Category Archives: Hear Res

The cerebellar (para)flocculus: A review on its auditory function and a possible role in tinnitus.

The cerebellar (para)flocculus: A review on its auditory function and a possible role in tinnitus.
Hear Res. 2020 Sep 23;398:108081
Authors: Mennink LM, van Dijk JMC, van Dijk P
Abstract
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Volume gradients in inner hair cell-auditory nerve fiber pre- and postsynaptic proteins differ across mouse strains.

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Volume gradients in inner hair cell-auditory nerve fiber pre- and postsynaptic proteins differ across mouse strains.
Hear Res. 2020 Mar 06;390:107933
Authors: Reijntjes DOJ, Köppl C, Pyott SJ
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Modeling the characteristics of spontaneous otoacoustic emissions in lizards.

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Modeling the characteristics of spontaneous otoacoustic emissions in lizards.
Hear Res. 2019 Nov 15;385:107840
Authors: Wit HP, Manley GA, van Dijk P
PMID: 31760263 [PubMed – as supplied by… Continue reading

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Frequency selectivity of the human cochlea: Suppression tuning of spontaneous otoacoustic emissions.

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Frequency selectivity of the human cochlea: Suppression tuning of spontaneous otoacoustic emissions.
Hear Res. 2016 Apr 29;
Authors: Manley GA, van Dijk P
Abstract
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A Neural-Based Vocoder Implementation for Evaluating Cochlear Implant Coding Strategies.

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A Neural-Based Vocoder Implementation for Evaluating Cochlear Implant Coding Strategies.

Hear Res. 2016 Jan 13;

Authors: El Boghdady N, Kegel A,…

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The immediate effects of acoustic trauma on excitation and inhibition in the inferior colliculus: a Wiener-kernel analysis.

The immediate effects of acoustic trauma on excitation and inhibition in the inferior colliculus: a Wiener-kernel analysis.

Hear Res. 2015 Oct 30;

Authors: Heeringa AN,…

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The effect of visual cues on top-down restoration of temporally interrupted speech, with and without further degradations.

The effect of visual cues on top-down restoration of temporally interrupted speech, with and without further degradations.

Hear Res. 2015 Jun 24;

Authors: Benard MR, Başkent D

Abstract
In complex listening situations, cognitive restoration mechanisms are commonly used to enhance perception of degraded speech with inaudible segments. Profoundly hearing-impaired people revalidated with a cochlear implant (CI) show less benefit from such mechanisms. However, both normal hearing (NH) listeners and CI users do benefit from visual speech cues in these listening situations. In this study we investigated if an accompanying video of the speaker can enhance the intelligibility of interrupted sentences, and the phonemic restoration benefit, measured by an increase in intelligibility when the silent intervals are filled with noise. Similar to previous studies, restoration benefit was observed with interrupted speech without spectral degradations (experiment 1), but was absent in acoustic simulations of CIs (experiment 2) and was present again in simulations of Electric Acoustic Stimulation (experiment 3). In all experiments, the additional speech information provided by the complementary visual cues lead to overall higher intelligibility, however, these cues did not influence the occurrence or extent of the phonemic restoration benefit of filler noise. Results imply that visual cues do not show a synergistic effect with the filler noise, as adding them equally increased the intelligibility of interrupted sentences with or without the filler noise.

PMID: 26117407 [PubMed – as supplied by publisher]

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Tinnitus-related abnormalities in visual and salience networks during a one-back task with distractors.

Tinnitus-related abnormalities in visual and salience networks during a one-back task with distractors.
Hear Res. 2015 Apr 2;
Authors: Amaral AA, Langers DR
Abstract
Tinnitus is highly prevalent in th… Continue reading

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Modulation frequency discrimination with single and multiple channels in cochlear implant users.

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Modulation frequency discrimination with single and multiple channels in cochlear implant users.

Hear Res. 2015 Mar 5;

Authors: Galvin JJ, Oba S, Başkent D, Fu QJ

Abstract
Temporal envelope cues convey important speech information for cochlear implant (CI) users. Many studies have explored CI users’ single-channel temporal envelope processing. However, in clinical CI speech processors, temporal envelope information is processed by multiple channels. Previous studies have shown that amplitude modulation frequency discrimination (AMFD) thresholds are better when temporal envelopes are delivered to multiple rather than single channels. In clinical fitting, current levels on single channels must often be reduced to accommodate multi-channel loudness summation. As such, it is unclear whether the multi-channel advantage in AMFD observed in previous studies was due to coherent envelope information distributed across the cochlea or to greater loudness associated with multi-channel stimulation. In this study, single- and multi-channel AMFD thresholds were measured in CI users. Multi-channel component electrodes were either widely or narrowly spaced to vary the degree of overlap between neural populations. The reference amplitude modulation (AM) frequency was 100 Hz, and coherent modulation was applied to all channels. In Experiment 1, single- and multi-channel AMFD thresholds were measured at similar loudness. In this case, current levels on component channels were higher for single-than for multi-channel AM stimuli, and the modulation depth was approximately 100% of the perceptual dynamic range (i.e., between threshold and maximum acceptable loudness). Results showed no significant difference in AMFD thresholds between similarly loud single- and multi-channel modulated stimuli. In Experiment 2, single- and multi-channel AMFD thresholds were compared at substantially different loudness. In this case, current levels on component channels were the same for single- and multi-channel stimuli (“summation-adjusted” current levels) and the same range of modulation (in dB) was applied to the component channels for both single- and multi-channel testing. With the summation-adjusted current levels, loudness was lower with single than with multiple channels and the AM depth resulted in substantial stimulation below single-channel audibility, thereby reducing the perceptual range of AM. Results showed that AMFD thresholds were significantly better with multiple channels than with any of the single component channels. There was no significant effect of the distribution of electrodes on multi-channel AMFD thresholds. The results suggest that increased loudness due to multi-channel summation may contribute to the multi-channel advantage in AMFD, and that that overall loudness may matter more than the distribution of envelope information in the cochlea.

PMID: 25746914 [PubMed – as supplied by publisher]

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Deletion of Shank1 has minimal effects on the molecular composition and function of glutamatergic afferent postsynapses in the mouse inner ear.

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Deletion of Shank1 has minimal effects on the molecular composition and function of glutamatergic afferent postsynapses in the mouse inner ear.

Hear Res….

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T’ain’t the way you say it, it’s what you say – Perceptual continuity of voice and top-down restoration of speech.

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T’ain’t the way you say it, it’s what you say – Perceptual continuity of voice and top-down restoration of speech.

Hear Res. 2014 Jul 11;

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The dissimilar time course of temporary threshold shifts and reduction of inhibition in the inferior colliculus following intense sound exposure.

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The dissimilar time course of temporary threshold shifts and reduction of inhibition in the inferior colliculus following intense sound exposure.

Hear Res. 2014 Mar…

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Tinnitus-related dissociation between cortical and subcortical neural activity in humans with mild to moderate sensorineural hearing loss.

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Tinnitus-related dissociation between cortical and subcortical neural activity in humans with mild to moderate sensorineural hearing loss.

Hear Res. 2014 Mar 11;

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Top-Down Restoration of Speech in Cochlear-Implant Users.

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Top-Down Restoration of Speech in Cochlear-Implant Users.

Hear Res. 2013 Dec 21;

Authors: Bhargava P, Gaudrain E, Başkent D

Abstract
In noisy listening conditions, intelligibility of degraded speech can be enhanced by top-down restoration. Cochlear implant (CI) users have difficulty understanding speech in noisy environments. This could partially be due to reduced top-down restoration of speech, caused by the changes that the electrical stimulation imposes on the bottom-up cues. We tested this hypothesis using the phonemic restoration (PhR) paradigm in which speech interrupted with periodic silent intervals is perceived illusorily continuous (continuity illusion or CoI) and becomes more intelligible (PhR benefit) when the interruptions are filled with noise bursts. Using meaningful sentences, both CoI and PhR benefit were measured in CI users, and compared with those of normal-hearing (NH) listeners presented with normal speech and 8-channel noise-band vocoded speech, simulating CIs. CI users showed different patterns in both PhR benefit and CoI, compared to NH results with or without the CI simulation. However, they were able to use top-down restoration under certain test conditions. This observation supports the idea that changes in bottom-up cues can impose changes to the top-down processes needed to enhance intelligibility of degraded speech. The knowledge that CI users seem to be able to do restoration under the right circumstances could be exploited in patient rehabilitation and product development.

PMID: 24368138 [PubMed – as supplied by publisher]

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Gray matter in the brain: differences associated with tinnitus and hearing loss.

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Gray matter in the brain: differences associated with tinnitus and hearing loss.

Hear Res. 2013 Jan;295:67-78

Authors: Boyen K, Langers DR, de Kleine E, van Dijk P

Abstract
Tinnitus, usually associated with hearing loss, is characterized by the perception of sound without an external sound source. The pathophysiology of tinnitus is poorly understood. In the present study, voxel-based morphometry (VBM) was employed to identify gray matter differences related to hearing loss and tinnitus. VBM was applied to magnetic resonance images of normal-hearing control subjects (n = 24), hearing-impaired subjects without tinnitus (n = 16, HI group) and hearing-impaired subjects with tinnitus (n = 31, HI + T group). This design allowed us to disentangle the gray matter (GM) differences related to hearing loss and tinnitus, respectively. Voxel-based VBM analyses revealed that both HI and HI + T groups, relative to the controls, had GM increases in the superior and middle temporal gyri, and decreases in the superior frontal gyrus, occipital lobe and hypothalamus. We did not find significant GM differences between both patient groups. Subsequent region-of-interest (ROI) analyses of all Brodmann Areas, the cerebellum and the subcortical auditory nuclei showed a GM increase in the left primary auditory cortex of the tinnitus patients compared to the HI and control groups. Moreover, GM decreases were observed in frontal areas and mainly GM increases in limbic areas, both of which occurred for hearing loss irrespective of tinnitus, relative to the controls. These results suggest a specific role of the left primary auditory cortex and the additional involvement of various non-auditory brain structures in tinnitus. Understanding the causal relation between these GM changes and tinnitus will be an important next step in understanding tinnitus mechanisms.

PMID: 22446179 [PubMed – indexed for MEDLINE]

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Wavelet analysis demonstrates no abnormality in contralateral suppression of otoacoustic emissions in tinnitus patients.

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Wavelet analysis demonstrates no abnormality in contralateral suppression of otoacoustic emissions in tinnitus patients.

Hear Res. 2012 Apr;286(1-2):30-40

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