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.