Histopathologic correlates of otoneurologic manifestations following head trauma.

The clinical course of patients dying of head trauma and the physiologic evaluation of audition in guinea pigs subjected to several forms of head trauma are correlated with the histopathologic findings in the brains and temporal bones. In the patients there was wide spread hemorrhage, edema, disorganization and disruption of neural tissue. Loss of Purkinje cells and other neural elements was prominent. The temporal bone findings in the patients included laceration of and hemorrhage into the VIIIth nerve as well as bleeding into the scala tympani. The membranous labyrinths demonstrated no specific changes secondary to the trauma. The guinea pigs developed a central form of hearing loss with elevated thresholds for evoked responses from the inferior colliculus and normal AC cochlear potentials. In the animals hemorrhage in the substance of the brain, necrosis of neural tissue, edema, disorganization and disruption were prominent. Although there was extravasation of blood in the tympanic and vestibular scalae, the membranous structures of the inner ears were well preserved.