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

<b><i>Introduction:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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; <i>p</i> = 0.01). <b><i>Conclusions:</i></b> 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.

<b><i>引言：</i></b> 眩晕是一类常见病症。即便接受了全科、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。<b><i>方法：</i></b> 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名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导致眩晕或头昏的病例。采用光学显微镜对前庭系统标本进行细致评估，对黏附于半规管壶腹帽（cupula）及迷路壁的嗜碱性沉积物（basophilic deposits）进行观察，并对前庭神经内的斯卡帕神经节（Scarpa’s ganglion）开展细胞计数。<b><i>结果：</i></b> 9例患者的15侧耳可见前庭病理改变，包括壶腹帽嗜碱性沉积物（8侧）、半规管管壁嗜碱性沉积物（7侧）、前庭神经退变（8侧）以及前庭萎陷（vestibular atelectasis，2侧）。同时还观察到部分未明确的病理表现，如壶腹嵴缺失、壶腹嵴上皮下沉积物以及壶腹帽与暗细胞区粘连。患者组嗜碱性沉积物的平均直径（191μm）大于正常对照组的隐匿性沉积物平均直径（101μm；<i>p</i> = 0.01）。<b><i>结论：</i></b> 本研究明确了部分外周前庭病理改变，包括半规管内沉积物、前庭神经退变及前庭萎陷，并推测不明原因眩晕可能的病因包括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。上述研究结果可为老年不明原因眩晕的多病因发病机制提供更深入的认识。