Modiolar Proximity of Three Perimodiolar Cochlear Implant Electrodes

Bałkany, Thomas J.; Eshraghi, Adrien A.; Yang, Nathaniel W.

doi:10.1080/00016480260000021

Cited by 51 publications

(51 citation statements)

References 7 publications

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“…Using the method of defining the angle of insertion of electrodes described by Cohen et al (1996b), all probe locations fell within the quadrants specified in Figure 3B. This is corroborated by Balkany et al (2002), who examined the electrode insertion angle of the Clarion Hi-Focus array with positioner and Nucleus Contour array with videofluoroscopy. An example of the nine interaction functions measured for one representative subject is shown in Figure 4, with the corresponding cumulative functions displayed in Figure 5.…”

Section: Figsupporting

confidence: 50%

“…As the exact angular location of the electrodes within the cochlea has some variability between subjects as measured by videofluoroscopy (Balkany et al 2002), we chose not to specifically localize each probe electrode location for each subject but rather to broadly choose electrodes that would reliably be found in the quadrants depicted in Figure 3B. The disadvantage of this approach is that the longitudinal location of electrodes cannot be ruled out as a contributor to the differences in interaction seen between subjects and array types.…”

Section: Discussionmentioning

confidence: 99%

“…These probe electrode positions are displayed as distance along the electrode array relative to the array's apical end in Figure 3A for each array type. These positions were chosen so as to test one electrode from each of the quadrants demonstrated in Figure 3B, defined by the electrode insertion angle described in several publications (Cohen et al 1996b;Xu et al 2000;Balkany et al 2002). The center-tocenter interelectrode spacing of the Clarion CII implant is 0.9 mm, and that of the Nucleus 24M straight array is 0.7 mm.…”

Section: Figmentioning

confidence: 99%

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Electrode Interaction in Pediatric Cochlear Implant Subjects

Eisen

Franck

2005

JARO

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Multielectrode cochlear implants rely on differential stimulation of the cochlear nerve for presenting the brain with the spectral and timing information required to understand speech. In implant patients, the degree of overlap among cochlear nerve fibers stimulated by the different electrodes constitutes the electrode interaction. Electrode interaction degrades the spectral resolution of the implant's stimulus. We sought to define electrode interaction in a cohort of pediatric cochlear implant subjects as a function of both stimulus intensity and electrode location along the array. The 27 pediatric subjects that completed the study were implanted with either the Clarion HiFocus array with or without positioner, the Nucleus 24 Contour array, or the Nucleus 24 Straight array. All but two of the patients had congenital hearing loss, and none of the patients had meningitis prior to the onset of deafness. The cochlear nerve response was measured with the electrically evoked compound action potential (ECAP). A forward masking protocol was used such that a probe stimulus electrode remained fixed while a preceding masker was moved across the array. Electrode interaction was estimated by measuring the unmasked probe response minus the masked probe response. Three probe locations and three probe intensities were examined for each subject. At all probe locations, electrode interaction increased as probe intensity increased (p G 0.05). Interaction at the basal probe was less than that at either the middle or apical probe locations (p G 0.05), and significant correlation found between probe distance from the basal end of the array and electrode interaction (p G 0.001). These results demonstrate that in this cohort of pediatric subjects, electrode interaction depended on both stimulus intensity and probe location. Implications of these findings on future implant array design and current implant fitting strategies are discussed. The impact of electrode interaction on implant performance is yet to be elucidated.

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Section: Figsupporting

confidence: 50%

Section: Discussionmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

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Electrode Interaction in Pediatric Cochlear Implant Subjects

Eisen

Franck

2005

JARO

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“…However, a large gain in the number of independent sites may well require a fundamentally new type of electrode or a fundamentally different placement of electrodes. The many issues related to electrode design, along with prospects for the future, are discussed elsewhere [15][16][17][18][19][20][21][22][23][24][25]. Figure 2 shows a complete presence of hair cells (in the labeled organ of Corti) and a pristine survival of cochlear neurons.…”

Section: Direct Electrical Stimulation Of Cochlear Neuronsmentioning

confidence: 99%

Cochlear implants: Current designs and future possibilities

Wilson¹

2008

JRRD

317

188

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Abstract-The cochlear implant is the most successful of all neural prostheses developed to date. It is the most effective prosthesis in terms of restoration of function, and the people who have received a cochlear implant outnumber the recipients of other types of neural prostheses by orders of magnitude. The primary purpose of this article is to provide an overview of contemporary cochlear implants from the perspective of two designers of implant systems. That perspective includes the anatomical situation presented by the deaf cochlea and how the different parts of an implant system (including the user's brain) must work together to produce the best results. In particular, we present the design considerations just mentioned and then describe in detail how the current levels of performance have been achieved. We also describe two recent advances in implant design and performance. In concluding sections, we first present strengths and limitations of present systems and then offer some possibilities for further improvements in this technology. In all, remarkable progress has been made in the development of cochlear implants but much room still remains for improvements, especially for patients presently at the low end of the performance spectrum.

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“…More recently, two perimodiolar electrode arrays, the HiFocus™ and Contour™ models (Advanced Bionics, Inc., www.advancedbionics.com, and Cochlear Corporation, www.cochlear.com, respectively), were introduced and are now in widespread use throughout the world (Cords et al, 2000;Tykocinski et al, 2000;Tykocinski et al, 2001;Zwolan et al, 2001;Balkany et al, 2002). Both of these arrays differ significantly from their predecessors in the size and location of stimulating contacts and in overall position within the scala tympani and are thus very different than the scale animal arrays that were developed to model earlier devices.…”

Section: Introductionmentioning

confidence: 99%