Optimizing frequency-to-electrode allocation for individual cochlear implant users

Grasmeder, Mary L.; Verschuur, Carl; Batty, V.

doi:10.1121/1.4900831

Cited by 21 publications

(16 citation statements)

References 44 publications

(27 reference statements)

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“…This raises the question of whether CIs could be fitted with the goal of mitigating the effect of decreased spectrotemporal resolution that may arise from channel interaction. Several studies (e.g., Di Nardo et al., 2011 ; El Boghdady et al., 2018 ; Fitzgerald et al., 2013 ; Fu & Shannon, 1999 ; Grasmeder et al., 2014 ; Leigh et al., 2004 ; McKay & Henshall, 2002 ; Omran et al., 2011 ) have proposed that optimizing the frequency-to-electrode allocation map could have the potential to address the limited spectral resolution in the implant. More specifically, using vocoder simulations, El Boghdady et al.…”

Section: Discussionmentioning

confidence: 99%

Effect of Channel Interaction on Vocal Cue Perception in Cochlear Implant Users

et al. 2021

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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.

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“…This raises the question of whether CIs could be fitted with the goal of mitigating the effect of decreased spectrotemporal resolution that may arise from channel interaction. Several studies (e.g., Di Nardo et al., 2011 ; El Boghdady et al., 2018 ; Fitzgerald et al., 2013 ; Fu & Shannon, 1999 ; Grasmeder et al., 2014 ; Leigh et al., 2004 ; McKay & Henshall, 2002 ; Omran et al., 2011 ) have proposed that optimizing the frequency-to-electrode allocation map could have the potential to address the limited spectral resolution in the implant. More specifically, using vocoder simulations, El Boghdady et al.…”

Section: Discussionmentioning

confidence: 99%

Effect of Channel Interaction on Vocal Cue Perception in Cochlear Implant Users

et al. 2021

View full text Add to dashboard Cite

show abstract

“…This raises the question of whether CIs could be fitted with the goal of mitigating the effect of decreased spectrotemporal resolution that may arise from channel interaction. Several studies (e.g., Di Nardo, Scorpecci, Giannantonio, Cianfrone, & Paludetti, 2011;El Boghdady et al, 2018;Fitzgerald, Sagi, Morbiwala, Tan, & Svirsky, 2013;Fu & Shannon, 1999;Grasmeder, Verschuur, & Batty, 2014;Leigh, Henshall, & McKay, 2004;McKay & Henshall, 2002Omran, Lai, & Dillier, 2011) have proposed that optimizing the frequency-to-electrode allocation map could have the potential to address the limited spectral resolution in the implant. More specifically, using vocoder simulations, El Boghdady et al (2018) have shown that the frequency-to-electrode allocation map could have a direct influence on VTL JNDs, and that the frequency mapping, if optimally fitted, could help reduce the detrimental effects of channel interaction and frequency mismatch in the cochlea on VTL JNDs.…”

Section: Discussionmentioning

confidence: 99%

Effect of Channel Interaction on Vocal Cue Perception in Cochlear Implant Users

Nogueira¹,

Boghdady²,

Langner³

et al. 2020

Preprint

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Speech intelligibility in multi-talker settings is challenging for most 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 both spectral and temporal 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, parallel channels were simultaneously stimulated in 14 Advanced Bionics users to simulate channel interaction. Three such patterns were created: Sequential (stimulation of 2 simultaneous electrodes), Paired (4 electrodes), and Triplet stimulation (6 electrodes). 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, a significant deterioration in performance was observed for all tasks, with no differences between Sequential and Paired stimulation. 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 utilizing parallel stimulation in CIs for reducing power consumption.

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“…Bierer and Litvak (2016) found improvements in phoneme recognition among some poorer performers when they used a partial tri-polar, as opposed to monopolar, stimulation strategy with either 1) a MAP with a full complement of electrodes (no site-selection) or 2) a site-selection program using monopolar stimulation (Bierer & Litvak, 2016). Grasmeder and colleagues (Grasmeder, Verschuur, & Batty, 2014) demonstrated that frequency-to-electrode assignment using a reduced-frequency MAP based on post-operative x-ray imaging and insertion angle can improve performance in some listeners. Results from Vickers and colleagues argue that site deactivation for n-of-m strategies (e.g., SPEAK, ACE) is not beneficial when choosing stimulation sites based on pitch-ranking tasks.…”

Section: Discussionmentioning

confidence: 99%

Effects of electrode deactivation on speech recognition in multichannel cochlear implant recipients

Schvartz-Leyzac

Zwolan

Pfingst

2017

Cochlear Implants International

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Objectives The objective of the current study is to evaluate how speech recognition performance is affected by the number of active electrodes that are turned off in multichannel cochlear implants. Several recent studies have demonstrated positive effects of deactivating stimulation sites based on an objective measure in cochlear implant processing strategies. Previous studies using an analysis of variance have shown that, on average, cochlear implant listeners’ performance does not improve beyond eight active electrodes. We hypothesized that using a generalized linear mixed model (GLMM) would allow for better examination of this question. Methods Seven peri- and post-lingual adult cochlear implant users (eight ears) were tested on speech recognition tasks using experimental MAPs which contained either 8, 12, 16 or 20 active electrodes. Speech recognition tests included CUNY sentences in speech-shaped noise, TIMIT sentences in quiet as well as vowel (CVC) and consonant (CV) stimuli presented in quiet and in signal-to-noise ratios of 0 and +10 dB. Results The speech recognition threshold in noise (dB SNR) significantly worsened by approximately 2 dB on average as the number of active electrodes was decreased from 20 to 8. Likewise, sentence recognition scores in quiet significantly decreased by an average of approximately 12%. Discussion/Conclusion Cochlear implant recipients can utilize and benefit from using more than eight spectral channels when listening to complex sentences or sentences in background noise. The results of the current study suggest a conservative approach for turning off stimulation sites is best when using site-selection procedures.

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Optimizing frequency-to-electrode allocation for individual cochlear implant users

Cited by 21 publications

References 44 publications

Effect of Channel Interaction on Vocal Cue Perception in Cochlear Implant Users

Effect of Channel Interaction on Vocal Cue Perception in Cochlear Implant Users

Effect of Channel Interaction on Vocal Cue Perception in Cochlear Implant Users

Effects of electrode deactivation on speech recognition in multichannel cochlear implant recipients

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