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
Time course of cochlear injury discharge (excitotoxicity) determined by ABR monitoring of contralateral cochlear events.
Abstract The dynamics of cochlear excitotoxicity can be monitored from effects on the contralateral ear. After unilateral mechanical ablation of the cochlea (in a mouse model) we observed immediate elevations in auditory brainstem evoked response (ABR) thresholds in the contralateral ear. Threshold elevations peaked at 2-3 hrs post ablation, and returned to baseline levels after 5-6 hrs. These contralateral effects are initiated by cochlear afferent injury discharges most likely activating the olivocochlear efferent system. Six hours after cochlear injury, ABR thresholds were fully returned to pre-lesion baseline ...
Source: Hearing Research - June 25, 2014 Category: Audiology Authors: Negandhi J, Harrison AL, Allemang C, Harrison RV Tags: Hear Res Source Type: research
Effects of deafness and cochlear implant use on temporal response characteristics in cat primary auditory cortex.
Abstract We have previously shown that neonatal deafness of 7-13 months duration leads to loss of cochleotopy in the primary auditory cortex (AI) that can be reversed by cochlear implant use. Here we describe the effects of a similar duration of deafness and cochlear implant use on temporal processing. Specifically, we compared the temporal resolution of neurons in AI of young adult normal-hearing cats that were acutely deafened and implanted immediately prior to recording with that in three groups of neonatally deafened cats. One group of neonatally deafened cats received no chronic stimulation. The other two gro...
Source: Hearing Research - June 14, 2014 Category: Audiology Authors: Fallon JB, Shepherd RK, Nayagam DA, Wise AK, Heffer LF, Landry TG, Irvine DR Tags: Hear Res Source Type: research
miR-204 suppresses cochlear spiral ganglion neuron survival in vitro by targeting TMPRSS3.
miR-204 suppresses cochlear spiral ganglion neuron survival in vitro by targeting TMPRSS3. Hear Res. 2014 Jun 9; Authors: Li Y, Peng A, Ge S, Wang Q, Liu J Abstract Sensorineural hearing loss (SNHL) is the most common cause of hearing impairment. One of the essential steps to prevent progressive hearing loss is to protect spiral ganglion neurons (SGNs) from ongoing degeneration. MicroRNAs and TMPRSS3 (transmembrane protease, serine 3) have been reported to be involved in development of SGNs and genesis of SNHL. The aim of this study was to investigate the role of miR-204 and TMPRSS3 in SGNs. Effe...
Source: Hearing Research - June 9, 2014 Category: Audiology Authors: Li Y, Peng A, Ge S, Wang Q, Liu J Tags: Hear Res Source Type: research
The auditory corticocollicular system: Molecular and circuit-level considerations.
Abstract We live in a world imbued with a rich mixture of complex sounds. Successful acoustic communication requires the ability to extract meaning from those sounds, even when degraded. One strategy used by the auditory system is to harness high-level contextual cues to modulate the perception of incoming sounds. An ideal substrate for this process is the massive set of top-down projections emanating from virtually every level of the auditory system. In this review, we provide a molecular and circuit-level description of one of the largest of these pathways: the auditory corticocollicular pathway. While its funct...
Source: Hearing Research - June 7, 2014 Category: Audiology Authors: Stebbings KA, Lesicko AM, Llano DA Tags: Hear Res Source Type: research
Prolonged sound exposure has different effects on increasing neuronal size in the auditory cortex and brainstem.
Abstract Tone at moderate levels presented to young rats at a stage (postnatal week-4) presumably that has passed the cortical critical period still can enlarge neurons in the auditory cortex. It remains unclear whether this delayed plastic change occurs only in the cortex, or reflects a change taking place in the auditory brainstem. Here we compared sound-exposure effects on neuronal size in the auditory cortex and the midbrain. Starting from postnatal day 22, young rats were exposed to a low-frequency tone (4 kHz at 65 dB SPL) for a period of 3 (postnatal day 22 to 25) or 7 (postnatal day 22 to 29) day...
Source: Hearing Research - June 6, 2014 Category: Audiology Authors: Lu HP, Syka J, Chiu TW, Poon PW Tags: Hear Res Source Type: research
Primary culture of human Schwann and schwannoma cells: Improved and simplified protocol.
Abstract Primary culture of human Schwann cells (SCs) and vestibular schwannoma (VS) cells are invaluable tools to investigate SC physiology and VS pathobiology, and to devise effective pharmacotherapies against VS, which are sorely needed. However, existing culture protocols, in aiming to create robust, pure cultures, employ methods that can lead to loss of biological characteristics of the original cells, potentially resulting in misleading biological findings. We have developed a minimally manipulative method to culture primary human SC and VS cells, without the use of selective mitogens, toxins, or time-consum...
Source: Hearing Research - June 5, 2014 Category: Audiology Authors: Dilwali S, Patel PB, Roberts DS, Basinsky GM, Harris GJ, Emerick K, Stankovic KM Tags: Hear Res Source Type: research
A novel perfusion-based method for cochlear implant electrode insertion.
Abstract A cochlear implant (CI) restores partial hearing to profoundly deaf individuals. CI electrodes are inserted manually in the cochlea and surgeons rely on tactile feedback from the implant to determine when to stop the insertion. This manual insertion method results in a large degree of variability in surgical outcomes and intra-cochlear trauma. Additionally, implants often span only the basal turn. In the present study we report on the development of a new method to assist CI electrode insertion. The design objectives are (1) an automated and standardized insertion technique across patients with (2) more a...
Source: Hearing Research - May 29, 2014 Category: Audiology Authors: Kale S, Cervantes VM, Wu MR, Pisano DV, Sheth N, Olson ES Tags: Hear Res Source Type: research
Localization of kainate receptors in inner and outer hair cell synapses.
har B Abstract Glutamate plays a role in hair cell afferent transmission, but the receptors that mediate neurotransmission between outer hair cells (OHCs) and type II ganglion neurons are not well defined. A previous study using in situ hybridization showed that several kainate-type glutamate receptor (KAR) subunits are expressed in cochlear ganglion neurons. To determine whether KARs are expressed in hair cell synapses, we performed X-gal staining on mice expressing lacZ driven by the GluK5 promoter, and immunolabeling of glutamate receptors in whole-mount mammalian cochleae. X-gal staining revealed GluK5 express...
Source: Hearing Research - May 20, 2014 Category: Audiology Authors: Fujikawa T, Petralia RS, Fitzgerald TS, Wang YX, Millis B, Morgado-Díaz JA, Kitamura K, Kachar B Tags: Hear Res Source Type: research
Psychometric function of jittered rate pitch discrimination.
In conclusion, pulse rate jitter affects JRPD and therefore should be considered in current coding strategies. PMID: 24821551 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - May 10, 2014 Category: Audiology Authors: Bahmer A, Baumann U Tags: Hear Res Source Type: research
Brainstem response to speech and non-speech stimuli in children with learning problems.
Abstract Neuronal firing synchronization is critical for recording auditory responses from the brainstem. Recent studies have shown that both click and/da/synthetic syllable (speech) stimuli perform well in evoking neuronal synchronization at the brainstem level. In the present study, brainstem responses to click and speech stimuli were compared between children with learning problems (LP) and those with normal learning (NL) abilities. The study included 49 children with LP and 34 children with NL. Auditory brainstem response (ABR) to 100-μs click stimulus and speech ABR (sABR) to/da/40-ms stimulus were tested ...
Source: Hearing Research - May 10, 2014 Category: Audiology Authors: Malayeri S, Lotfi Y, Moossavi SA, Rostami R, Faghihzadeh S Tags: Hear Res Source Type: research
Individual differences in attentional modulation of cortical responses correlate with selective attention performance.
Abstract Many studies have shown that attention modulates the cortical representation of an auditory scene, emphasizing an attended source while suppressing competing sources. Yet, individual differences in the strength of this attentional modulation and their relationship with selective attention ability are poorly understood. Here, we ask whether differences in how strongly attention modulates cortical responses reflect differences in normal-hearing listeners' selective auditory attention ability. We asked listeners to attend to one of three competing melodies and identify its pitch contour while we measured cor...
Source: Hearing Research - May 9, 2014 Category: Audiology Authors: Choi I, Wang L, Bharadwaj H, Shinn-Cunningham B Tags: Hear Res Source Type: research
The connexin 30.3 of zebrafish homologue of human connexin 26 may play similar role in the inner ear.
In this study, using bioinformatics, we found that two zebrafish cx genes, cx27.5 and cx30.3, are likely homologous to human and mouse GJB2. During embryogenesis, zebrafish cx27.5 was rarely expressed at 1.5-3 hours post-fertilization (hpf), but a relatively high level of cx27.5 expression was detected from 6-96 hpf. However, zebrafish cx30.3 transcripts were hardly detected until 9 hpf. The temporal experiment was conducted in whole larvae. Both cx27.5 and cx30.3 transcripts were revealed significantly in the inner ear by reverse transcription polymerase chain reaction (RT-PCR) and whole-mount in situ hybridization (WISH)...
Source: Hearing Research - May 5, 2014 Category: Audiology Authors: Chang-Chien J, Yen YC, Chien KH, Li SY, Hsu TC, Yang JJ Tags: Hear Res Source Type: research
Behavioral responses of deafened guinea pigs to intracochlear electrical stimulation: A new rapid psychophysical procedure.
In conclusion, the present study demonstrates that guinea pigs can be trained relatively fast to respond to acoustic stimuli, and that the training has a lasting effect, which generalizes to intracochlear electrical stimulation after deafening. Furthermore, it demonstrates that bilaterally deafened guinea pigs with substantial (∼50%) loss of spiral ganglion cells (SGCs), detect intracochlear electrical stimulation. PMID: 24811981 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - May 5, 2014 Category: Audiology Authors: Agterberg MJ, Versnel H Tags: Hear Res Source Type: research
Acetaminophen and NAPQI are toxic to auditory cells via oxidative and endoplasmic reticulum stress-dependent pathways.
In this study, we report cellular, genomic, and proteomic experiments revealing that cytotoxicity by APAP and NAPQI involves two different pathways in Immortomouse™-derived HEI-OC1 cells, implicating ROS overproduction, alterations in ER morphology, redistribution of intra-cisternal chaperones, activation of the eIF2α-CHOP pathway, as well as changes in ER stress and protein folding response markers. Thus, both oxidative and ER stress are part of the cellular and molecular mechanisms that contribute to the cytotoxic effects of APAP and NAPQI in these cells. We suggest that these in vitro findings should be...
Source: Hearing Research - April 30, 2014 Category: Audiology Authors: Kalinec GM, Thein P, Parsa A, Yorgason J, Luxford W, Urrutia R, Kalinec F Tags: Hear Res Source Type: research
Effects of the intensity of masking noise on ear canal recorded low-frequency cochlear microphonic waveforms in normal hearing subjects.
In conclusion, when masked with high-pass noise, the low-frequency CMs are measurable at the human ear canal. Such noise reduces the low-frequency CM amplitude. The reduction is noise-intensity dependent but not completely linear. The reduction may be caused by the excited basal cochlea which the low-frequency has to travel and pass through. Although not completely clear, six mechanisms related to such reduction are discussed. PMID: 24793117 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - April 30, 2014 Category: Audiology Authors: Zhang M Tags: Hear Res Source Type: research
Thin and open vessel windows for intra-vital fluorescence imaging of murine cochlear blood flow.
Abstract Normal microvessel structure and function in the cochlea is essential for maintaining the ionic and metabolic homeostasis required for hearing function. Abnormal cochlear microcirculation has long been considered an etiologic factor in hearing disorders. A better understanding of cochlear blood flow (CoBF) will enable more effective amelioration of hearing disorders that result from aberrant blood flow. However, establishing the direct relationship between CoBF and other cellular events in the lateral wall and response to physio-pathological stress remains a challenge due to the lack of feasible interroga...
Source: Hearing Research - April 26, 2014 Category: Audiology Authors: Shi X, Zhang F, Urdang Z, Dai M, Neng L, Zhang J, Chen S, Ramamoorthy S, Nuttall AL Tags: Hear Res Source Type: research
Comparison of auditory responses determined by acoustic stimulation and by mechanical round window stimulation at equivalent stapes velocities.
In conclusion, this study showed that the amplitudes and latencies of the ABRs of acoustic and RW stimulation showed significant differences at comparable stapes velocities in an in vivo system. These differences in the ABR amplitudes and latencies reflect different output functions of the cochlea in response to different stimulation pathways. Therefore, it is necessary to develop a new method for quantifying the output of the cochlea in the case of RW stimulation. PMID: 24768763 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - April 24, 2014 Category: Audiology Authors: Lee J, Seong K, Lee SH, Lee KY, Cho JH Tags: Hear Res Source Type: research
Time-frequency analysis of transient evoked-otoacoustic emissions in individuals with auditory neuropathy spectrum disorder.
Abstract The aim of the study was to describe and quantify the cochlear active mechanisms in individuals with Auditory Neuropathy Spectrum Disorders (ANSD). Transient Evoked Otoacoustic Emissions (TEOAEs) were recorded in 15 individuals with ANSD and 22 individuals with normal hearing. TEOAEs were analyzed by Wavelet transform method to describe and quantify the characteristics of TEOAEs in narrow-band frequency regions. It was noted that the amplitude of TEOAEs was higher and latency slightly shorter in individuals with ANSD compared to normal hearing individuals at low and mid frequencies. The increased amplitud...
Source: Hearing Research - April 24, 2014 Category: Audiology Authors: Narne VK, Prabhu PP, Chatni S Tags: Hear Res Source Type: research
Loudness perception affected by early age hearing loss.
In this study, sound loudness changes in rats affected by perforation of the tympanic membranes (TM) have been studied using an operant conditioning based behavioral task. We detected significant increases of sound loudness and susceptibility to audiogenic seizures (AGS) in rats with bilateral TM damage at postnatal 16 days. As increase to sound sensitivity is commonly seen in hyperacusis and tinnitus patients, these results suggest that early age hearing loss is a high risk factor to induce tinnitus and hyperacusis in children. In the TM damaged rats, we also detected a reduced expression of GABA receptor δ and &alp...
Source: Hearing Research - April 18, 2014 Category: Audiology Authors: Sun W, Fu Q, Zhang C, Manohar S, Kumaraguru A, Li J Tags: Hear Res Source Type: research
Modeling the utility of binaural cues for underwater sound localization.
Abstract The binaural cues used by terrestrial animals for sound localization in azimuth may not always suffice for accurate sound localization underwater. The purpose of this research was to examine the theoretical limits of interaural timing and level differences available underwater using computational and physical models. A paired-hydrophone system was used to record sounds transmitted underwater and recordings were analyzed using neural networks calibrated to reflect the auditory capabilities of terrestrial mammals. Estimates of source direction based on temporal differences were most accurate for frequencies...
Source: Hearing Research - April 12, 2014 Category: Audiology Authors: Schneider JN, Lloyd DR, Banks PN, Mercado E Tags: Hear Res Source Type: research
Selective attention reduces physiological noise in the external ear canals of humans. I: Auditory attention.
In this study, a nonlinear version of the stimulus-frequency OAE (SFOAE), called the nSFOAE, was used to measure cochlear responses from human subjects while they simultaneously performed behavioral tasks requiring, or not requiring, selective auditory attention. Appended to each stimulus presentation, and included in the calculation of each nSFOAE response, was a 30-ms silent period that was used to estimate the level of the inherent physiological noise in the ear canals of our subjects during each behavioral condition. Physiological-noise magnitudes were higher (noisier) for all subjects in the inattention task, and lowe...
Source: Hearing Research - April 11, 2014 Category: Audiology Authors: Walsh KP, Pasanen EG, McFadden D Tags: Hear Res Source Type: research
Selective attention reduces physiological noise in the external ear canals of humans. II: Visual attention.
Abstract Human subjects performed in several behavioral conditions requiring, or not requiring, selective attention to visual stimuli. Specifically, the attentional task was to recognize strings of digits that had been presented visually. A nonlinear version of the stimulus-frequency otoacoustic emission (SFOAE), called the nSFOAE, was collected during the visual presentation of the digits. The segment of the physiological response discussed here occurred during brief silent periods immediately following the SFOAE-evoking stimuli. For all subjects tested, the physiological-noise magnitudes were substantially weake...
Source: Hearing Research - April 11, 2014 Category: Audiology Authors: Walsh KP, Pasanen EG, McFadden D Tags: Hear Res Source Type: research
Round Window Stimulation with the Floating Mass Transducer at Constant Pretension.
Abstract OBJECTIVE: Mechanical stimulation of the round window (RW) of the cochlea is successfully done with the Vibrant Soundbridge (Med-El), but clinical outcomes show a substantial degree of variability. One source of variability is variation in the pre-load static force applied by the stimulator to the round window (Maier et al., 2013), in this study we investigate other sources of variability by maintaining a constant static-force pre-load while investigating the effect of a coupler device and the interposition of soft tissue between the stimulator and the RW. STUDY DESIGN: Experimental METHODS: The stap...
Source: Hearing Research - April 10, 2014 Category: Audiology Authors: Salcher R, Schwab B, Lenarz T, Maier H Tags: Hear Res Source Type: research
Natural variability in species-specific vocalizations constrains behavior and neural activity.
Abstract A listener's capacity to discriminate between sounds is related to the amount of acoustic variability that exists between these sounds. However, a full understanding of how this natural variability impacts neural activity and behavior is lacking. Here, we tested monkeys' ability to discriminate between different utterances of vocalizations from the same acoustic class (i.e., coos and grunts), while neural activity was simultaneously recorded in the anterolateral belt region (AL) of the auditory cortex, a brain region that is a part of a pathway that mediates auditory perception. Monkeys could discriminate...
Source: Hearing Research - April 7, 2014 Category: Audiology Authors: Christison-Lagay KL, Bennur S, Blackwell J, Lee JH, Schroeder T, Cohen YE Tags: Hear Res Source Type: research
Photons and Neurons.
Abstract Methods to control neural activity by light have been introduced to the field of neuroscience. During the last decade, several techniques have been established, including optogenetics, thermogenetics, and infrared neural stimulation. The techniques allow investigators to turn-on or turn-off neural activity. This review is an attempt to show the importance of the techniques for the auditory field and provide insight in the similarities, overlap, and differences of the techniques. Discussing the mechanism of each of the techniques will shed light on the abilities and challenges for each of the techniques. T...
Source: Hearing Research - April 4, 2014 Category: Audiology Authors: Richter CP, Tan X Tags: Hear Res Source Type: research
Independent or integrated processing of interaural time and level differences in human auditory cortex?
We presented a series of diotic standards (perceived at a midline position) that were interrupted by deviants that entailed either a change in a) ITD only, b) ILD only, c) congruent ITD and ILD, or d) counterbalanced ITD/ILD (ITD/ILD trading). The sound stimuli were either i) pure tones with a frequency of 500 Hz, or ii) amplitude modulated tones with a carrier frequency of 4000 Hz and a modulation frequency of 125 Hz. We observed significant MMN for the ITD/ILD traded deviants in case of the 500 Hz pure tones, and for the 4000 Hz amplitude-modulated tone. This speaks for independent processing of ITD and ILD at the level ...
Source: Hearing Research - April 4, 2014 Category: Audiology Authors: Altmann CF, Terada S, Kashino M, Goto K, Mima T, Fukuyama H, Furukawa S Tags: Hear Res Source Type: research
The pupil response is sensitive to divided attention during speech processing.
Abstract Dividing attention over two streams of speech strongly decreases performance compared to focusing on only one. How divided attention affects cognitive processing load as indexed with pupillometry during speech recognition has so far not been investigated. In 12 young adults the pupil response was recorded while they focused on either one or both of two sentences that were presented dichotically and masked by fluctuating noise across a range of signal-to-noise ratios. In line with previous studies, the performance decreases when processing two target sentences instead of one. Additionally, dividing attenti...
Source: Hearing Research - April 4, 2014 Category: Audiology Authors: Koelewijn T, Shinn-Cunningham BG, Zekveld AA, Kramer SE Tags: Hear Res Source Type: research
Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz pips.
Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz pips. Hear Res. 2014 Apr 1; Authors: Todd NP, Paillard AC, Kluk K, Whittle E, Colebatch JG Abstract Todd et al. (2014) have recently demonstrated the presence of vestibular dependent changes both in the morphology and in the intensity dependence of auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs). In this paper we extend this work by comparing left vs. right ear stimulat...
Source: Hearing Research - April 1, 2014 Category: Audiology Authors: Todd NP, Paillard AC, Kluk K, Whittle E, Colebatch JG Tags: Hear Res Source Type: research
Viscoelastic properties of the human tympanic membrane studied with stroboscopic holography and finite element modeling.
Abstract A new anatomically-accurate Finite Element (FE) model of the tympanic membrane (TM) and malleus was combined with measurements of the sound-induced motion of the TM surface and the bony manubrium, in an isolated TM-malleus preparation. Using the results, we were able to address two issues related to how sound is coupled to the ossicular chain: (i) Estimate the viscous damping within the tympanic membrane itself, the presence of which may help smooth the broadband response of a potentially highly resonant TM, and (ii) Investigate the function of a peculiar feature of human middle-ear anatomy, the thin muco...
Source: Hearing Research - March 19, 2014 Category: Audiology Authors: De Greef D, Aernouts J, Aerts J, Cheng JT, Horwitz R, Rosowski JJ, Dirckx JJ Tags: Hear Res Source Type: research
The dissimilar time course of temporary threshold shifts and reduction of inhibition in the inferior colliculus following intense sound exposure.
Abstract Excessive noise exposure is known to produce an auditory threshold shift, which can be permanent or transient in nature. Recent studies showed that noise-induced temporary threshold shifts are associated with loss of synaptic connections to the inner hair cells and with cochlear nerve degeneration, which is reflected in a decreased amplitude of wave I of the auditory brainstem response (ABR). This suggests that, despite normal auditory thresholds, central auditory processing may be abnormal. We recorded changes in central auditory processing following a sound-induced temporary threshold shift. Anesthetize...
Source: Hearing Research - March 18, 2014 Category: Audiology Authors: Heeringa AN, van Dijk P Tags: Hear Res Source Type: research
Mechanisms of radiation-induced sensorineural hearing loss and radioprotection.
Abstract Patients that receive radiotherapy are at risk of late sensorineural hearing loss when the inner ear is included within the radiation field. Preclinical and human temporal bone studies have shown that there is differential damage to cochlear structures depending on the amount of dose delivered to the inner ear. In vitro studies have suggested that reactive oxygen species (ROS) are the main initial actors in radiation-induced damage. The interaction of ROS with different cellular components can result in different apoptotic pathways. Therefore, approaches to radioprotection are mainly aimed to reduce ...
Source: Hearing Research - March 18, 2014 Category: Audiology Authors: Mujica-Mota MA, Lehnert S, Devic S, Gasbarrino K, Daniel SJ Tags: Hear Res Source Type: research
Cochlear implantation in the mouse via the round window: Effects of array insertion.
Cochlear implantation in the mouse via the round window: Effects of array insertion. Hear Res. 2014 Mar 18; Authors: Mistry N, Nolan LS, Saeed SR, Forge A, Taylor RR Abstract Animal models are the only means of assessing the effects of cochlear implantation (CI) at a cellular and molecular level. The range of naturally occurring and genetically-modified mouse strains which mimic human deafness provide excellent opportunities for auditory research. To date, there are very few studies of CI in mice. The main aims of this study were to develop a reproducible and viable technique to enable long term CI in...
Source: Hearing Research - March 18, 2014 Category: Audiology Authors: Mistry N, Nolan LS, Saeed SR, Forge A, Taylor RR Tags: Hear Res Source Type: research
Tinnitus-related dissociation between cortical and subcortical neural activity in humans with mild to moderate sensorineural hearing loss.
In this study, cortical and sub-cortical sound-evoked brain responses in 34 hearing-impaired chronic tinnitus patients and 19 hearing level-matched controls were studied using 3-T functional magnetic resonance imaging (fMRI). Auditory stimuli were presented to either the left or the right ear at levels of 30-90 dB SPL. We extracted neural activation as a function of sound intensity in eight auditory regions (left and right auditory cortices, medial geniculate bodies, inferior colliculi and cochlear nuclei), the cerebellum and a cinguloparietal task-positive region. The activation correlated positively with the stimulus int...
Source: Hearing Research - March 11, 2014 Category: Audiology Authors: Boyen K, de Kleine E, van Dijk P, Langers DR Tags: Hear Res Source Type: research
Localization and interaural time difference (ITD) thresholds for cochlear implant recipients with preserved acoustic hearing in the implanted ear.
Abstract The purpose of this study was to investigate horizontal plane localization and interaural time difference (ITD) thresholds for 14 adult cochlear implant recipients with hearing preservation in the implanted ear. Localization to broadband noise was assessed in an anechoic chamber with a 33-loudspeaker array extending from -90 to +90 degrees. Three listening conditions were tested including bilateral hearing aids, bimodal (implant + contralateral hearing aid) and best aided (implant + bilateral hearing aids). ITD thresholds were assessed, under headphones, for low-frequency stimuli including a 250-Hz tone a...
Source: Hearing Research - March 6, 2014 Category: Audiology Authors: Gifford RH, Grantham DW, Sheffield SW, Davis TJ, Dwyer R, Dorman MF Tags: Hear Res Source Type: research
Manganese enhanced magnetic resonance imaging (MEMRI): A powerful new imaging method to study tinnitus.
This article is part of a Special Issue entitled . PMID: 24583078 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - February 26, 2014 Category: Audiology Authors: Cacace AT, Brozoski T, Berkowitz B, Bauer C, Odintsov B, Bergkvist M, Castracane J, Zhang J, Holt AG Tags: Hear Res Source Type: research
Contribution of Bimodal Hearing to Lexical Tone Normalization in Mandarin-speaking Cochlear Implant Users.
In this study, native Mandarin NH listeners and pre-lingually deafened unilaterally implanted CI users were asked to recognize a series of Mandarin tones varying from Tone 1 (high-flat) to Tone 2 (mid-rising) with or without a preceding sentence context. Most of the CI subjects used a hearing aid (HA) in the non-implanted ear (i.e., bimodal users) and were tested both with CI alone and CI+HA. In the test without context, typical S-shaped tone recognition functions were observed for most CI subjects and the function slopes and perceptual boundaries were similar with either CI alone or CI+HA. Compared to NH subjects, CI subj...
Source: Hearing Research - February 24, 2014 Category: Audiology Authors: Luo X, Chang YP, Lin CY, Chang RY Tags: Hear Res Source Type: research
Central auditory function of deafness genes.
Abstract The highly variable benefit of hearing devices is a serious challenge in auditory rehabilitation. Various factors contribute to this phenomenon such as the diversity in ear defects, the different extent of auditory nerve hypoplasia, the age of intervention, and cognitive abilities. Recent analyses indicate that, in addition, central auditory functions of deafness genes have to be considered in this context. Since reduced neuronal activity acts as the common denominator in deafness, it is widely assumed that peripheral deafness influences development and function of the central auditory system in a stereot...
Source: Hearing Research - February 21, 2014 Category: Audiology Authors: Willaredt MA, Ebbers L, Nothwang HG Tags: Hear Res Source Type: research
Insertion Site and Sealing Technique Affect Residual Hearing and Tissue Formation after Cochlear Implantation.
Abstract Tissue formation around the electrode array of a cochlear implant has been suggested to influence preservation of residual hearing as well as electrical hearing performance of implanted subjects. Further, inhomogeneity in the electrical properties of the scala tympani shape the electrical field and affect current spread. Intracochlear trauma due to electrode insertion and the insertion site itself are commonly seen as triggers for the tissue formation. The present study investigates whether the insertion site, round window membrane (RWM) vs. cochleostomy (CS), or the sealing material, no seal vs. muscle g...
Source: Hearing Research - February 21, 2014 Category: Audiology Authors: Burghard A, Lenarz T, Kral A, Paasche G Tags: Hear Res Source Type: research
Ocular vestibular evoked myogenic potential frequency tuning in certain Menière's disease.
Ocular vestibular evoked myogenic potential frequency tuning in certain Menière's disease. Hear Res. 2014 Feb 13; Authors: Jerin C, Berman A, Krause E, Ertl-Wagner B, Gürkov R Abstract Ocular vestibular evoked myogenic potentials (oVEMP) represent extraocular muscle activity in response to vestibular stimulation. To specify the value of oVEMP in the diagnostics of Menière's disease, the amplitude ratio between 500 and 1000 Hz stimuli was investigated. Thirty-nine patients with certain Menière's disease, i.e. definite Menière's disease with visualization of endolymphatic hyd...
Source: Hearing Research - February 13, 2014 Category: Audiology Authors: Jerin C, Berman A, Krause E, Ertl-Wagner B, Gürkov R Tags: Hear Res Source Type: research
Residual inhibition of tinnitus induced by 30-kHz bone-conducted ultrasound.
This study investigated whether RI could be induced by BCU. Five types of the masker sounds were used to measure RI in 21 subjects with tinnitus. A bone-conducted 30-kHz pure tone was used as a BCU, and an air-conducted 4-kHz pure tone, narrow-band noise, white noise, and a bone-conducted 4-kHz pure tone were used as controls of audible sounds. The masker intensities of the 30-kHz BCU and audible sounds were set at the minimum masking levels of tinnitus plus 3 and 10 dB, respectively, considering the narrow dynamic range of BCU. The duration of RI induced by the 30-kHz BCU was significantly longer than those induced b...
Source: Hearing Research - February 12, 2014 Category: Audiology Authors: Koizumi T, Nishimura T, Yamashita A, Yamanaka T, Imamura T, Hosoi H Tags: Hear Res Source Type: research
Spatial and temporal modifications of multitalker speech can improve speech perception in older adults.
This study investigated two signal-processing techniques that have been suggested as a means of improving speech perception accuracy of older adults: time stretching and spatial separation of target talkers. Stimuli in each experiment comprised 2-4 fixed-form utterances in which listeners were asked to consecutively 1) detect concurrently spoken keywords in the beginning of the utterance (divided attention); and, 2) identify additional keywords from only one talker at the end of the utterance (selective attention). In Experiment 1, the overall tempo of each utterance was unaltered or slowed down by 25%; in Experiment 2 the...
Source: Hearing Research - February 12, 2014 Category: Audiology Authors: Gygi B, Shafiro V Tags: Hear Res Source Type: research
A summary of research investigating echolocation abilities of blind and sighted humans.
Abstract There is currently considerable interest in the consequences of loss in one sensory modality on the remaining senses. Much of this work has focused on the development of enhanced auditory abilities among blind individuals, who are often able to use sound to navigate through space. It has now been established that many blind individuals produce sound emissions and use the returning echoes to provide them with information about objects in their surroundings, in a similar manner to bats navigating in the dark. In this review, we summarize current knowledge regarding human echolocation. Some blind individuals...
Source: Hearing Research - February 10, 2014 Category: Audiology Authors: Kolarik AJ, Cirstea S, Pardhan S, Moore BC Tags: Hear Res Source Type: research
Auditory responses to electric and infrared neural stimulation of the rat cochlear nucleus.
Abstract In an effort to improve the auditory brainstem implant, a prosthesis in which user outcomes are modest, we applied electric and infrared neural stimulation (INS) to the cochlear nucleus in a rat animal model. Electric stimulation evoked regions of neural activation in the inferior colliculus and short-latency, multipeaked auditory brainstem responses (ABRs). Pulsed INS, delivered to the surface of the cochlear nucleus via an optical fiber, evoked broad neural activation in the inferior colliculus. Strongest responses were recorded when the fiber was placed at lateral positions on the cochlear nucleus, clo...
Source: Hearing Research - February 5, 2014 Category: Audiology Authors: Verma R, Guex AA, Hancock KE, Durakovic N, McKay CM, Slama MC, Brown MC, Lee DJ Tags: Hear Res Source Type: research