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363 records returned

Phonemic restoration by hearing-impaired listeners with mild to moderate sensorineural hearing loss.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The auditory system is capable of perceptually restoring inaudible portions of speech. This restoration may be compromised as a result of hearing impairment, particularly if it is combined with advanced age, because of degradations in the bottom-up and top-down processes. To test this hypothesis, phonemic restoration was quantitatively measured with hearing-impaired listeners of varying ages and degrees of hearing impairment, as well as with a normal-hearing control group. The results showed that the restoration benefit was negatively correlated with both hearing impairment and age, supporting the original hypothesis. ...
Source: Hearing Research - November 13, 2009 Category: Audiology Authors: Başkent D, Eiler CL, Edwards B Tags: Hear Res Source Type: journals

A Major Effect QTL on Chromosome 18 for Noise Injury to the Mouse Cochlear Lateral Wall.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We recently demonstrated a striking difference among inbred mouse strains in the effects of a single noise exposure, whereby CBA/J and CBA/CaJ (CBA) mice show moderate reversible reduction in the endocochlear potential (EP) while C57BL/6J (B6) mice do not (Ohlemiller, K.K., Gagnon, P.M. 2007. Genetic dependence of cochlear cells and structures injured by noise. Hearing Res. 224, 34-50). Acute EP reduction in CBA was reliably associated with characteristic pathology of the spiral ligament and stria vascularis, both immediately after noise and 8 weeks later. Analysis of B6xCBA F1 hybrid mice indicated that EP reduction a...
Source: Hearing Research - November 11, 2009 Category: Audiology Authors: Ohlemiller KK, Rosen AD, Gagnon PM Tags: Hear Res Source Type: journals

A System to Simulate and Reproduce Audio-Visual Environments for Spatial Hearing Research.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The article reports the experience gained from two implementations of the "Simulated Open-Field Environment" (SOFE), a setup that allows sounds to be played at calibrated levels over a wide frequency range from multiple loudspeakers in an anechoic chamber. Playing sounds from loudspeakers in the free-field has the advantage that each participant listens with their own ears, and individual characteristics of the ears are captured in the sound they hear. This makes an easy and accurate comparison between various listeners with and without hearing devices possible. The SOFE uses custom calibration software to assure indiv...
Source: Hearing Research - November 9, 2009 Category: Audiology Authors: Seeber BU, Kerber S, Hafter ER Tags: Hear Res Source Type: journals

Motion of the Tympanic Membrane after Cartilage Tympanoplasty Determined by Stroboscopic Holography.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Stroboscopic holography was used to quantify dynamic deformations of the tympanic membrane (TM) of the entire surface of the TM before and after cartilage tympanoplasty of the posterior or posterior-superior part of the TM. Cartilage is widely used in tympanoplasties to provide mechanical stability for the TM. Three human cadaveric temporal bones were used. A 6 mm x 3 mm oval cartilage graft was placed through the widely opened facial recess onto the medial surface of the posterior or posterior-superior part of the TM. The graft was either in contact with the bony tympanic rim and manubrium or not. Graft thickness was ...
Source: Hearing Research - November 9, 2009 Category: Audiology Authors: Aarnisalo AA, Cheng JT, Ravicz ME, Furlong C, Merchant SN, Rosowski JJ Tags: Hear Res Source Type: journals

The Fischer 344 rat as a model of presbycusis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Due to the rising number of the aged human population all over the world, presbycusis is a phenomenon that deserves the increasing attention of the medical community as regards to prevention and treatment. This requires finding appropriate animal models for human presbycusis that will be useful in future experiments. Among the available rat strains, the Fischer 344 (F344) strain promises to serve as a model producing prompt and profound presbycusis. Hearing thresholds begin to increase in this strain within the first year of life, toward the end of the second year the thresholds are very high. The threshold shifts prog...
Source: Hearing Research - November 7, 2009 Category: Audiology Authors: Syka J Tags: Hear Res Source Type: journals

On the ability of human listeners to distinguish between front and back.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In order to determine whether a sound source is in front or in back, listeners can use location-dependent spectral cues caused by diffraction from their anatomy. This capability was studied using a precise virtual-reality technique (VRX) based on a transaural technology. Presented with a virtual baseline simulation accurate up to 16 kHz, listeners could not distinguish between the simulation and a real source. Experiments requiring listeners to discriminate between front and back locations were performed using controlled modifications of the baseline simulation to test hypotheses about the important spectral cues. The ...
Source: Hearing Research - November 6, 2009 Category: Audiology Authors: Zhang PX, Hartmann WM Tags: Hear Res Source Type: journals

Middle-Ear Function At High Frequencies Quantified With Advanced Bone Conduction Measures.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Auditory thresholds with standardized clinical procedures are obtained over a much nar- rower frequency range by bone conduction than by air conduction. As a result, diagnostic information for both sensorineural and conductive-mechanism function is incomplete for high frequencies. A new magnetostrictive bone-conduction transducer that has the poten- tial for improved output in the high-frequency range was evaluated in the laboratory and in a variety of subjects with normal hearing (N=11) or sensorineural hearing loss (N=9). La- boratory results indicated that harmonic distortion and acoustic radiation were both suffi- ...
Source: Hearing Research - November 6, 2009 Category: Audiology Authors: Popelka GR, Telukuntla G, Puria S Tags: Hear Res Source Type: journals

Effects of isoflurane on auditory evoked potentials in the cochlea and brainstem of guinea pigs.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study evaluated the effects of various concentrations of the volatile anesthetic isoflurane (1 - 3%) on the compound action potential (CAP), cochlear microphonic (CM) and auditory brainstem response (ABR). Recordings were initiated in the awake, lightly restrained animal. Anesthesia was induced with a single dose of Hypnorm((R)) (fentanyl and fluanisone). After tracheostomy increasing isoflurane concentrations were applied in N(2)O/O(2) via controlled ventilation. Data were compared to recordings in the awake animal using repeated measures ANOVA and Dunnett's post hoc test. On average, isoflurane dose-dependently supp...
Source: Hearing Research - October 27, 2009 Category: Audiology Authors: Stronks HC, Aarts MC, Klis SF Tags: Hear Res Source Type: journals

A Method for Removing Cochlear Implant Artifact.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
When cortical auditory evoked potentials (CAEPs) are recorded in individuals with a cochlear implant (CI), electrical artifact can make the CAEP difficult or impossible to measure. Since increasing the interstimulus interval (ISI) increases the amplitude of physiological responses without changing the artifact, subtracting CAEPs recorded with a short ISI from those recorded with a longer ISI should show the physiological response without any artifact. In the first experiment, N1-P2 responses were recorded using a speech syllable and tone, paired with ISIs that changed randomly between 0.5 and 4 seconds. In the second e...
Source: Hearing Research - October 27, 2009 Category: Audiology Authors: Friesen LM, Picton TW Tags: Hear Res Source Type: journals

A sum of simple and complex motions on the eardrum and manubrium in gerbil.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Based on comparisons of ear canal and scala vestibuli pressures the gerbil middle ear transmits sound with a gain of approximately 25 dB that is almost flat from 2 to 40 kHz, and with a delay-like phase corresponding to a 25 - 30 mus delay. How the middle ear is able to transmit sound with such high temporal and amplitude fidelity is not known, and is particularly mysterious given the complex motion the ossicles and tympanic membrane (TM) are known to undergo. To explore this question, we looked at the velocities of the manubrium and along a line on the TM. The TM motion was complex, and could be approximated as the co...
Source: Hearing Research - October 27, 2009 Category: Audiology Authors: de La Rochefoucauld O, Olson ES Tags: Hear Res Source Type: journals

Tympanic membrane and malleus-incus complex co-adaptations for high-frequency hearing in mammals.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The development of the unique capacity for high frequency hearing in many mammals was due in part to changes in the middle ear, such as the evolution of three distinct middle ear bones and distinct radial and circumferential collagen fiber layers in the eardrum. Ossicular moment(s) of inertia (MOI) and principal rotational axes, as well as eardrum surface areas, were calculated from micro-CT-based 3-D reconstructions of human, cat, chinchilla, and guinea pig temporal bones. For guinea pig and chinchilla, the fused malleus-incus complex rotates about an anterior-posterior axis, due to the relatively lightweight ossicles...
Source: Hearing Research - October 27, 2009 Category: Audiology Authors: Puria S, Steele C Tags: Hear Res Source Type: journals

Electrical impedance measurements of cochlear structures using the four-electrode reflection-coefficient technique.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In individuals with severe-to-profound hearing loss, cochlear implants (CIs) bypass normal inner ear function by applying electrical current directly into the cochlea, thereby stimulating surviving auditory nerve fibers. Although cochlear implants are able to restore some auditory sensation, they are far from providing normal hearing. It has been estimated that up to 75% of the current injected via a CI is shunted along scala tympani and is not available to stimulate auditory neurons. The path of the injected current and the consequent population of stimulated spiral ganglion cells are dependent upon the positions of t...
Source: Hearing Research - October 23, 2009 Category: Audiology Authors: Kumar G, Chokshi M, Richter CP Tags: Hear Res Source Type: journals

Neural Substrate of Sound Duration Discrimination during an Auditory Sequence in the Guinea Pig Primary Auditory Cortex.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mismatch negativity (MMN) is a negative component of event-related brain potentials elicited by stimulus transitions. Stimulus duration transition also elicits MMN (duration MMN), with a magnitude that is related to the degree of duration change and the discrimination ability. The neural substrates of duration MMN have not yet been investigated. We therefore studied how duration transitions in an auditory stimulus train are represented in neurons in the primary auditory cortex of anesthetized guinea pigs. Two types of neuronal responses to the context of changes in stimulus duration were found. One was a reduced respon...
Source: Hearing Research - October 23, 2009 Category: Audiology Authors: Okazaki S, Kanoh S, Tsukada M, Oka K Tags: Hear Res Source Type: journals

Age-Related Loss of Spiral Ganglion Neurons.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Spiral ganglion neurons (SGNs) are the relay station for auditory information between hair cells and central nervous system. Age-related decline of auditory function due to SGN loss can not be ameliorated by hearing aids or cochlear implants. Recent findings clearly indicate that survival of SGNs during aging depends on genetic and environmental interactions, which can be demonstrated at the systemic, tissue, cellular, and molecular levels. At the systemic level, both insulin/insulin-like growth factor-1 and lipophilic/steroid hormone pathways influence SGN survival during aging. At the level of organ of the Corti, it ...
Source: Hearing Research - October 22, 2009 Category: Audiology Authors: Bao J, Ohlemiller KK Tags: Hear Res Source Type: journals

Education, Occupation, Noise Exposure History and the 10-yr Cumulative Incidence of Hearing Impairment in Older Adults.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The purpose of this study was to determine the 10-yr cumulative incidence of hearing impairment and associations of education, occupation and noise exposure history with the incidence of hearing impairment in a population-based cohort study of 3753 adults ages 48-92 years at the baseline examinations during 1993-1995 in Beaver Dam, WI. Hearing thresholds were measured at baseline, 2.5 yr, 5 yr, and 10-yr follow-up examinations. Hearing impairment was defined as a pure-tone average (PTA) > 25 dB HL at 500, 1000, 2000, and 4000 Hz. Demographic characteristics and occupational histories were obtained by questionnaire. ...
Source: Hearing Research - October 21, 2009 Category: Audiology Authors: Cruickshanks KJ, Nondahl DM, Tweed TS, Wiley TL, Klein BE, Klein R, Chappell R, Dalton DS, Nash SD Tags: Hear Res Source Type: journals

Multiple roles for the tectorial membrane in the active cochlea.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This review is concerned with experimental results that reveal multiple roles for the tectorial membrane in active signal processing in the mammalian cochlea. We discuss the dynamic mechanical properties of the tectorial membrane as a mechanical system with several degrees of freedom and how its different modes of movement can lead to hair-cell excitation. The role of the tectorial membrane in distributing energy along the cochlear partition and how it channels this energy to the inner hair cells is described. PMID: 19853029 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 20, 2009 Category: Audiology Authors: Lukashkin AN, Richardson GP, Russell IJ Tags: Hear Res Source Type: journals

Recording of electrically evoked auditory brainstem responses after electrical stimulation with biphasic, triphasic and precision triphasic pulses.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Biphasic electrical pulses are the standard stimulation pulses in current cochlear implants. In auditory brainstem recordings biphasic pulses generate a significant artifact that disrupts brainstem responses, which are magnitudes smaller. Triphasic pulses may minimize artifacts by restoring the neural membrane to its resting potential faster than biphasic pulses and make auditory brainstem responses detection easier. We compared biphasic pulses with triphasic and precision triphasic pulses to evoke brainstem responses in human subjects. For this purpose, electrically evoked brainstem response audiometry was performed i...
Source: Hearing Research - October 19, 2009 Category: Audiology Authors: Bahmer A, Polak M, Baumann U Tags: Hear Res Source Type: journals

Stress induces transient auditory hypersensitivity in rats.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Exposure to harsh environment induces stress reactions that increase probability of survival. Stress influences the endocrine, nervous and immune systems and affects the functioning of a variety of organs. Numerous researchers demonstrated that a 24-hour exposure to an acoustic rodent repellent provokes stress reaction in exposed animals. In addition to the activated hypothalamus-pituitary-adrenal (HPA) axis, exposed animals had pathological reactions in the reproductive organs, bronchia and skin. Here, we examined the effect of above stress model on the auditory system of Wistar rats. We found that 24-hour stress decr...
Source: Hearing Research - October 15, 2009 Category: Audiology Authors: Mazurek B, Haupt H, Joachim R, Klapp BF, Stöver T, Szczepek AJ Tags: Hear Res Source Type: journals

Suppression of the acoustically evoked auditory-nerve response by electrical stimulation in the cochlea of the guinea pig.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
There is increasing interest in the use of electro-acoustical stimulation in people with a cochlear implant that have residual low-frequency hearing in the implanted ear. This raises the issue of how electrical and acoustical stimulation interact in the cochlea. We have investigated the effect of electrical stimulation on the acoustically evoked compound action potential (CAP) in normal-hearing guinea pigs. CAPs were evoked by tone bursts, and electric stimuli were delivered at the base of the cochlea using extracochlear electrodes. CAPs could be suppressed by electrical stimulation under various conditions. The depend...
Source: Hearing Research - October 15, 2009 Category: Audiology Authors: Stronks HC, Versnel H, Prijs VF, Klis SF Tags: Hear Res Source Type: journals

Cochlear amplification - somatic or stereocilial forces? A first-person response.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19835941 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 12, 2009 Category: Audiology Authors: Ashmore J Tags: Hear Res Source Type: journals

Measurement of Conductive Hearing Loss in Mice.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In order to discriminate conductive hearing loss from sensorineural impairment, quantitative measurements were used to evaluate the effect of artificial conductive pathology on distortion product otoacoustic emissions (DPOAEs), auditory brainstem responses (ABRs) and laser Doppler vibrometry (LDV) in mice. The conductive manipulations were created by perforating the pars flaccida of the tympanic membrane, filling or partially filling the middle-ear cavity with saline, fixing the ossicular chain, and interrupting the incudo-stapedial joint. In the saline-filled and ossicular-fixation groups, averaged DPOAE thresholds in...
Source: Hearing Research - October 12, 2009 Category: Audiology Authors: Qin Z, Wood M, Rosowski JJ Tags: Hear Res Source Type: journals

Coupled hair bundles could endow the cochlear amplifier with sharp frequency tuning and nonlinear compression.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19818839 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 6, 2009 Category: Audiology Authors: Dierkes K, Lindner B, Jülicher F Tags: Hear Res Source Type: journals

Elasticity modulus of rabbit middle ear ossicles determined by a novel micro-indentation technique.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
For the purpose of creating a finite element model of the middle ear, the ossicles can be modelled as rigid bodies or as linear elastic materials. The general elasticity parameters used are usually measured on larger bones like the femur. In order to obtain a highly realistic model, the actual elastic modulus (Young's modulus) of the ossicles themselves is needed. We developed a novel 2-needle indentation method of determining the Young's modulus of small samples based on Sneddon's solution. We introduce the second needle in such a way that small specimens can be clamped between the 2 needles and a symmetry plane is ob...
Source: Hearing Research - October 6, 2009 Category: Audiology Authors: Soons JA, Aernouts J, Dirckx JJ Tags: Hear Res Source Type: journals

Predicting the role of OHC somatic motility and HB motility in cochlear amplification using a mathematical model.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In most models of the mammalian cochlea, either mathematical or conceptual, the sensitivity of the BM to low level acoustic stimulus is explained by the presence of outer hair cell (OHC) somatic motility. However, recent experimental evidence indicates that OHC hair bundle (HB) motility can operate with submillisecond time constants. In this paper, we implement a simple phenomenological mathematical model of HB motility, based on the ansatz that HB forcing adds mechanical energy to the system. Our preliminary predictions using models that combine HB and somatic OHC motility indicate that HB motility is not necessary fo...
Source: Hearing Research - October 6, 2009 Category: Audiology Authors: Meaud J, Grosh K Tags: Hear Res Source Type: journals

The origin of the cochlear amplifier.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The strengths and weakness of the outer hair cell bundle and somatic motors as the source of cochlear amplification are discussed. PMID: 19818388 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 5, 2009 Category: Audiology Authors: Fettiplace R, Hackney C Tags: Hear Res Source Type: journals

Top connectors of the hair bundle are required for waveform distortion and suppression masking but not cochlear amplification.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19818389 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 5, 2009 Category: Audiology Authors: Avan P, Petit C Tags: Hear Res Source Type: journals

Membrane-based amplification in hearing.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Acoustic vibrations enter and neuronal action potentials leave the inner ear. An interplay of mechanical and electrical energy results in hair cell receptor potentials that ultimately trigger neurotransmitter release at the afferent synapse. The diffusion of neurotransmitter across the synaptic cleft depolarizes 8(th) nerve terminals and initiates action potentials that travel to the central nervous system. The action potentials encode information about the spectral and temporal content of environmental sounds. The ability to localize predator or prey is improved by analyzing sounds over a wide range of frequencies res...
Source: Hearing Research - October 5, 2009 Category: Audiology Authors: Brownell WE Tags: Hear Res Source Type: journals

Differential passage of gadolinium through the mouse inner ear barriers evaluated with 4.7 T MRI.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Magnetic resonance imaging (MRI), supplemented by contrast agents, is a powerful tool that can be used to visualise the structures of the inner ear in vivo and assess some aspects of physiology, such as the permeability of agents through membranes. The mouse is an excellent animal species for investigating human diseases, including hearing loss but detailed MRI studies with contrast have not been reported. In the present work, we aimed to demonstrate the limits of MR imaging resolution of the fine inner ear structures in the mouse and to explore the permeability of the intracochlear barriers to gadolinium- tetra-azacyc...
Source: Hearing Research - October 5, 2009 Category: Audiology Authors: Zou J, Zhang W, Poe D, Zhang Y, Ramadan UA, Pyykkö I Tags: Hear Res Source Type: journals

Effects of natural versus artificial spatial cues on electrophysiological correlates of auditory motion.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The effect of the type of the auditory motion stimulus on neural correlates of motion processing were investigated using high-density electroencephalography. Sound motion was implemented by (a) gradual shifts in interaural time or (b) level difference; (c) motion of virtual 3D sound sources; or (d) successive activation of 45 loudspeakers along the horizontal plane. In a subset of trials, listeners (N = 20) performed a two-alternative forced-choice motion discrimination task. Each trial began with a stationary phase of the acoustic stimulus in a central position, immediately followed by a motion of the stimulus. The mo...
Source: Hearing Research - September 30, 2009 Category: Audiology Authors: Getzmann S, Lewald J Tags: Hear Res Source Type: journals

Age-related differences in gap detection: Effects of task difficulty and cognitive ability.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Differences in gap detection for younger and older adults have been shown to vary with the complexity of the task or stimuli, but the factors that contribute to these differences remain unknown. To address this question, we examined the extent to which age-related differences in processing speed and workload predicted age-related differences in gap detection. Gap detection thresholds were measured for 10 younger and 11 older adults in two conditions that varied in task complexity but used identical stimuli: (1) gap location fixed at the beginning, middle, or end of a noise burst and (2) gap location varied randomly fro...
Source: Hearing Research - September 30, 2009 Category: Audiology Authors: Harris KC, Eckert MA, Ahlstrom JB, Dubno JR Tags: Hear Res Source Type: journals

Expression of Aquaporins and Vasopressin type 2 receptor in the stria vascularis of the cochlea.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Recently, considerable evidence has been accumulated to support the novel view that water homeostasis in the inner ear is regulated via the vasopressin-aquaporin 2 (VP-AQP2) system in the same fashion as in the kidney. Indeed, multiple subtypes of AQPs including AQP-2 are reported to be expressed in the cochlea. However, the mechanism that underlies VP-AQP2 mediated water homeostasis remains to be elucidated. In the present study, the localization of AQP-1, -2, -3, -4, -5, -7, -8, -9, and vasopressin type 2 receptor (V(2)-R) in the stria vascularis (SV) were molecular biologically and immunohistochemically examined to ...
Source: Hearing Research - September 27, 2009 Category: Audiology Authors: Nishioka R, Takeda T, Kakigi A, Okada T, Takebayashi S, Taguchi D, Nishimura M, Hyodo M Tags: Hear Res Source Type: journals

Pitch, Harmonicity and Concurrent Sound Segregation: Psychoacoustical and Neurophysiological Findings.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Harmonic complex tones are a particularly important class of sounds found in both speech and music. Although these sounds contain multiple frequency components, they are usually perceived as a coherent whole, with a pitch corresponding to the fundamental frequency (F0). However, when two or more harmonic sounds occur concurrently, e.g., at a cocktail party or in a symphony, the auditory system must separate harmonics and assign them to their respective F0s so that a coherent and veridical representation of the different sounds sources is formed. Here we review both psychophysical and neurophysiological (single-unit and...
Source: Hearing Research - September 25, 2009 Category: Audiology Authors: Micheyl C, Oxenham AJ Tags: Hear Res Source Type: journals

An evolutionary perspective on middle ears.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The traditional view that a tympanic middle ear developed only once, when vertebrates made the transition from fish in water to land-living animals, has been shown to be incorrect. Middle ears with a tympanum connected by one or more ossicles to the cochlea developed very much later in evolutionary history and independently in many amniote vertebrate lineages - most now extinct. The mammalian middle ear is unique but it is not simply an "improved" single-ossicle middle ear. It is a radical and fortuitous new development that owes its origin more to changes in feeding patterns than to hearing. It happened to transmit hi...
Source: Hearing Research - September 24, 2009 Category: Audiology Authors: Manley GA Tags: Hear Res Source Type: journals

Measures of Hearing Threshold and Temporal Processing across the Adult Lifespan.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Psychophysical data on hearing sensitivity and various measures of supra-threshold auditory temporal processing are presented for large groups of young (18-35 y), middle-aged (40-55 y) and older (60-89 y) adults. Hearing thresholds were measured at 500, 1414 and 4000 Hz. Measures of temporal processing included gap-detection thresholds for bands of noise centered at 1000 and 3500 Hz, stimulus onset asynchronies for monaural and dichotic temporal-order identification for brief vowels, and stimulus onset/offset asynchronies for the monaural temporal masking of vowel identification. For all temporal-processing measures, t...
Source: Hearing Research - September 24, 2009 Category: Audiology Authors: Humes LE, Kewley-Port D, Fogerty D, Kinney D Tags: Hear Res Source Type: journals

The menopause triggers hearing decline in healthy women.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusion: The menopause appears to act as a trigger of a relatively rapid age-related hearing decline in healthy women, starting in the left ear. PMID: 19781610 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - September 21, 2009 Category: Audiology Authors: Hederstierna C, Hultcrantz M, Collins A, Rosenhall U Tags: Hear Res Source Type: journals

Quantification of tympanic membrane elasticity parameters from in situ point indentation measurements: validation and preliminary study.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Correct quantitative parameters to describe tympanic membrane elasticity are an important input for realistic modeling of middle ear mechanics. In the past, several attempts have been made to determine tympanic membrane elasticity from tensile experiments on cut-out strips. The strains and stresses in such experiments may be far out of the physiologically relevant range and the elasticity parameters are only partially determined. We developed a setup to determine tympanic membrane elasticity in situ, using a combination of point micro-indentation and Moiré profilometry. The measuring method was tested on latex pha...
Source: Hearing Research - September 20, 2009 Category: Audiology Authors: Aernouts J, Soons JA, Dirckx JJ Tags: Hear Res Source Type: journals

Processing of Broadband Stimuli Across A1 Layers in Young and Aged Rats.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Presbycusis can be considered a slow age-related peripheral and central deterioration of auditory function which manifests itself as deficits in speech comprehension, especially in noisy environments. The present study examined neural correlates of a simple broadband noise stimulus in primary auditory cortex (A1) of young and aged Fisher-Brown Norway (FBN) rats. Age-related changes in unit responses to broadband noise-bursts and spontaneous activity were simultaneously recorded across A1 layers using a single shank, 16-channel electrode. Noise bursts were presented contralateral to the left A1 at 80 dB SPL. Aged A1 uni...
Source: Hearing Research - September 18, 2009 Category: Audiology Authors: Hughes LF, Turner JG, Parrish JL, Caspary DM Tags: Hear Res Source Type: journals

Wideband acoustic reflex test in a test battery to predict middle-ear dysfunction.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A wideband (WB) aural acoustical test battery of middle-ear status, including acoustic-reflex thresholds (ARTs) and acoustic-transfer functions (ATFs, i.e., absorbance and admittance) was hypothesized to be more accurate than 1-kHz tympanometry in classifying ears that pass or refer on a newborn hearing screening (NHS) protocol based on otoacoustic emissions. Assessment of middle-ear status may improve NHS programs by identifying conductive dysfunction and cases in which auditory neuropathy exists. Ipsilateral ARTs were assessed with a stimulus including four broadband-noise or tonal activator pulses alternating with f...
Source: Hearing Research - September 18, 2009 Category: Audiology Authors: Keefe DH, Fitzpatrick D, Liu YW, Sanford CA, Gorga MP Tags: Hear Res Source Type: journals

Clarin-1 protein expression in photoreceptors.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19772908 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - September 18, 2009 Category: Audiology Authors: Cosgrove D, Zallocchi M Tags: Hear Res Source Type: journals

A Totally Implantable Hearing System - Design and Function Characterization in 3D Computational Model and Temporal Bones.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Implantable middle ear hearing devices are emerging as an effective technology for patients with mild to moderately severe sensorineural hearing loss. Several devices with electromagnetic or piezoelectric transducers have been investigated or developed in the US and Europe since 1990. This paper reports a totally implantable hearing system (TIHS) currently under investigation in Oklahoma. The TIHS consists of implant transducer (magnet), implantable coil and microphone, DSP-audio signal processor, rechargeable battery, and remote control unit. The design of TIHS is based on a 3D finite element model of the human ear an...
Source: Hearing Research - September 18, 2009 Category: Audiology Authors: Gan RZ, Dai C, Wang X, Nakmali D, Wood MW Tags: Hear Res Source Type: journals

The influence of postoperative tissue formation on sound transmission after stapes surgery.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the surgical treatment of otosclerosis, the coupling between the stapes prosthesis and the long process of the incus is critical. After surgery, connective tissue and mucosa may grow over the coupling area and thereby influence the sound transmission properties of the incus-prosthesis interface. It was the hypothesis of this study that tissue ongrowth in the incus-prosthesis interface has little influence on sound transmission following stapes surgery. The goals of the study were to: 1) investigate the extent of postoperative tissue ongrowth over the stapes prosthesis; 2) objectively evaluate intra- and postoperativ...
Source: Hearing Research - September 15, 2009 Category: Audiology Authors: Sim JH, Chatzimichalis M, Huber AM Tags: Hear Res Source Type: journals

PTEN attenuates PIP(3)/Akt signaling in the cochlea of the aging CBA/J mouse.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have previously reported the activation of cell death pathways in the sensory cells of the aging cochlea. Here we investigate age-associated changes in survival mechanisms focusing on phosphatidylinositol 3,4,5-trisphosphate (PIP(3))/Akt signaling. The animal model is the CBA/J mouse of 18 months of age prior to the onset of major functional loss (ABR thresholds, 26 +/- 8 dB SPL) which is compared to young animals of 3 months of age (ABR thresholds, 19 +/- 7 dB SPL). Immunostaining on cochlear cryosections revealed a wide-spread distribution of PIP(3) in the cochlea which was markedly attenuated in old animals in in...
Source: Hearing Research - September 13, 2009 Category: Audiology Authors: Sha SH, Chen FQ, Schacht J Tags: Hear Res Source Type: journals

Fundamental frequency and speech intelligibility in background noise.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Speech reception in noise is an especially difficult problem for listeners with hearing impairment as well as for users of cochlear implants (CIs). One likely cause of this is an inability to 'glimpse' a target talker in a fluctuating background, which has been linked to deficits in temporal fine-structure processing. A fine-structure cue that has the potential to be beneficial for speech reception in noise is fundamental frequency (F0). A challenging problem, however, is delivering the cue to these individuals. The benefits to speech intelligibility of F0 for both listeners with hearing impairment and users of CIs are...
Source: Hearing Research - September 9, 2009 Category: Audiology Authors: Brown CA, Bacon SP Tags: Hear Res Source Type: journals

Age-related hearing loss: Is it a preventable condition?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Numerous techniques have been tested to attempt to prevent the onset or progression of age-related hearing loss (ARHL): raising the animals in an augmented acoustic environment (used successfully in mouse and rat models), enhancing the antioxidant defenses with exogenous antioxidant treatments (used with mixed results in mouse and rat models), raising the animals with a calorie restricted diet (used successfully in mouse and rat models), restoring lost endocochlear potential voltage with exogenous electrical stimulation (used successfully in the Mongolian gerbil model), and hypothetical enhancement of outer hair cell e...
Source: Hearing Research - September 3, 2009 Category: Audiology Authors: Bielefeld EC, Tanaka C, Chen GD, Henderson D Tags: Hear Res Source Type: journals

Permanent and transient effects of locally delivered n-acetyl cysteine in a guinea pig model of cochlear implantation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Protection of residual hearing after cochlear implant surgery can improve the speech and music perception of cochlear implant recipients, particularly in the presence of background noise. Surgical trauma and chronic inflammation are thought to be responsible for a significant proportion of residual hearing loss after surgery. Local delivery of the anti-oxidant precursor n-acetyl cysteine (NAC) to the cochlea via round window 30 minutes prior to surgery, increased the level of residual hearing at 24-32 kHz four weeks post surgery compared to controls. The hearing protection was found in the basal turn near the site of i...
Source: Hearing Research - August 31, 2009 Category: Audiology Authors: Eastwood H, Pinder D, James D, Chang A, Galloway S, Richardson R, O'Leary S Tags: Hear Res Source Type: journals

Electrocochleographic and Mechanical Assessment of Round Window Stimulation with an Active Middle Ear Prosthesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mechanical stimulation of the round window (RW) with an active middle ear prosthesis (AMEP) has shown functional benefit in clinical reports in patients with mixed hearing loss (MHL). Further objective physiological data on the efficacy of RW stimulation is needed, however, to demonstrate that RW stimulation with an AMEP can generate input to the inner ear comparable to acoustic input. Cochlear microphonic (CM) and mechanical (stapes velocity) responses to sinusoidal stimuli were measured by electrode and laser Doppler vibrometry in 8 chinchillas in response to normal acoustic stimulation via sealed calibrated insert e...
Source: Hearing Research - August 27, 2009 Category: Audiology Authors: Koka K, Holland NJ, Lupo JE, Jenkins HA, Tollin DJ Tags: Hear Res Source Type: journals

Mechanisms of Rapid Sensory Hair-Cell Death Following Co-administration of Gentamicin and Ethacrynic Acid.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Concurrent administration of a high dose of gentamicin (GM; 125 mg/kg IM) and ethacrynic acid (EA; 40 mg/kg IV) results in rapid destruction of virtually all cochlear hair cells; however, the cell death signaling pathways underlying this rapid form of hair-cell degeneration are unclear. To elucidate the mechanisms underlying GM/EA-mediated cell death, several key cell death markers were assessed in the chinchilla cochlea during the early stages of degeneration. In the middle and basal turns of the cochlea, massive hair-cell loss including destruction of the stereocilia and cuticular plate occurred 12 h after GM/EA trea...
Source: Hearing Research - August 24, 2009 Category: Audiology Authors: Ding D, Jiang H, Salvi RJ Tags: Hear Res Source Type: journals

Examining the role of frequency specificity in the enhancement and suppression of human cortical activity by auditory selective attention.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, our results show partial support for frequency-specific enhancement. PMID: 19706320 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - August 21, 2009 Category: Audiology Authors: Paltoglou AE, Sumner CJ, Hall DA Tags: Hear Res Source Type: journals

Effects of neonatal partial deafness and chronic intracochlear electrical stimulation on auditory and electrical response characteristics in primary auditory cortex.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The use of cochlear implants in patients with severe hearing losses but residual low-frequency hearing raises questions concerning the effects of chronic intracochlear electrical stimulation (ICES) on cortical responses to auditory and electrical stimuli. We investigated these questions by studying responses to tonal and electrical stimuli in primary auditory cortex (AI) of two groups of neonatally-deafened cats with residual high-threshold, low-frequency hearing. One group were implanted with a multi-channel intracochlear electrode at eight weeks of age, and received chronic ICES for up to nine months before cortical ...
Source: Hearing Research - August 20, 2009 Category: Audiology Authors: Fallon JB, Shepherd RK, Brown M, Irvine DR Tags: Hear Res Source Type: journals

Rate perception and the auditory 40-Hz steady-state fields evoked by two-tone sequences.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The rate perception of tone sequences reflects the physical repetition rate for identical sound elements. More complex sequences are perceived at the physical rate or at lower rates, depending on perceptual organization. Here, we used magnetoencephalography and psychophysical studies to evaluate the possible relationship between rate perception of such rapid, 40-Hz tone trains and the 40-Hz steady-state response (SSR) in human primary auditory cortex. In Experiment 1, the 40-Hz SSR evoked by monotone sequences of 1000 and 600 Hz were compared to the response evoked by alternating-tone sequences of the same frequencies....
Source: Hearing Research - August 18, 2009 Category: Audiology Authors: Gutschalk A, Oldermann K, Rupp A Tags: Hear Res Source Type: journals