Channel interaction in cochlear implant acoustic models

Author(s):  
Charles T. M. Choi ◽  
Shang-Yi Huang ◽  
Yi-Hsuan Lee
2013 ◽  
Vol 133 (6) ◽  
pp. 4124-4132 ◽  
Author(s):  
Paul Bader ◽  
Mathias Kals ◽  
Reinhold Schatzer ◽  
Andreas Griessner ◽  
Clemens Zierhofer

2010 ◽  
Vol 21 (01) ◽  
pp. 052-065 ◽  
Author(s):  
Richard S. Tyler ◽  
Shelley A. Witt ◽  
Camille C. Dunn ◽  
Ann Perreau ◽  
Aaron J. Parkinson ◽  
...  

Objectives: The purpose of this investigation was to determine if adult bilateral cochlear implant recipients could benefit from using a speech processing strategy in which the input spectrum was interleaved among electrodes across the two implants. Design: Two separate experiments were conducted. In both experiments, subjects were tested using a control speech processing strategy and a strategy in which the full input spectrum was filtered so that only the output of half of the filters was audible to one implant, while the output of the alternative filters was audible to the other implant. The filters were interleaved in a way that created alternate frequency “holes” between the two cochlear implants. Results: In experiment one, four subjects were tested on consonant recognition. Results indicated that one of the four subjects performed better with the interleaved strategy, one subject received a binaural advantage with the interleaved strategy that they did not receive with the control strategy, and two subjects showed no decrement in performance when using the interleaved strategy. In the second experiment, 11 subjects were tested on word recognition, sentences in noise, and localization (it should be noted that not all subjects participated in all tests). Results showed that for speech perception testing one subject achieved significantly better scores with the interleaved strategy on all tests, and seven subjects showed a significant improvement with the interleaved strategy on at least one test. Only one subject showed a decrement in performance on all speech perception tests with the interleaved strategy. Out of nine subjects, one subject preferred the sound quality of the interleaved strategy. No one performed better on localization with the interleaved strategy. Conclusion: Data from this study indicate that some adult bilateral cochlear implant recipients can benefit from using a speech processing strategy in which the input spectrum is interleaved among electrodes across the two implants. It is possible that the subjects in this study who showed a significant improvement with the interleaved strategy did so because of less channel interaction; however, this hypothesis was not directly tested.


2020 ◽  
Vol 81 (1-4) ◽  
pp. 17-23
Author(s):  
P.A. Cucis ◽  
C. Berger-Vachon ◽  
R. Hermann ◽  
H. Thaï-Van ◽  
S. Gallego ◽  
...  

The cochlear implant is the most successful implantable device for the rehabilitation of profound deafness. However, in some cases, the electrical stimulation delivered by the electrode can spread inside the cochlea creating overlap and interaction between frequency channels. By using channel-selection algorithms like the “nofm” coding-strategy, channel interaction can be reduced. This paper describes the preliminary results of experiments conducted with normal hearing subjects (n = 9). Using a vocoder, the present study simulated the hearing through a cochlear implant. Speech understanding in noise was measured by varying the number of selected channels (“nofm”: 4, 8, 12 and 16of20) and the degree of simulated channel interaction (“Low”, “Medium”, “High”). Also, with the vocoder, we evaluated the impact of simulated channel interaction on frequency selectivity by measuring psychoacoustic tuning curves. The results showed a significant average effect of the signal-to-noise ratio (p < 0.0001), the degree of channel interaction (p < 0.0001) and the number of selected channels, (p = 0.029). The highest degree of channel interaction significantly decreases intelligibility as well as frequency selectivity. These results underline the importance of measuring channel interaction for cochlear implanted patients to have a prognostic test and to adjust fitting methods in consequence. The next step of this project will be to transpose these experiments to implant users, to support our results.


2021 ◽  
Vol 25 ◽  
pp. 233121652110301
Author(s):  
Waldo Nogueira ◽  
Nawal El Boghdady ◽  
Florian Langner ◽  
Etienne Gaudrain ◽  
Deniz Başkent

Speech intelligibility in multitalker settings is challenging for most cochlear implant (CI) users. One possibility for this limitation is the suboptimal representation of vocal cues in implant processing, such as the fundamental frequency (F0), and the vocal tract length (VTL). Previous studies suggested that while F0 perception depends on spectrotemporal cues, VTL perception relies largely on spectral cues. To investigate how spectral smearing in CIs affects vocal cue perception in speech-on-speech (SoS) settings, adjacent electrodes were simultaneously stimulated using current steering in 12 Advanced Bionics users to simulate channel interaction. In current steering, two adjacent electrodes are simultaneously stimulated forming a channel of parallel stimulation. Three such stimulation patterns were used: Sequential (one current steering channel), Paired (two channels), and Triplet stimulation (three channels). F0 and VTL just-noticeable differences (JNDs; Task 1), in addition to SoS intelligibility (Task 2) and comprehension (Task 3), were measured for each stimulation strategy. In Tasks 2 and 3, four maskers were used: the same female talker, a male voice obtained by manipulating both F0 and VTL (F0+VTL) of the original female speaker, a voice where only F0 was manipulated, and a voice where only VTL was manipulated. JNDs were measured relative to the original voice for the F0, VTL, and F0+VTL manipulations. When spectral smearing was increased from Sequential to Triplet, a significant deterioration in performance was observed for Tasks 1 and 2, with no differences between Sequential and Paired stimulation. Data from Task 3 were inconclusive. These results imply that CI users may tolerate certain amounts of channel interaction without significant reduction in performance on tasks relying on voice perception. This points to possibilities for using parallel stimulation in CIs for reducing power consumption.


2013 ◽  
Vol 133 (1) ◽  
pp. 425-433 ◽  
Author(s):  
Gary L. Jones ◽  
Jong Ho Won ◽  
Ward R. Drennan ◽  
Jay T. Rubinstein

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