[Evaluation of post-traumatic coma using evoked potentials].

In 130 cases of post-traumatic coma a study of multimodality evoked potentials (MEP) was carried out shortly after the traumatism (within 72 h). According to the morphology of the records they were classified in grades (I-IV) in agreement with Greenberg et al. The worst grade of EP in the different types was related to the outcome at 6 months, distinguishing between focal lesions and diffuse lesions. Only a group (22.9%) of the 109 patients in which the auditory brain-stem evoked potentials (ABEP) could be studied, showed severe disorders (grade III-IV). There was a significant correlation between the ABEP grades and the outcome in the focal lesions (p less than 0.001). In the diffuse lesions the ABEP grades did not show significant differences with the outcome. A 22.4% of the patients with diffuse lesions had some visual evoked potentials (VEP) in grades III-IV against almost the double (41.6%) in the focal lesions. The grades of the VEP in the focal lesions did not have differences with outcome and in the diffuse lesions they did (p less than 0.05). Approximately half of the cases with focal lesions and one third of the diffuse lesions showed severe disorders (grades III-IV) of the somatosensory evoked potentials (SEP). In the two types of lesions there were significant differences with the outcome (p less than 0.001) and (p less than 0.01). The multimodality evoked potentials (MEP) are useful for predicting the outcome, especially in the patients where the neurological examination is impossible. Among the different modalities, the SEP were shown to be more predictive.(ABSTRACT TRUNCATED AT 250 WORDS)