Audiology & neuro-otology
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Audiology & neuro-otology · Jan 2006
Comparative StudyComparison of round window and cochleostomy approaches with a prototype hearing preservation electrode.
Preservation of residual hearing in cochlear implant recipients has been demonstrated to be possible and provides the potential benefit of combined electric and acoustic auditory stimulation. A prototype 16-mm multichannel array has been designed to facilitate placement of 22 electrodes without damage to intracochlear structures. The electrode array is suitable for insertion via the round window membrane (RWM) or a small cochleostomy. ⋯ A prototype hearing preservation electrode array was inserted by either a RWM or a scala tympani cochleostomy without evidence of significant intracochlear trauma.
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Audiology & neuro-otology · Jan 2006
Audiometric patterns in ototoxicity of intra-arterial Cisplatin chemoradiation in patients with locally advanced head and neck cancer.
This study describes audiometric patterns of ototoxicity in a consecutive series of patients uniformly treated with intra-arterial high-dose cisplatin chemoirradiation for advanced cancer of the head and neck. Air conduction thresholds were measured from 0.125 to 16 kHz and bone conduction thresholds were measured from 0.5 to 4 kHz. ⋯ Cisplatin chemoradiation-induced hearing loss seemed to reach a plateau at higher levels (75-80 dB HL) for frequencies above 8 kHz compared to frequencies up to 8 kHz (45-60 dB HL). Recovery of SNHL was found after therapy in 27 ears characterized by extensive hearing loss at frequencies 1, 2 and 4 kHz.
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Adenosine triphosphate (ATP) is a major intercellular signalling molecule that is involved in neurotransmission in the central and autonomic nervous systems, regulation of blood flow, and neuroendocrine function. It is also a key signalling molecule involved in normal cochlear homoeostasis, regulating hearing sensitivity, controlling vascular tone and acting as a candidate neurotransmitter at the hair cell afferent synapses. ⋯ Evidence for a profound influence of extracellular ATP on normal cochlear function offers the tantalizing possibility that extracellular purine nucleotides may play a role in disease processes in the inner ear. This review draws on the current understanding of the pathophysiological role of extracellular ATP in tissues, and the evidence for the functional expression of purinergic signalling elements in the inner ear, to speculate on the potential role of purine nucleotides in cochlear pathology.
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Audiology & neuro-otology · Sep 2001
A novel microperfusion system for the long-term local supply of drugs to the inner ear: implantation and function in the rat model.
Local therapy is practiced for middle and inner ear diseases but is usually restricted to cases of ear drum perforation or repeated invasive intratympanic drug application. Perfusion of drugs on the round window or through the scalae of animals using a pump system suggests that the chronic local drug treatment might also be feasible in humans. However, drug delivery systems that are currently on the market involve repeated reimplantation if they are to be used for long-term drug supply. ⋯ In 2 animals which carried the MDS for more than 8 months the proper functioning of the pumping device was examined in a 2-3 week interval over a 3 month period. The MDS can be autoclaved even after long-term implantation and can then be reused for subsequent implantations. Designed for life-long implantation in humans, the demonstration of an effective long-term drug supply to the inner ear using the MDS provides an encouraging first step towards future long-term drug treatment of the inner ear in humans.