Inner Ear Degeneration in Acoustic Neurinoma

1976 ◽  
Vol 85 (3) ◽  
pp. 343-358 ◽  
Author(s):  
Fumiro Suga ◽  
John R. Lindsay
Keyword(s):  
Inner Ear ◽  
Blood Circulation ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Nerve Fibers ◽  
Sensory Cells ◽  
Tectorial Membrane ◽  
Acoustic Neurinoma ◽  
Pathological Findings ◽  
Temporal Bones

The temporal bones of three cases of acoustic neurinoma are described to illustrate histopathological features of inner ear lesions due to chronic partial obstruction of blood circulation by the tumor in the internal auditory meatus. Degenerative changes in the inner ear due to acoustic neurinoma were evaluated and compared with changes in the opposite ear. The main pathological findings in the inner ear which were attributed to the tumor were degeneration of nerve fibers and of ganglion cells, degeneration of the stria vascularis, degeneration of the tectorial membrane, fibrosis and ossification of a semicircular canal. Fairly good preservation of sensory cells was observed in the presence of total degeneration of nerve fibers and ganglion cells and subtotal degeneration of the stria vascularis.

Localization of Type IV Collagen and Laminin in the Guinea Pig Inner Ear

1992 ◽  
Vol 101 (10_suppl) ◽  
pp. 58-62 ◽  
Author(s):  
Mitsuaki Takahashi ◽  
Kazuhiko Hokunan
Keyword(s):  
Inner Ear ◽  
Type Iv Collagen ◽  
Fluid Transport ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Sensory Epithelium ◽  
Nerve Fibers ◽  
Endolymphatic Sac ◽  
Tectorial Membrane ◽  
Type Iv

The distribution of type IV collagen (C-IV) and laminin, which are important components of the basement membrane (BM), was studied immunohistochemically in the inner ear of healthy Hartley guinea pigs. Antibodies against C-IV and laminin were used in this study. The distribution of C-IV in the inner ear was almost the same as that of laminin, but the extent of staining for laminin was less than that for C-IV in some sites. The sites of the inner ear in which these components were most densely localized were the areas surrounding the spiral ganglion cells and nerve fibers, the capillary vessels in the stria vascularis and the spiral prominence, and an area directly beneath the epithelium of the endolymphatic sac. Type IV collagen and laminin were also localized around the other vascular BM and the epithelial BM in the inner ear, but the tectorial membrane, the cupula of the crista ampulla, and the sensory epithelium did not take up stain. These results suggest that the vascular BM of the stria vascularis and spiral prominence, as well as the epithelial BM of the endolymphatic sac, may play an important role in fluid transport, and that the perineural BM of the inner ear might play an important role in the functional maintenance of the optimal environment of the inner ear nervous system.

Chronic Intracochlear Electrode Implantation: Cochlear Pathology and Acoustic Nerve Survival

1974 ◽  
Vol 83 (2) ◽  
pp. 202-215 ◽  
Author(s):  
Robert A. Schindler ◽  
Michael M. Merzenich
Keyword(s):  
Hair Cells ◽  
Bone Growth ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Round Window ◽  
Spiral Ganglion ◽  
Nerve Fibers ◽  
Spiral Ligament ◽  
Scala Tympani ◽  
Temporal Bones

The temporal bones of ten cats implanted with intracochlear electrodes for three to 117 weeks were stained with hematoxylin and eosin and examined with light microscopy. The electrodes were embedded in Silastic® which was molded to fill the most basal 9 mm of the scala tympani. They were inserted directly into the scala through the round window. Among our observations were the following: 1) All or nearly all hair cells were lost in the basal coil during the first several weeks after implantation. Some, but not all, supporting cells were also lost. There was extensive hair cell loss in the middle and apical turns, although some hair cells were seen there in all examined cats. 2) There was evidence of degeneration of spiral ganglion cells in the basal cochlea in several animals, but most primary auditory neurons including (with two exceptions) most of those in the region directly over the electrode, survived implantation in every cat. The radial nerve fibers of the spiral ganglion cells also survived long-term implantation. The functional viability of remaining spiral ganglion cells was confirmed in acute neurophysiological experiments conducted just before the animals were sacrificed. 3) More severe degeneration was seen in two cats in which the electrode perforated the basilar partition. In these animals, there was loss of many spiral ganglion cells, and evidence of new bone growth in the region of the perforation. 4) The appearance of the stria vascularis and spiral ligament in some implanted animals paralleled their descriptions following occlusion of the cochlear vein. 5) Connective tissue formed around the electrode surfaces, apparently displacing perilymph and sealing the electrode into the scala tympani. There was no evidence of perilymph fistula in any animal. 6) There was little evidence of progressive degeneration of the organ of Corti or spiral ganglion from three to 34 weeks after implantation. Some of the implications and limitations of these findings are discussed.

The Temporal Bone in the Preauricular Pit, Cervical Fistula, Hearing Loss Syndrome

1976 ◽  
Vol 85 (2) ◽  
pp. 268-275 ◽  
Author(s):  
Naomi Fitch ◽  
John R. Lindsay ◽  
Herbert Srolovitz
Keyword(s):  
Hearing Loss ◽  
Middle Ear ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Histological Study ◽  
Spiral Ganglion ◽  
Middle Cranial Fossa ◽  
Nerve Fibers ◽  
Horizontal Canal ◽  
Temporal Bones

Histological study of the temporal bones of an infant with the preauricular pit, cervical fistula, hearing loss syndrome revealed abnormalities in the middle ear, the vestibular system, and the cochlea. There is a gross bilateral abnormality in the form and relationship of the middle ear spaces, the middle cranial fossa and the inner ear. The horizontal canal lacks ampulla and crista; the posterior canal terminates a short distance from the ampulla. The cochlear cavity is approximately four fifths of normal size. The modiolus of the cochlea shows minor abnormalities. Spiral ganglion cells and peripheral nerve fibers are present in all coils, but are below normal in population in the basal and apical coils. The stria vascularis is slightly deformed and partly atrophic in the upper apical coil. An occasional concretion is present in the base of the stria vascularis in the middle and apical coils.

Electron Microscopic Findings in Presbycusic Degeneration of the Basal Turn of the Human Cochlea

1979 ◽  
Vol 87 (6) ◽  
pp. 818-836 ◽  
Author(s):  
Joseph B. Nadol
Keyword(s):  
Light Microscopy ◽  
Hair Cells ◽  
Basilar Membrane ◽  
Ganglion Cells ◽  
Nerve Fibers ◽  
Degenerative Changes ◽  
Supporting Cells ◽  
Neural Degeneration ◽  
Basal Turn ◽  
Temporal Bones

Three human temporal bones with presbycusis affecting the basal turn of the cochlea were studied by light and electron microscopy. Conditions in two ears examined by light microscopy were typical of primary neural degeneration, with a descending audiometric pattern, loss of cochlear neurons in the basal turn, and preservation of the organ of Corti. Ultrastructural analysis revealed normal hair cells and marked degenerative changes of the remaining neural fibers, especially in the basal turn. These changes included a decrease in the number of synapses at the base of hair cells, accumulation of cellular debris in the spiral bundles, abnormalities of the dendritic fibers and their sheaths in the osseous spiral lamina, and degenerative changes in the spiral ganglion cells and axons. These changes were interpreted as an intermediate stage of degeneration prior to total loss of nerve fibers and ganglion cells as visualized by light microscopy. In the third ear the changes observed were typical of primary degeneration of hair and supporting cells in the basal turn with secondary neural degeneration. Additional observations at an ultrastructural level included maintenance of the tight junctions of the scala media despite loss of both hair and supporting cells, suggesting a capacity for cellular “healing” in the inner ear. Degenerative changes were found in the remaining neural fibers in the osseous spiral lamina. In addition, there was marked thickening of the basilar membrane in the basal turn, which consisted of an increased number of fibrils and an accumulation of amorphous osmiophilic material in the basilar membrane. This finding supports the concept that mechanical alterations may occur in presbycusis of the basal turn.

Otopathology in a Case of Type I Waardenburg's Syndrome

2001 ◽  
Vol 110 (9) ◽  
pp. 875-882 ◽  
Author(s):  
Saumil N. Merchant ◽  
Michael J. McKenna ◽  
Aubrey Milunsky ◽  
Clinton T. Baldwin ◽  
Joseph B. Nadol
Keyword(s):  
Neural Crest ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Low Frequency ◽  
Tectorial Membrane ◽  
Type I ◽  
Dark Cells ◽  
Pathological Alteration ◽  
Microscopic Studies

We report a case of type I Waardenburg's syndrome that provides insight into the etiopathogenesis of sensorineural hearing loss (SNHL) in this syndrome. The subject, a 76-year-old woman with type I Waardenburg's syndrome (dystopia canthorum, heterochromia irides, and white hair), had congenital low-frequency SNHL in her right ear only, which had remained relatively stable throughout her life. Blood leukocyte DNA studies revealed a PAX-3 mutation with a 1 base pair C-to-A substitution in exon 5 at base 602. Light microscopic studies of the right cochlea showed intact neurosensory structures in only the lower basal turn, with the remainder of the cochlea showing absence of melanocytes, absence of stria vascularis, missing hair cells, dysmorphogenesis of the tectorial membrane, and lack of peripheral processes of the spiral ganglion cells. There was pathological alteration of the vestibular dark cells with marked reduction of melanocytes associated with these dark cells. The left inner ear was normal, with a full complement of neurosensory structures, including melanocytes. Because the PAX-3 gene is involved in neural crest development and melanocytes migrate from the neural crest to the ear, the findings in this case are consistent with the hypothesis that defective melanocyte migration or defective melanocyte function results in defective development of the stria vascularis (and perhaps other structures of the ear). leading to SNHL.

Influence of Manganese on Genetically Defective Otolith

1974 ◽  
Vol 83 (5) ◽  
pp. 565-581 ◽  
Author(s):  
David J. Lim ◽  
Lawrence C. Erway
Keyword(s):  
Animal Model ◽  
Inner Ear ◽  
Genetic Basis ◽  
Ganglion Cells ◽  
Genetic Disorders ◽  
Basic Research ◽  
Sensory Epithelium ◽  
Nerve Fibers ◽  
Scanning Electronmicroscopy

The genetically mutant pallid mouse (which possesses specific otolith defects) and the manganese-supplemented (Mn) pallid mouse (in which otolith defects were prevented) were studied using light and transmission and scanning electronmicroscopy. Untreated pallid mice which showed head-tilting, circling and ataxia also had swimming difficulty. In these animals, the otolith defects were the only consistent findings. With one exception, no pronounced anomalies were found in the sensory epithelium, nerve fibers and ganglion cells. Only a few vestibular melanocytes, in which the melanin granules failed to fully mature, were observed in the pallid mouse. Melanization in vestibular melanocytes appeared to be improved by Mn-supplementation. The genetic basis for involvement of Mn in otolith development was discussed. This animal model provides opportunities for basic research concerning the possible prevention of genetic disorders involving the inner ear.

Serotonin-Induced Plasma Extravasation in the Murine Inner Ear: Possible Mechanism of Migraine-Associated Inner ear Dysfunction

Cephalalgia ◽  
2006 ◽  
Vol 26 (11) ◽  
pp. 1310-1319 ◽  
Author(s):  
J-W Koo ◽  
CD Balaban
Keyword(s):  
Inner Ear ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Brain Parenchyma ◽  
Vestibular Nerve ◽  
Tectorial Membrane ◽  
Plasma Extravasation ◽  
Protein Extravasation ◽  
Inferior Vestibular Nerve ◽  
Sound Sensitivity

Sensitivity to sound and vertigo are often components of migraine. Recent studies suggest that plasma extravasation from intradural blood vessels may contribute to migraine pain. This study documented plasma extravasation in the mouse inner ear after intravenous administration of serotonin (5-HT). Horseradish peroxidase (HRP) was injected intravenously to trace protein extravasation in mice, followed 15 min later by intravenous 5-HT or saline. Forty-five minutes later, mice were euthanized. HRP extravasation was visualized immunohistochemically and quantified densitometrically. Baseline and evoked extravasation in stria vascularis and tectorial membrane were indistinguishable from skin, dura mater and tympanic membrane. Brain parenchyma, Scarpa's ganglion, basal spiral ganglion and modiolus, and the central vestibular nerve segment showed no significant 5-HT-induced extravasation. In contrast, 5-HT produced extravasation in the apical spiral ganglion, modiolus, and intralabyrinthine superior and inferior vestibular nerve. Thus, inner ear plasma extravasation is a potential mechanism for migraine-associated vertigo and sound sensitivity.

Is There a Conductive Type of Presbycusis?

1989 ◽  
Vol 100 (1) ◽  
pp. 30-34 ◽  
Author(s):  
Hassan H. Ramadan ◽  
Harold F. Schuknecht
Keyword(s):  
Stria Vascularis ◽  
Sensory Cells ◽  
High Tone ◽  
Speech Discrimination ◽  
Atrophic Change ◽  
Histologic Study ◽  
Fourth Group ◽  
Study Support ◽  
Cochlear Neurons ◽  
Temporal Bones

Many ears that manifest hearing losses caused by aging show combinations of atrophic change in the sensory cells, cochlear neurons, and stria vascularis. When it occurs in pure form, the loss of sensory cells produces an abruptly sloping high-tone threshold loss, the loss of cochlear neurons decreases the capability for speech discrimination, and the loss of strial tissue produces a flat threshold loss. There remains a fourth group of cases that have gradual sloping high-tone threshold losses for which a pathological correlate has not been identified. We performed a quantitative histologic study, using light microscopy on the temporal bones of such cases, and again could find no pathologic explanation. We believe that the findings of this study support the concept of an alteration in cochlear motion mechanics as the most probable cause for the gradually sloping high-tone hearing loss.

Electron Microscopic Observations in a Case of Long-Standing Profound Sensorineural Deafness

1977 ◽  
Vol 86 (4) ◽  
pp. 507-517 ◽  
Author(s):  
Joseph B. Nadol
Keyword(s):  
Connective Tissue ◽  
Endolymphatic Hydrops ◽  
Stria Vascularis ◽  
Sensorineural Deafness ◽  
Organ Of Corti ◽  
Nerve Fibers ◽  
Junctional Complex ◽  
Tectorial Membrane ◽  
Electron Microscopic ◽  
Spiral Limbus

The ultrastructural pathology in an ear with long-standing profound deafness is presented. Endolymphatic hydrops was present, although there had been no vestibular symptoms. Although hair cells were absent, the intercellular junctional complex at the endolymphatic surface of the organ of Corti was maintained, suggesting “healing” by migration or proliferation of supporting cells to fill the empty spaces. Severe atrophy of the stria vascularis was present, and crystalline deposits were found within the strial remnant. An encapsulated tectorial membrane was interpreted in light of ultrastructural findings as either herniation of the fibrillar connective tissue of the spiral limbus into the scala media or alternatively demonstrating abnormal continuity between the connective tissue of the spiral limbus and the remnant of tectorial membrane. Neural degeneration was severe in all cochlear turns. However, more nerve fibers were seen in the proximal portion of Rosenthal's canal than at the habenula perforata or in the organ of Corti, and central processes from the ganglion area were more numerous than peripheral processes. The ganglion cell population was reduced to approximately 10% of normal, and only unmyelinated cell bodies were found. Few recognizable neural fibers were seen within the organ of Corti, although bizarre collections of apparent cellular debris and cell processes containing many mitochondria or vesicles were seen in regions normally containing neural fibers.

Cochlear Changes in Patients with Type 1 Diabetes Mellitus

2005 ◽  
Vol 133 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Hisaki Fukushima ◽  
Sebahattin Cureoglu ◽  
Patricia A. Schachern ◽  
Takeshi Kusunoki ◽  
Mehmet F. Oktay ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Type 1 Diabetes ◽  
Type 1 Diabetes Mellitus ◽  
Hair Cells ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Temporal Bones ◽  
Lateral Walls

OBJECTIVE: To evaluate the effects of diabetes on cochlear elements in human beings. STUDY DESIGN AND SETTING: Twenty-six temporal bones (mean age, 37.5 years) with type 1 diabetes and 30 age-matched controls were examined by light microscopy. We compared the findings of cochlear vessels, hair cells, spiral ganglion cells, and cochlear lateral walls. RESULTS: In diabetics, the walls of vessels of the basilar membrane ( P < 0.001) and vessels of the stria vascularis were ( P < 0.01) significantly thicker in all turns and loss of outer hair cells (OHCs) was significantly greater in the lower basal turn ( P < 0.01). Atrophy of the stria vascularis in all turns ( P < 0.0001) and loss of spiral ligament cells in upper turns ( P < 0.01) were significantly higher than controls. No significant difference was obtained in the number of spiral ganglion cells between groups. CONCLUSION: This study suggests that type 1 diabetes mellitus can cause cochlear microangiopathy and subsequently degeneration of cochlear lateral walls and OHCs.

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