Supplementary Material for: Temporal Bone Histopathology of Undiagnosed Dizziness in the Elderly

Introduction: Dizziness is a common disease. However, approximately 10–40% of patients were diagnosed unknown dizziness even though general, neurological, and otological examinations were performed. The aim of this otopathological study was to investigate the histopathology of the peripheral vestibular system of patients who suffered from undiagnosed dizziness. Methods: Eighteen temporal bone specimens from 9 patients with undiagnosed dizziness and 20 temporal bone specimens from age-matched 10 normal controls were selected. Cases with a history of dizziness and vertigo caused by particular peripheral vestibular disease and central etiology were excluded. Specimens of the vestibular system were carefully assessed by light microscopy. The basophilic deposits adhered to cupulae of the semicircular canals and the wall of the labyrinth were investigated. Scarpa’s ganglion cell counts in the vestibular nerves were performed. Results: Fifteen ears of 9 patients had the findings of vestibular pathology such as a basophilic deposit on cupula (8 ears), on canal wall (7 ears), vestibular nerve loss (8 ears), or vestibular atelectasis (2 ears). Unclear pathological findings such as crista neglecta, subepithelial deposits of the crista ampullaris, and adhesion of the cupula to dark cell area were demonstrated. The mean size of basophilic deposits seen in the patients (mean: 191 µm) was larger than that of latent deposits seen in the normal controls (mean: 101 µm; p = 0.01). Conclusions: We demonstrated some peripheral vestibular pathological findings such as deposit within the semicircular canal, vestibular nerve loss, and vestibular atelectasis and suggested the possible diagnosis of dizziness (benign paroxysmal positional vertigo, presbyvestibulopathy, vestibular atelectasis). These findings will provide a better insight into the multiple etiologies of the unknown dizziness in the elderly.

引言：眩晕是一种常见临床病症。然而，即便接受全科、神经科及耳科系统检查，仍有约10%~40%的患者被确诊为不明原因眩晕。本耳病理研究旨在探究不明原因眩晕患者外周前庭系统的组织病理学特征。
方法：本研究纳入9例不明原因眩晕患者的18份颞骨标本，以及10例年龄匹配的正常对照者的20份颞骨标本。排除因明确外周前庭疾病及中枢性病因引发头晕或眩晕的病例。采用光学显微镜对前庭系统标本进行细致评估，观察黏附于半规管壶腹嵴及迷路壁的嗜碱性沉积物，并对前庭神经内的斯卡帕神经节（Scarpa's ganglion）细胞进行计数。
结果：9例患者的15耳存在前庭病理改变，包括壶腹嵴嗜碱性沉积物（8耳）、半规管壁嗜碱性沉积物（7耳）、前庭神经缺失（8耳）及前庭萎陷（vestibular atelectasis，2耳）。此外还观察到若干不明确的病理表现，如嵴缺失（crista neglecta）、壶腹嵴（crista ampullaris）上皮下沉积物，以及壶腹嵴黏附于暗细胞区（dark cell area）。患者组嗜碱性沉积物的平均尺寸（平均191 µm）大于正常对照组的潜伏性沉积物（平均101 µm；p=0.01）。
结论：本研究明确了若干外周前庭病理表现，包括半规管内沉积物、前庭神经缺失及前庭萎陷，并推测此类不明原因眩晕可能的诊断方向为良性阵发性位置性眩晕（benign paroxysmal positional vertigo）、老年性前庭病（presbyvestibulopathy）及前庭萎陷。上述发现有助于进一步阐明老年人群不明原因眩晕的多病因发病机制。