scholarly journals The Relationship Between Impedance, Programming and Word Recognition in a Large Clinical Dataset of Cochlear Implant Recipients

2022 ◽  
Vol 26 ◽  
pp. 233121652110609
Author(s):  
Benjamin Caswell-Midwinter ◽  
Elizabeth M. Doney ◽  
Meisam K. Arjmandi ◽  
Kelly N. Jahn ◽  
Barbara S. Herrmann ◽  
...  
Keyword(s):  
Word Recognition ◽  
Cochlear Implant ◽  
Speech Processing ◽  
Dynamic Range ◽  
Electrode Impedance ◽  
Current Steering ◽  
Processing Strategy ◽  
Monosyllabic Word ◽  
Negatively Associated ◽  
Clinical Dataset

Cochlear implant programming typically involves measuring electrode impedance, selecting a speech processing strategy and fitting the dynamic range of electrical stimulation. This study retrospectively analyzed a clinical dataset of adult cochlear implant recipients to understand how these variables relate to speech recognition. Data from 425 implanted post-lingually deafened ears with Advanced Bionics devices were analyzed. A linear mixed-effects model was used to infer how impedance, programming and patient factors were associated with monosyllabic word recognition scores measured in quiet. Additional analyses were conducted on subsets of data to examine the role of speech processing strategy on scores, and the time taken for the scores of unilaterally implanted patients to plateau. Variation in basal impedance was negatively associated with word score, suggesting importance in evaluating the profile of impedance. While there were small, negative bivariate correlations between programming level metrics and word scores, these relationships were not clearly supported by the model that accounted for other factors. Age at implantation was negatively associated with word score, and duration of implant experience was positively associated with word score, which could help to inform candidature and guide expectations. Electrode array type was also associated with word score. Word scores measured with traditional continuous interleaved sampling and current steering speech processing strategies were similar. The word scores of unilaterally implanted patients largely plateaued within 6-months of activation. However, there was individual variation which was not related to initially measured impedance and programming levels.

Efficacy of a Cochlear Implant Simultaneous Analog Stimulation Strategy Coupled with a Monopolar Electrode Configuration

2005 ◽  
Vol 114 (11) ◽  
pp. 886-893 ◽  
Author(s):  
Li Xu ◽  
Teresa A. Zwolan ◽  
Catherine S. Thompson ◽  
Bryan E. Pfingst
Keyword(s):  
Speech Recognition ◽  
Cochlear Implant ◽  
Speech Processing ◽  
Dynamic Range ◽  
Recognition Performance ◽  
Electrode Configuration ◽  
Processing Strategy ◽  
Open Set ◽  
Hearing In Noise ◽  
Noise Test

Objectives: The present study was performed to evaluate the efficacy and clinical feasibility of using monopolar stimulation with the Clarion Simultaneous Analog Stimulation (SAS) strategy in patients with cochlear implants. Methods: Speech recognition by 10 Clarion cochlear implant users was evaluated by means of 4 different speech processing strategy/electrode configuration combinations; ie, SAS and Continuous Interleaved Sampling (CIS) strategies were each used with monopolar (MP) and bipolar (BP) electrode configurations. The test measures included consonants, vowels, consonant-nucleus-consonant words, and Hearing in Noise Test sentences with a +10 dB signal-to-noise ratio. Additionally, subjective judgments of sound quality were obtained for each strategy/configuration combination. Results: All subjects but 1 demonstrated open-set speech recognition with the SAS/MP combination. The group mean Hearing in Noise Test sentence score for the SAS/MP combination was 31.6% (range, 0% to 92%) correct, as compared to 25.0%, 46.7%, and 37.8% correct for the CIS/BP, CIS/MP, and SAS/BP combinations, respectively. Intersubject variability was high, and there were no significant differences in mean speech recognition scores or mean preference ratings among the 4 strategy/configuration combinations tested. Individually, the best speech recognition performance was with the subject's everyday strategy/configuration combination in 72% of the applicable cases. If the everyday strategy was excluded from the analysis, the subjects performed best with the SAS/MP combination in 37.5% of the remaining cases. Conclusions: The SAS processing strategy with an MP electrode configuration gave reasonable speech recognition in most subjects, even though subjects had minimal previous experience with this strategy/configuration combination. The SAS/MP combination might be particularly appropriate for patients for whom a full dynamic range of electrical hearing could not be achieved with a BP configuration.

scholarly journals An Attempt to Improve Bilateral Cochlear Implants by Increasing the Distance between Electrodes and Providing Complementary Information to the Two Ears

2010 ◽  
Vol 21 (01) ◽  
pp. 052-065 ◽  
Author(s):  
Richard S. Tyler ◽  
Shelley A. Witt ◽  
Camille C. Dunn ◽  
Ann Perreau ◽  
Aaron J. Parkinson ◽  
...  
Keyword(s):  
Speech Perception ◽  
Cochlear Implant ◽  
Cochlear Implants ◽  
Speech Processing ◽  
Processing Strategy ◽  
Bilateral Cochlear Implants ◽  
Channel Interaction ◽  
Consonant Recognition ◽  
Bilateral Cochlear Implant ◽  
Input Spectrum

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.

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

1986 ◽  
Vol 29 (2) ◽  
pp. 282-287 ◽  
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.

Speech-Processing Strategies and Their Implementation

1987 ◽  
Vol 96 (1_suppl) ◽  
pp. 71-74 ◽  
Author(s):  
P. Seligman
Keyword(s):  
Cochlear Implant ◽  
Pulse Rate ◽  
Speech Processing ◽  
Temporal Coding ◽  
Electrode Position ◽  
Processing Strategy ◽  
Limited Information ◽  
Processing Strategies ◽  
Speech Information

Since 1979, the Australian speech-processing strategy has been based on the presentation of an estimate of F2 coded by electrode position and F0 coded by pulse rate. Although providing limited information, this strategy has produced good results with significant hearing-alone performance. This paper describes a number of strategies that provide further speech information in an attempt to increase hearing-alone performance to a level where the cochlear implant is able to operate in its own right rather than as an adjunct to lipreading. The strategies are all based on the addition of F1 to the existing strategy. Both electrode and temporal coding of F1 is described, and the performance and percepts produced are discussed. Amplitudes of the two formants must be carefully controlled to avoid masking. The implications of the strategies on the design of hardware are described.

Signal Coding in Cochlear Implants: Exploiting Stochastic Effects of Electrical Stimulation

2003 ◽  
Vol 112 (9_suppl) ◽  
pp. 14-19 ◽  
Author(s):  
Jay T. Rubinstein ◽  
Robert Hong
Keyword(s):  
Electrical Stimulation ◽  
Speech Perception ◽  
Cochlear Implants ◽  
Speech Processing ◽  
Music Perception ◽  
Dynamic Range ◽  
High Rate ◽  
Monosyllabic Word ◽  
Stochastic Effects ◽  
Processing Strategies

Speech perception in quiet with cochlear implants has increased substantially over the past 17 years. If current trends continue, average monosyllabic word scores will be nearly 80% by 2010. These improvements are due to enhancements in speech processing strategies, to the implantation of patients with more residual hearing and shorter durations of deafness, and to unknown causes. Despite these improvements, speech perception in noise and music perception are still poor in most implant patients. These deficits may be partly due to poor representation of temporal fine structure by current speech processing strategies. It may be possible to improve both this representation and the dynamic range of electrical stimulation through the exploitation of stochastic effects produced by high-rate (eg, 5-kilopulse-per-second) pulse trains. Both the loudness growth and the dynamic range of low-frequency sinusoids have been enhanced via this technique. A laboratory speech processor using this strategy is under development. Although the clinical programming for such an algorithm is likely to be complex, some guidelines for the psychophysical and electrophysiological techniques necessary can be described now.

scholarly journals Amplitude Growth Functions of Auditory Nerve Responses to Electric Pulse Stimulation With Varied Interphase Gaps in Cochlear Implant Users With Ipsilateral Residual Hearing

2021 ◽  
Vol 25 ◽  
pp. 233121652110141
Author(s):  
Marina Imsiecke ◽  
Andreas Büchner ◽  
Thomas Lenarz ◽  
Waldo Nogueira
Keyword(s):  
Cochlear Implant ◽  
Dynamic Range ◽  
Electric Pulse ◽  
Objective Measure ◽  
Stimulus Level ◽  
Control Group ◽  
Electrode Impedance ◽  
Residual Hearing ◽  
Growth Functions ◽  
Amplitude Growth

Amplitude growth functions (AGFs) of electrically evoked compound action potentials (eCAPs) with varying interphase gaps (IPGs) were measured in cochlear implant users with ipsilateral residual hearing (electric-acoustic stimulation [EAS]). It was hypothesized that IPG effects on AGFs provide an objective measure to estimate neural health. This hypothesis was tested in EAS users, as residual low-frequency hearing might imply survival of hair cells and hence better neural health in apical compared to basal cochlear regions. A total of 16 MED-EL EAS subjects participated, as well as a control group of 16 deaf cochlear implant users. The IPG effect on the AGF characteristics of slope, threshold, dynamic range, and stimulus level at 50% maximum eCAP amplitude (level50%) was investigated. AGF threshold and level50% were significantly affected by the IPG in both EAS and control group. The magnitude of AGF characteristics correlated with electrode impedance and electrode-modiolus distance (EMD) in both groups. In contrast, the change of the AGF characteristics with increasing IPG was independent of these electrode-specific measures. The IPG effect on the AGF level50% in both groups, as well as on the threshold in EAS users, correlated with the duration of hearing loss, which is a predictor of neural health. In EAS users, a significantly different IPG effect on level50% was found between apical and medial electrodes. This outcome is consistent with our hypothesis that the influence of IPG effects on AGF characteristics provides a sensitive measurement and may indicate better neural health in the apex compared to the medial cochlear region in EAS users.

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