Electro-acoustic pitch matching experiments in patients with single-sided deafness and a cochlear implant: Is there a need for adjustment of the default frequency allocation tables?
Abstract Patients with single-sided deafness (SSD) and a cochlear implant (CI) can compare the pitch of stimulated electrodes and acoustic tones. A pitch mismatch may negatively bear on the fusion of the signals from the two ears, which may limit auditory performance. We aimed to explore this mismatch, correlate it to performance, and finally to discuss its possible clinical consequences. Ten patients with SSD and a CI (Cochlear Ltd.) compared the pitch of electrical and acoustic stimuli. Patients had to choose one of two acoustic stimuli, with the pitch closest to the pitch of the electrical stimulus at electrode...
Source: Hearing Research - October 24, 2016 Category: Audiology Authors: Peters JP, Bennink E, Grolman W, van Zanten GA Tags: Hear Res Source Type: research

Long-term noise exposures: A brief review.
PMID: 27780746 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 22, 2016 Category: Audiology Authors: Davis R Tags: Hear Res Source Type: research

Effects of brain-derived neurotrophic factor (BDNF) on the cochlear nucleus in cats deafened as neonates.
PMID: 27773647 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 20, 2016 Category: Audiology Authors: Kandathil CK, Stakhovskaya O, Leake PA Tags: Hear Res Source Type: research

Editorial introduction: Special issue on plasticity following hearing loss and deafness.
PMID: 27771426 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 19, 2016 Category: Audiology Authors: Butler BE, Meredith MA, Lomber SG Tags: Hear Res Source Type: research

Performance in noise: Impact of reduced speech intelligibility on Sailor performance in a Navy command and control environment.
Abstract Noise, hearing loss, and electronic signal distortion, which are common problems in military environments, can impair speech intelligibility and thereby jeopardize mission success. The current study investigated the impact that impaired communication has on operational performance in a command and control environment by parametrically degrading speech intelligibility in a simulated shipborne Combat Information Center. Experienced U.S. Navy personnel served as the study participants and were required to monitor information from multiple sources and respond appropriately to communications initiated by inves...
Source: Hearing Research - October 19, 2016 Category: Audiology Authors: Keller MD, Ziriax JM, Barns W, Sheffield B, Brungart D, Thomas T, Jaeger B, Yankaskas K Tags: Hear Res Source Type: research

The influence of memory and attention on the ear advantage in dichotic listening.
Abstract The role of memory retention and attentional control on hemispheric asymmetry was investigated using a verbal dichotic listening paradigm, with the consonant-vowel syllables (/ba/,/da/,/ga/,/ka/,/pa/and/ta/), while manipulating the focus of attention and the time interval between stimulus and response. Attention was manipulated using three conditions: non-forced (NF), forced left (FL) and forced right (FR) attention. Memory involvement was varied using four delays (0, 1, 3 and 4 s) between stimulus presentation and response. Results showed a significant right ear advantage (REA) in the NF condition a...
Source: Hearing Research - October 19, 2016 Category: Audiology Authors: D'Anselmo A, Marzoli D, Brancucci A Tags: Hear Res Source Type: research

Category selectivity of the N170 and the role of expertise in deaf signers.
This study was designed to characterize the effects of early deafness and lifelong sign language use on visual category sensitivity of the N170 event-related potential. Images from nine categories of visual forms including upright faces, inverted faces, and hands were presented to twelve typically hearing adults and twelve adult congenitally deaf signers. Classic N170 category sensitivity was observed in both participant groups, whereby faces elicited larger amplitudes than all other visual categories, and inverted faces elicited larger amplitudes and slower latencies than upright faces. In hearing adults, hands elicited a...
Source: Hearing Research - October 19, 2016 Category: Audiology Authors: Mitchell TV Tags: Hear Res Source Type: research

Musicians' edge: A comparison of auditory processing, cognitive abilities and statistical learning.
Abstract It has been hypothesized that musical expertise is associated with enhanced auditory processing and cognitive abilities. Recent research has examined the relationship between musicians' advantage and implicit statistical learning skills. In the present study, we assessed a variety of auditory processing skills, cognitive processing skills, and statistical learning (auditory and visual forms) in age-matched musicians (N = 17) and non-musicians (N = 18). Musicians had significantly better performance than non-musicians on frequency discrimination, and backward digit span. A key finding w...
Source: Hearing Research - October 19, 2016 Category: Audiology Authors: Mandikal Vasuki PR, Sharma M, Demuth K, Arciuli J Tags: Hear Res Source Type: research

Spatial and temporal disparity in signals and maskers affects signal detection in non-human primates.
Abstract Detection thresholds for auditory stimuli (signals) increase in the presence of maskers. Natural environments contain maskers/distractors that can have a wide range of spatiotemporal properties relative to the signal. While these parameters have been well explored psychophysically in humans, they have not been well explored in animal models, and their neuronal underpinnings are not well understood. As a precursor to the neuronal measurements, we report the effects of systematically varying the spatial and temporal relationship between signals and noise in macaque monkeys (Macaca mulatta and Macaca radiata...
Source: Hearing Research - October 19, 2016 Category: Audiology Authors: Rocchi F, Dylla ME, Bohlen PA, Ramachandran R Tags: Hear Res Source Type: research

Hearing testing in the U.S. Department of Defense: Potential impact on Veterans Affairs hearing loss disability awards.
Abstract Hearing loss is the second most common disability awarded by the U.S. Department of Veterans Affairs (VA) to former members of the U.S. uniformed services. Hearing readiness and conservation practices differ among the four largest uniformed military services (Air Force, Army, Marine Corps, and Navy). Utilizing a data set consisting of all hearing loss claims submitted to the VA from fiscal years 2003-2013, we examined characteristics of veterans submitting claims within one year of separation from military service. Our results indicate that having a hearing loss disability claim granted was significantly ...
Source: Hearing Research - October 18, 2016 Category: Audiology Authors: Nelson JT, Swan AA, Swiger B, Packer M, Pugh MJ Tags: Hear Res Source Type: research

Developmental hearing loss impedes auditory task learning and performance in gerbils.
Abstract The consequences of developmental hearing loss have been reported to include both sensory and cognitive deficits. To investigate these issues in a non-human model, auditory learning and asymptotic psychometric performance were compared between normal hearing (NH) adult gerbils and those reared with conductive hearing loss (CHL). At postnatal day 10, before ear canal opening, gerbil pups underwent bilateral malleus removal to induce a permanent CHL. Both CHL and control animals were trained to approach a water spout upon presentation of a target (Go stimuli), and withhold for foils (Nogo stimuli). To asses...
Source: Hearing Research - October 13, 2016 Category: Audiology Authors: von Trapp G, Aloni I, Young S, Semple MN, Sanes DH Tags: Hear Res Source Type: research

Early age noise exposure increases loudness perception - A novel animal model of hyperacusis.
Abstract The neural mechanisms that give rise to hyperacusis, a reduction in loudness tolerance, are largely unknown. Some reports suggest that hyperacusis is linked to childhood hearing loss. However, the evidence for this is largely circumstantial. In order to rigorously test this hypothesis, we studied loudness changes in rats caused by intense noise exposure (12 kHz narrow band noise, 115 dB SPL, 4 h) at postnatal 16 days. Rats without noise exposure were used as controls. The exposed noise group (n = 7) showed a mean 40-50 dB hearing loss compared to the control group (n =&n...
Source: Hearing Research - October 13, 2016 Category: Audiology Authors: Alkharabsheh A, Xiong F, Manohar S, Chen G, Salvi R, Sun W Tags: Hear Res Source Type: research

Effects of noise on speech recognition: Challenges for communication by service members.
This article provides readers with an overview of the challenges associated with speech communication in noisy backgrounds, as well as its assessment and potential impact on functional performance, and provides guidance for important new research directions relevant not only to military personnel, but also to employees who work in high noise environments. PMID: 27743882 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 12, 2016 Category: Audiology Authors: Le Prell CG, Clavier O Tags: Hear Res Source Type: research

Perilymph pharmacokinetics of locally-applied gentamicin in the guinea pig.
In this study, gentamicin was applied to the round window niche as a 20 μL bolus of 40 mg/ml solution. Ten 2 μL samples of perilymph were collected sequentially from the lateral semi-circular canal (LSCC) at times from 1 to 4 h after application. Gentamicin concentration was typically highest in samples originating from the vestibule and was lower in samples originating from scala tympani. To interpret these results, perilymph elimination kinetics for gentamicin was quantified by loading the entire perilymph space by injection at the LSCC with a 500 μg/ml gentamicin solution followed by se...
Source: Hearing Research - October 8, 2016 Category: Audiology Authors: Salt AN, Hartsock JJ, Gill RM, King E, Kraus FB, Plontke SK Tags: Hear Res Source Type: research

Top-down and bottom-up neurodynamic evidence in patients with tinnitus.
Abstract Although a peripheral auditory (bottom-up) deficit is an essential prerequisite for the generation of tinnitus, central cognitive (top-down) impairment has also been shown to be an inherent neuropathological mechanism. Using an auditory oddball paradigm (for top-down analyses) and a passive listening paradigm (for bottom-up analyses) while recording electroencephalograms (EEGs), we investigated whether top-down or bottom-up components were more critical in the neuropathology of tinnitus, independent of peripheral hearing loss. We observed significantly reduced P300 amplitudes (reflecting fundamental cogni...
Source: Hearing Research - October 8, 2016 Category: Audiology Authors: Hong SK, Park S, Ahn MH, Min BK Tags: Hear Res Source Type: research

Quercetin protects against hair cell loss in the zebrafish lateral line and guinea pig cochlea.
Abstract Eighteen supplement drugs were screened using hair cells to determine a protective effect against the adverse effects of neomycin by using the zebrafish lateral line. The zebrafish were administered the supplement drugs 1 h before neomycin exposure. One hour later, animals were fixed in paraformaldehyde. Dose-response curves were generated to evaluate the protective effect on hair cells. The screen identified 3 supplements (quercetin, catechin and tannic acid). Three minutes after exposure to neomycin, increased antioxidant activity was found in the lateral line hair cells, as determined by the analy...
Source: Hearing Research - October 4, 2016 Category: Audiology Authors: Hirose Y, Sugahara K, Kanagawa E, Takemoto Y, Hashimoto M, Yamashita H Tags: Hear Res Source Type: research

Acute high-intensity noise induces rapid Arc protein expression but fails to rapidly change GAD expression in amygdala and hippocampus of rats: Effects of treatment with D-cycloserine.
Abstract Tinnitus is a devastating auditory disorder impacting a growing number of people each year. The aims of the current experiment were to assess neuronal mechanisms involved in the initial plasticity after traumatic noise exposure that could contribute to the emergence of tinnitus and to test a potential pharmacological treatment to alter this early neural plasticity. Specifically, this study addressed rapid effects of acute noise trauma on amygdalo-hippocampal circuitry, characterizing biomarkers of both excitation and inhibition in these limbic regions, and compared them to expression of these same markers...
Source: Hearing Research - October 1, 2016 Category: Audiology Authors: Kapolowicz MR, Thompson LT Tags: Hear Res Source Type: research

The potential use of low-frequency tones to locate regions of outer hair cell loss.
In this study, we lowered the concentration of ouabain to 1 mM and determined the physiologic effects on outer hair cells using distortion-product otoacoustic emissions. As well as quantifying the effects of 1 mM ouabain on the auditory nerve and outer hair cells, we attempted to reduce the neural contribution to the CR by using near-infrasonic stimulus frequencies of 45 and 85 Hz, and hypothesized that these low-frequency stimuli would generate a cumulative amplitude function (CAF) that could reflect damage to hair cells in the apex more accurately than the 762 stimuli. One hour after application of 1 ...
Source: Hearing Research - September 24, 2016 Category: Audiology Authors: Kamerer A, Diaz FJ, Peppi M, Chertoff M Tags: Hear Res Source Type: research

Differential tinnitus-related neuroplastic alterations of cortical thickness and surface area.
Abstract Structural neuroimaging techniques have been used to identify cortical and subcortical regions constituting the neuroarchitecture of tinnitus. One recent investigation used voxel-based morphometry (VBM) to analyze a sample of tinnitus patients (TI, n=257) [1]. A negative relationship between individual distress and cortical volume (CV) in bilateral auditory regions was observed. However, CV has meanwhile been identified as a neuroanatomical measurement that confounds genetically distinct neuroanatomical traits, namely cortical thickness (CT) and cortical surface area (CSA). We performed a re-analysis of t...
Source: Hearing Research - September 23, 2016 Category: Audiology Authors: Meyer M, Neff P, Liem F, Kleinjung T, Weidt S, Langguth B, Schecklmann M Tags: Hear Res Source Type: research

Reorganization of neural systems mediating peripheral visual selective attention in the deaf: An optical imaging study.
We report data from severe to profoundly deaf adults and normal-hearing controls who performed the Useful Field of View task while cortical activity was recorded using the event-related optical signal. Behavioral performance, obtained in a separate session, showed that deaf subjects had lower thresholds (i.e., better performance) on the Useful Field of View task. The event-related optical data indicated greater activity for the deaf adults than for the normal-hearing controls during the task in the posterior portion of Brodmann area 22 in the right hemisphere. Furthermore, the behavioral thresholds correlated significantly...
Source: Hearing Research - September 23, 2016 Category: Audiology Authors: Seymour JL, Low KA, Maclin EL, Chiarelli AM, Mathewson KE, Fabiani M, Gratton G, Dye MW Tags: Hear Res Source Type: research

Circadian regulation of auditory function.
PMID: 27665709 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - September 22, 2016 Category: Audiology Authors: Basinou V, Park JS, Cederroth CR, Canlon B Tags: Hear Res Source Type: research

Study of tonotopic brain changes with functional MRI and FDG-PET in a patient with unilateral objective cochlear tinnitus.
The objective cochlear tinnitus was measured by Spontaneous Otoacoustic Emissions (SOAE) equipment (frequency 9689 Hz, intensity 57 dB SPL) and is clearly audible to anyone standing near the patient. Functional modifications in primary auditory areas and other brain regions were evaluated using 3T and 7T fMRI and FDG-PET. In the fMRI evaluations, a saturation of the auditory cortex at the tinnitus frequency was observed, but the global cortical tonotopic organization remained intact when compared to the results of fMRI of healthy subjects. The FDG-PET showed no evidence of an increase or decrease of activity in the auditor...
Source: Hearing Research - September 20, 2016 Category: Audiology Authors: Guinchard AC, Ghazaleh N, Saenz M, Fornari E, Prior JO, Maeder P, Adib S, Maire R Tags: Hear Res Source Type: research

Hearing sensitivity differs between zebrafish lines used in auditory research.
Abstract Zebrafish are increasingly used in auditory studies, in part due to the development of several transgenic lines that express hair cell-specific fluorescent proteins. However, it is largely unknown how transgene expression influences auditory phenotype. We previously observed reduced auditory sensitivity in adult Brn3c:mGFP transgenic zebrafish, which express membrane-bound green fluorescent protein (GFP) in sensory hair cells. Here, we examine the auditory sensitivity of zebrafish from multiple transgenic and background strains. We recorded auditory evoked potentials in adult animals and observed signific...
Source: Hearing Research - September 17, 2016 Category: Audiology Authors: Monroe JD, Manning DP, Uribe PM, Bhandiwad A, Sisneros JA, Smith ME, Coffin AB Tags: Hear Res Source Type: research

Higher-order auditory areas in congenital deafness: Top-down interactions and corticocortical decoupling.
Abstract The theory of predictive coding assumes that higher-order representations influence lower-order representations by generating predictions about sensory input. In congenital deafness, one identified dysfunction is a reduced activation of deep layers in the auditory cortex. Since these layers play a central role for processing top-down influences, congenital deafness might interfere with the integration of top-down and bottom-up information flow. Studies in humans suggest more deficits in higher-order than in primary cortical areas in congenital deafness. That opens up the question how well neurons in highe...
Source: Hearing Research - September 13, 2016 Category: Audiology Authors: Kral A, Yusuf PA, Land R Tags: Hear Res Source Type: research

Time course and frequency specificity of sub-cortical plasticity in adults following acute unilateral deprivation.
Abstract Auditory deprivation and stimulation can change the threshold of the acoustic reflex, but the mechanisms underlying these changes remain largely unknown. In order to elucidate the mechanism, we sought to characterize the time-course as well as the frequency specificity of changes in acoustic reflex thresholds (ARTs). In addition, we compared ipsilateral and contralateral measurements because the pattern of findings may shed light on the anatomical location of the change in neural gain. Twenty-four normal-hearing adults wore an earplug continuously in one ear for six days. We measured ipsilateral and contr...
Source: Hearing Research - September 10, 2016 Category: Audiology Authors: Brotherton H, Plack CJ, Schaette R, Munro KJ Tags: Hear Res Source Type: research

Dopaminergic projections of the subparafascicular thalamic nucleus to the auditory brainstem.
Abstract Neuromodulators can alter the response properties of sensory neurons, including those in the auditory system. Dopamine, which plays a major role in reward and movement, has been shown to alter neural responses in the auditory brainstem and midbrain. Recently we identified the subparafascicular thalamic nucleus (SPF), part of the A11 dopaminergic cell group, as the source of dopamine to the inferior colliculus (IC). The superior olivary complex (SOC) is also a likely target of dopaminergic projections from the SPF because it receives projections from the SPF and contains fibers and terminals immunoreactive...
Source: Hearing Research - September 10, 2016 Category: Audiology Authors: Nevue AA, Felix RA, Portfors CV Tags: Hear Res Source Type: research

Cross-modal Plasticity in Developmental and Age-Related Hearing Loss: Clinical Implications.
We describe developmental cross-modal re-organization in the context of congenital or pre-lingual deafness in childhood and in the context of adult-onset, age-related hearing loss, with a focus on how cross-modal plasticity relates to clinical outcomes. We provide both single-subject and group-level evidence of cross-modal re-organization by the visual and somatosensory systems in bilateral, congenital deafness, single-sided deafness, adults with early-stage, mild-moderate hearing loss, and individual adult and pediatric patients exhibit excellent and average speech perception with hearing aids and cochlear implants. We di...
Source: Hearing Research - September 6, 2016 Category: Audiology Authors: Glick H, Sharma A Tags: Hear Res Source Type: research

A tri-coil bellows-type round window transducer with improved frequency characteristics for middle-ear implants.
In this study, a new tri-coil bellows-type transducer (TCBT), which has excellent low frequency output and is easy to implant, is proposed. To design the frequency characteristics of the TCBT, mechanical and electrical simulations were performed, and then a comparative analysis was conducted between a floating mass type transducer (like the FMT) and a fixed type transducer (like the TCBT). The features of the proposed TCBT are as follows. First, the TCBT's housing is fixed to the RW niche so that it does not vibrate. Second, the internal end of a tiny bellows is connected to a vibrating three-pole permanent magnet located ...
Source: Hearing Research - September 2, 2016 Category: Audiology Authors: Shin DH, Seong KW, Puria S, Lee KY, Cho JH Tags: Hear Res Source Type: research

A fast, stochastic, and adaptive model of auditory nerve responses to cochlear implant stimulation.
In this study, a computationally efficient model that accurately predicts auditory nerve responses to CI pulse train input was developed. A three-dimensional volume conduction and active nerve model developed at Leiden University Medical Center was extended with stochasticity, adaptation, and accommodation. This complete model includes spatial and temporal characteristics of both the cochlea and the auditory nerve. The model was validated by comparison with experimentally measured single fiber action potential responses to pulse trains published in the literature. The effects of pulse rate and pulse amplitude on spiking pa...
Source: Hearing Research - September 2, 2016 Category: Audiology Authors: van Gendt MJ, Briaire JJ, Kalkman RK, Frijns JH Tags: Hear Res Source Type: research

Speech perception adjusts to stable spectrotemporal properties of the listening environment.
Abstract When perceiving speech, listeners compensate for reverberation and stable spectral peaks in the speech signal. Despite natural listening conditions usually adding both reverberation and spectral coloration, these processes have only been studied separately. Reverberation smears spectral peaks across time, which is predicted to increase listeners' compensation for these peaks. This prediction was tested using sentences presented with or without a simulated reverberant sound field. All sentences had a stable spectral peak (added by amplifying frequencies matching the second formant frequency [F2] in the tar...
Source: Hearing Research - September 2, 2016 Category: Audiology Authors: Stilp CE, Anderson PW, Assgari AA, Ellis GM, Zahorik P Tags: Hear Res Source Type: research

The effect of distraction on change detection in crowded acoustic scenes.
Abstract In this series of behavioural experiments we investigated the effect of distraction on the maintenance of acoustic scene information in short-term memory. Stimuli are artificial acoustic 'scenes' composed of several (up to twelve) concurrent tone-pip streams ('sources'). A gap (1000 ms) is inserted partway through the 'scene'; Changes in the form of an appearance of a new source or disappearance of an existing source, occur after the gap in 50% of the trials. Listeners were instructed to monitor the unfolding 'soundscapes' for these events. Distraction was measured by presenting distractor stimuli du...
Source: Hearing Research - September 2, 2016 Category: Audiology Authors: Petsas T, Harrison J, Kashino M, Furukawa S, Chait M Tags: Hear Res Source Type: research

Modelling the effect of round window stiffness on residual hearing after cochlear implantation.
Abstract Preservation of residual hearing after cochlear implantation is now considered an important goal of surgery. However, studies indicate an average post-operative hearing loss of around 20 dB at low frequencies. One factor which may contribute to post-operative hearing loss, but which has received little attention in the literature to date, is the increased stiffness of the round window, due to the physical presence of the cochlear implant, and to its subsequent thickening or to bone growth around it. A finite element model was used to estimate that there is approximately a 100-fold increase in the round wi...
Source: Hearing Research - August 29, 2016 Category: Audiology Authors: Elliott SJ, Ni G, Verschuur CA Tags: Hear Res Source Type: research

The effects of aging and sex on detection of ultrasonic vocalizations by adult CBA/CaJ mice (Mus musculus).
In conclusion, the results highlight the importance of studying complex signals across the lifespan. PMID: 27579993 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - August 27, 2016 Category: Audiology Authors: Kobrina A, Dent ML Tags: Hear Res Source Type: research

The contribution of inferior colliculus activity to the auditory brainstem response (ABR) in mice.
In conclusion, the slow ABR wave P0 in the scalp ABR may represent a complementary non-invasive marker for IC activity in the mouse. Further, the latency of synchronized click-evoked activity in the IC supports the view that IC contributes to ABR wave V, and possibly also to ABR wave IV. PMID: 27562195 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - August 22, 2016 Category: Audiology Authors: Land R, Burghard A, Kral A Tags: Hear Res Source Type: research

Auditory Thalamic Circuits and GABAA Receptor Function: Putative Mechanisms in Tinnitus Pathology.
Abstract Tinnitus is defined as a phantom sound (ringing in the ears), and can significantly reduce the quality of life for those who suffer its effects. Ten to fifteen percent of the general adult population report symptoms of tinnitus with 1-2% reporting that tinnitus negatively impacts their quality of life. Noise exposure is the most common cause of tinnitus and the military environment presents many challenging high-noise situations. Military noise levels can be so intense that standard hearing protection is not adequate. Recent studies suggest a role for inhibitory neurotransmitter dysfunction in response to...
Source: Hearing Research - August 20, 2016 Category: Audiology Authors: Caspary DM, Llano DA Tags: Hear Res Source Type: research

Endothelin-1 Mediated Induction of Extracellular Matrix Genes in Strial Marginal Cells Underlies Strial Pathology in Alport Mice.
Abstract Alport syndrome, a type IV collagen disorder, manifests as glomerular disease associated with hearing loss with thickening of the glomerular and strial capillary basement membranes (SCBMs). We have identified a role for endothelin-1 (ET-1) activation of endothelin A receptors (ETARs) in glomerular pathogenesis. Here we explore whether ET-1 plays a role in strial pathology. Wild type (WT) and Alport mice were treated with the ETAR antagonist, sitaxentan. The stria vascularis was analyzed for SCBM thickness and for extracellular matrix (ECM) proteins. Additional WT and Alport mice were exposed to noise or h...
Source: Hearing Research - August 20, 2016 Category: Audiology Authors: Meehan DT, Delimont D, Dufek B, Zallocchi M, Phillips G, Gratton MA, Cosgrove D Tags: Hear Res Source Type: research

Low-Frequency Bias Tone Suppression of Auditory-Nerve Responses to Low-Level Clicks and Tones.
Abstract We used low-frequency "bias" tones (BT's) to explore whether click and tone responses are affected in the same way by cochlear active processes. In nonlinear systems the responses to clicks are not always simply related to the responses to tones. Cochlear amplifier gain depends on the incremental slope of the outer-hair-cell (OHC) stereocilia mechano-electric transductance (MET) function. BTs transiently change the operating-point of OHC MET channels and can suppress cochlear-amplifier gain by pushing OHC METs into low-slope saturation regions. BT effects on single auditory-nerve (AN) fibers hav...
Source: Hearing Research - August 18, 2016 Category: Audiology Authors: Nam H, Guinan JJ Tags: Hear Res Source Type: research

Differences in synaptic and intrinsic properties result in topographic heterogeneity of temporal processing of neurons within the inferior colliculus.
Abstract The identification and characterization of organization principals is essential for the understanding of neural function of brain areas. The inferior colliculus (IC) represents a midbrain nexus involved in numerous aspects of auditory processing. Likewise, neurons throughout the IC are tuned to a diverse range of specific stimulus features. Yet beyond a topographic arrangement of the cochlea-inherited frequency tuning, the functional organization of the IC is not well understood. Particularly, a common principle that links the diverse tuning characteristics is unknown. Here we used in vitro patch cla...
Source: Hearing Research - August 17, 2016 Category: Audiology Authors: Yassin L, Pecka M, Kajopoulos J, Gleiss H, Li L, Leibold C, Felmy F Tags: Hear Res Source Type: research

Across-site patterns of electrically evoked compound action potential amplitude-growth functions in multichannel cochlear implant recipients and the effects of the interphase gap.
Abstract Electrically evoked compound action potential (ECAP) measures of peak amplitude, and amplitude-growth function (AGF) slope have been shown to reflect characteristics of cochlear health (primarily spiral ganglion density) in anesthetized cochlear-implanted guinea pigs. Likewise, the effect of increasing the interphase gap (IPG) in each of these measures also reflects SGN density in the implanted guinea pig. Based on these findings, we hypothesize that suprathreshold ECAP measures, and also how they change as the IPG is increased, have the potential to be clinically applicable in human subjects. However, fu...
Source: Hearing Research - August 10, 2016 Category: Audiology Authors: Schvartz-Leyzac KC, Pfingst BE Tags: Hear Res Source Type: research

Effects of sustained release dexamethasone hydrogels in hearing preservation cochlear implantation.
r C Abstract It has been shown that glucocorticoids reduce the hearing threshold shifts associated with cochlear implantation. Previous studies evaluated the administration of glucocorticoids immediately before surgery or the repeated pre- or perioperative systemic application of glucocorticoids. The aim of this study was to evaluate the effects of a sustained release dexamethasone hydrogel in hearing preservation cochlear implantation. To address this issue, a guinea pig model of cochlear implantation was used. 30 normal hearing pigmented guinea pigs were randomized into a group receiving a single dose of a dexam...
Source: Hearing Research - August 9, 2016 Category: Audiology Authors: Honeder C, Zhu C, Schöpper H, Gausterer JC, Walter M, Landegger LD, Saidov N, Riss D, Plasenzotti R, Gabor F, Arnoldner C Tags: Hear Res Source Type: research

Controlled exploration of the effects of conductive hearing loss on wideband acoustic immittance in human cadaveric preparations.
We report measurements before and after simulation of stapes fixation (n = 8), malleus fixation (n = 10), ossicular disarticulation (n = 10), and superior canal dehiscence (n = 8). Our results are consistent with the small set of previously published reflectance measurements made in temporal bones and patients. In this present study, these temporal bone experiments with different middle- and inner-ear pathologies were compared to the initial normal state by analyzing both WAI and ossicular motion, demonstrating that WAI can be a valuable tool in the diagnosis of conductive hearing lo...
Source: Hearing Research - August 3, 2016 Category: Audiology Authors: Merchant GR, Merchant SN, Rosowski JJ, Nakajima HH Tags: Hear Res Source Type: research

Vestibular-dependent inter-stimulus interval effects on sound evoked potentials of central origin.
Abstract Todd et al. (2014ab) have recently demonstrated the presence of vestibular-dependent contributions to auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs), including a particular deflection labeled as an N42/P52 prior to the long-latency AEPs N1 and P2. In this paper we report the results of an experiment to determine the effect of inter-stimulus interval (ISI) and regularity on potentials recorded above and below VEMP threshold. Five healthy, right-handed subjects were recruited and evoked potentials were recor...
Source: Hearing Research - August 3, 2016 Category: Audiology Authors: Todd NP, Govender S, Colebatch JG Tags: Hear Res Source Type: research

Frequency discrimination in the common marmoset (Callithrix jacchus).
Abstract The common marmoset (Callithrix jacchus) is a highly vocal New World primate species that has emerged in recent years as a promising model system for studies of auditory and vocal processing. Our recent studies have examined perceptual mechanisms related to the pitch of harmonic complex tones in this species. However, no previous psychoacoustic work has measured marmosets' frequency discrimination abilities for pure tones across a broad frequency range. Here we systematically examined frequency difference limens (FDLs), which measure the minimum discriminable frequency difference between two pure tones, i...
Source: Hearing Research - August 3, 2016 Category: Audiology Authors: Osmanski MS, Song X, Guo Y, Wang X Tags: Hear Res Source Type: research

Drug discovery for hearing loss: Phenotypic screening of chemical compounds on primary cultures of the spiral ganglion.
Abstract In the United States there are, at present, no drugs that are specifically FDA approved to treat hearing loss. Although several clinical trials are ongoing, including one testing D-methionine that is supported by the US Army, none of these trials directly address the effect of noise exposure on cochlear spiral ganglion neurons. We recently published the first report of a systematic chemical compound screen using primary, mammalian spiral ganglion cultures in which we were able to detect a compound and others in its class that increased neurite elongation, a critical step in restoring cochlear synapses aft...
Source: Hearing Research - August 2, 2016 Category: Audiology Authors: Whitlon DS Tags: Hear Res Source Type: research

Does the degree of linguistic experience (native versus nonnative) modulate the degree to which listeners can benefit from a delay between the onset of the maskers and the onset of the target speech?
Abstract Background noise has a greater adverse effect on word recognition when people are listening in their second language (L2) as opposed to their first language (L1). The present study investigates the extent to which linguistic experience affects the ability of L2 listeners to benefit from a delay between the onset of a masker and the onset of a word. In a previous study (Ben-David, Tse & Schneider, 2012), word recognition thresholds for young L1s were found to improve with the increase in the delay between the onset of a masker (either a stationary noise or a babble of voices) and the onset of a word. T...
Source: Hearing Research - August 2, 2016 Category: Audiology Authors: Ben-David BM, Avivi-Reich M, Schneider BA Tags: Hear Res Source Type: research

Evidence of activity-dependent plasticity in the dorsal cochlear nucleus, in  vivo, induced by brief sound exposure.
We examined the levels of multi- and single-unit spontaneous activity before and immediately following brief exposure (2 min) to tones at levels of either 109 or 85 dB SPL. Exposure frequency was selected to either correspond to the units' best frequency (BF) or fall within the borders of its inhibitory side band. The results demonstrate that these exposure conditions caused significant alterations in spontaneous activity and responses to BF tones. The induced changes have a fast onset (minutes) and are persistent for durations of at least 20 min. The directions of the change were found to depend on the freq...
Source: Hearing Research - August 1, 2016 Category: Audiology Authors: Gao Y, Manzoor N, Kaltenbach JA Tags: Hear Res Source Type: research

Motion of tympanic membrane in guinea pig otitis media model measured by scanning laser Doppler vibrometry.
In this study, the guinea pig AOM and OME models were created by transbullar injection of Streptococcus pneumoniae type 3 and lipopolysaccharide, respectively. To explore the effects of OM on the entire TM vibration, the measurements of full-field TM motions were performed in the AOM, OME and untreated control ears by using scanning laser Doppler vibrometry (SLDV). The results showed that both AOM and OME generally reduced the displacement peak and produced the traveling-wave-like motions at relatively low frequencies. Compared with the normal ear, OME resulted in a significant change of the TM displacement mainly in the i...
Source: Hearing Research - August 1, 2016 Category: Audiology Authors: Wang X, Guan X, Pineda M, Gan RZ Tags: Hear Res Source Type: research

Plasticity in bilateral superior temporal cortex: effects of deafness and cochlear implantation on auditory and visual speech processing.
Abstract While many individuals can benefit substantially from cochlear implantation, the ability to perceive and understand auditory speech with a cochlear implant (CI) remains highly variable amongst adult recipients. Importantly, auditory performance with a CI cannot be reliably predicted based solely on routinely obtained information regarding clinical characteristics of the CI candidate. This review argues that central factors, notably cortical function and plasticity, should also be considered as important contributors to the observed individual variability in CI outcome. Superior temporal cortex (STC), incl...
Source: Hearing Research - July 26, 2016 Category: Audiology Authors: Anderson CA, Lazard DS, Hartley DE Tags: Hear Res Source Type: research

The effect of progressive hearing loss on the morphology of endbulbs of Held and bushy cells.
Abstract Studies of congenital and early-onset deafness have demonstrated that an absence of peripheral sound-evoked activity in the auditory nerve causes pathological changes in central auditory structures. The aim of this study was to establish whether progressive acquired hearing loss could lead to similar brain changes that would degrade the precision of signal transmission. We used complementary physiologic hearing tests and microscopic techniques to study the combined effect of both magnitude and duration of hearing loss on one of the first auditory synapses in the brain, the endbulb of Held (EB), along with...
Source: Hearing Research - July 26, 2016 Category: Audiology Authors: Connelly CJ, Ryugo DK, Muniak MA Tags: Hear Res Source Type: research

Cortical reorganization in postlingually deaf cochlear implant users: intra-modal and cross-modal considerations.
Abstract With the advances of cochlear implant (CI) technology, many deaf individuals can partially regain their hearing ability. However, there is a large variation in the level of recovery. Cortical changes induced by hearing deprivation and restoration with CIs have been thought to contribute to this variation. The current review aims to identify these cortical changes in postlingually deaf CI users and discusses their maladaptive or adaptive relationship to the CI outcome. Overall, intra-modal and cross-modal reorganization patterns have been identified in postlingually deaf CI users in visual and in auditory ...
Source: Hearing Research - July 26, 2016 Category: Audiology Authors: Stropahl M, Chen LC, Debener S Tags: Hear Res Source Type: research