Banca de DEFESA: NATÁLIA CARASEK MATOS CASCUDO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : NATÁLIA CARASEK MATOS CASCUDO
DATE: 15/04/2026
TIME: 14:00
LOCAL: Auditório 2 FS
TITLE:

Otopathology of Unilateral Severe to Profound Hearing Loss

KEY WORDS:

Keywords: Hearing loss, unilateral; otopathology; cochlea; spiral ganglion; organ of Corti

PAGES: 100
BIG AREA: Ciências da Saúde
AREA: Medicina
SUMMARY:

Introduction: The impact of single-sided deafness for the patients has often been underestimated, as it was believed that the normal contralateral ear would compensate for the deficits of the other side. Nowadays it is known that a particularly increased effort is required to compensate for it in complex listening environments, leading to a reduced performance and an increased hearing handicap. Otopathology allows the study of diseases affecting the ear and it is the gold standard for evaluating intracochlear pathology, providing sensitive and specific identification of pathophysiological mechanisms. Objectives: To evaluate the histopathological findings of unilateral hearing loss and spiral ganglion cell counts, comparing them to the normal contralateral ear, and discussing implications of these findings for auditory rehabilitation. Methods: This study included 88 ears from 44 human subjects with a diagnosis of severe to profound unilateral hearing loss, from the Temporal Bone collection of the Otopathology laboratory of Massachusetts Eye and Ear Infirmary, with age ranging from 5 to 90 years old. Within the study group, we included 6 different etiologies of hearing loss: sudden sensorineural hearing loss, Meniere’s disease, internal auditory canal tumors, chronic otitis media, stapes fixation and central nervous system disorders. Results: The analysis for all causes of unilateral severe to profound sensorineural hearing loss showed that the loss of spiral ganglion cells was directly correlated with the loss of neural fibers (dendrites and axons) in all cochlear turns (p<0.001). The duration of hearing loss (in years) did not show a direct correlation with neuronal loss in the spiral ganglion, which may indicate that even with a longer time of hearing deprivation, depending on the etiology, cochlear implantation may be an effective measure for rehabilitation. On the other hand, inner ear surgeries (including cochleosacculotomy, labyrinthectomy, lateral canal fenestration, stapedectomy, stapedotomy, manipulation of the internal auditory canal and iatrogenic injury to the lateral semicircular canal) were positively correlated with spiral ganglion atrophy (p=0.013), suggesting that rehabilitation should be near or at the same surgical time, for a better prognosis. There is a correlation between unilateral loss and abnormalities of the organ of Corti (p<0.001), atrophy of the stria vascularis (p=0.002) and atrophy of the vestibular sensory organs (p<0.001). Evaluation of the ‘inner ear disease’ subgroup, excluding middle ear and central nervous system disorders, was positively correlated with some degree of hydrops (p<0.001), tectorial membrane abnormalities (p=0.001) and Scarpa’s ganglion atrophy (p=0.002). Inner ear surgery for this group was also correlated with spiral ganglion atrophy (p=0.008), and fibrosis (p=0.006) or ossification (p=0.005) of the cochlear lumen. In the Meniere’s disease subgroup, there was no correlation between hydrops and the percentage of neuronal loss (versus control), supporting the theory that hydrops is in fact an adaptive mechanism to an inner ear insult rather than the cause of hearing loss. In the internal auditory canal tumor subgroup, spiral ganglion degeneration appears to occur regardless of the intervention, even when the approach was retrosigmoid. Conclusion: The multiple causes of unilateral hearing loss have different histopathological implications in the inner ear, which may reflect in different outcomes for auditory rehabilitation.

COMMITTEE MEMBERS:
Presidente - ***.299.221-** - FAYEZ BAHMAD JUNIOR - HUB
Externa ao Programa - 2142935 - ISABELLA MONTEIRO DE CASTRO SILVA - nullExterna à Instituição - PAULIANA LAMOUNIER E SILVA DUARTE - CRER
Externo à Instituição - SADY SELAIMEN DA COSTA - UFRGS
Externa à Instituição - THAIS ABRAHÃO GOMES ELIAS - IBO