Häusler R, Levine R A
Department of ENT, Head and Neck Surgery, Inselspital, University of Berne, Switzerland.
Acta Otolaryngol. 2000 Sep;120(6):689-703. doi: 10.1080/000164800750000207.
The auditory and vestibular systems share the same end organ and cranial nerve, yet vestibular signs and symptoms are common with stroke, whereas hearing disturbances are much less frequent. Several reasons would appear to account for this striking dissimilarity. One is that the auditory pathway is less ubiquitous than the vestibular pathways. The likelihood that a stroke involves the auditory pathway is, therefore, less on this basis alone. A second difference, to our knowledge not previously reported, is that the auditory pathway is often spared by the most common strokes. This is because major parts of the auditory pathway, such as the cochlear nucleus, inferior colliculus and medial geniculate body, have multiple sources of blood supply. A third well-recognized factor is the redundancy of the central auditory system and its strong bilateral representation above the level of the cochlear nuclei. Consequently, rostral to the cochlear nuclei gross deficits in hearing, such as those measured by standard pure-tone audiometry and speech discrimination, only occur if lesions are bilateral. Furthermore, widespread bilateral lesions of the auditory system typically render the patient unable to respond or are incompatible with life. In contrast, language disorders are more frequent because language is usually unilaterally represented in the cortex. Certainly, cerebral stroke often includes the auditory system, resulting in various types of auditory disorders, but most hemispherical lesions produce subtle hearing dysfunctions that can only be detected with sophisticated psychoacoustic and electrophysiological testing. The purpose of this review is to provide an overview of the auditory system and its blood supply and to review how auditory processing can be affected by stroke. Psychoacoustic and electrophysiological test procedures for identifying lesions in the central auditory system are described. The literature of hearing disorders due to stroke is reviewed and illustrative cases are presented.
听觉系统和前庭系统共用相同的终器和脑神经，但前庭症状在中风中很常见，而听力障碍则要少见得多。有几个原因似乎可以解释这种显著的差异。一是听觉通路不如前庭通路普遍。因此，仅基于这一点，中风累及听觉通路的可能性就较小。第二个差异，据我们所知此前未曾报道过，是听觉通路通常在最常见的中风中得以 spared（此处原文有误，推测应为“幸免”）。这是因为听觉通路的主要部分，如蜗神经核、下丘和内侧膝状体，有多个血液供应来源。第三个广为人知的因素是中枢听觉系统的冗余性及其在蜗神经核水平以上的强大双侧代表。因此，在蜗神经核水平以上，只有双侧病变才会导致明显的听力缺陷，如通过标准纯音听力测定和言语辨别所测量的那样。此外，听觉系统广泛的双侧病变通常会使患者无法做出反应或与生命不相容。相比之下，语言障碍更为常见，因为语言通常在皮质中是单侧代表的。当然，脑中风常常累及听觉系统，导致各种类型的听觉障碍，但大多数半球病变会产生细微的听力功能障碍，只有通过复杂的心理声学和电生理测试才能检测到。本综述的目的是概述听觉系统及其血液供应，并回顾中风如何影响听觉处理。描述了用于识别中枢听觉系统病变的心理声学和电生理测试程序。回顾了中风导致听力障碍的文献并给出了示例病例。
