Auditory Implant Research at the House Ear Institute 1989-2013.
This article is part of a Special Issue entitled . PMID: 25449009 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - November 17, 2014 Category: Audiology Authors: Shannon RV Tags: Hear Res Source Type: research

Simulating the dual-peak excitation pattern produced by bipolar stimulation of a cochlear implant: Effects on speech intelligibility.
Abstract Several electrophysiological and psychophysical studies have shown that the spatial excitation pattern produced by bipolar stimulation of a cochlear implant (CI) can have a dual-peak shape. The perceptual effects of this dual-peak shape were investigated using noise-vocoded CI simulations in which synthesis filters were designed to simulate the spread of neural activity produced by various electrode configurations, as predicted by a simple cochlear model. Experiments 1 and 2 tested speech recognition in the presence of a concurrent speech masker for various sets of single-peak and dual-peak synthesis filt...
Source: Hearing Research - November 15, 2014 Category: Audiology Authors: Mesnildrey Q, Macherey O Tags: Hear Res Source Type: research

Further tests of the local nonlinear interaction-based mechanism for simultaneous suppression of tone burst-evoked otoacoustic emissions.
Abstract Tone burst-evoked otoacoustic emission (TBOAE) components measured in response to a 1 kHz tone burst (TB1) are suppressed by the simultaneous presence of an additional tone burst (TB2). This "simultaneous suppression of TBOAEs" has been explained in terms of a mechanism based on local nonlinear interactions between the basilar membrane (BM) travelling waves caused by TB1 and TB2. A test of this local nonlinear interaction (LNI)-based mechanism, as a function of the frequency separation (Δf, expressed in kHz) between TB1 and TB2, has previously been reported by Killan et al. (2012...
Source: Hearing Research - November 7, 2014 Category: Audiology Authors: Killan EC, Lutman ME, Thyer NJ Tags: Hear Res Source Type: research

Neural correlates of perceptual grouping effects in the processing of sound omission by musicians and nonmusicians.
Abstract Perceptual grouping is the process of organizing sounds into perceptually meaningful elements. Psychological studies have found that tones presented as a regular frequency or temporal pattern are grouped according to gestalt principles, such as similarity, proximity, and good continuity. Predictive coding theory suggests that this process helps create an internal model for the prediction of sounds in a tone sequence and that an omission-related brain response reflects the violation of this prediction. However, it remains unclear which brain areas are related to this process, especially in paying attention...
Source: Hearing Research - November 7, 2014 Category: Audiology Authors: Ono K, Altmann CF, Matsuhashi M, Mima T, Fukuyama H Tags: Hear Res Source Type: research

Gradual adaptation to auditory frequency mismatch.
This article is part of a Special Issue entitled . PMID: 25445816 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - November 6, 2014 Category: Audiology Authors: Svirsky MA, Talavage TM, Sinha S, Neuburger H, Azadpour M Tags: Hear Res Source Type: research

Assessment of responses to cochlear implant stimulation at different levels of the auditory pathway.
This article is part of a Special Issue entitled . PMID: 25445817 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - November 4, 2014 Category: Audiology Authors: Abbas PJ, Brown CJ Tags: Hear Res Source Type: research

Deep electrode insertion and sound coding in cochlear implants.
This article discusses the potential benefits of deep insertion which are obtained using pitch-locked temporal stimulation patterns. Besides the access to low frequency information, further advantages of deeply inserted long electrodes are the possibility to better approximate the correct tonotopic location of contacts, the coverage of a wider range of cochlear locations, and the somewhat reduced channel interaction due to the wider contact separation for a given number of channels. A newly developed set of strategies has been shown to improve speech understanding in noise and to enhance sound quality by providing a more &...
Source: Hearing Research - October 22, 2014 Category: Audiology Authors: Hochmair I, Hochmair E, Nopp P, Waller M, Jolly C Tags: Hear Res Source Type: research

Disparities in auditory physiology and pathology between C57BL/6J and C57BL/6N substrains.
Abstract C57BL/6 inbred mice are frequently used as models in auditory research, mostly the C57BL/6J and C57BL/6N substrains. Genetic variation and phenotypic disparities between these two substrains have been extensively investigated, but conflicting information exists about differences in their auditory and vestibular phenotypes. Literature-based comparisons are rendered difficult or impossible because most auditory publications do not designate the substrain used. We therefore evaluated commercial C57BL/6N and C57BL/6J mice for their baseline auditory brainstem response (ABR) thresholds at 3 months of age as we...
Source: Hearing Research - October 22, 2014 Category: Audiology Authors: Kendall A, Schacht J Tags: Hear Res Source Type: research

Perception and coding of interaural time differences with bilateral cochlear implants.
This article is part of a Special Issue entitled . PMID: 25456088 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 19, 2014 Category: Audiology Authors: Laback B, Egger K, Majdak P Tags: Hear Res Source Type: research

PET-imaging of brain plasticity after cochlear implantation.
This article is part of a Special Issue entitled . PMID: 25448166 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 16, 2014 Category: Audiology Authors: Strelnikov K, Marx M, Lagleyre S, Fraysse B, Deguine O, Barone P Tags: Hear Res Source Type: research

Voice emotion recognition by cochlear-implanted children and their normally-hearing peers.
This article is part of a Special Issue entitled . PMID: 25448167 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 16, 2014 Category: Audiology Authors: Chatterjee M, Zion DJ, Deroche ML, Burianek BA, Limb CJ, Goren AP, Kulkarni AM, Christensen JA Tags: Hear Res Source Type: research

Tinnitus and Neural Plasticity (Tonndorf lecture at XI(th) International Tinnitus Seminar, Berlin, 2014).
Abstract Ten years ago, animal models of noise-induced hearing loss predicted three cortical neural correlates of tinnitus resulting from noise-induced hearing loss: increased spontaneous firing rates, increased neural synchrony, and reorganization of tonotopic maps. Salicylate also induces tinnitus, however, the cortical correlates were reduced spontaneous firing rates, unchanged neural synchrony but some change to the tonotopic map. In both conditions increased central gain, potentially a correlate of hyperacusis, was found. Behavioral animal models suggested that tinnitus occurred, albeit not in all cases. The ...
Source: Hearing Research - October 11, 2014 Category: Audiology Authors: Eggermont JJ Tags: Hear Res Source Type: research

Electric-acoustic interactions in the hearing cochlea: single fiber recordings.
Abstract The present study investigates interactions of simultaneous electric and acoustic stimulation in single auditory nerve fibers in normal hearing cats. First, the auditory nerve was accessed with a microelectrode and response areas of single nerve fibers were determined for acoustic stimulation. Second, response thresholds to extracochlear sinusoidal electric stimulation using ball electrodes positioned at the round window were measured. Third, interactions that occurred with combined electric-acoustic stimulation were investigated in two areas: (1) the spectral domain (frequency-level dependent response ar...
Source: Hearing Research - October 3, 2014 Category: Audiology Authors: Tillein J, Hartmann R, Kral A Tags: Hear Res Source Type: research

Cellular Immunologic responses to cochlear implantation In the human.
In conclusion, a cochlear implant generates a vigorous cellular immune response consisting of B and T lymphocytes, foreign body giant cells, and macrophages. Platinum was identified as one of the antigens likely responsible for this cellular response. This foreign body response may in certain cases result in migration or even extrusion of an implant device. PMID: 25285622 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 3, 2014 Category: Audiology Authors: Nadol JB, O'Malley JT, Burgess BJ, Galler D Tags: Hear Res Source Type: research

An examination of the effects of broadband air-conduction masker on the speech intelligibility of speech-modulated bone-conduction ultrasound.
In this study, eight volunteers with normal hearing participated. The intelligibilities of speech-modulated BCU were measured using a numeral word list under masking conditions. Because the masker can mask the demodulated sounds, the evaluation of the masking reveals the contribution of the demodulation to the recognition of speech-modulated BCU. In the current results, the masking of speech-modulated BCU differed from that of original non-modulated speech. Although the masking shifted the recognition curve for the original speech upward, the same results were not observed for the speech-modulated BCU. The masking generate...
Source: Hearing Research - October 3, 2014 Category: Audiology Authors: Nishimura T, Okayasu T, Saito O, Shimokura R, Yamashita A, Yamanaka T, Hosoi H, Kitahara T Tags: Hear Res Source Type: research

Factors constraining the benefit to speech understanding of combining information from low-frequency hearing and a cochlear implant.
In this study we assessed the role of three factors in determining the magnitude of bimodal benefit -- (i) the level of CI-only performance, (ii) the magnitude of the hearing loss in the ear with low-frequency acoustic hearing and (iii) the type of test material. The patients had low-frequency PTAs (average of 125, 250 and 500 Hz) varying over a large range (70 dB HL) in the ear contralateral to the implant. The patients were tested with (i) CNC words presented in quiet (n=105) (ii) AzBio sentences presented in quiet (n=102), (iii) AzBio sentences in noise at +10 dB signal-to-noise ratio (SNR) (n=69), and (iv) AzBio senten...
Source: Hearing Research - October 3, 2014 Category: Audiology Authors: Dorman MF, Cook S, Spahr T, Zhang T, Loiselle L, Schramm D, Whittingham J, Gifford R Tags: Hear Res Source Type: research

Development and Evaluation of the Nurotron 26-Electrode Cochlear Implant System.
The objective measures show that electrode impedance decreased within the first month of device use, but was stable until a slight increase at the end of two years. The subjective loudness measures show that electric stimulation threshold was stable while the maximal comfort level increased over the 3 years. Mandarin sentence recognition increased from the pre-surgical 0%-correct score to a plateau of about 80% correct with 6-month use of the device. Both indirect and direct comparisons indicate indistinguishable performance differences between the Nurotron system and other commercially available devices. The present 26-el...
Source: Hearing Research - October 1, 2014 Category: Audiology Authors: Zeng FG, Rebscher SJ, Fu QJ, Chen H, Sun X, Yin L, Ping L, Feng H, Yang S, Gong S, Yang B, Kang HY, Gao N, Chi F Tags: Hear Res Source Type: research

Structural alterations of brain grey and white matter in early deaf adults.
Abstract Functional and structural brain alterations in the absence of the auditory input have been described, but the observed structural brain changes in the deaf are not uniform. Some of the previous researchers focused only on the auditory areas, while others investigated the whole brain or other selected regions of interest. Majority of studies revealed decreased white matter (WM) volume or altered WM microstructure and preserved grey matter (GM) structure of the auditory areas in the deaf. However, preserved WM and increased or decreased GM volume of the auditory areas in the deaf have also been reported. Se...
Source: Hearing Research - September 25, 2014 Category: Audiology Authors: Hribar M, Suput D, Carvalho AA, Battelino S, Vovk A Tags: Hear Res Source Type: research

Sensitivity, specificity and efficiency of speech-evoked ABR.
Abstract We determined the sensitivity, specificity and efficiency of speech-evoked Auditory Brainstem Response (ABR) as a diagnostic support for Auditory Processing Disorder (APD) and specific language impairment (SLI). Speech-evoked ABRs were elicited using the five-formant syllable/da/. The waveforms V, A, C, D, E, F, and O of all groups were analyzed. The sensitivity and specificity were calculated, and receiver operating characteristic analyses were performed to determine the optimum cut-off. Seventy-five children who were native speakers of Brazilian-Portuguese participated. The participants included 25 chil...
Source: Hearing Research - September 25, 2014 Category: Audiology Authors: Rocha-Muniz CN, Befi-Lopes DM, Schochat E Tags: Hear Res Source Type: research

Response to best-frequency tone bursts in the ventral cochlear nucleus is governed by ordered inter-spike interval statistics.
Abstract The spike-trains generated by short constant-amplitude constant-frequency tone bursts in the ventral cochlear nucleus of the anaesthetised guinea pig are examined. Spikes are grouped according to the order in which they occur following the onset of the stimulus. It is found that successive inter-spike intervals have low statistical dependence according to information-theoretic measures. This is in contrast to previous observations with long duration tone bursts in the cat dorsal and posteroventral cochlear nuclei and lateral superior olive, where it was found that long intervals tended to be followed by s...
Source: Hearing Research - September 24, 2014 Category: Audiology Authors: Wright MC, Winter IM, Forster JJ, Bleeck S Tags: Hear Res Source Type: research

Importance of cochlear health for implant function.
Abstract Amazing progress has been made in providing useful hearing to hearing-impaired individuals using cochlear implants, but challenges remain. One such challenge is understanding the effects of partial degeneration of the auditory nerve, the target of cochlear implant stimulation. Here we review studies from our human and animal laboratories aimed at characterizing the health of the implanted cochlea and the auditory nerve. We use the data on cochlear and neural health to guide rehabilitation strategies. The data also motivate the development of tissue-engineering procedures to preserve or build a healthy coc...
Source: Hearing Research - September 24, 2014 Category: Audiology Authors: Pfingst BE, Zhou N, Colesa DJ, Watts MM, Strahl SB, Garadat SN, Schvartz-Leyzac KC, Budenz CL, Raphael Y, Zwolan TA Tags: Hear Res Source Type: research

Simultaneous comparison of two sound Localization Measures.
Abstract Almost all behavioral studies of sound localization have used either an approach-to-target or pointing/orienting task to assess absolute sound localization performance, yet there are very few direct comparisons of these measures. In an approach-to-target task, the subject is trained to walk to a sound source from a fixed location. In an orienting task, finger, head and/or eye movements are monitored while the subject's body is typically constrained. The fact that subjects may also initiate head and eye movements toward the target during the approach-to-target task allows us to measure the accuracy of the ...
Source: Hearing Research - September 24, 2014 Category: Audiology Authors: Jones AE, Ruhland JL, Gai Y, Yin TC Tags: Hear Res Source Type: research

Amplitude-modulation detection by recreational-noise-exposed humans with near-normal hearing thresholds and its medium-term progression.
Abstract Noise exposure can affect the functioning of cochlear inner and outer hair cells (IHC/OHC), leading to multiple perceptual changes. This work explored possible changes in detection of amplitude modulation (AM) at three Sensation Levels (SL) for carrier frequencies of 3, 4 and 6 kHz. There were two groups of participants, aged 19 to 24 (Young) and 26 to 35 (Older) years. All had near-normal audiometric thresholds. Participants self-assessed exposure to high-level noise in recreational settings. Each group was sub-grouped into low-noise (LN) or high-noise (HN) exposure. AM detection thresholds were worse fo...
Source: Hearing Research - September 23, 2014 Category: Audiology Authors: Stone MA, Moore BC Tags: Hear Res Source Type: research

Correlations of decision weights and cognitive function for the masked discrimination of vowels by young and old adults.
Abstract Older adults are often reported in the literature to have greater difficulty than younger adults understanding speech in noise [Helfer and Wilber (1988). J. Acoust. Soc. Am, 859-893]. The poorer performance of older adults has been attributed to a general deterioration of cognitive processing, deterioration of cochlear anatomy, and/or greater difficulty segregating speech from noise. The current work used perturbation analysis [Berg(1990). J. Acoust. Soc. Am., 149-158] to provide a more specific assessment of the effect of cognitive factors on speech perception in noise. Sixteen older (age 56-79 years) an...
Source: Hearing Research - September 22, 2014 Category: Audiology Authors: Gilbertson L, Lutfi RA Tags: Hear Res Source Type: research

What can we expect of normally-developing children implanted at a young age with respect to their auditory, linguistic and cognitive skills?
Abstract As a result of neonatal hearing screening and subsequent early cochlear implantation (CI) profoundly deaf children have access to important information to process auditory signals and master spoken language skills at a young age. Nevertheless, auditory, linguistic and cognitive outcome measures still reveal great variability in individual achievements: some children with CI(s) perform within normal limits, while others lag behind. Understanding the causes of this variation would allow clinicians to offer better prognoses to CI candidates and efficient follow-up and rehabilitation. This paper summarizes wh...
Source: Hearing Research - September 11, 2014 Category: Audiology Authors: van Wieringen En A, Wouters J Tags: Hear Res Source Type: research

Prolonged noise exposure-induced auditory threshold shifts in rats.
Abstract Noise-induced hearing loss (NIHL) initially increases with exposure duration, but eventually reaches an asymptotic threshold shift (ATS) once the exposure duration exceeds 18-24 h. Equations for predicting the ATS have been developed for several species, but not for rats, even though this species is extensively used in noise exposure research. To fill this void, we exposed rats to narrowband noise (NBN, 16-20 kHz) for 5 weeks starting at 80 dB SPL in the first week and then increasing the level by 6 dB per week to a final level of 104 dB SPL. Auditory brainstem responses (ABR) wer...
Source: Hearing Research - September 9, 2014 Category: Audiology Authors: Chen GD, Decker B, Krishnan Muthaiah VP, Sheppard A, Salvi R Tags: Hear Res Source Type: research

Application of a pitch perception model to investigate the effect of stimulation field spread on the pitch ranking abilities of cochlear implant recipients.
This study proposes a model of auditory perception to predict the performance of CI users in pitch ranking tasks using an existing sound processing scheme. The model is then used as a platform to investigate the effect of stimulation field spread on performance. PMID: 25193552 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - September 2, 2014 Category: Audiology Authors: Saeedi NE, Blamey PJ, Burkitt AN, Grayden DB Tags: Hear Res Source Type: research

Binaural hearing with electrical stimulation.
Abstract Bilateral cochlear implantation is becoming a standard of care in many clinics. While much benefit has been shown through bilateral implantation, patients who have bilateral cochlear implants (CIs) still do not perform as well as normal hearing listeners in sound localization and understanding speech in noisy environments. This difference in performance can arise from a number of different factors, including the areas of hardware and engineering, surgical precision and pathology of the auditory system in deaf persons. While surgical precision and individual pathology are factors that are beyond careful co...
Source: Hearing Research - September 2, 2014 Category: Audiology Authors: Kan A, Litovsky RY Tags: Hear Res Source Type: research

The contributions of William F. House to the field of implantable auditory devices.
Abstract William F. House was a pioneer in the evolving field of cochlear implants and auditory brainstem implants. Because of his vision, innovation and perseverance, the way was paved for future clinicians and researchers to carry on the work and advance a field that has been dedicated to serving adults and children with severe to profound hearing loss. Several of William House's contributions are highlighted in this prestigious volume to honor of the recipients of the 2013 Lasker-Debakey Clinical Medical Research Award. Discussed are the early inventive years, clinical trials with the single-channel cochlear im...
Source: Hearing Research - August 23, 2014 Category: Audiology Authors: Eisenberg LS Tags: Hear Res Source Type: research

The multi-channel cochlear implant: Multi-disciplinary development of electrical stimulation of the Cochlea and the resulting clinical benefit.
Abstract This multi-disciplinary research showed sound could be coded by electrical stimulation of the cochlea and peripheral auditory nervous system. But the temporal coding of frequency as seen in the experimental animal, for responses from single or groups of neurons was inadequate for the important speech frequencies. This was also consistent with the behavioural findings on the experimental animal and perception from electrical stimulation in people with cochlear implants. The data indicated the limitation was due in particular to deterministic firing of neurons and failure to reproduce the normal fine tempor...
Source: Hearing Research - August 23, 2014 Category: Audiology Authors: Clark GM Tags: Hear Res Source Type: research

Event-related potentials for better speech perception in noise in cochlear implant users.
This study aimed to investigate neurophysiological and behavioral foundations for CI-dependent speech perception in noise. Seventeen post-lingual CI users and twelve age-matched normal hearing adults participated in two experiments. In Experiment 1, CI users' auditory-only word perception in noise (white noise, two-talker babble; at 10 dB SNR) degraded by about 15 %, compared to that in quiet (48 % accuracy). CI users' auditory-visual word perception was generally better than auditory-only perception. Auditory-visual word perception was degraded under information masking by the two-talker noise (69 % accuracy), compared to...
Source: Hearing Research - August 22, 2014 Category: Audiology Authors: Soshi T, Hisanaga S, Kodama N, Kanekama Y, Samejima Y, Yumoto E, Sekiyama K Tags: Hear Res Source Type: research

Excitatory and inhibitory tonotopic bands in chinchilla inferior colliculus revealed by c-fos immuno-labeling.
We report on resting-level neural activity in inferior colliculus (IC) of auditory midbrain, and on tonotopic bands present following 90 minutes of pure-tone sound stimulation. Neurons activated by 6-kHz sound stimulation lay ventro-medial to those activated at 2 kHz. This is consistent with the known tonotopic organization of IC, and verified in the present report by multi-unit neuron response recordings in central nucleus of IC. Of particular interest, we observe a significant reduction in cell labeling adjacent to the tonotopic bands, and suggest that such decreases represent inhibitory regions. The width of the c-fos l...
Source: Hearing Research - August 22, 2014 Category: Audiology Authors: D'Alessandro LM, Harrison RV Tags: Hear Res Source Type: research

Auditory velocity discrimination in the horizontal plane at very high velocities.
ino C Abstract We determined velocity discrimination thresholds and Weber fractions for sounds revolving around the listener at very high velocities. Sounds used were a broadband white noise and two harmonic sounds with fundamental frequencies at 330 Hz and 1760 Hz. Experiment 1 used velocities ranging between 288°/s and 720°/s in an acoustically treated room and Experiment 2 used velocities between 288°/s and 576°/s in a highly reverberant hall. A third experiment addressed potential confounds in the first two experiments. The results show that people can reliably discriminate velocities at very h...
Source: Hearing Research - August 14, 2014 Category: Audiology Authors: Frissen I, Féron FX, Guastavino C Tags: Hear Res Source Type: research

Factors associated with hearing loss in a normal-hearing guinea pig model of hybrid cochlear implants.
Abstract The Hybrid cochlear implant (CI), also known as Electro- Acoustic Stimulation (EAS), is a new type of CI that preserves residual acoustic hearing and enables combined cochlear implant and hearing aid use in the same ear. However, 30-55% of patients experience acoustic hearing loss within days to months after activation, suggesting that both surgical trauma and electrical stimulation may cause hearing loss. The goals of this study were to: 1) determine the contributions of both implantation surgery and EAS to hearing loss in a normal-hearing guinea pig model; 2) determine which cochlear structural changes ...
Source: Hearing Research - August 13, 2014 Category: Audiology Authors: Tanaka C, Nguyen-Huynh A, Loera K, Stark G, Reiss L Tags: Hear Res Source Type: research

Cochlear length determination using Cone Beam Computed Tomography in a clinical setting.
This study introduces a methodology to determine individual cochlear length in clinical setting by using Cone Beam Computed Tomography. METHODS: Cochlear length determination was performed retrospectively with an OsiriX curved 3D Multiplanar Reconstruction tool on subjects who underwent temporal bone imaging from January 2011 to February 2013. Cochlear length was defined as the spiral route from the center-distal point of the bony round window along the lateral wall towards the helicotrema, which is the endpoint of the measurement. RESULTS: Cochlear length was measured in 436 temporal bones (218 left ears, 218 ri...
Source: Hearing Research - August 11, 2014 Category: Audiology Authors: Würfel W, Lanfermann H, Lenarz T, Majdani O Tags: Hear Res Source Type: research

Abnormal intelligibility of speech in competing speech and in noise in a frequency region where audiometric thresholds are near-normal for hearing-impaired listeners.
nzi C Abstract The ability to identify syllables in the presence of speech-shaped noise and a single-talker background was measured for 18 normal-hearing (NH) listeners, and for eight hearing-impaired (HI) listeners with near-normal audiometric thresholds for frequencies up to 1.5 kHz and a moderate to severe hearing loss above 2 kHz. The stimulus components were restricted to the low-frequency (≤1.5 kHz) region, where audiometric thresholds were classified clinically as normal or near normal for all listeners. Syllable identification in a speech background was measured as a function of the fundamental-frequenc...
Source: Hearing Research - August 11, 2014 Category: Audiology Authors: Léger AC, Ives DT, Lorenzi C Tags: Hear Res Source Type: research

Differential modulation of auditory responses to attended and unattended speech in different listening conditions.
This study investigates how top-down attention modulates neural tracking of the speech envelope in different listening conditions. In the quiet conditions, a single speech stream was presented and the subjects paid attention to the speech stream (active listening) or watched a silent movie instead (passive listening). In the competing speaker (CS) conditions, two speakers of opposite genders were presented diotically. Ongoing electroencephalographic (EEG) responses were measured in each condition and cross-correlated with the speech envelope of each speaker at different time lags. In quiet, active and passive listening res...
Source: Hearing Research - August 11, 2014 Category: Audiology Authors: Kong YY, Mullangi A, Ding N Tags: Hear Res Source Type: research

Inner ear stem cells derived feeder layer promote directional differentiation of amniotic fluid stem cells into functional neurons.
Abstract Intact spiral ganglion neurons are required for cochlear implantation or conventional hearing amplification as an intervention for sensorineural hearing loss. Treatment strategies to replace the loss of spiral ganglion neurons are needed. Recent reports have suggested that amniotic fluid-derived stem cells are capable of differentiating into neuron-like cells in response to cytokines and are not tumorigenic. Amniotic fluid stem cells represent a potential resource for cellular therapy of neural deafness due to spiral ganglion pathology. However, the directional differentiation of amniotic fluid stem cells...
Source: Hearing Research - August 11, 2014 Category: Audiology Authors: Zong L, Chen K, Zhou W, Jiang D, Sun L, Zhang X, Jiang H Tags: Hear Res Source Type: research

The relation between auditory-nerve temporal responses and perceptual rate integration in cochlear implants.
Abstract The purpose of this study was to examine auditory-nerve temporal response properties and their relation to psychophysical threshold for electrical pulse trains of varying rates ("rate integration"). The primary hypothesis was that better rate integration (steeper slope) would be correlated with smaller decrements in ECAP amplitude as a function of stimulation rate (shallower slope of the amplitude-rate function), reflecting a larger percentage of the neural population contributing more synchronously to each pulse in the train. Data were obtained for 26 ears in 23 cochlear-implant recipients. Ele...
Source: Hearing Research - August 2, 2014 Category: Audiology Authors: Hughes ML, Baudhuin JL, Goehring JL Tags: Hear Res Source Type: research

Brain structural and functional alterations in patients with unilateral hearing loss.
In this study, we aim to investigate regional brain structural and functional alterations in patients with UHL. T1-weighted volumetric images and task-free fMRIs were acquired from 14 patients with right-sided UHL (pure tone average ≥ 40 dB HL) and 19 healthy controls. Hearing ability was assessed by pure tone audiometry. Voxel-based morphometry (VBM) was performed to detect brain regions with changed gray matter volume or white matter volume in UHL. The amplitude of low-frequency fluctuation (ALFF) was calculated to analyze brain activity at the baseline and was compared between two groups. Compared with controls, UHL...
Source: Hearing Research - August 2, 2014 Category: Audiology Authors: Yang M, Chen HJ, Liu B, Huang ZC, Feng Y, Li J, Chen JY, Zhang LL, Ji H, Feng X, Zhu X, Teng GJ Tags: Hear Res Source Type: research

Age-related hearing loss increases cross-modal distractibility.
Abstract Recent electrophysiological studies have provided evidence that changes in multisensory processing in auditory cortex cannot only be observed following extensive hearing loss, but also in moderately hearing-impaired subjects. How the reduced auditory input affects audio-visual interactions is however largely unknown. Here we used a cross-modal distraction paradigm to investigate multisensory processing in elderly participants with an age-related high-frequency hearing loss as compared to young and elderly subjects with normal hearing. During the experiment, participants were simultaneously presented with ...
Source: Hearing Research - July 28, 2014 Category: Audiology Authors: Puschmann S, Sandmann P, Bendixen A, Thiel CM Tags: Hear Res Source Type: research

Optimized loudness function estimation for categorical loudness scaling data.
Abstract Individual loudness perception can be assessed using categorical loudness scaling (CLS). The procedure does not require any training and is frequently used in clinics. The goal of this study was to investigate different methods of loudness function estimation from CLS data in terms of their test-retest behaviour and to suggest an improved method compared to Brand and Hohmann [J Acoust Soc Am 112:1597 (2002)] for adaptive CLS. Four different runs of the CLS procedure were conducted using 13 normal-hearing and 11 hearing-impaired listeners. The following approaches for loudness function estimation (fitting)...
Source: Hearing Research - July 21, 2014 Category: Audiology Authors: Oetting D, Brand T, Ewert SD Tags: Hear Res Source Type: research

The acoustical cues to sound location in the Guinea pig (cavia porcellus).
Abstract There are three main acoustical cues to sound location, each attributable to space-and frequency-dependent filtering of the propagating sound waves by the outer ears, head, and torso: Interaural differences in time (ITD) and level (ILD) as well as monaural spectral shape cues. While the guinea pig has been a common model for studying the anatomy, physiology, and behavior of binaural and spatial hearing, extensive measurements of their available acoustical cues are lacking. Here, these cues were determined from directional transfer functions (DTFs), the directional components of the head-related transfer f...
Source: Hearing Research - July 19, 2014 Category: Audiology Authors: Greene NT, Anbuhl KL, Williams W, Tollin DJ Tags: Hear Res Source Type: research

Peak I of the human auditory brainstem response results from the somatic regions of type I spiral ganglion cells: evidence from computer modeling.
Abstract Early neural responses to acoustic signals can be electrically recorded as a series of waves, termed the auditory brainstem response (ABR). The latencies of the ABR waves are important for clinical and neurophysiological evaluations. Using a biophysical model of transmembrane currents along spiral ganglion cells, we show that in human (i) the non-myelinated somatic regions of type I cells, which innervate inner hair cells, predominantly contribute to peak I, (ii) the supra-strong postsynaptic stimulating current (400 pA) and transmembrane currents of the myelinated peripheral axons of type I cells are an ...
Source: Hearing Research - July 11, 2014 Category: Audiology Authors: Rattay F, Danner SM Tags: Hear Res Source Type: research

T'ain't the way you say it, it's what you say - Perceptual continuity of voice and top-down restoration of speech.
Abstract Phonemic restoration, or top-down repair of speech, is the ability of the brain to perceptually reconstruct missing speech sounds, using remaining speech features, linguistic knowledge and context. This usually occurs in conditions where the interrupted speech is perceived as continuous. The main goal of this study was to investigate whether voice continuity was necessary for phonemic restoration. Restoration benefit was measured by the improvement in intelligibility of meaningful sentences interrupted with periodic silent gaps, after the gaps were filled with noise bursts. A discontinuity was induced on ...
Source: Hearing Research - July 11, 2014 Category: Audiology Authors: Clarke J, Gaudrain E, Chatterjee M, Başkent D Tags: Hear Res Source Type: research

Inner ear tissue preservation by rapid freezing: Improving fixation by high-pressure freezing and hybrid methods.
Abstract In the preservation of tissues in as 'close to life' state as possible, rapid freeze fixation has many benefits over conventional chemical fixation. One technique by which rapid freeze-fixation can be achieved, high pressure freezing (HPF), has been shown to enable ice crystal artefact-free freezing and tissue preservation to greater depths (more than 40 μm) than other quick-freezing methods. Despite increasingly becoming routine in electron microscopy, the use of HPF for the fixation of inner ear tissue has been limited. Assessment of the quality of preservation showed routine HPF techniques were...
Source: Hearing Research - July 10, 2014 Category: Audiology Authors: Bullen A, Taylor RR, Kachar B, Moores C, Fleck RA, Forge A Tags: Hear Res Source Type: research

Morphological brain network assessed using graph theory and network filtration in deaf adults.
Abstract Prolonged deprivation of auditory input can change brain networks in pre- and postlingual deaf adults by brain-wide reorganization. To investigate morphological changes in these brains voxel-based morphometry, voxel-wise correlation with the primary auditory cortex, and whole brain network analyses using morphological covariance were performed in eight prelingual deaf, eleven postlingual deaf, and eleven hearing adults. Network characteristics based on graph theory and network filtration based on persistent homology were examined. Gray matter density in the primary auditor cortex was preserved in prelingu...
Source: Hearing Research - July 10, 2014 Category: Audiology Authors: Kim E, Kang H, Lee H, Lee HJ, Suh MW, Song JJ, Oh SH, Lee DS Tags: Hear Res Source Type: research

Behavioral frequency discrimination ability of partially deafened cats using cochlear implants.
In this study we were able to show, for the first time, that cats can utilize information provided by a CI in performing a behavioral frequency discrimination task. PMID: 25008966 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - July 4, 2014 Category: Audiology Authors: Benovitski YB, Blamey PJ, Rathbone GD, Fallon JB Tags: Hear Res Source Type: research

Acoustic trauma triggers upregulation of serotonin receptor genes.
Abstract Hearing loss induces plasticity in excitatory and inhibitory neurotransmitter systems in auditory brain regions. Excitatory-inhibitory balance is also influenced by a range of neuromodulatory regulatory systems, but less is known about the effects of auditory damage on these networks. In this work, we studied the effects of acoustic trauma on neuromodulatory plasticity in the auditory midbrain of CBA/J mice. Quantitative PCR was used to measure the expression of serotonergic and GABAergic receptor genes in the inferior colliculus (IC) of mice that were unmanipulated, sham controls with no hearing loss, an...
Source: Hearing Research - July 2, 2014 Category: Audiology Authors: Smith AR, Kwon JH, Navarro M, Hurley LM Tags: Hear Res Source Type: research

Place pitch versus electrode location in a realistic computational model of the implanted human cochlea.
Abstract Place pitch was investigated in a computational model of the implanted human cochlea containing nerve fibres with realistic trajectories that take the variable distance between the organ of Corti and spiral ganglion into account. The model was further updated from previous studies by including fluid compartments in the modiolus and updating the electrical conductivity values of (temporal) bone and the modiolus, based on clinical data. Four different cochlear geometries are used, modelled with both lateral and perimodiolar implants, and their neural excitation patterns were examined for nerve fibres modell...
Source: Hearing Research - June 26, 2014 Category: Audiology Authors: Kalkman RK, Briaire JJ, Dekker DM, Frijns JH Tags: Hear Res Source Type: research