The afferent signaling complex: regulation of type I spiral ganglion neuron responses in the auditory periphery.
Abstract The spiral ganglion neurons (SGNs) are the first action potential generating neurons in the auditory pathway. The type I SGNs contact the sensory inner hair cells via their peripheral dendrites and relay auditory information to the brainstem via their central axon fibers. Individual afferent fibers show differences in response properties that are essential for normal hearing. The mechanisms that give rise to the heterogeneity of afferent responses are very poorly understood but are likely already in place at the peripheral dendrites where synapses are formed and action potentials are generated. To identif...
Source: Hearing Research - March 24, 2016 Category: Audiology Authors: Reijntjes DO, Pyott SJ Tags: Hear Res Source Type: research

The Calyx of Held in the auditory system: structure, function, and development.
Abstract The calyx of Held synapse plays an important role in the auditory system, relaying information about sound localization via fast and precise synaptic transmission, which is achieved by its specialized structure and giant size. During development, the calyx of Held undergoes anatomical, morphological, and physiological changes necessary for performing its functions. The large dimensions of the calyx of Held nerve terminal are well suited for direct electrophysiological recording of many presynaptic events that are difficult, if not impossible to record at small conventional synapses. This unique accessibil...
Source: Hearing Research - March 24, 2016 Category: Audiology Authors: Baydyuk M, Xu J, Wu LG Tags: Hear Res Source Type: research

Spectral and binaural loudness summation for hearing-impaired listeners.
Abstract Sensorineural hearing loss typically results in a steepened loudness function and a reduced dynamic range from elevated thresholds to uncomfortably loud levels for narrowband and broadband signals. Restoring narrowband loudness perception for hearing-impaired (HI) listeners can lead to overly loud perception of broadband signals and it is unclear how binaural presentation affects loudness perception in this case. Here, loudness perception quantified by categorical loudness scaling for nine normal-hearing (NH) and ten HI listeners was compared for signals with different bandwidth and different spectral sha...
Source: Hearing Research - March 19, 2016 Category: Audiology Authors: Oetting D, Hohmann V, Appell JE, Kollmeier B, Ewert SD Tags: Hear Res Source Type: research

Auditory steady-state responses in cochlear implant users: Effect of modulation frequency and stimulation artifacts.
Abstract Previous studies have shown that objective measures based on stimulation with low-rate pulse trains fail to predict the threshold levels of cochlear implant (CI) users for high-rate pulse trains, as used in clinical devices. Electrically evoked auditory steady-state responses (EASSRs) can be elicited by modulated high-rate pulse trains, and can potentially be used to objectively determine threshold levels of CI users. The responsiveness of the auditory pathway of profoundly hearing-impaired CI users to modulation frequencies is, however, not known. In the present study we investigated the responsiveness o...
Source: Hearing Research - March 17, 2016 Category: Audiology Authors: Gransier R, Deprez H, Hofmann M, Moonen M, van Wieringen A, Wouters J Tags: Hear Res Source Type: research

The effect of noise exposure during the developmental period on the function of the auditory system.
™ J, Syka J Abstract Recently, there has been growing evidence that development and maturation of the auditory system depends substantially on the afferent activity supplying inputs to the developing centers. In cases when this activity is altered during early ontogeny as a consequence of, e.g., an unnatural acoustic environment or acoustic trauma, the structure and function of the auditory system may be severely affected. Pathological alterations may be found in populations of ribbon synapses of the inner hair cells, in the structure and function of neuronal circuits, or in auditory driven behavioral and psychoph...
Source: Hearing Research - March 16, 2016 Category: Audiology Authors: Bureš Z, Popelář J, Syka J Tags: Hear Res Source Type: research

Design, Fabrication, and In Vitro Testing of Novel Three-Dimensionally Printed Tympanic Membrane Grafts.
This study demonstrates the design, fabrication and preliminary in vitro acoustic and mechanical evaluation of 3D printed TM grafts. Data illustrate the feasibility of creating TM grafts with acoustic properties that reflect sound induced motion patterns of the human TM; furthermore, 3D printed grafts have mechanical properties that demonstrate increased resistance to deformation compared to temporalis fascia. PMID: 26994661 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - March 16, 2016 Category: Audiology Authors: Kozin ED, Black NL, Cheng JT, Cotler MJ, McKenna MJ, Lee DJ, Lewis JA, Rosowski JJ, Remenschneider AK Tags: Hear Res Source Type: research

Time-frequency decomposition of click evoked otoacoustic emissions in children.
This study investigated the time-frequency properties of CEOAEs in 5 to 10 year old children. In the first part, we examined the feasibility of the S transform to characterize the time-frequency features of CEOAEs. A synthetic signal with known gammatones was analyzed using the S transform, as well as a wavelet transform with the basis function used traditionally for CEOAE analysis. The S and wavelet transforms provided similar representations of the gammatones of the synthetic signal in the mid and high frequencies. However, the S transform yielded a slightly more precise time-frequency representation at low frequencies (...
Source: Hearing Research - March 11, 2016 Category: Audiology Authors: Mishra SK, Biswal M Tags: Hear Res Source Type: research

Effects of high intensity noise on the vestibular system in rats.
Abstract Some individuals with noise-induced hearing loss (NIHL) also report balance problems. These accompanying vestibular complaints are not well understood. The present study used a rat model to examine the effects of noise exposure on the vestibular system. Rats were exposed to continuous broadband white noise (0-24kHz) at an intensity of 116dB sound pressure level (SPL) via insert ear phones in one ear for three hours under isoflurane anesthesia. Seven days after the exposure, a significant increase in ABR threshold (43.3+1.9dB) was observed in the noise-exposed ears, indicating hearing loss. Effects of nois...
Source: Hearing Research - March 9, 2016 Category: Audiology Authors: Stewart C, Yu Y, Huang J, Maklad A, Tang X, Allison J, Mustain W, Zhou W, Zhu H Tags: Hear Res Source Type: research

Effects of pulsatile electrical stimulation of the round window on central hyperactivity after cochlear trauma in guinea pig.
This study aimed to investigate the effects of electrical stimulation in the form of brief biphasic shocks delivered to the round window of the cochlea on the spontaneous firing rates of hyperactive inferior colliculus neurons following acoustic trauma in guinea pigs. Effects during the stimulation itself included both inhibition and excitation but spontaneous firing was suppressed for up to hundreds of ms after the cessation of the shock train in all sampled hyperactive neurons. Pharmacological block of olivocochlear efferent action on outer hair cells did not eliminate the prolonged suppression observed in inferior colli...
Source: Hearing Research - March 9, 2016 Category: Audiology Authors: Mulders WH, Spencer TC, Robertson D Tags: Hear Res Source Type: research

Impulse noise injury prediction based on the cochlear energy.
Abstract The current impulse noise criteria for the protection against impulse noise injury do not incorporate an objective measure of hearing protection. A new biomechanically-based model has been developed based on improvement of the Auditory Hazard Assessment Algorithm for the Human (AHAAH) using the integrated cochlear energy (ICE) as the damage risk correlate (DRC). The model parameters have been corrected using the latest literature data. The anomalous dose-response inversion behavior of the AHAAH model was eliminated. The modeling results show that the annular ligament (AL) parameters are the dominant cause...
Source: Hearing Research - March 8, 2016 Category: Audiology Authors: Zagadou B, Chan P, Ho K, Shelley D Tags: Hear Res Source Type: research

Disrupted Functional Brain Connectome in Unilateral Sudden Sensorineural Hearing Loss.
Abstract Sudden sensorineural hearing loss (SSNHL) is generally defined as sensorineural hearing loss of 30 dB or greater over at least three contiguous audiometric frequencies and within a three-day period. This hearing loss is usually unilateral and can be associated with tinnitus and vertigo. The pathogenesis of unilateral sudden sensorineural hearing loss is still unknown, and the alterations in the functional connectivity are suspected to involve one possible pathogenesis. Despite scarce findings with respect to alterations in brain functional networks in unilateral sudden sensorineural hearing loss, the alte...
Source: Hearing Research - March 8, 2016 Category: Audiology Authors: Xu H, Fan W, Zhao X, Li J, Zhang W, Lei P, Liu Y, Wang H, Cheng H, Shi H Tags: Hear Res Source Type: research

Congestion of mastoid mucosa and influence on middle ear pressure - effect of retroauricular injection of adrenaline.
Abstract Micro-CT scanning of temporal bones has revealed numerous retroauricular microchannels, which connect the outer bone surface directly to the underlying mastoid air cells. Their structure and dimensions have suggested a separate vascular supply to the mastoid mucosa, which may play a role in middle ear (ME) pressure regulation. This role may be accomplished by changes in the mucosa congestion resulting in volumetric changes, which ultimately affect the pressure of the enclosed ME gas pocket (Boyle's law). Further, such mucosa congestion may be susceptible to α-adrenergic stimulation similar to the mu...
Source: Hearing Research - March 2, 2016 Category: Audiology Authors: Fooken Jensen PV, Gaihede M Tags: Hear Res Source Type: research

Perinatal Thiamine Deficiency Causes Cochlear Innervation Abnormalities in Mice.
Abstract Neonatal thiamine deficiency can cause auditory neuropathy in humans. To probe the underlying cochlear pathology, mice were maintained on a thiamine-free or low-thiamine diet during fetal development or early postnatal life. At postnatal ages from 18 days to 22 wks, cochlear function was tested and cochlear histopathology analyzed by plastic sections and cochlear epithelial whole-mounts immunostained for neuronal and synaptic markers. Although none of the thiamine-deprivation protocols resulted in any loss of hair cells or any obvious abnormalities in the non-sensory structures of the cochlear duct, all t...
Source: Hearing Research - March 1, 2016 Category: Audiology Authors: Maison SF, Yin Y, Liberman LD, Liberman MC Tags: Hear Res Source Type: research

HEI-OC1 Cells as a Model for Investigating Drug Cytotoxicity.
Abstract The House Ear Institute-Organ of Corti 1 (HEI-OC1) is one of the few, and arguable the most used, mouse auditory cell line available for research purposes. Originally proposed as an in vitro system for screening of ototoxic drugs, it has been used to investigate, among other topics, apoptotic pathways, autophagy and senescence, mechanism of cell protection, inflammatory responses, cell differentiation, effects of hypoxia, oxidative and endoplasmic reticulum stress, and expression of molecular channels and receptors. However, the use of different techniques with different goals resulted in apparent contrad...
Source: Hearing Research - February 27, 2016 Category: Audiology Authors: Kalinec G, Thein P, Park C, Kalinec F Tags: Hear Res Source Type: research

Human Audiometric Thresholds do not Predict Specific Cellular Damage in the Inner Ear.
CONCLUSIONS: Audiometric thresholds do not predict specific cellular damage in the human inner ear. Our study highlights the need for better non- or minimally-invasive tools, such as cochlear endoscopy, to establish cellular-level diagnosis and thereby guide therapy and monitor response to treatment. PMID: 26924453 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - February 25, 2016 Category: Audiology Authors: Landegger LD, Psaltis D, Stankovic KM Tags: Hear Res Source Type: research

Middle-ear and inner-ear contribution to bone bonduction in chinchilla: The development of Carhart's notch.
We present acoustical measurements of sound in the inner ear that separate out the components of BC stimulation that stimulate the inner ear via ossicular motion (compression of the walls of the ear canal or ossicular inertia) from the components that act directly on the cochlea (cochlear compression or inertia, and extra-cochlear 'third-window' pathways). The results are consistent with our earlier suggestion that the inner-ear mechanisms play a large role in bone-conduction stimulation in the chinchilla at all frequencies. However, the data also suggest the pathways that conduct vibration to the inner ear via ossicular-m...
Source: Hearing Research - February 23, 2016 Category: Audiology Authors: Chhan D, Bowers P, McKinnon ML, Rosowski JJ Tags: Hear Res Source Type: research

Graded and discontinuous EphA-ephrinB expression patterns in the developing auditory brainstem.
Abstract Eph-ephrin interactions guide topographic mapping and pattern formation in a variety of systems. In contrast to other sensory pathways, their precise role in the assembly of central auditory circuits remains poorly understood. The auditory midbrain, or inferior colliculus (IC) is an intriguing structure for exploring guidance of patterned projections as adjacent subdivisions exhibit distinct organizational features. The central nucleus of the IC (CNIC) and deep aspects of its neighboring lateral cortex (LCIC, Layer 3) are tonotopically-organized and receive layered inputs from primarily downstream auditor...
Source: Hearing Research - February 20, 2016 Category: Audiology Authors: Wallace MM, Harris JA, Brubaker DQ, Klotz CA, Gabriele ML Tags: Hear Res Source Type: research

Can place-specific cochlear dispersion be represented by auditory steady-state responses?
Abstract The present study investigated to what extent properties of local cochlear dispersion can be objectively assessed through auditory steady-state responses (ASSR). The hypothesis was that stimuli compensating for the phase response at a particular cochlear location generate a maximally modulated basilar membrane (BM) response at that BM position, due to the large "within-channel" synchrony of activity. This, in turn, leads to a larger ASSR amplitude than other stimuli of corresponding intensity and bandwidth. Two stimulus types were chosen: 1] Harmonic tone complexes consisting of equal-amplitude ...
Source: Hearing Research - February 20, 2016 Category: Audiology Authors: Gallardo AP, Epp B, Dau T Tags: Hear Res Source Type: research

Anatomical and physiological development of the human inner ear.
We describe the development of the human inner ear with the invagination of the otic vesicle at 4 weeks gestation (WG), the growth of the semicircular canals from 5 WG, and the elongation and coiling of the cochlea at 10 WG. As the membranous labyrinth takes shape, there is a concomitant development of the sensory neuroepithelia and their associated structures within. This review details the growth and differentiation of the vestibular and auditory neuroepithelia, including synaptogenesis, the expression of stereocilia and kinocilia, and innervation of hair cells by afferent and efferent nerve fibres. Along with developmen...
Source: Hearing Research - February 18, 2016 Category: Audiology Authors: Lim R, Brichta AM Tags: Hear Res Source Type: research

Musical experience sharpens human cochlear tuning.
Abstract The mammalian cochlea functions as a filter bank that performs a spectral, Fourier-like decomposition on the acoustic signal. While tuning can be compromised (e.g., broadened with hearing impairment), whether or not human cochlear frequency resolution can be sharpened through experiential factors (e.g., training or learning) has not yet been established. Previous studies have demonstrated sharper psychophysical tuning curves in trained musicians compared to nonmusicians, implying superior peripheral tuning. However, these findings are based on perceptual masking paradigms, and reflect engagement of the en...
Source: Hearing Research - February 18, 2016 Category: Audiology Authors: Bidelman GM, Nelms C, Bhagat SP Tags: Hear Res Source Type: research

Functional magnetic resonance imaging confirms forward suppression for rapidly alternating sounds in human auditory cortex but not in the inferior colliculus.
Abstract Forward suppression at the level of the auditory cortex has been suggested to subserve auditory stream segregation. Recent results in non-streaming stimulation contexts have indicated that forward suppression can also be observed in the inferior colliculus; whether this holds for streaming-related contexts remains unclear. Here, we used cardiac-gated fMRI to examine forward suppression in the inferior colliculus (and the rest of the human auditory pathway) in response to canonical streaming stimuli (rapid tone sequences comprised of either one repetitive tone or two alternating tones). The first stimulus ...
Source: Hearing Research - February 17, 2016 Category: Audiology Authors: Uhlig CH, Dykstra AR, Gutschalk A Tags: Hear Res Source Type: research

Vestibular function is associated with residual low-frequency hearing loss in patients with bi-allelic mutations in the SLC26A4 gene.
In conclusion, DFNB4 shows vestibular dysfunction, which is strongly linked to hearing loss at low frequencies without any allelic or anatomical predisposing factor. PMID: 26900070 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - February 17, 2016 Category: Audiology Authors: Jung J, Seo YW, Choi JY, Kim SH Tags: Hear Res Source Type: research

Reply to: Psychometric properties of the Tinnitus Functional Index (TFI): Assessment in a UK research volunteer population.
PMID: 26900071 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - February 17, 2016 Category: Audiology Authors: Folmer RL Tags: Hear Res Source Type: research

Morphology and microchemistry of the otoliths of the inner ear of anuran larvae.
Morphology and microchemistry of the otoliths of the inner ear of anuran larvae. Hear Res. 2016 Feb 16; Authors: Bassó A, Peltzer PM, Lajmanovich RC, Attademo AM, Junges CM, Chialvo DR Abstract To navigate in space most vertebrates need precise positional cues provided by a variety of sensors, including structures in the inner ear, which are exquisitely sensitive to gravity and linear acceleration. Although these structures have been described in many vertebrates, no information is available for anuran larvae. The purpose of our study was to describe, for the first time, the size, complexi...
Source: Hearing Research - February 16, 2016 Category: Audiology Authors: BassĂł A, Peltzer PM, Lajmanovich RC, Attademo AM, Junges CM, Chialvo DR Tags: Hear Res Source Type: research

Electrode array-eluted dexamethasone protects against electrode insertion trauma induced hearing and hair cell losses, damage to neural elements, increases in impedance and fibrosis: A dose response study.
In conclusion, DXMb eluting electrodes protected the cochlea against long term increases in hearing thresholds, loss of hair cells, damage to neural elements and increases in impedance and fibrosis that result from EIT-initiated damage. The protection achieved by DXMb-eluting electrodes was dose dependent. Establishing a significant level of trauma induced elevation in hearing thresholds was important for the determination of the otoprotective effects of array-eluted DXMb. PMID: 26892906 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - February 15, 2016 Category: Audiology Authors: Bas E, Bohorquez J, Goncalves S, Perez E, Dinh CT, Garnham C, Hessler R, Eshraghi AA, Van De Water TR Tags: Hear Res Source Type: research

Functional near-infrared spectroscopy for neuroimaging in cochlear implant recipients.
Abstract Functional neuroimaging can provide insight into the neurobiological factors that contribute to the variations in individual hearing outcomes following cochlear implantation. To date, measuring neural activity within the auditory cortex of cochlear implant (CI) recipients has been challenging, primarily because the use of traditional neuroimaging techniques is limited in people with CIs. Functional near-infrared spectroscopy (fNIRS) is an emerging technology that offers benefits in this population because it is non-invasive, compatible with CI devices, and not subject to electrical artifacts. However, the...
Source: Hearing Research - February 13, 2016 Category: Audiology Authors: Saliba J, Bortfeld H, Levitin DJ, Oghalai JS Tags: Hear Res Source Type: research

Response of the human tympanic membrane to transient acoustic and mechanical stimuli.
Abstract The response of the tympanic membrane (TM) to transient environmental sounds and the contributions of different parts of the TM to middle-ear sound transmission were investigated by measuring the TM response to global transients (acoustic clicks) and to local transients (mechanical impulses) applied to the umbo and various locations on the TM. A lightly-fixed human temporal bone was prepared by removing the ear canal, inner ear, and stapes, leaving the incus, malleus, and TM intact. Motion of nearly the entire TM was measured by a digital holography system with a high speed camera at a rate of 42 000 fram...
Source: Hearing Research - February 12, 2016 Category: Audiology Authors: Razavi P, Ravicz ME, Dobrev I, Cheng JT, Furlong C, Rosowski JJ Tags: Hear Res Source Type: research

Sensitivity of the Cochlear Nerve to Acoustic and Electrical Stimulation Months After a Vestibular Labyrinthectomy in Guinea Pigs.
Abstract Single-sided deafness patients are now being considered candidates to receive a cochlear implant. With this, many people who have undergone a unilateral vestibular labyrinthectomy for the treatment of chronic vertigo are now being considered for cochlear implantation. There is still some concern regarding the potential efficacy of cochlear implants in these patients, where factors such as cochlear fibrosis or nerve degeneration following unilateral vestibular labyrinthectomy may preclude their use. Here, we have performed a unilateral vestibular labyrinthectomy in normally hearing guinea pigs, and allowed...
Source: Hearing Research - February 9, 2016 Category: Audiology Authors: Brown DJ, Mukherjee P, Pastras C, Gibson WP, Curthoys IS Tags: Hear Res Source Type: research

The role of connectivity and stochastic osteocyte behavior in the distribution of perilabyrinthine bone degeneration. A Monte Carlo based simulation study.
en MS Abstract Previous studies of undecalcified temporal bones labeled with fluorescent tissue time markers and basic fuchsine have documented the unique spatial and temporal patterns underlying inner ear bone development, morphology and degeneration, and has led to the identification of inner ear OPG as the candidate inhibiter of perilabyrinthine bone resorption. Resulting age related excessive matrix microdamage, osteocyte death and degeneration of the OPG signaling pathway is expected to trigger bone remodeling in the otic capsule, but when this happens the morphology of the remodeling bone is abnormal and the...
Source: Hearing Research - February 9, 2016 Category: Audiology Authors: Bloch SL, Sørensen MS Tags: Hear Res Source Type: research

HEI-OC1 Cells as a Model for Investigating Prestin Function.
Abstract The House Ear Institute-Organ of Corti 1 (HEI-OC1) is a mouse auditory cell line that endogenously express, among other several markers of cochlear hair cells, the motor protein prestin (SLC26A5). Since its discovery fifteen years ago, and because of the difficulties associated with working with outer hair cells, prestin studies have been performed mostly by expressing it exogenously in non-specific systems such as HEK293 and TSA201, embryonic kidney cells from human origin, or Chinese Hamster Ovary (CHO) cells. Here, we report flow cytometry and confocal laser scanning microscopy studies on the pattern o...
Source: Hearing Research - February 5, 2016 Category: Audiology Authors: Park C, Thein P, Kalinec G, Kalinec F Tags: Hear Res Source Type: research

A next-generation sequencing gene panel (MiamiOtoGenes) for comprehensive analysis of deafness genes.
Abstract Extreme genetic heterogeneity along with remarkable variation in the distribution of causative variants across in different ethnicities makes single gene testing inefficient for hearing loss. We developed a custom capture/next-generation sequencing gene panel of 146 known deafness genes with a total target size of approximately 1 MB. The genes were identified by searching databases including Hereditary Hearing Loss Homepage, the Human Genome Mutation Database (HGMD), Online Mendelian Inheritance in Man (OMIM) and most recent peer-reviewed publications related to the genetics of deafness. The design c...
Source: Hearing Research - February 2, 2016 Category: Audiology Authors: Tekin D, Yan D, Bademci G, Feng Y, Guo S, Foster J, Blanton S, Tekin M, Liu X Tags: Hear Res Source Type: research

Indication of Direct Acoustical Cochlea Stimulation in Comparison to Cochlear Implants.
r H Abstract The new implantable hearing system Codacs™ was designed to close the treatment gap between active middle ear implants and cochlear implants in cases of severe-to-profound mixed hearing loss. The Codacs™ actuator is attached to conventional stapes prosthesis during the implantation and thereby provides acoustical stimulation through a stapedotomy to the cochlea. Cochlear implants (CIs) on the other hand are an established treatment option for profoundly deaf patients including mixed hearing losses that are possible candidates for the Codacs™. In this retrospective study, we compared t...
Source: Hearing Research - January 30, 2016 Category: Audiology Authors: Kludt E, BĂĽchner A, Schwab B, Lenarz T, Maier H Tags: Hear Res Source Type: research

Channeling Your Inner Ear Potassium: K(+) Channels in Vestibular Hair Cells.
Abstract During development of vestibular hair cells, K(+) conductances are acquired in a specific pattern. Functionally mature vestibular hair cells express different complements of K(+) channels which uniquely shape the hair cell receptor potential and filtering properties. In amniote species, type I hair cells (HCI) have a large input conductance due to a ubiquitous low-voltage-activated K(+) current that activates with slow sigmoidal kinetics at voltages negative to the membrane resting potential. In contrast type II hair cells (HCII) from mammalian and non-mammalian species have voltage-dependent outward K(+)...
Source: Hearing Research - January 30, 2016 Category: Audiology Authors: Meredith FL, Rennie KJ Tags: Hear Res Source Type: research

Bilateral cochlear implants in children: Effects of auditory experience and deprivation on auditory perception.
Abstract Spatial hearing skills are essential for children as they grow, learn and play. They provide critical cues for determining the locations of sources in the environment, and enable segregation of important sources, such as speech, from background maskers or interferers. Spatial hearing depends on availability of monaural cues and binaural cues. The latter result from integration of inputs arriving at the two ears from sounds that vary in location. The binaural system has exquisite mechanisms for capturing differences between the ears in both time of arrival and intensity. The major cues that are thus referr...
Source: Hearing Research - January 29, 2016 Category: Audiology Authors: Litovsky RY, Gordon K Tags: Hear Res Source Type: research

Decoding four different sound-categories in the auditory cortex using functional near-infrared spectroscopy.
This study investigated whether activations in the auditory cortex caused by different sounds can be distinguished using functional near-infrared spectroscopy (fNIRS). The hemodynamic responses (HRs) in both hemispheres using fNIRS were measured in 18 subjects while exposing them to four sound categories (English-speech, non-English-speech, annoying sounds, and nature sounds). As features for classifying the different signals, the mean, slope, and skewness of the oxy-hemoglobin (HbO) signal were used. With regard to the language-related stimuli, the HRs evoked by understandable speech (English) were observed in a broader b...
Source: Hearing Research - January 29, 2016 Category: Audiology Authors: Hong KS, Santosa H Tags: Hear Res Source Type: research

3D morphometric analysis of the human incudomallear complex using clinical cone-beam CT.
We present statistical shape analysis based on clinical cone beam CT (CBCT) scans of 100 patients. This allowed us to include surface information on the incudomallear (IM) complex (joint, ligaments and tendon not included) of 123 healthy ears with a scanning resolution of 150 μm and without a priori assumptions. Statistical shape modeling yields an average geometry for the IM complex and the variations present in the population with a high precision. Mean values, variation and correlations among anatomical features (length of manubrium, combined length of malleus head and neck, lengths of incus long and short process, e...
Source: Hearing Research - January 27, 2016 Category: Audiology Authors: Soons JA, Danckaers F, Keustermans W, Huysmans T, Sijbers J, Casselman JW, Dirckx JJ Tags: Hear Res Source Type: research

Effects of auditory enhancement on the loudness of masker and target components.
Abstract Auditory enhancement refers to the observation that the salience of one spectral region (the "signal") of a broadband sound can be enhanced and can "pop out" from the remainder of the sound (the "masker") if it is preceded by the broadband sound without the signal. The present study investigated auditory enhancement as an effective change in loudness, to determine whether it reflects a change in the loudness of the signal, the masker, or both. In the first experiment, the 500-ms precursor, an inharmonic complex with logarithmically spaced components, was followed after a 50-m...
Source: Hearing Research - January 22, 2016 Category: Audiology Authors: Wang N, Oxenham AJ Tags: Hear Res Source Type: research

Interaction between osseous and non-osseous vibratory stimulation of the human cadaveric head.
l;sli C Abstract Bone conduction (BC) stimulation can be applied by vibration to the bony or skin covered skull (osseous BC), or on soft tissue such as the neck (non-osseous BC). The interaction between osseous and non-osseous bone conduction pathways is assessed in this study. The relation between bone vibrations measured at the cochlear promontory and the intracranial sound pressure for stimulation directly on the dura and for stimulation at the mastoid between 0.2 - 10 kHz was compared. First, for stimulation on the dura, varying the static coupling force of the BC transducer on the dura had only a small effect...
Source: Hearing Research - January 22, 2016 Category: Audiology Authors: Sim JH, Dobrev I, Gerig R, Pfiffner F, Stenfelt S, Huber AM, Röösli C Tags: Hear Res Source Type: research

Mechanical Damage of Tympanic Membrane in Relation to Impulse Pressure Waveform - A Study in Chinchillas.
Abstract Mechanical damage to middle ear components in blast exposure directly causes hearing loss, and the rupture of the tympanic membrane (TM) is the most frequent injury of the ear. However, it is unclear how the severity of injury graded by different patterns of TM rupture is related to the overpressure waveforms induced by blast waves. In the present study, the relationship between the TM rupture threshold and the impulse or overpressure waveform has been investigated in chinchillas. Two groups of animals were exposed to blast overpressure simulated in our lab under two conditions: open field and shielded wi...
Source: Hearing Research - January 22, 2016 Category: Audiology Authors: Gan RZ, Nakmali D, Ji XD, Leckness K, Yokell Z Tags: Hear Res Source Type: research

Comparison of Mouse Minimum Audible Angle Determined in Prepulse Inhibition and Operant Conditioning Procedures.
Abstract Both reward based operant conditioning (OC) and reflex-based prepulse inhibition (PPI) procedures are used in sound localisation studies in mice. Since the results of both procedures are compared in the literature, it is important to assess whether they provide similar results if the same stimulus paradigm is applied. Here, we compare the sensitivity of C57BL/6 mice in OC and PPI procedures for detecting a switch in speaker location using broadband and narrowband noise stimuli and determined their minimum audible angle (MAA). In the OC procedure, we calculated d' values from the hit and false alarm rates....
Source: Hearing Research - January 22, 2016 Category: Audiology Authors: Behrens D, Klump GM Tags: Hear Res Source Type: research

Pathophysiology of the cochlear intrastrial fluid-blood barrier (review).
Abstract The blood-labyrinth barrier (BLB) in the stria vascularis is a highly specialized capillary network that controls exchanges between blood and the intrastitial space in the cochlea. The barrier shields the inner ear from blood-born toxic substances and selectively passes ions, fluids, and nutrients to the cochlea, playing an essential role in the maintenance of cochlear homeostasis. Anatomically, the BLB is comprised of endothelial cells (ECs) in the strial microvasculature, elaborated tight and adherens junctions, pericytes (PCs), basement membrane (BM), and perivascular resident macrophage-like melanocyt...
Source: Hearing Research - January 20, 2016 Category: Audiology Authors: Shi X Tags: Hear Res Source Type: research

Prevalence and Audiological Profiles of GJB2 Mutations in a Large Collective of Hearing Impaired Patients.
In this study, a complete sequencing of the GJB2 gene in a cohort of 506 patients from a single, large cochlear implant program in Europe was performed. Audiological testing for those patients who could actively participate was performed using pure tone audiometry (PTA). Those unable to undergo PTA were measured using click-auditory brainstem response (ABR). Data analysis was performed to determine genotype-phenotype correlations of the mutational status vs. audiological profiles and vs. age at the time of presentation. An overall prevalence of biallelic mutations of 13.4 % was found for the total collective. When subsets ...
Source: Hearing Research - January 14, 2016 Category: Audiology Authors: Burke WF, Warnecke A, Schöner-Heinisch A, Lesinski-Schiedat A, Maier H, Lenarz T Tags: Hear Res Source Type: research

Temperature Sensitive Auditory Neuropathy.
Abstract Temperature sensitive auditory neuropathy is a very rare and puzzling disorder. In the present study, we reported three unrelated 2 to 6 year-old children who were diagnosed as auditory neuropathy patients who complained of severe hearing loss when they had fever. Their hearing thresholds varied from the morning to the afternoon. Two of these patients' hearing improved with age, and one patient received positive results from cochlear implant. Genetic analysis revealed that these three patients had otoferlin (OTOF) homozygous or compound heterozygous mutations with the genotypes c.2975_2978delAG/c.4819C>...
Source: Hearing Research - January 14, 2016 Category: Audiology Authors: Zhang Q, Lan L, Shi W, Yu L, Xie LY, Xiong F, Zhao C, Li N, Yin Z, Zong L, Guan J, Wang D, Sun W, Wang Q Tags: Hear Res Source Type: research

Auditory intensity processing: Effect of MRI background noise.
Abstract Studies on active auditory intensity discrimination in humans showed equivocal results regarding the lateralization of processing. Whereas experiments with a moderate background found evidence for right lateralized processing of intensity, functional magnetic resonance imaging (fMRI) studies with background scanner noise suggest more left lateralized processing. With the present fMRI study, we compared the task dependent lateralization of intensity processing between a conventional continuous echo planar imaging (EPI) sequence with a loud background scanner noise and a fast low-angle shot (FLASH) sequence...
Source: Hearing Research - January 14, 2016 Category: Audiology Authors: Angenstein N, Stadler J, Brechmann A Tags: Hear Res Source Type: research

A Neural-Based Vocoder Implementation for Evaluating Cochlear Implant Coding Strategies.
Abstract Most simulations of cochlear implant (CI) coding strategies rely on standard vocoders that are based on purely signal processing techniques. However, these models neither account for various biophysical phenomena, such as neural stochasticity and refractoriness, nor for effects of electrical stimulation, such as spectral smearing as a function of stimulus intensity. In this paper, a neural model that accounts for stochastic firing, parasitic spread of excitation across neuron populations, and neuronal refractoriness, was developed and augmented as a preprocessing stage for a standard 22-channel noise-band...
Source: Hearing Research - January 13, 2016 Category: Audiology Authors: El Boghdady N, Kegel A, Lai WK, Dillier N Tags: Hear Res Source Type: research

A 3D-printed functioning anatomical human middle ear model.
TC Abstract The middle ear is a sophisticated and complex structure with a variety of functions, yet a delicate organ prone to injuries due to various reasons. Both, understanding and reconstructing its functions has always been an important topic for researchers from medical and technical background. Currently, human temporal bones are generally used as model for tests, experiments and validation of the numerical results. However, fresh human preparations are not always easily accessible and their mechanical properties vary with time and between individuals. Therefore we have built an anatomically based and func...
Source: Hearing Research - January 7, 2016 Category: Audiology Authors: Kuru I, Maier H, MĂĽller M, Lenarz T, Lueth TC Tags: Hear Res Source Type: research

The hippocampus may be more susceptible to environmental noise than the auditory cortex.
Abstract Noise exposure can cause structural and functional problem in the auditory cortex (AC) and hippocampus, the two brain regions in the auditory and non-auditory systems respectively. The aim of the present study was to explore which one of these two brain regions may be more susceptible to environmental noise. The AC and hippocampus of mice were separated following 1 or 3 weeks exposure to moderate noise (80 dB SPL, 2 h/day). The levels of oxidative stress and tau phosphorylation were then measured to evaluate the effects by noise. Results showed significant peroxidation and tau hyperphosphorylati...
Source: Hearing Research - January 7, 2016 Category: Audiology Authors: Cheng L, Wang SH, Huang Y, Liao XM Tags: Hear Res Source Type: research

Auditory and visual 3D virtual reality therapy as a new treatment for chronic subjective tinnitus: results of a randomized controlled trial.
CONCLUSION: VR appears to be at least as effective as CBT in unilateral ST patients. PMID: 26773752 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - January 7, 2016 Category: Audiology Authors: Malinvaud D, Londero A, Niarra R, Peignard P, Warusfel O, Viaud-Delmon I, Chatellier G, Bonfils P Tags: Hear Res Source Type: research

English vowel identification and vowel formant discrimination by native Mandarin Chinese- and native English-speaking listeners: the effect of vowel duration dependence.
This study revealed individual variability in using multiple acoustic cues to identify English vowels for both native and non-native listeners. PMID: 26768853 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - January 5, 2016 Category: Audiology Authors: Mi L, Tao S, Wang W, Dong Q, Guan J, Liu C Tags: Hear Res Source Type: research

Delayed low frequency hearing loss caused by cochlear implantation interventions via the round window but not cochleostomy.
This study tested whether this "delayed" hearing loss was influenced by the route of electrode array insertion and/or position of the electrode array within scala tympani in a guinea pig model of cochlear implantation. Five treatment groups were monitored over 12 weeks: (1) round window implant; (2) round window incised with no implant; (3) cochleostomy with medially-oriented implant; (4) cochleostomy with laterally-oriented implant; and (5) cochleostomy with no implant. Hearing was measured at selected time points by the auditory brainstem response. Cochlear condition was assessed histologically, with cochleae t...
Source: Hearing Research - December 29, 2015 Category: Audiology Authors: Rowe D, Chambers S, Hampson A, Eastwood H, Campbell L, O'Leary S Tags: Hear Res Source Type: research