Channel interactions with high-rate biphasic electrical stimulation in cochlear implant subjects

Balthasar, Chloe de; Boëx, Colette; Cosendai, Gregoire; Valentini, Gregory; Sigrist, Alain; Pelizzone, M.

doi:10.1016/s0378-5955(03)00174-6

Cited by 66 publications

(66 citation statements)

References 25 publications

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“…The larger number of active neurons would likely result in a louder percept than in Figure 1A, but it also causes partial overlap of the two neural populations. The excitation of common neural elements with dual-channel stimulation can ultimately affect perception of the separate stimulus components, a phenomenon referred to as channel interaction (Bierer, 2007;Bierer & Faulkner, 2010;Boëx, Kos, & Pelizzone, 2003;Chatterjee et al, 2006;de Balthasar et al, 2003;Kwon & van den Honert, 2006;McKay et al, 1996;Nelson et al, 2008;Stickney et al, 2006). Acoustic stimulation is generally "multichannel" in the sense that different frequency components, having different time-varying amplitudes, can fall within the passband of the same neuron.…”

Section: Current Flow and Channel Interactionmentioning

confidence: 99%

“…Interactions between spectral components have been well documented in studies presenting sounds simultaneously or successively (e,g., Moore, 2002;Oxenham & Shera, 2003). Likewise in electrical hearing, channel interactions have been observed in response to both simultaneous and nonsimultaneous pulse trains, the former presumably governed by the summation of current in the cochlea (Bierer 2007;de Balthasar et al, 2003;Stickney et al, 2006) and the latter by forward-masking effects in the auditory nerve and central pathways (Bierer & Faulkner, 2010;Boëx et al, 2003;Chatterjee et al, 2006;Kwon & van den Honert, 2006;Nelson et al, 2008). As in acoustic hearing, some degree of channel interaction is expected and probably desirable for discriminating complex sounds.…”

Section: Current Flow and Channel Interactionmentioning

confidence: 99%

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Probing the Electrode-Neuron Interface With Focused Cochlear Implant Stimulation

Bierer

2010

Trends in Amplification

111

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Cochlear implants are highly successful neural prostheses for persons with severe or profound hearing loss who gain little benefit from hearing aid amplification. Although implants are capable of providing important spectral and temporal cues for speech perception, performance on speech tests is variable across listeners. Psychophysical measures obtained from individual implant subjects can also be highly variable across implant channels. This review discusses evidence that such variability reflects deviations in the electrode-neuron interface, which refers to an implant channel's ability to effectively stimulate the auditory nerve. It is proposed that focused electrical stimulation is ideally suited to assess channel-to-channel irregularities in the electrode-neuron interface. In implant listeners, it is demonstrated that channels with relatively high thresholds, as measured with the tripolar configuration, exhibit broader psychophysical tuning curves and smaller dynamic ranges than channels with relatively low thresholds. Broader tuning implies that frequency-specific information intended for one population of neurons in the cochlea may activate more distant neurons, and a compressed dynamic range could make it more difficult to resolve intensity-based information, particularly in the presence of competing noise. Degradation of both types of cues would negatively affect speech perception.

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Section: Current Flow and Channel Interactionmentioning

confidence: 99%

Section: Current Flow and Channel Interactionmentioning

confidence: 99%

Probing the Electrode-Neuron Interface With Focused Cochlear Implant Stimulation

Bierer

2010

Trends in Amplification

111

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“…Residual potential effects were investigated with CI users in two different studies using BP pulses with phase durations shorter than 50 ms (Eddington et al 1994;de Balthasar et al 2003). de Balthasar measured the threshold of a BP pulse-train probe, which was interleaved with a subthreshold BP pulse-train masker presented on an adjacent channel.…”

Section: Additional Potential Mechanismsmentioning

confidence: 99%

A Dual-Process Integrator–Resonator Model of the Electrically Stimulated Human Auditory Nerve

Macherey

Carlyon

Wieringen

et al. 2007

JARO

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A phenomenological dual-process model of the electrically stimulated human auditory nerve is presented and compared to threshold and loudness data from cochlear implant users. The auditory nerve is modeled as two parallel processes derived from linearized equations of conductance-based models. The first process is an integrator, which dominates stimulation for short-phase duration biphasic pulses and high-frequency sinusoidal stimuli. It has a relatively short time constant (0.094 ms) arising from the passive properties of the membrane. The second process is a resonator, which induces nonmonotonic functions of threshold vs frequency with minima around 80 Hz. The ion channel responsible for this trend has a relatively large relaxation time constant of about 1 ms. Membrane noise is modeled as a Gaussian noise, and loudness sensation is assumed to relate to the probability of firing of a neuron during a 20-ms rectangular window. Experimental psychophysical results obtained in seven previously published studies can be interpreted with this model. The model also provides a physiologically based account of the nonmonotonic threshold vs frequency functions observed in biphasic and sinusoidal stimulation, the large threshold decrease obtained with biphasic pulses having a relatively long inter-phase gap and the effects of asymmetric pulses.

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“…The lack of spectral resolution due to the small number of electrode can contribute to poor speech perception in noise, music perception, and tonal language understanding. 25 For speech processing strategies, electrical stimulation by two electrodes can produce two pitch components, but channel interactions are generated by stimulating individual electrodes simultaneously, 3 which produce threshold changes consistent with instantaneous electric field summation. This will affect or distort the intended perception and usually is undesirable.…”

Section: Introductionmentioning

confidence: 99%

Conditions for Generating Virtual Channels in Cochlear Prosthesis Systems

Choi

Hsu

2008

Ann Biomed Eng

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Abstract-Simultaneous electrical stimulation of neighboring electrodes in cochlear prosthesis systems generates channel interaction. However, intermediate channels, or virtual channels between the neighboring electrodes can be created through controlled channel interaction. This effect may be exploited for sending new information to the hearing nerves by stimulating in a suitable manner. The actual stimulation sites are therefore not limited to the number of electrodes. Clinical experiments, however, show that virtual channels are not always perceived. In this paper, electrical simulation with finite element analysis on a half turn human cochlea model is adopted to model the virtual channel effect, and the conditions for generating virtual channels are discussed. Five input current ratios (100/0, 70/30, 50/50, 30/70, 0/100) are applied to generate virtual channels. Three electrode arrays parameters are taken into consideration: distance between electrode contact and modiolus, spacing between adjacent electrode contacts and scale of electrode contact size. By observing the activating function contours, the virtual channel patterns and performances can be measured and examined. The results showed that a broad excitation pattern is necessary to produce the kind of electrode interaction that can form distinct virtual channels.

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Channel interactions with high-rate biphasic electrical stimulation in cochlear implant subjects

Cited by 66 publications

References 25 publications

Probing the Electrode-Neuron Interface With Focused Cochlear Implant Stimulation

Probing the Electrode-Neuron Interface With Focused Cochlear Implant Stimulation

A Dual-Process Integrator–Resonator Model of the Electrically Stimulated Human Auditory Nerve

Conditions for Generating Virtual Channels in Cochlear Prosthesis Systems

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