Understanding the effect of noise on electrical stimulation sequences in cochlear implants and its impact on speech intelligibility

Qazi, Obaid ur Rehman; Dijk, Bas van; Moonen, Marc; Wouters, Jan

doi:10.1016/j.heares.2013.01.018

Cited by 36 publications

(52 citation statements)

References 36 publications

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“…Plant et al (2002) found that varying the number of maxima between 6 and 16 had little effect on speech understanding in silence, but that a 6-maxima program was significantly worse in noise. It has also been described by Qazi et al (2013) that ''wrong maxima selection'' is likely to occur when listening to speech in noise with the ACE strategy, with a large portion of maxima being occupied by noise. The reduction in number of maxima could therefore have influenced our results in noise, but not in silence.…”

Section: Discussionmentioning

confidence: 99%

Fitting prelingually deafened adult cochlear implant users based on electrode discrimination performance

Debruyne

Francart

Janssen

et al. 2016

International Journal of Audiology

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Objective: This study investigated the hypotheses that (1) prelingually deafened CI users do not have perfect electrode discrimination ability and (2) the deactivation of non-discriminable electrodes can improve auditory performance. Design: Electrode discrimination difference limens were determined for all electrodes of the array. The subjects' basic map was subsequently compared to an experimental map, which contained only discriminable electrodes, with respect to speech understanding in quiet and in noise, listening effort, spectral ripple discrimination and subjective appreciation. Study Sample: Subjects were six prelingually deafened, late implanted adults using the Nucleus cochlear implant. Results: Electrode discrimination difference limens across all subjects and electrodes ranged from 0.5 to 7.125, with significantly larger limens for basal electrodes. No significant differences were found between the basic map and the experimental map on auditory tests. Subjective appreciation was found to be significantly poorer for the experimental map. Conclusions: Prelingually deafened CI users were unable to discriminate between all adjacent electrodes. There was no difference in auditory performance between the basic and experimental map. Potential factors contributing to the absence of improvement with the experimental map include the reduced number of maxima, incomplete adaptation to the new frequency allocation, and the mainly basal location of deactivated electrodes.

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Section: Discussionmentioning

confidence: 99%

Fitting prelingually deafened adult cochlear implant users based on electrode discrimination performance

Debruyne

Francart

Janssen

et al. 2016

International Journal of Audiology

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“…In the ideal case (i.e. when the speech and noise components are known), these algorithms can lead to highly increased intelligibility, close to that for noise-free speech for NH listeners (Madhu et al., 2013) and CI users (Koning et al., 2015, Mauger et al., 2012a, Qazi et al., 2013). Similarly, extensive studies on the SI benefits of time-frequency masking with the ideal binary mask (IBM) support the potential of SNR-based suppression criteria for improving the intelligibility of speech in noise (Anzalone et al., 2006, Brungart et al., 2006, Hu and Loizou, 2008, Wang et al., 2009).…”

Section: Introductionmentioning

confidence: 99%

Speech enhancement based on neural networks improves speech intelligibility in noise for cochlear implant users

et al. 2017

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Speech understanding in noisy environments is still one of the major challenges for cochlear implant (CI) users in everyday life. We evaluated a speech enhancement algorithm based on neural networks (NNSE) for improving speech intelligibility in noise for CI users. The algorithm decomposes the noisy speech signal into time-frequency units, extracts a set of auditory-inspired features and feeds them to the neural network to produce an estimation of which frequency channels contain more perceptually important information (higher signal-to-noise ratio, SNR). This estimate is used to attenuate noise-dominated and retain speech-dominated CI channels for electrical stimulation, as in traditional n-of-m CI coding strategies. The proposed algorithm was evaluated by measuring the speech-in-noise performance of 14 CI users using three types of background noise. Two NNSE algorithms were compared: a speaker-dependent algorithm, that was trained on the target speaker used for testing, and a speaker-independent algorithm, that was trained on different speakers. Significant improvements in the intelligibility of speech in stationary and fluctuating noises were found relative to the unprocessed condition for the speaker-dependent algorithm in all noise types and for the speaker-independent algorithm in 2 out of 3 noise types. The NNSE algorithms used noise-specific neural networks that generalized to novel segments of the same noise type and worked over a range of SNRs. The proposed algorithm has the potential to improve the intelligibility of speech in noise for CI users while meeting the requirements of low computational complexity and processing delay for application in CI devices.

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“…One approach to improve speech perception is to increase the number of electrode channels. However, due to current spread, this may result in channel cross talk (Boe_x et al , 2003; Karg et al , 2013; Qazi et al , 2013). …”

Section: Introductionmentioning

confidence: 99%

Superior temporal resolution of Chronos versus channelrhodopsin-2 in an optogenetic model of the auditory brainstem implant

et al. 2015

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The contemporary auditory brainstem implant (ABI) performance is limited by reliance on electrical stimulation with its accompanying channel cross talk and current spread to non-auditory neurons. A new generation ABI based on optogenetic-technology may ameliorate limitations fundamental to electrical neurostimulation. The most widely studied opsin is channelrhodopsin-2 (ChR2); however, its relatively slow kinetic properties may prevent the encoding of auditory information at high stimulation rates. In the present study, we compare the temporal resolution of light-evoked responses of a recently developed fast opsin, Chronos, to ChR2 in a murine ABI model. Viral mediated gene transfer via a posterolateral craniotomy was used to express Chronos or ChR2 in the mouse nucleus (CN). Following a four to six week incubation period, blue light (473 nm) was delivered via an optical fiber placed directly on the surface of the infected CN, and neural activity was recorded in the contralateral inferior colliculus (IC). Both ChR2 and Chronos evoked sustained responses to all stimuli, even at high driven rates. In addition, optical stimulation evoked excitatory responses throughout the tonotopic axis of the IC. Synchrony of the light-evoked response to stimulus rates of 14–448 pulses/s was higher in Chronos compared to ChR2 mice (p<0.05 at 56, 168, and 224 pulses/s). Our results demonstrate that Chronos has the ability to drive the auditory system at higher stimulation rates than ChR2 and may be a more ideal opsin for manipulation of auditory pathways in future optogenetic-based neuroprostheses.

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Understanding the effect of noise on electrical stimulation sequences in cochlear implants and its impact on speech intelligibility

Cited by 36 publications

References 36 publications

Fitting prelingually deafened adult cochlear implant users based on electrode discrimination performance

Fitting prelingually deafened adult cochlear implant users based on electrode discrimination performance

Speech enhancement based on neural networks improves speech intelligibility in noise for cochlear implant users

Superior temporal resolution of Chronos versus channelrhodopsin-2 in an optogenetic model of the auditory brainstem implant

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