Experimental Study of Head Trauma

Abstract

In order to clarify injury of the inner ear and of the brain after head trauma, we observed morphological changes in guinea pigs immediately after experimentary induced trauma. The relationship between morphological changes and function were studied in some of the animal with the use of the auditory brain stem response (ABR).1) The presence or absence of skull fracture lines and histological changes were examined in 12 guinea pigs.2) Histological changes immediatly after death due to a blow to the parietal region were examined in five guinea pigs.3) Eighteen guinea pigs were allowed to survive for two to five days after blows were inflicted to the parietal and temporal regions, and changes occurring while the head was mobilized or immobilized were examined.4) Histological changes and ABR were examined after a direct blow to the bulla in 10 guinea pigs (Nembutal was injected intraperitoneally for anesthesia.)The main disorders found were hemorrhagic changes in the brain stem and subarachnoid region and in the tympanic canal and cochlear window. Animals with concussion after a blow to the bulla showed no marked changes in ABR, but two of the five with a fractured bulla showed changes in ABR that were suspected of being central. Although it is somehat dangerous to compare head trauma in guinea pigs with that in man, it is considered highly possible that central hemorrhagic changes are present even when the injury seems to be only peripheral.