A Binaural CI Research Platform for Oticon Medical SP/XP Implants Enabling ITD/ILD and Variable Rate Processing

Backus, Bradford C.; Adiloğlu, Kamil; Herzke, Tobias

doi:10.1177/2331216515618655

Cited by 6 publications

(4 citation statements)

References 8 publications

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“…We applied the Oticon Medical (OM) Research Platform, provided by Oticon Medical (Backus, Adilog˘lu, & Herzke, 2015), as a real-time vocoder, in which the sound is recorded and processed online. This novel technique enabled testing in free-field listening conditions, rather than with virtual acoustic stimulation Jones et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Sound Localization in Real-Time Vocoded Cochlear-Implant Simulations With Normal-Hearing Listeners

et al. 2019

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Bilateral cochlear-implant (CI) users and single-sided deaf listeners with a CI are less effective at localizing sounds than normal-hearing (NH) listeners. This performance gap is due to the degradation of binaural and monaural sound localization cues, caused by a combination of device-related and patient-related issues. In this study, we targeted the device-related issues by measuring sound localization performance of 11 NH listeners, listening to free-field stimuli processed by a real-time CI vocoder. The use of a real-time vocoder is a new approach, which enables testing in a free-field environment. For the NH listening condition, all listeners accurately and precisely localized sounds according to a linear stimulus–response relationship with an optimal gain and a minimal bias both in the azimuth and in the elevation directions. In contrast, when listening with bilateral real-time vocoders, listeners tended to orient either to the left or to the right in azimuth and were unable to determine sound source elevation. When listening with an NH ear and a unilateral vocoder, localization was impoverished on the vocoder side but improved toward the NH side. Localization performance was also reflected by systematic variations in reaction times across listening conditions. We conclude that perturbation of interaural temporal cues, reduction of interaural level cues, and removal of spectral pinna cues by the vocoder impairs sound localization. Listeners seem to ignore cues that were made unreliable by the vocoder, leading to acute reweighting of available localization cues. We discuss how current CI processors prevent CI users from localizing sounds in everyday environments.

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Section: Introductionmentioning

confidence: 99%

Sound Localization in Real-Time Vocoded Cochlear-Implant Simulations With Normal-Hearing Listeners

et al. 2019

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“…Aside from the technical improvements, we are also planning to extend the evaluation methodology into a more realistic direction. Incorporating the MHA and a CI research interface, such as the so-called ABCIT (Advanced Binaural Cochlear Implant Technology) binaural research platform ( Adiloğlu et al., 2014 ; Backus, Adiloğlu, & Herzke, 2015 ) allows evaluation using real acoustic input in different reverberant environments. As the MHA also runs on portable computers such as laptops, small form factor computers (e.g., intel NUC), or single board computers (e.g., beaglebone black, raspberry pie), performing field tests with this setup will be conducted and give us valuable information about the performance of the system.…”

Section: Discussionmentioning

confidence: 99%

A Binaural Steering Beamformer System for Enhancing a Moving Speech Source

et al. 2015

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In many daily life communication situations, several sound sources are simultaneously active. While normal-hearing listeners can easily distinguish the target sound source from interfering sound sources—as long as target and interferers are spatially or spectrally separated—and concentrate on the target, hearing-impaired listeners and cochlear implant users have difficulties in making such a distinction. In this article, we propose a binaural approach composed of a spatial filter controlled by a direction-of-arrival estimator to track and enhance a moving target sound. This approach was implemented on a real-time signal processing platform enabling experiments with test subjects in situ. To evaluate the proposed method, a data set of sound signals with a single moving sound source in an anechoic diffuse noise environment was generated using virtual acoustics. The proposed steering method was compared with a fixed (nonsteering) method that enhances sound from the frontal direction in an objective evaluation and subjective experiments using this database. In both cases, the obtained results indicated a significant improvement in speech intelligibility and quality compared with the unprocessed signal. Furthermore, the proposed method outperformed the nonsteering method.

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“…We used the Oticon Medical Research Platform (OMRP) [9] to directly stimulate single electrodes on the Neuro-Zti Implant in two ways: (1) using stimulus parameters designed to replicate those of their prior CI, and (2) using the parameters of their current clinical CI mode. With Subject S2, we also investigated reversing the polarity of these pulses for a total of 4 stimulus types (Table 1 and Figure 1).…”

Section: Stimulimentioning

confidence: 99%

Cochlear Implant Stimulation Parameters Play a Key Role in Reducing Facial Nerve Stimulation

Gärtner,

Backus,

Le Goff

et al. 2023

JCM

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A percentage (i.e., 5.6%) of Cochlear Implant (CI) users reportedly experience unwanted facial nerve stimulation (FNS). For some, the effort to control this problem results in changing stimulation parameters, thereby reducing their hearing performance. For others, the only viable solution is to deactivate the CI completely. A growing body of evidence in the form of case reports suggests that undesired FNS can be effectively addressed through re-implantation with an Oticon Medical (OM) Neuro-Zti implant. However, the root of this benefit is still unknown: is it due to surgical adjustments, such as varied array geometries and/or positioning, or does it stem from differences in stimulation parameters and/or grounding? The OM device exhibits two distinct features: (1) unique stimulation parameters, including anodic leading pulses and loudness controlled by pulse duration—not current—resulting in lower overall current amplitudes; and (2) unconventional grounding, including both passive (capacitive) discharge, which creates a pseudo-monophasic pulse shape, and a ‘distributed-all-polar’ (DAP) grounding scheme, which is thought to reduce current spread. Unfortunately, case reports alone cannot distinguish between surgical factors and these implant-related ones. In this paper, we present a novel follow-up study of two CI subjects who previously experienced FNS before re-implantation with Neuro-Zti implants. We used the Oticon Medical Research Platform (OMRP) to stimulate a single electrode in each subject in two ways: (1) with traditional monopolar biphasic cathodic-first pulses, and (2) with distinct OM clinical stimulation. We progressively increased the stimulation intensity until FNS occurred or the sound became excessively loud. Non-auditory/FNS sensations were observed with the traditional stimulation but not with the OM clinical one. This provides the first direct evidence demonstrating that stimulation parameters and/or grounding—not surgical factors—play a key role in mitigating FNS.

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A Binaural CI Research Platform for Oticon Medical SP/XP Implants Enabling ITD/ILD and Variable Rate Processing

Cited by 6 publications

References 8 publications

Sound Localization in Real-Time Vocoded Cochlear-Implant Simulations With Normal-Hearing Listeners

Sound Localization in Real-Time Vocoded Cochlear-Implant Simulations With Normal-Hearing Listeners

A Binaural Steering Beamformer System for Enhancing a Moving Speech Source

Cochlear Implant Stimulation Parameters Play a Key Role in Reducing Facial Nerve Stimulation

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