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A rotationally symmetric model of electrical stimulation of the guinea pig cochlea with active neural elements is used to study the influence of temporal stimulus parameters and electrode configurations on the spatial selectivity of electrical stimulation by cochlear implants. The width of the excitation patterns is determined with respect to the position(More)
Cochlear implant research endeavors to optimize the spatial selectivity, threshold and dynamic range with the objective of improving the speech perception performance of the implant user. One of the ways to achieve some of these goals is by electrode design. New cochlear implant electrode designs strive to bring the electrode contacts into close proximity(More)
With the advent of eCAP recording tools such as NRT and NRI for cochlear implants, neural monitoring has become widely used to ascertain the integrity of the neural/electrode interface as well as for assisting in the setting of program levels. The basic concepts of eCAP recordings are deduced from the acoustical equivalent of the electrocochleogram. There(More)
In spite of many satisfactory results, the clinical outcome of cochlear implantation is poorly predictable and further insight into the fundamentals of electrical nerve stimulation in this complex geometry is necessary. For this purpose we developed a rotationally symmetric volume conductor model of the implanted cochlea, using the Boundary Element Method(More)
This paper presents an upgraded cable model of mammalian myelinated nerve fibers in an extracellularly applied field. The kinetics of the nodes is based upon voltage clamp data in rat motor fibers at 37 degrees C, while the resting membrane potential is computed with the Goldman equation. The resulting spike shape, conduction velocity, strength/duration(More)
HYPOTHESIS An objective cochlear framework, for evaluation of the cochlear anatomy and description of the position of an implanted cochlear implant electrode, would allow the direct comparison of measures performed within the various subdisciplines involved in cochlear implant research. BACKGROUND Research on the human cochlear anatomy in relation to(More)
OBJECTIVE To evaluate psychophysically the spatial spread of excitation in electrical hearing with a new dual contact masker and to investigate under which conditions it is possible to stimulate fibers in the immediate neighborhood of an electrode contact, which were not excited by neighboring electrode contacts. DESIGN In this study a psychophysical(More)
Several multipolar current focussing strategies are examined in a computational model of the implanted human cochlea. The model includes a realistic spatial distribution of cell bodies of the auditory neurons throughout Rosenthal's canal. Simulations are performed of monopolar, (partial) tripolar and phased array stimulation. Excitation patterns, estimated(More)
Starting with the spatially extended non-linear node model (Reilly et al., 1985), which incorporates Frankenhaeuser-Huxley non-linearities at each of several nodes in a row, a model is developed to describe many aspects of the behaviour of mammalian nerve fibres in a quantitative way. By taking into account the effects of temperature and by introducing a(More)