Bilateral total deafness after preparation of wild boar meat

IntroductionStreptococcus suis is responsible for a zoonosis for which Suidae (pigs and wild boars) constitute the reservoir, mainly in Asia, with a much lower prevalence in Europe. The predominant clinical manifestation is meningitis, possibly resulting in deafness.Case reportWe report the case of a woman hospitalised for meningitis complicated by labyrinthitis, occurring several hours after preparing a meal composed of wild boar meat. Despite the presence of intracochlear fibrosis, the patient was managed by sequential bilateral cochlear implants.DiscussionThe discussion presents a review of the international literature and describes the mechanisms responsible for hearing loss related to this rare zoonosis.     

影像学评估在耳蜗植入术中的价值

目的：评价影像学检查在耳蜗植入术中的价值。方法：37例感音性神经性聋患者术前常规行颞骨HRCT及MRI检查，术后行改良斯氏位X线拍片，其中5例术后行CT复查。结果：CT显示2例Mondini畸形（4耳），2例前庭导水管扩张（4耳），1例迷路骨化（1耳），1例内听道狭窄（2耳）。MRI显示Mondini畸形3例（6耳），前庭导水管扩张2例（4耳），1例并内淋巴囊扩张（2耳），2例迷路纤维化（2耳）。术后改良斯氏位X线拍片显示植入电极形态、位置良好。CT显示1例电极滑脱。结论：CT及MRI对耳蜗植入术术前评估具有重要价值，改良斯氏位X线拍片结合CT对术后评估更有意义。     

Pyramidal cells in primary auditory cortex project to cochlear nucleus in rat

Recent work has demonstrated that the auditory cortex in rat sends direct projections to the auditory nuclei of the brainstem, including the cochlear nucleus and superior olive. To determine the cortical origin of the projections to cochlear nucleus, Fast Blue, a retrograde fluorescent tracer, was injected into the cochlear nucleus. Labeled cells in the forebrain were then studied with light microscopy and mapped. The projection was found to originate from large pyramidal neurons in layer V of primary auditory cortex. The projection was predominantly ipsilateral, and no labeled neurons were found in other cortical areas. These data imply that primary auditory cortex exerts influence over ascending auditory information at the earliest stages of the central auditory system.     

Enkephalin mRNA production by cochlear and vestibular efferent neurons in the gerbil brainstem

Summary Preproenkephalin mRNA production by efferent neurons projecting to the gerbil inner ear was assessed using combined in situ hybridization and retrograde labeling with florescent tracers. Virtually all vestibular efferent neurons were positive for preproenkephalin mRNA. Of the cochlear efferents, one-half of the medial olivocochlear neurons were positive for enkephalin. All lateral olivocochlear neurons were negative for enkephalin. The results suggest that there are two, biochemically distinct subpopulations of medial olivocochlear efferents in the gerbil. Offprint requests to: Division of Otolaryngology, ENT, V-112C     

The effects of anesthesia on otoacoustic emissions

We have measured transient-evoked and distortion-product otoacoustic emissions (OAEs) in the chinchilla and compared them in the awake and anesthetized animal (using either ketamine or barbiturate agents). We report a significant increase in OAE amplitudes during anesthesia, particularly using ketamine. These effects are most evident for transient-evoked otoacoustic emissions (TEOAEs) as measured in the non-linear mode. Our data support the hypothesis that tonic activity levels in cochlear efferents may be reduced by anesthetic effects, either directly or indirectly (e.g., by general reductions in descending pathway activity), and that reduced cochlear efferent activity will result in the observed increase of OAE amplitudes.     

The anterior inferior cerebellar arterial network supplying the rat cochlea and its role in autoregulation of cochlear blood flow

Summary The sensitivity of the cochlea is dependent upon maintenance of a delicate homeostatic environment. One mechanism which participates in providing this environment is the autoregulation of cochlear blood flow. This autoregulation is ensured through the interaction of sympathetic, peptidergic and hemodynamic mechanisms. The current study demonstrates an adaptation that also participates in cochlear blood flow autoregulation. Specifically, an anterior inferior cerebellar arterial network is described and the relative contributions of each of its vessels to total cochlear blood flow is measured using laser Doppler flowmetry. The results show that each collateral vessel contributes to the blood supply of the cochlea and that reperfusion is accompanied by hyperemia. These findings suggest an adaptation that provides stable blood flow through redundancy and compensatory potential. Additionally, these observations have implications for experimental models of ischemia.     

16通道人工耳蜗植入装置的原理和研制

人工耳蜗植入是利用电听觉原理恢复聋人听觉的一种有效方法，作者依据耳蜗在电刺激条件下的听觉生理学原理和心理声学参量，提出汉语主意编码方案的设想，研制出１６通道耳蜗植入电极系统和语言处理装置，并进行初步动物实验研究。     

滤波器概念与听觉外周的频率分析

本文从生理学实验结果讨论了听觉外周特别是耳蜗在频率分析中的作用，通过对耳蜗的某些性质与线性带通滤波器的比较，指出了我们在采用工程语言对听觉系统进行描述时，以及在用工程的方法提高人的听力时所必需注意的某些问题，尤其是听觉外周所表现的非线性性质。     

Pressure Transfer Between Intracranial and Cochlear Fluids in Patients With Meniere's Disease

Objectives: To elucidate the pressure transfer between intracranial and labyrinthine fluids in patients with well‐defined unilateral Meniere's disease. Study Design: Eleven patients previously exposed to hypobaric pressure agreed to be investigated further with the tympanic membrane displacement (TMD) technique. TMD was used to indirectly analyze perilymph pressure changes as the result of changes in body position. Methods: Repeated measurements for both the diseased and the healthy ears were made with the patients supine and then in a sitting position. The TMD parameters for the maximum inward displacement, the Vi, and the mean volume displacement, the Vm, were calculated and compared. Results: The paired comparison showed statistically significant larger Vi values for both ears in the supine position. A similar tendency was observed for the Vm value. This difference of the Vi was significantly larger for the diseased ear compared with the currently healthy ear. The results were compared to the audiometric and electrocochleographic results previously obtained on the same patients when they were subjected to hypobaric pressure. Patients who experienced the largest differences in hearing level thresholds in the lower frequencies also showed the greatest differences in TMD values as the result of postural changes. Conclusions: Despite the limited number, the statistically supported results suggest a relation between the efficiency of the routes of pressure transfer and the observed effect of hypobaric exposure. The results also indicate that for the patients tested, the routes of communication are more effective in the diseased ear than in the healthy ear—a condition that may relate to the pathogeneses of Meniere's disease.