE, covering all three types EPs at G. IV-V. In this EP pattern classification, PA signifies no severe damage, PB localized damage, PC severe cerebral damage, PD severe brainstem damage, PE severe diffuse damage. The significance was studied for an understanding of the pathological state, and for making a prognosis. The following conclusions were reached. 1. In severe head trauma, primary brainstem damage is very rare, and in cases where brainstem damage is shown, it is accompanied by extensive cerebral damage. To assess the pathological state of such primary cerebral damage EP in the acute stage is useful, and by performing further EP, successively, it becomes also possible to evaluate the secondary cerebral damage.(ABSTRACT TRUNCATED AT 250 WORDS)