Electrophysiological Evidence of the Basilar-Membrane Travelling Wave and Frequency Place Coding of Sound in Cochlear Implant Recipients

2017 ◽  
Vol 22 (3) ◽  
pp. 180-189 ◽  
Author(s):  
Luke Campbell ◽  
Christofer Bester ◽  
Claire Iseli ◽  
David Sly ◽  
Adrian Dragovic ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Direct Evidence ◽  
Basilar Membrane ◽  
Diagnostic Value ◽  
Travelling Wave ◽  
Phase Delay ◽  
Neural Function ◽  
Specific Information ◽  
Auditory Prosthesis ◽  
Frequency Dependent

Aim: To obtain direct evidence for the cochlear travelling wave in humans by performing electrocochleography from within the cochlea in subjects implanted with an auditory prosthesis. Background: Sound induces a travelling wave that propagates along the basilar membrane, exhibiting cochleotopic tuning with a frequency-dependent phase delay. To date, evoked potentials and psychophysical experiments have supported the presence of the travelling wave in humans, but direct measurements have not been made. Methods: Electrical potentials in response to rarefaction and condensation acoustic tone bursts were recorded from multiple sites along the human cochlea, directly from a cochlear implant electrode during, and immediately after, its insertion. These recordings were made from individuals with residual hearing. Results: Electrocochleography was recorded from 11 intracochlear electrodes in 7 ears from 6 subjects, with detectable responses on all electrodes in 5 ears. Cochleotopic tuning and frequency-dependent phase delay of the cochlear microphonic were demonstrated. The response latencies were slightly shorter than those anticipated which we attribute to the subjects' hearing loss. Conclusions: Direct evidence for the travelling wave was observed. Electrocochleography from cochlear implant electrodes provides site-specific information on hair cell and neural function of the cochlea with potential diagnostic value.

Magnetic Steering of Robotically Inserted Lateral-wall Cochlear-implant Electrode Arrays Reduces Forces on the Basilar Membrane In Vitro

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Cameron M. Hendricks ◽  
Matt S. Cavilla ◽  
David E. Usevitch ◽  
Trevor L. Bruns ◽  
Katherine E. Riojas ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Basilar Membrane ◽  
Lateral Wall ◽  
Electrode Arrays ◽  
Magnetic Steering

scholarly journals The Effect of Pulling Out Cochlear Implant Electrodes on Inner Ear Microstructures: A Temporal Bone Study

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
Ingo Todt ◽  
Rainer O. Seidl ◽  
Arne Ernst
Keyword(s):  
Cochlear Implant ◽  
Inner Ear ◽  
Temporal Bone ◽  
Basilar Membrane ◽  
Temporal Sequence ◽  
Pull Out ◽  
Temporal Bones

The exchange of an cochlear implant or the re-positioning of an electrode have become more frequently required than a decade ago. The consequences of such procedures at a microstructural level within the cochlea are not known. It was the aim of the present study to further investigate the effects of an CI electrode pull-out. Therefore 10 freshly harvested temporal bones (TB) were histologically evaluated after a cochlear implant electrode pull-out of a perimodiolar electrode. In additional 9 TB the intrascalar movements of the CI electrode while being pulled-out were digitally analysed by video- capturing. Histologically, a disruption of the modiolar wall or the spiral osseous lamina were not observed. In one TB, a basilar membrane lifting up was found, but it could not be undoubtedly attributed to the pull-out of the electrode. When analyzing the temporal sequence of the electrode movement during the pull-out, the electrode turned in one case so that the tip elevates the basilar membrane. The pull- out of perimodiolarly placed CI electrodes does not damage the modiolar wall at a microstructural level and should be guided (e.g., forceps) to prevent a 90 o turning of the electrode tip into the direction of the basilar membrane.

A fully coupled subwavelength resonance approach to filtering auditory signals

2019 ◽  
Vol 475 (2228) ◽  
pp. 20190049 ◽  
Author(s):  
Habib Ammari ◽  
Bryn Davies
Keyword(s):  
Basilar Membrane ◽  
Travelling Wave ◽  
Frequency Separation ◽  
Mathematical Explanation ◽  
Layer Potential ◽  
Cochlear Hair Cells ◽  
Resonant Modes ◽  
Acoustic Pressure Wave ◽  
Frequency Map ◽  
Set Up

The aim of this paper is to understand the behaviour of a large number of coupled subwavelength resonators. We use layer potential techniques in combination with numerical computations to study an acoustic pressure wave scattered by a graded array of subwavelength resonators. Using this approach, the spatial frequency separation properties of such an array can be understood. Our set-up is inspired by the graded structure of cochlear hair cells on the surface of the basilar membrane. We compute the resonant modes of the system and explore the model's ability to decompose incoming signals. We propose a mathematical explanation for phenomena identified with the cochlea's ‘travelling wave’ behaviour and tonotopic frequency map.

scholarly journals Evaluation of cochlear implant electrode scalar position by 3 Tesla magnet resonance imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Riemann ◽  
L. U. Scholtz ◽  
H. B. Gehl ◽  
M. Schürmann ◽  
H. Sudhoff ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Basilar Membrane ◽  
Single Case ◽  
Lateral Wall ◽  
Electrode Position ◽  
Voxel Size ◽  
Recent Developments ◽  
A Prospective Study ◽  
Magnet Resonance

AbstractThe estimation of scalar electrode position is a central point of quality control during the cochlear implant procedure. Ionic radiation is a disadvantage of commonly used radiologic estimation of electrode position. Recent developments in the field of cochlear implant magnets, implant receiver magnet position, and MRI sequence usage allow the postoperative evaluation of inner ear changes after cochlear implantation. The aim of the present study was to evaluate the position of lateral wall and modiolar cochlear implant electrodes using 3 T MRI scanning. In a prospective study, we evaluated 20 patients (10× Med-El Flex 28; 5× HFMS AB and 5× SlimJ AB) with a 3 T MRI and a T2 2D Drive MS sequence (voxel size: 0.3 × 0.3 × 0.9 mm) for the estimation of the intracochlear position of the cochlear implant electrode. In all cases, MRI allowed a determination of the electrode position in relation to the basilar membrane. This observation made the estimation of 19 scala tympani electrode positions and a single case of electrode translocation possible. 3 T MRI scanning allows the estimation of lateral wall and modiolar electrode intracochlear scalar positions.

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