Processing of communication sounds: Contributions of learning, memory, and experience.
This article is part of a Special Issue entitled "Vocalizations and Hearing". PMID: 23792078 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - June 18, 2013 Category: Audiology Authors: Poremba A, Bigelow J, Rossi B Tags: Hear Res Source Type: research

Influence of inter-field communication on neuronal response synchrony across auditory cortex.
Abstract Sensory information is encoded by cortical neurons in the form of synaptic discharge time and rate level. These neuronal codes generate response patterns across cell assemblies that are crucial to various cognitive functions. Despite pivotal information about structural and cognitive factors involved in the generation of synchronous neuronal responses such as stimulus context, attention, age, cortical depth, sensory experience, and receptive field properties, the influence of cortico-cortical connectivity on the emergence of neuronal response patterns is poorly understood. The present investigation assess...
Source: Hearing Research - June 18, 2013 Category: Audiology Authors: Carrasco A, Lomber SG Tags: Hear Res Source Type: research

Prophylactic and therapeutic functions of drug combinations against noise-induced hearing loss.
Abstract Noise is the most common occupational and environmental hazard. Noise-induced hearing loss (NIHL) is the second most common form of sensorineural hearing deficit, after age-related hearing loss (presbycusis). Although promising approaches have been identified for reducing NIHL, currently there are no effective medications to prevent NIHL. Development of an efficacious treatment has been hampered by the complex array of cellular and molecular pathways involved in NIHL. We turned this difficulty into an advantage by asking whether NIHL could be effectively prevented by targeting multiple signaling pathways ...
Source: Hearing Research - June 18, 2013 Category: Audiology Authors: Bao J, Hungerford M, Luxmore R, Ding D, Qiu Z, Lei D, Yang A, Liang R, Ohlemiller KK Tags: Hear Res Source Type: research

Changes in utricular function during artificial endolymph injections in guinea pigs.
Abstract Various theories suggest endolymphatic hydrops may cause a rupture of the membranous labyrinth or may force open the utriculo-saccular duct, resulting in a sudden change in inner ear function. Here, we have used slow injections of artificial endolymph into either scala media or the utricle of anaesthetised guinea pigs to investigate the effects of hydrops. Vestibular function was continuously monitored in addition to the measurements of cochlear function developed in our laboratory (Brown et al. Hear Res, 2013). Scala media injection induced consistent functional changes, which occurred in two stages...
Source: Hearing Research - June 18, 2013 Category: Audiology Authors: Brown DJ, Chihara Y, Wang Y Tags: Hear Res Source Type: research

Acoustic basis of context dependent brainstem encoding of speech.
Abstract The newfound context dependent brainstem encoding of speech is evidence of online regularity detection and modulation of the sub-cortical responses. We studied the influence of spectral structure of the contextual stimulus on context dependent encoding of speech at the brainstem, in an attempt to understand the acoustic basis for this effect. Fourteen normal hearing adults participated in a randomized true experimental design in whom brainstem responses were recorded. Brainstem responses for a high pass filtered /da/ in the context of syllables, that either had same or different spectral structure were co...
Source: Hearing Research - June 18, 2013 Category: Audiology Authors: Gnanateja GN, Ranjan R, Firdose H, Sinha SK, Sandeep M Tags: Hear Res Source Type: research

A new Atp2b2 deafwaddler allele, dfw(i5), interacts strongly with Cdh23 and other auditory modifiers.
This study characterizes a novel null Atp2b2 allele, dfw(i5), by examining cochlear anatomy, vestibular function and auditory physiology in mutant mice. Loss of auditory function in PMCA2 mutants can be attributed to dysregulation of intracellular Ca(2+) inside the stereocilia bundles. However, extracellular Ca(2+) ions surrounding the stereocilia are also required for rigidity of cadherin 23, a component of the stereocilia tip-link encoded by the Cdh23 gene. This study further resolves the interaction between Atp2b2 and Cdh23 in a gene dosage and frequency-dependent manner, and finds that low frequencies are significantly...
Source: Hearing Research - June 18, 2013 Category: Audiology Authors: Watson CJ, Tempel BL Tags: Hear Res Source Type: research

Sound localization in noise and sensitivity to spectral shape.
in AT Abstract Individual differences exist in sound localization performance even for normal-hearing listeners. Some of these differences might be related to acoustical differences in localization cues carried by the head related transfer functions (HRTF). Recent data suggest that individual differences in sound localization performance could also have a perceptual origin. The localization of an auditory target in the up/down and front/back dimensions requires the analysis of the spectral shape of the stimulus. In the present study, we investigated the role of an acoustic factor, the prominence of the spectral sh...
Source: Hearing Research - June 11, 2013 Category: Audiology Authors: Andéol G, Macpherson EA, Sabin AT Tags: Hear Res Source Type: research

Development of pitch processing: Infants' discrimination of iterated rippled noise stimuli with unresolved spectral content.
Abstract Sound frequency is extracted at the level of the cochlea, and is represented by two neural codes: a spectral (place) code that is maintained by tonotopic maps extending into primary auditory cortex, and a temporal code based on the periodicity of action potentials in auditory nerve fibres. To date, little work has examined infants' ability to perceive pitch when spectral content cannot be resolved by cochlear filters; the present experiments do so using high-pass filtered iterated rippled noise (IRN) stimuli. Using a conditioned head-turn paradigm, most 8-month-old infants showed above-chance discriminati...
Source: Hearing Research - June 10, 2013 Category: Audiology Authors: Butler BE, Folland NA, Trainor LJ Tags: Hear Res Source Type: research

Uptake Mechanism of Furosemide Loaded Pegylated Nanoparticles by Cochlear Cell Lines.
This study tests the hypothesis that pegylated nanoparticles (NPs) could be taken up by the cochlear cells [House Ear Institute-organ of Corti 1 (HEI-OC1) and Stria vascularis K-1 (SVK-1)], through endocytic pathways. Furthermore, the in vitro drug release and the cytotoxicity of Furosemide (FUR)-loaded NPs on these two cochlear cells are investigated. FUR-loaded pegylated NPs are prepared by the emulsion-solvent diffusion method without surfactant. The NPs are characterized for particle mean diameter, polydispersity index (PDI), morphology, percent drug encapsulation efficiency (EE%), and FUR release kinetics. The methyl ...
Source: Hearing Research - June 6, 2013 Category: Audiology Authors: Youm I, Youan BB Tags: Hear Res Source Type: research

Cerebral origins of the auditory projection to the superior colliculus of the cat.
Abstract The superior colliculus (SC) is critical for directing accurate head and eye movements to visual and acoustic targets. In visual cortex, areas involved in orienting of the head and eyes to a visual stimulus have direct projections to the SC. In auditory cortex of the cat, four areas have been identified to be critical for the accurate orienting of the head and body to an acoustic stimulus. These areas include primary auditory cortex (A1), the posterior auditory field (PAF), the dorsal zone of auditory cortex (DZ), and the auditory field of the anterior ectosylvian sulcus (fAES). Therefore, we hypothesized...
Source: Hearing Research - May 24, 2013 Category: Audiology Authors: Chabot N, Mellott JG, Hall AJ, Tichenoff EL, Lomber SG Tags: Hear Res Source Type: research

School-age children's environmental object identification in natural auditory scenes: Effects of masking and contextual congruence.
This study investigated the development of children's skills in identifying ecologically relevant sound objects within naturalistic listening environments, using a non-linguistic analog of the classic 'cocktail-party' situation. Children aged 7-12.5 years completed a closed-set identification task in which brief, commonly encountered environmental sounds were presented at varying signal-to-noise ratios. To simulate the complexity of real-world acoustic environments, target sounds were embedded in either a single, stereophonically presented scene, or in one of two different scenes, with each scene presented to a single ear....
Source: Hearing Research - May 24, 2013 Category: Audiology Authors: Krishnan S, Leech R, Aydelott J, Dick F Tags: Hear Res Source Type: research

A null mutation of mouse Kcna10 causes significant vestibular and mild hearing dysfunction.
Abstract KCNA10 is a voltage gated potassium channel that is expressed in the inner ear. The localization and function of KCNA10 was studied in a mutant mouse, B6-Kcna10(TM45), in which the single protein coding exon of Kcna10 was replaced with a beta-galactosidase reporter cassette. Under the regulatory control of the endogenous Kcna10 promoter and enhancers, beta-galactosidase was expressed in hair cells of the vestibular organs and the organ of Corti. KCNA10 expression develops in opposite tonotopic gradients in the inner and outer hair cells. Kcna10(TM45) homozygotes display only a mild elevation in pure tone ...
Source: Hearing Research - May 24, 2013 Category: Audiology Authors: Lee SI, Conrad T, Jones SM, Lagziel A, Starost MF, Belyantseva IA, Friedman TB, Morell RJ Tags: Hear Res Source Type: research

Identification of the lateral position of a virtual object based on echoes by humans.
Abstract Echolocation offers a promising approach to improve the quality of life of people with blindness although little is known about the factors influencing object localisation using a 'searching' strategy. In this paper, we describe a series of experiments using sighted and blind human listeners and a 'virtual auditory space' technique to investigate the effects of the distance and orientation of a reflective object and the effect of stimulus bandwidth on ability to identify the right-versus-left position of the object, with bands of noise and durations from 10-400 ms. We found that performance reduced w...
Source: Hearing Research - May 24, 2013 Category: Audiology Authors: Rowan D, Papadopoulos T, Edwards D, Holmes H, Hollingdale A, Evans L, Allen R Tags: Hear Res Source Type: research

Clinical aspects of an autosomal dominantly inherited hearing impairment linked to the DFNA60 locus on chromosome 2q23.1-2q23.3.
Abstract A total of 64 loci for autosomal dominant non-syndromic hearing impairment have been described, and the causative genes have been identified for 24 of these. The present study reports on the clinical characteristics of an autosomal dominantly inherited hearing impairment that is linked to a region within the DFNA60 locus located on chromosome 2 in q22.1-24.1. A pedigree spanning four generations was established with 13 affected individuals. Linkage analysis demonstrated that the locus extended over a 2.96 Mb region flanked by markers D2S2335 and D2S2275. The audiograms mainly showed a distinctive U-s...
Source: Hearing Research - May 24, 2013 Category: Audiology Authors: van Beelen E, Schraders M, Huygen PL, Oostrik J, Plantinga RF, van Drunen W, Collin RW, Kooper DP, Pennings RJ, Cremers CW, Kremer H, Kunst HP Tags: Hear Res Source Type: research

A dynamic auditory-cognitive system supports speech-in-noise perception in older adults.
Abstract Understanding speech in noise is one of the most complex activities encountered in everyday life, relying on peripheral hearing, central auditory processing, and cognition. These abilities decline with age, and so older adults are often frustrated by a reduced ability to communicate effectively in noisy environments. Many studies have examined these factors independently; in the last decade, however, the idea of an auditory-cognitive system has emerged, recognizing the need to consider the processing of complex sounds in the context of dynamic neural circuits. Here, we used structural equation modeling to...
Source: Hearing Research - May 24, 2013 Category: Audiology Authors: Anderson S, White-Schwoch T, Parbery-Clark A, Kraus N Tags: Hear Res Source Type: research

Pitch and loudness matching of unmodulated and modulated stimuli in cochlear implantees.
Abstract The pitch elicited by unmodulated and amplitude modulated electrical pulse trains was examined with six adult cochlear implantees. In addition, for three of those subjects who had some hearing in their contralateral ear, the pitch of unmodulated electrical pulse trains was compared to that of complex harmonic acoustic tones. In the first experiment, pulse rate discrimination and the effects of place and level differences on pitch were examined for unmodulated pulse trains. General results were consistent with previous studies showing that variations in pulse rate, while holding loudness fixed, elicit chan...
Source: Hearing Research - May 16, 2013 Category: Audiology Authors: Vandali A, Sly D, Cowan R, van Hoesel R Tags: Hear Res Source Type: research

The neural processing of masked speech.
Abstract Spoken language is rarely heard in silence, and a great deal of interest in psychoacoustics has focused on the ways that the perception of speech is affected by properties of masking noise. In this review we first briefly outline the neuroanatomy of speech perception. We then summarise the neurobiological aspects of the perception of masked speech, and investigate this as a function of masker type, masker level and task. PMID: 23685149 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - May 16, 2013 Category: Audiology Authors: Scott SK, McGettigan C Tags: Hear Res Source Type: research

Tracing Sox10-expressing cells elucidates the dynamic development of the mouse inner ear.
Abstract The inner ear is constituted by complicated cochlear and vestibular compartments, which are derived from the otic vesicle, an embryonic structure of ectodermal origin. Although the inner ear development has been analyzed using various techniques, the developmental events have not been fully elucidated because of the intricate structure. We previously developed a Sox10-IRES-Venus mouse designed to express green fluorescent protein under the control of the Sox10 promoter. In the present study, we showed that the Sox10-IRES-Venus mouse enabled the non-destructive visualization and understanding of the morpho...
Source: Hearing Research - May 15, 2013 Category: Audiology Authors: Wakaoka T, Motohashi T, Hayashi H, Kuze B, Aoki M, Mizuta K, Kunisada T, Ito Y Tags: Hear Res Source Type: research

The incentive salience of courtship vocalizations: Hormone-mediated 'wanting' in the auditory system.
This article is part of a Special Issue entitled "Vocalizations and Hearing". PMID: 23665125 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - May 7, 2013 Category: Audiology Authors: Maney DL Tags: Hear Res Source Type: research

Technological, biological, and acoustical constraints to music perception in cochlear implant users.
This article is part of a Special Issue entitled "Music: A window into the hearing brain". PMID: 23665130 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - May 7, 2013 Category: Audiology Authors: Limb CJ, Roy AT Tags: Hear Res Source Type: research

Effect of monopolar and bipolar electric stimulation on survival and size of human spiral ganglion cells as studied by postmortem histopathology.
This study is designed to test the hypothesis that chronic electrical stimulation tends to preserve SGCs in implanted hearing-impaired ears. A total of 26 pairs of temporal bones were studied from 26 individuals who in life suffered bilateral profound hearing impairment that was symmetric (in degree of impairment and etiology) across ears and then underwent unilateral cochlear implantation. The subjects were divided in two groups by stimulus configuration: bipolar (n = 16) or monopolar (n = 10). The temporal bones were prepared for histological review by standard methods and two measures of SGC status w...
Source: Hearing Research - May 6, 2013 Category: Audiology Authors: Seyyedi M, Eddington DK, Nadol JB Tags: Hear Res Source Type: research

RNA analysis of inner ear cells from formalin fixed paraffin embedded (FFPE) archival human temporal bone section using laser microdissection - A technical report.
CONCLUSION: We detected COCH and SLC26A5 mRNA in specific structures and cells of the inner ear from archival human temporal bone. Our innovative method using laser microdissection and semi-nested RT-PCR should advance future RNA study of human inner ear diseases. PMID: 23660400 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - May 6, 2013 Category: Audiology Authors: Kimura Y, Kubo S, Koda H, Shigemoto K, Sawabe M, Kitamura K Tags: Hear Res Source Type: research

Effects of hearing aid amplification on voice F0 variability in speakers with prelingual hearing loss.
Abstract To investigate the audio-vocal feedback responses of (F0) to hearing amplification in severe-to-profound prelingual hearing loss (SPHL) using power spectral analysis of F0 contour of sustained vowels. Sustained phonations of vowel/a/of seventeen participants with SPHL were acquired with and without hearing-aid amplifications. The vocal intensity was visually fed back to the participants to help controlling the vocal intensity at 65-75 dBA and 85-95 dBA. The F0 contour of the phonations was extracted and submitted to spectral analysis to measure the extent of F0 fluctuations at different frequenc...
Source: Hearing Research - May 4, 2013 Category: Audiology Authors: Lee GS, Liu C, Lee SH Tags: Hear Res Source Type: research

Improving speech perception in noise with current focusing in cochlear implant users.
In this study, we compared speech perception in noise with experimental monopolar and partial tripolar speech processing strategies. The two strategies were matched in terms of number of active electrodes, microphone, filterbanks, stimulation rate and loudness (although both strategies used a lower stimulation rate than typical clinical strategies). The results of this study showed a significant improvement in speech perception in noise with partial tripolar stimulation. All subjects benefited from the current focused speech processing strategy. There was a mean improvement in speech recognition threshold of 2.7 dB in...
Source: Hearing Research - May 1, 2013 Category: Audiology Authors: Srinivasan AG, Padilla M, Shannon RV, Landsberger DM Tags: Hear Res Source Type: research

Cisplatin-induced ototoxicity: Transporters playing a role in cisplatin toxicity.
Abstract Cisplatin is a potent antineoplastic agent widely used for a variety of cancer types. Unfortunately, its use leads to dose limiting side effects such as ototoxicity. Up to 93% of patients receiving cisplatin chemotherapy will develop progressive and irreversible sensorineural hearing loss which leads to a decreased quality of life in cancer survivors. No treatment is currently available for cisplatin-induced ototoxicity. It appears that cisplatin causes apoptosis by binding DNA, activating the inflammatory cascade as well as generating oxidative stress in the cell. Various studies have aimed to assess the...
Source: Hearing Research - May 1, 2013 Category: Audiology Authors: Waissbluth S, Daniel SJ Tags: Hear Res Source Type: research

Effects of sex and age on auditory spatial scene analysis.
Abstract Recently, it has been demonstrated that men outperform women in spatial analysis of complex auditory scenes (Zündorf et al., 2011). The present study investigated the relation between the effects of ageing and sex on the spatial segregation of concurrent sounds in younger and middle-aged adults. The experimental design allowed simultaneous presentation of target and distractor sound sources at different locations. The resulting spatial "pulling" effect (that is, the bias of target localization toward that of the distractor) was used as a measure of performance. The pulling effect was s...
Source: Hearing Research - May 1, 2013 Category: Audiology Authors: Lewald J, Hausmann M Tags: Hear Res Source Type: research

Characterization of a novel ENU-generated myosin VI mutant mouse strain with congenital deafness and vestibular dysfunction.
Abstract Myosin VI (Myo6) is known to play an important role in the mammalian auditory and vestibular systems. We have identified a novel N-ethyl-N-nitrosourea mutagenised mouse strain, charlie, carrying an intronic Myo6 splice site mutation. This mutation (IVS5+5G > A) results in skipping of exon 5, and is predicted to cause a frameshift and premature termination of the protein. We detected essentially no Myo6 transcript in tissue from charlie homozygous mutant mice (Myo6(chl/chl)). Myo6(chl/chl) mice exhibit vestibular dysfunction and profound hearing impairment when first tested at four weeks of ag...
Source: Hearing Research - May 1, 2013 Category: Audiology Authors: Williams LH, Miller KA, Dahl HH, Manji SS Tags: Hear Res Source Type: research

Auditory evoked magnetic fields in individuals with tinnitus.
Abstract Some forms of tinnitus are likely to be perceptual consequences of altered neural activity in the central auditory system triggered by damage to the auditory periphery. Animal studies report changes in the evoked responses after noise exposure or ototoxic drugs in inferior colliculus and auditory cortex. However, human electrophysiological evidence is rather equivocal: increased, reduced or no difference in N1/N1m evoked amplitudes and latencies in tinnitus participants have been reported. The present study used magnetoencephalography to seek evidence for altered evoked responses in people with tinnitus c...
Source: Hearing Research - April 29, 2013 Category: Audiology Authors: Sereda M, Adjamian P, Edmondson-Jones M, Palmer AR, Hall DA Tags: Hear Res Source Type: research

Electrically evoked compound action potential artifact rejection by independent component analysis: Technique validation.
Abstract The electrically-evoked compound action potential (ECAP) is the synchronous whole auditory nerve activity in response to an electrical stimulus, and can be recorded in situ on cochlear implant (CI) electrodes. A novel procedure (ECAP-ICA) to isolate the ECAP from the stimulation artifact, based on independent component analysis (ICA), is described here. ECAPs with artifact (raw-ECAPs) were sequentially recorded for the same stimulus on 9 different intracochlear recording electrodes. The raw-ECAPs were fed to ICA, which separated them into independent sources. Restricting the ICA projection to 4 independen...
Source: Hearing Research - April 28, 2013 Category: Audiology Authors: Akhoun I, McKay CM, El-Deredy W Tags: Hear Res Source Type: research

Amplitude-modulation detection by gerbils in reverberant sound fields.
Abstract Reverberation can dramatically reduce the depth of amplitude modulations which are critical for speech intelligibility. Psychophysical experiments indicate that humans' sensitivity to amplitude modulation in reverberation is better than predicted from the acoustic modulation depth at the receiver position. Electrophysiological studies on reverberation in rabbits highlight the contribution of neurons sensitive to interaural correlation. Here, we use a prepulse-inhibition paradigm to quantify the gerbils' amplitude modulation threshold in both anechoic and reverberant virtual environments. Data show that pr...
Source: Hearing Research - April 18, 2013 Category: Audiology Authors: Lingner A, Kugler K, Grothe B, Wiegrebe L Tags: Hear Res Source Type: research

How do auditory cortex neurons represent communication sounds?
ne JM Abstract A major goal in auditory neuroscience is to characterize how communication sounds are represented at the cortical level. The present review aims at investigating the role of auditory cortex in the processing of speech, bird songs and other vocalizations, which all are spectrally and temporally highly structured sounds. Whereas earlier studies have simply looked for neurons exhibiting higher firing rates to particular conspecific vocalizations over their modified, artificially synthesized versions, more recent studies determined the coding capacity of temporal spike patterns, which are prominent in p...
Source: Hearing Research - April 17, 2013 Category: Audiology Authors: Gaucher Q, Huetz C, Gourévitch B, Laudanski J, Occelli F, Edeline JM Tags: Hear Res Source Type: research

MEMRO 2012 - Middle-ear bridge between science and otology.
PMID: 23598165 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - April 15, 2013 Category: Audiology Authors: Cho JH, Puria S, Gummer AW Tags: Hear Res Source Type: research

Investigation of bacterial biofilm in the human middle ear using optical coherence tomography and acoustic measurements.
This article is part of a Special Issue entitled "MEMRO 2012". PMID: 23588039 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - April 12, 2013 Category: Audiology Authors: Nguyen CT, Robinson SR, Jung W, Novak MA, Boppart SA, Allen JB Tags: Hear Res Source Type: research

Insensitivity of the audiogram to carboplatin induced inner hair cell loss in chinchillas.
Abstract Noise trauma, aging, and ototoxicity preferentially damage the outer hair cells of the inner ear, leading to increased hearing thresholds and poorer frequency resolution. Whereas outer hair cells make synaptic connections with less than 10% of afferent auditory nerve fibers (type-II), inner hair cells make connections with over 90% of afferents (type-I). Despite these extensive connections, little is known about how selective inner hair cell loss impacts hearing. In chinchillas, moderate to high doses of the anticancer compound carboplatin produce selective inner hair cell and type-I afferent loss with li...
Source: Hearing Research - April 6, 2013 Category: Audiology Authors: Lobarinas E, Salvi R, Ding D Tags: Hear Res Source Type: research

Musicians change their tune: How hearing loss alters the neural code.
Abstract Individuals with sensorineural hearing loss have difficulty understanding speech, especially in background noise. This deficit remains even when audibility is restored through amplification, suggesting that mechanisms beyond a reduction in peripheral sensitivity contribute to the perceptual difficulties associated with hearing loss. Given that normal-hearing musicians have enhanced auditory perceptual skills, including speech-in-noise perception, coupled with heightened subcortical responses to speech, we aimed to determine whether similar advantages could be observed in middle-aged adults with hearing lo...
Source: Hearing Research - April 6, 2013 Category: Audiology Authors: Parbery-Clark A, Anderson S, Kraus N Tags: Hear Res Source Type: research

Superior-semicircular-canal dehiscence: Effects of location, shape, and size on sound conduction.
In this study, BC excitations were simulated by applying rigid-body vibrations to the model along the directions of the (arbitrarily defined) x, y, and z axes of the model. Simulation results are consistent with previous clinical measurements on patients with an SSCD and with results from earlier lumped-element electrical-circuit modeling studies, with the dehiscence decreasing the hearing threshold (i.e., increasing vBM) by about 35 dB for BC excitation at low frequencies, while for AC excitation the dehiscence increases the hearing threshold (i.e., decreases vBM) by about 15 dB. A new finding from this study is...
Source: Hearing Research - April 3, 2013 Category: Audiology Authors: Kim N, Steele CR, Puria S Tags: Hear Res Source Type: research

Loudness functions with air and bone conduction stimulation in normal-hearing subjects using a categorical loudness scaling procedure.
This article is part of a Special Issue entitled "MEMRO 2012". PMID: 23562775 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - April 3, 2013 Category: Audiology Authors: Stenfelt S, Zeitooni M Tags: Hear Res Source Type: research

The dominant role of inhibition in creating response selectivities for communication calls in the brainstem auditory system.
Abstract This review is concerned with how communication calls are processed and represented by populations of neurons in both the inferior colliculus (IC), the auditory midbrain nucleus, and the dorsal nucleus of the lateral lemniscus (DNLL), the nucleus just caudal to the IC. The review has five sections where focus in each section is on inhibition and its role in shaping response selectivity for communication calls. In the first section, the lack of response selectivity for calls in DNLL neurons is presented and discusses why inhibition plays virtually no role in shaping selectivity. In the second section, the ...
Source: Hearing Research - March 29, 2013 Category: Audiology Authors: Pollak GD Tags: Hear Res Source Type: research

Characterizing the ear canal acoustic impedance and reflectance by pole-zero fitting.
This study characterizes middle ear complex acoustic reflectance (CAR) and impedance by fitting poles and zeros to real-ear measurements. The goal of this work is to establish a quantitative connection between pole-zero locations and the underlying physical properties of CAR data. Most previous studies have analyzed CAR magnitude; while the magnitude accounts for reflected power, it does not encode latency information. Thus, an analysis that studies the real and imaginary parts of the data together, being more general, should be more powerful. Pole-zero fitting of CAR data is examined using data compiled from various studi...
Source: Hearing Research - March 22, 2013 Category: Audiology Authors: Robinson SR, Nguyen CT, Allen JB Tags: Hear Res Source Type: research

Micro-channels in the mastoid anatomy. Indications of a separate blood supply of the air cell system mucosa by micro-CT scanning.
In this study we have applied micro-CT scanning on a series of three human temporal bones. This approach greatly enhances the resolution (40-60 μm), so that we have discovered anatomical details, which has not been reported earlier. Thus, qualitative analysis using volume rendering has demonstrated notable micro-channels connecting the surface of the compact bone directly to the mastoid air cells as well as forming a network of connections between the air cells. Quantitative analysis on 2D slices was employed to determine the average diameter of these micro-channels (158 μm; range = 40-440 &m...
Source: Hearing Research - March 19, 2013 Category: Audiology Authors: Cros O, Borga M, Pauwels E, Dirckx JJ, Gaihede M Tags: Hear Res Source Type: research

The Bonebridge: Preclinical evaluation of a new transcutaneously-activated bone anchored hearing device.
CONCLUSIONS: Preclinical results imply that the BB has functional performance similar to the BAHA and could be beneficial to patients suffering with conductive and mixed hearing losses as well as for those with unilateral impairment. Based on these preliminary results, a carefully designed clinical trial with conservative inclusion criteria can be recommended. This article is part of a Special Issue entitled "MEMRO 2012". PMID: 23467173 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - March 1, 2013 Category: Audiology Authors: Huber AM, Sim JH, Xie YZ, Chatzimichalis M, Ullrich O, Röösli C Tags: Hear Res Source Type: research

Two-port network analysis and modeling of a balanced armature receiver.
This study analyzes a widely-used commercial hearing-aid receiver ED series, manufactured by Knowles Electronics, Inc. Electromagnetic transducer modeling must consider two key elements: a semi-inductor and a gyrator. The semi-inductor accounts for electromagnetic eddy-currents, the 'skin effect' of a conductor (Vanderkooy, 1989), while the gyrator (McMillan, 1946; Tellegen, 1948) accounts for the anti-reciprocity characteristic [Lenz's law (Hunt, 1954, p. 113)]. Aside from Hunt (1954), no publications we know of have included the gyrator element in their electromagnetic transducer models. The most prevalent method of tran...
Source: Hearing Research - February 26, 2013 Category: Audiology Authors: Kim N, Allen JB Tags: Hear Res Source Type: research

Estimation of bone conduction skull transmission by hearing thresholds and ear-canal sound pressure.
on B Abstract Bone conduction sound transmission in the human skull and the occlusion effect were estimated from hearing thresholds and ear-canal sound pressure (ECSP) measured by a probe tube microphone when stimulation was at three positions on the skull (ipsilateral mastoid, contralateral mastoid, and forehead). The measurements were done with the ear-canal open as well as occluded by an ear-plug. Depending on the estimation method, transcranial transmission at frequencies below 1 kHz was between -8 and 5 dB, around 0 dB at 1 kHz that decreased with frequency to between -17 and -7 dB at 8 kHz. The forehead tran...
Source: Hearing Research - February 16, 2013 Category: Audiology Authors: Reinfeldt S, Stenfelt S, Håkansson B Tags: Hear Res Source Type: research

Current concepts in age-related hearing loss: epidemiology and mechanistic pathways.
Abstract Age-related hearing loss (AHL), also known as presbycusis, is a universal feature of mammalian aging and is characterized by a decline of auditory function, such as increased hearing thresholds and poor frequency resolution. The primary pathology of AHL includes the hair cells, stria vascularis, and afferent spiral ganglion neurons as well as the central auditory pathways. A growing body of evidence in animal studies has suggested that cumulative effect of oxidative stress could induce damage to macromolecules such as mitochondrial DNA (mtDNA) and that the resulting accumulation of mtDNA mutations/deletio...
Source: Hearing Research - February 16, 2013 Category: Audiology Authors: Yamasoba T, Lin FR, Someya S, Kashio A, Sakamoto T, Kondo K Tags: Hear Res Source Type: research

Neural substrates predicting improvement of tinnitus after cochlear implantation in patients with single-sided deafness.
Abstract Notwithstanding successful reduction of tinnitus after cochlear implantation (CI) in patients with single-sided deafness (SSD) in recent studies, neither the exact mechanism of suppression nor the predictors of the amount of improvement are fully understood yet. We collected quantitative electroencephalography (qEEG) data from nine SSD patients who underwent CI for tinnitus management. By correlating the degree of improvement in tinnitus intensity and tinnitus-related distress with preoperative source-localized qEEG findings and comparing qEEG findings of patients with marked improvement after CI with tho...
Source: Hearing Research - February 13, 2013 Category: Audiology Authors: Song JJ, Punte AK, De Ridder D, Vanneste S, Van de Heyning P Tags: Hear Res Source Type: research

Stem Cell Transplantation via the Cochlear Lateral Wall for Replacement of Degenerated Spiral Ganglion Neurons.
In this study, we attempted to establish a new stem cell transplantation route into the cochlea via the cochlear lateral wall (CLW). First, we tested the precision of this route by injecting Fluorogold into the CLW and next assessed its safety by mock surgeries. Then, using a degenerated SGN animal model, we transplanted neural stem cells (NSCs), derived from the olfactory bulb of C57BL/6- green fluorescent protein (GFP) mice, via the CLW route and examined the cells' distribution in the cochlea. We found the CLW transplantation route is precise and safe. In addition, NSCs migrated into RC with a high efficiency and differ...
Source: Hearing Research - February 9, 2013 Category: Audiology Authors: Zhang PZ, He Y, Jiang XW, Chen FQ, Chen Y, Shi L, Chen J, Chen X, Li X, Xue T, Wang Y, Mi WJ, Qiu JH Tags: Hear Res Source Type: research

Expression and Dexamethasone-induced Nuclear Translocation of Glucocorticoid and Mineralocorticoid Receptors in Guinea Pig Cochlear Cells.
Abstract Glucocorticoids (GC) are powerful anti-inflammatory agents frequently used to protect the auditory organ against damage associated with a variety of conditions, including noise exposure and ototoxic drugs as well as bacterial and viral infections. In addition to glucocorticoid receptors (GC-R), natural and synthetic GC are known to bind mineralocorticoid receptors (MC-R) with great affinity. We used light and laser scanning confocal microscopy to investigate the expression of GC-R and MC-R in different cell populations of the guinea pig cochlea, and their translocation to different cell compartments after...
Source: Hearing Research - February 8, 2013 Category: Audiology Authors: Kil SH, Kalinec F Tags: Hear Res Source Type: research

Understanding the effect of noise on electrical stimulation sequences in cochlear implants and its impact on speech intelligibility.
Abstract The present study investigates the most important factors that limit the intelligibility of the cochlear implant (CI) processed speech in noisy environments. The electrical stimulation sequences provided in CIs are affected by the noise in the following three manners. First of all, the natural gaps in the speech are filled, which distorts the low-frequency ON/OFF modulations of the speech signal. Secondly, speech envelopes are distorted to include modulations of both speech and noise. Lastly, the N-of-M type of speech coding strategies may select the noise dominated channels instead of the dominant speech...
Source: Hearing Research - February 7, 2013 Category: Audiology Authors: Qazi OU, van Dijk B, Moonen M, Wouters J Tags: Hear Res Source Type: research

Developmental Origin and Fate of Middle Ear Structures.
Abstract Results from developmental and phylogenetic studies have converged to facilitate insight into two important steps in vertebrate evolution: (1) the ontogenetic origin of articulating elements of the buccal skeleton, i.e. jaws, and (2) the later origins of middle ear impedance-matching systems that convey air-borne sound to the inner ear fluids. Middle ear ossicles and other skeletal elements of the viscerocranium (i.e. gill suspensory arches and jaw bones) share a common origin both phylogenetically and ontogenetically. The intention of this brief overview of middle-ear development is to emphasize the inti...
Source: Hearing Research - February 7, 2013 Category: Audiology Authors: Sienknecht UJ Tags: Hear Res Source Type: research

Temporal interaction in electrical hearing elucidates auditory nerve dynamics in humans.
In this study we have developed a double-pulse method and, for the first time, reversed stimulus polarity systematically between consecutive pulses to elucidate subthreshold-induced temporal interaction effects. This method allowed us to determine the time-course of subthreshold temporal interaction in human subjects which identifies the limits of encoded temporal precision. Our results show significant temporal interaction up to 600 μs inter pulse interval. In all the cases tested we saw a facilitation effect on threshold. Interaction effects at a 20% below threshold pre-conditioning stimulation showed up to 38% &plu...
Source: Hearing Research - February 7, 2013 Category: Audiology Authors: Karg SA, Lackner C, Hemmert W Tags: Hear Res Source Type: research