Diversity in Cochlear Morphology and Its Influence on Cochlear Implant Electrode Position

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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The effects of electrode position and stimulus period on the hearing sensations in a multiple‐channel cochlear implant patient

The Journal of the Acoustical Society of America ◽

10.1121/1.2018917 ◽

1981 ◽

Vol 70 (S1) ◽

pp. S52-S53 ◽

Cited By ~ 1

Author(s):

Y. C. Tong ◽

P. J. Blamey ◽

R. C. Dowell ◽

G. M. Clark

Keyword(s):

Cochlear Implant ◽

Electrode Position ◽

Stimulus Period ◽

Multiple Channel

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Pitch Matching in Cochlear Implant Users With Single-Sided Deafness: Effects of Electrode Position and Acoustic Stimulus Type

Frontiers in Neuroscience ◽

10.3389/fnins.2019.01119 ◽

2019 ◽

Vol 13 ◽

Cited By ~ 2

Author(s):

Youssef Adel ◽

Sharon Nagel ◽

Tobias Weissgerber ◽

Uwe Baumann ◽

Olivier Macherey

Keyword(s):

Cochlear Implant ◽

Stimulus Type ◽

Acoustic Stimulus ◽

Electrode Position ◽

Pitch Matching ◽

Single Sided Deafness

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Rotational tomography in cochlear implant patients: a new tool for quality control of the electrode position

Cochlear Implants International ◽

10.1002/cii.208 ◽

2004 ◽

Vol 5 (S1) ◽

pp. 147-149 ◽

Cited By ~ 4

Author(s):

A Aschendorff ◽

R Kubalek ◽

A Bink ◽

FE Zanella ◽

A Hochmuth ◽

...

Keyword(s):

Quality Control ◽

Cochlear Implant ◽

Electrode Position

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Electrically Elicited Stapedius Reflex and Preferred Listening Level in a Patient with a Cochlear Implant

Annals of Otology Rhinology & Laryngology ◽

10.1177/00034894870960s153 ◽

1987 ◽

Vol 96 (1_suppl) ◽

pp. 99-101

Author(s):

J. F. Jerger ◽

H. A. Jenkins ◽

R. Chmiel ◽

T. A. Oliver

Keyword(s):

Cochlear Implant ◽

Spacing Effect ◽

Current Level ◽

Constant Current ◽

Electrode Spacing ◽

Electrode Position ◽

Apical Position ◽

Reflex Amplitude ◽

Stapedial Reflex ◽

Intensity Functions

In a patient with a multichannel cochlear implant, it was possible to demonstrate stapedial reflex contraction to intracochlear electrical stimulation. Using a standard immittance measurement technique, characteristics of the electrically evoked reflex were compared to analogous characteristics of the acoustically evoked reflex. Latency-intensity functions were similar for the two modes of excitation, but reflex waveform morphology and amplitude growth functions were different. The effects of electrode position and electrode spacing were of particular interest. In our patient, neither position nor spacing affected onset latency. Both electrode position and electrode spacing did, however, affect reflex amplitude. As position moved from base to apex, reflex amplitude increased systematically and substantially. Although we have reported amplitude results in suprathreshold current level, we also found the same relationship across electrode position for stimulation at constant current level. Reflex amplitude by electrode spacing was also affected. The widest spacing (3 mm) produced the largest reflex amplitude, and the narrowest spacing (1.5 mm) produced the smallest amplitude. The spacing effect, however, showed a strong interaction with electrode position, being greatest at the apical position and least at the basal position.

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Previous Experience as a Confounding Factor in Comparing Cochlear-Implant Processing Schemes

Journal of Speech Language and Hearing Research ◽

10.1044/jshr.2902.282 ◽

1986 ◽

Vol 29 (2) ◽

pp. 282-287 ◽

Cited By ~ 31

Author(s):

Richard S. Tyler ◽

John P. Preece ◽

Bruce J. Gantz ◽

Steven R. Otto ◽

Charissa R. Lansing

Keyword(s):

Cochlear Implant ◽

Hearing Aids ◽

Speech Processing ◽

Dynamic Range ◽

Prior Experience ◽

Previous Experience ◽

Electrode Position ◽

Formant Frequency ◽

Processing Scheme ◽

The Subject

It is of great importance to compare the relative merits of different cochlear-implant speech-processing strategies. Some groups have compared different strategies within single subjects, but usually the subject has prior experience with one strategy, and no allowance is made for this prior experience. We show in the present study that this is inappropriate. We tested one subject using the Melbourne (Cochlear Corp.) multichannel implant with the device set to process sounds in two different ways. In the first processing scheme, the device functioned normally, extracting information about voicing frequency, amplitude and second-formant frequency. This information activated the 21-channel device, determining pulse rate, pulse amplitude and electrode position (respectively). In the second processing scheme, a single electrode (with the largest dynamic range) was activated. This electrode coded overall amplitude and voicing frequency. The subject was tested on an audiovisual test of a 14-choice consonant recognition in the form/iCi/ over a period of over 4 months. During this time the subject used the 21-channel processor outside of the laboratory. Upon initial connection, there was little difference between the results obtained with the two schemes when tested in sound alone or in sound plus vision. However, after about 4 months, scores obtained with the 21-channel processor in sound plus vigion were superior to the scores obtained with the one channel. This advantage came from a superiority in the features of voicing and nasality, but not place. Scores for sound-alone conditions between the two processing schemes remained similar for the 4-month period. Studies investigating the relative merits of speech processing systems (including tactile and conventional hearing aids) must consider previous experience as an important factor.

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