RESUMO
Recent animal work has suggested that cochlear synapses are more vulnerable than hair cells in both noise-induced and age-related hearing loss. This synaptopathy is invisible in conventional histopathological analysis, because cochlear nerve cell bodies in the spiral ganglion survive for years, and synaptic analysis requires special immunostaining or serial-section electron microscopy. Here, we show that the same quadruple-immunostaining protocols that allow synaptic counts, hair cell counts, neuronal counts and differentiation of afferent and efferent fibers in mouse can be applied to human temporal bones, when harvested within 9 h post-mortem and prepared as dissected whole mounts of the sensory epithelium and osseous spiral lamina. Quantitative analysis of five "normal" ears, aged 54-89 yrs, without any history of otologic disease, suggests that cochlear synaptopathy and the degeneration of cochlear nerve peripheral axons, despite a near-normal hair cell population, may be an important component of human presbycusis. Although primary cochlear nerve degeneration is not expected to affect audiometric thresholds, it may be key to problems with hearing in noise that are characteristic of declining hearing abilities in the aging ear.
Assuntos
Cóclea/inervação , Nervo Coclear/patologia , Microscopia Confocal , Degeneração Neural , Presbiacusia/patologia , Osso Temporal/patologia , Idoso , Idoso de 80 Anos ou mais , Limiar Auditivo , Autopsia , Axônios/patologia , Estudos de Casos e Controles , Nervo Coclear/química , Nervo Coclear/fisiopatologia , Feminino , Imunofluorescência , Células Ciliadas Auditivas/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Ruído/efeitos adversos , Mascaramento Perceptivo , Presbiacusia/metabolismo , Presbiacusia/fisiopatologia , Gânglio Espiral da Cóclea/patologia , Sinapses/patologia , Osso Temporal/químicaRESUMO
Numerous changes continue to occur in cochlear implant candidacy. In general, these have been accompanied by concomitant and satisfactory changes in surgical techniques. Together, this has advanced the utility and safety of cochlear implantation. Most devices are now approved for use in patients with severe to profound unilateral hearing loss rather then the prior requirement of a bilateral profound loss. Furthermore, studies have begun utilizing short electrode arrays for shallow insertion in patients with considerable low-frequency residual hearing. This technique will allow the recipient to continue to use acoustically amplified hearing for the low frequencies simultaneously with a cochlear implant for the high frequencies. The advances in design of, and indications for, cochlear implants have been matched by improvements in surgical techniques and decrease in complications. The resulting improvements in safety and efficacy have further encouraged the use of these devices. This paper will review the new concepts in the candidacy of cochlear implant. Medline data base was used to search articles dealing with the following topics: cochlear implant in younger children, cochlear implant and hearing preservation, cochlear implant for unilateral deafness and tinnitus, genetic hearing loss and cochlear implant, bilateral cochlear implant, neuropathy and cochlear implant and neural plasticity, and the selection of patients for cochlear implant.
RESUMO
Introdução: As lesões do forame jugular são raras, sendo os paragangliomas os tumores mais comuns desta região seguidos pelos schwannomas. Os schwannomas são tumores benignos de crescimento lento e origem principalmente nos nervos cranianos sensitivos. Quando localizados no forame jugular, apresentam-se clinicamente com perda auditiva, ataxia e cefaleia, sendo comuns as alterações dos nervos cranianos IX, X e XI. A excisão cirúrgica é a opção terapêutica de escolha. Relato do Caso: Relatamos o caso de um paciente adulto jovem que procurou o serviço de Otorrinolaringologia do Hospital Universitário de Brasília com quadro de otalgia e otorreia piossanguinolenta no ouvido esquerdo, associada a zumbido, hipoacusia e tumor no conduto auditivo externo. Iniciada investigação diagnóstica com tomografia computadorizada e biópsia, ambas com resultados inconclusivos. Realizadas então nova biópsia e ressonância nuclear magnética, com diagnóstico definitivo de schwannoma do foram jugular. Na ocasião a lesão foi definida como tipo D pela classificação de Kaye-Pellet, por envolver o forame jugular, apresentar formato de halter e componentes intra e extracraniano. Realizada cirurgia por craniotomia com excisão parcial do tumor. Não houve sequelas do procedimento, apesar da persistência dos sintomas otológicos. Comentários Finais: O caso é um exemplo de uma doença rara, com pouco mais de duzentos casos relatados na literatura, e apresentação clínica incomum. O desafio diagnóstico e terapêutico é enfrentado pelas equipes de Otorrinolaringologia e Neurocirurgia, que programam para breve nova abordagem cirúrgica combinada para extirpação completa do tumor.
Introduction: Lesions of the jugular foramen are uncommon, and the paragangliomas are the most common tumors in this region, followed by schwannomas. Schwannomas are benign tumors, of slow growth and origin mainly in the sensitive cranial nerves. When located in the jugular foramen, the patients present with clinically auditory hearing loss, ataxia and headache, and cranial nerves IX, X and XI alterations are also common. Surgical excision is the therapeutic choice. Case Report: We reported the case of a young adult patient who sought the Otorhinolaryngology service at the School Hospital of Brasília for investigation of otalgia and chronic infection in the left ear, associated with tinnitus, hypacusis and tumor in the external ear canal. Initial diagnostic investigation by computed tomography and biopsy was inconclusive. New biopsy and magnetic resonance imaging were performed and definitive diagnosis of jugular foramen schwannoma was given. The lesion was then defined as type D by the classification of Kaye-Pellet, for it involved the jugular foramen, presented format of dumbbell and intra and extracranial components. The patient underwent a craniotomy and partial excision of the tumor. He did not have sequels of the procedure, although the otologic symptoms persisted. Final Comments: This case is an example of a rare disease. No more than two hundred cases have been reported in the literature and the clinical presentation is uncommon. The diagnostic and therapeutic challenge is faced by Otorhinolaryngology and Neurosurgery teams who are scheduling a new combined surgical procedure for a complete excision of the tumor.
Assuntos
Humanos , Masculino , Adulto , Forame Magno , Veias Jugulares , Neoplasias Cranianas/diagnóstico , Neuroma Acústico/diagnósticoRESUMO
OBJECTIVE: The objective of this study was to perform a morphometric analysis of a series of temporal bones with cochleosaccular dysplasia to clarify the extent of inner ear changes in this disease. STUDY DESIGN: This human temporal bone histopathologic study of a series of deaf-mute cases involves morphometric analysis, including stria vascularis and spiral ligament area measurements and spiral ganglion and hair cells counts. SUBJECTS: Thirteen temporal bones were selected from 35 with deaf mutism based on the histopathologic findings described by Scheibe. Twenty normal age-matched control subjects were used for comparisons. RESULTS: All temporal bones had the main histopathologic findings described by Scheibe, as well as severe affected stria vascularis. Seven temporal bones had cystic areas in the stria and three had concretions. Cross-sectional strial areas in temporal bones with cochleosaccular dysplasia were smaller than normal in all cochlear turns; however, no difference was found in spiral ligament cross-sectional areas. Reissner's membrane was hydropic in three temporal bones and the organ of Corti was absent in at least one cochlear turn in five. Concretions were present in the macula of seven temporal bones. Twelve temporal bones showed some level of spiral ganglion cell loss. No hair cells were observed in any temporal bone. A familial history of deafness was found in three cases. CONCLUSION: Pathologic findings were variable and limited to the saccule and scala media. The variation, perhaps, reflects the different etiologies involved in the origin of cochleosaccular dysplasia.