Hisako Ito

Effects of Circulatory Disturbance on the Cochlea

In order to determine the effects on the cochlea of circulatory disturbance in the basilar artery system, the cochlear action potential (AP) and the cochlear blood flow were measured in cats with the artery occluded. The occlusion was performed in the basilar, the anterior cerebellar and in the internal auditory arteries. During occlusion the decrease in the cochlear blood flow was greatest in the internal auditory artery and the least in the basilar artery. While the cochlear blood flow showed various levels of decrease depending on the occlusion site and the individual animal, the degree of AP alteration correlated with the decreased rate in the cochlear blood flow.

Preoperative Diagnosis of Intratemporal Facial Nerve Tumor: High-Resolution CT and Otoscopic Findings in 4 Cases

Four cases of facial nerve tumor were treated in our clinic during the past 16 years, one of which was a recurrence 12 years after the resection. Another case presented with relapsing facial palsy of sudden onset. The others presented with slowly progressive facial palsy. In each of the four cases, the horizontal and vertical portions were included in the tumor extension, and a mass was revealed in the posterior tympanic cavity by use of otoscopy. High-resolution CT, performed in all but the earliest case, proved to be the most valuable diagnostic tool, indicating the anatomical correlation of the tumor with the facial canal. With the diagnosis preoperatively established, facial reanimation procedure could be applied immediately after the tumor resection except in the recurrent case.

Acoustic Tumor with Hearing Loss of Sudden Onset and Recovery

In many cases of acoustic tumor the hearing loss is gradually progressive, but some cases of acoustic tumor show a sudden onset of hearing loss. In this paper we report two interesting cases of acoustic tumors which were diagnosed as sudden deafness at the first examination. Being treated with steroid hormones, their hearing was partially recovered. But the hearing loss recurred in both cases. At the second examination, CT showed the cerebellopontine angle tumors. So it was emphasized that careful questioning as well as the caloric test and the auditory brainstem response (ABR) was important. If one of these tests shows abnormality, the patient should be examined by the CT scan. The same may be said of patients who show recovery due to steroid hormone therapy.

Auditory brainstem response in NICU infants

To assess the I-V interpeak latency (I-V IPL) as an index of neural development in a premature population, auditory brainstem response (ABR) performed on 145 ears of 89 neonatal intensive care unit (NICU) infants was analyzed. The obtained I-V IPLs were compared with conceptional age and risk factors such as neonatal asphyxia, respiratory distress, metabolic disorders, etc. Those infants who received phototherapy or aminoglycoside antibiotics had statistically significant prolongation of I-V IPL. Thus, measurement of I-V IPL might be a valuable monitor against risk factors.

Total Laryngeal Stenosis in Cicatricial Pemphigoid

Cicatricial pemphigoid in the aerodigestive system is rare, but can be life-threatening. We report a case of total laryngeal stenosis. During an exacerbation, the airway of the patient was obliterated with a cicatrix and necessitated an emergency tracheostomy. Six years later when no recurrence of pemphigoid was confirmed, laryngofissure operations were performed with a satisfactory restoration of laryngeal function. Though otolaryngological treatment in the active phases is symptomatic including tracheostomy, surgical procedures should be encouraged once the disease has reached a remission.