抄録
It is often reported that a brain stem tumor occasionally causes pure tone hearing loss. Abnormal findings in the auditory brain stem responses (ABRs) are also reported. In this article we report 5 cases of brain stem tumor we had experienced and consideres the mechanism of the onset of the pure tone hearing loss. We compare different types of pure tone hearing loss with abnormal ABR findings. In the patients with unilateral profound pure tone hearing loss, the normal wave III were not detected in the affected ear. From our results and from other workers' similar findings, we concluded that a unilateral and more than moderate pure tone hearing loss, accompanied by a brain stem tumor, is caused by the extention of the tumor at or near the site of the origin of the ABR wave III.
