Quantitative assessment of cochlear and vestibular ganglion neurons in temporal bones with chronic otitis media.

PURPOSE: In this study, we aimed to determine whether or not COM leads to loss of spiral and Scarpa ganglion neurons. METHODS: From the human temporal bone (HTB) collection at the University of Minnesota we selected human temporal bones with COM, defined as the presence of clinically intractable tissue abnormalities in the middle ear (cholesteatoma, perforation of the eardrum, granulation tissue, fibrosis, tympanosclerosis, and cholesterol granuloma). We also selected HTBs from donors with no ear diseases as controls. We quantitatively analyzed the number of spiral and Scarpa ganglion cells and compared the results obtained in the control and study groups. RESULTS: In both COM and control groups we observed a significant negative correlation between age and number of both spiral (R = -0.632; P < 0.001; 95% CI - 0.766 to - 0.434) and Scarpa ganglion (R = - 0.404; P = 0.008; 95% CI - 0.636 to - 0.051) cells. We did not find any significant differences in the number of spiral ganglion cells (in total or per segment) or in the density of Scarpa ganglion cells (in each vestibular nerve or both) in the COM group as compared with controls (P > 0.05). CONCLUSIONS AND RELEVANCE: Our results did not demonstrate significant loss of cochlear or vestibular peripheral ganglion neuron loss in HTBs with COM as compared with controls.

Quantitative assessment of vestibular otopathology in otosclerosis: A temporal bone study.

OBJECTIVES/HYPOTHESIS: To determine if peripheral vestibular otopathology is present in human temporal bones with otosclerosis. STUDY DESIGN: Comparative human temporal bone study. METHODS: Seventy-four human temporal bones from 46 subjects with otosclerosis (mean age of 61 ± 18 years) and 20 within histologically normal limits from 17 subjects (mean age of 59 ± 14 years) were included in this study. Temporal bones with otosclerosis were divided into those with and without endosteal involvement. Using differential interference contrast microscopy at 1008× magnification, type I and type II vestibular hair cell counts were performed on each vestibular sense organ in which the neuroepithelia was oriented perpendicular to the plane of section. The organ-specific cell densities (cells/0.01 mm(2) surface area) were compared between the groups with and without endosteal involvement, and also compared to counts in the nonotosclerosis control group using Student's t-test. RESULTS: Mean type I and type II hair cell densities of all vestibular structures in the group with endosteal involvement were significantly lower compared to the group without endosteal involvement. Mean type I and type II hair cell densities of all vestibular structures in the group with endosteal involvement were also significantly lower compared to the control group, but they were not in the group without endosteal involvement compared to the control group. CONCLUSION: Endosteal involvement of otosclerotic foci is associated with vestibular hair cell loss that may contribute to the vestibular symptoms in otosclerosis. LEVEL OF EVIDENCE: N/A. Laryngoscope, 126:E118-E122, 2016.

Peripheral vestibular system in Down syndrome: quantitative assessment of vestibular histopathology.

OBJECTIVE: To evaluate the maturity of the peripheral vestibular system in Down syndrome by examining the number of Scarpa's ganglion cells and the density of vestibular hair cells. STUDY DESIGN: Case-control study using human temporal bones. SETTING: Tertiary academic center, otopathology laboratory. SUBJECTS AND METHODS: Sixteen temporal bones from 8 patients with Down syndrome and 15 control temporal bones from 8 individuals with no history of otologic disease were selected. Hypoplasia of the lateral semicircular canal (LSC) and vestibule was investigated by measuring the dimensions of the structures. Scarpa's ganglion cells were counted under light microscopy. The vestibular hair cells were counted in the LSC crista and the utricular and saccular maculae under differential interference contrast (Nomarski) microscopy and expressed as density. RESULTS: The patients with Down syndrome were divided into 2 groups: with and without LSC hypoplasia. The number of Scarpa's ganglion cells and the density of vestibular hair cells were significantly smaller in both groups of patients with Down syndrome than in the control group. There was no significant difference in the number of Scarpa's ganglion cells or the density of vestibular hair cells between the groups with and without LSC hypoplasia. CONCLUSION: The peripheral vestibular system, including Scarpa's ganglion cells and vestibular hair cells, is hypoplastic irrespective of the vestibular malformation in Down syndrome.