Cortical cross-modal plasticity following deafness measured using functional near-infrared spectroscopy.
Abstract Evidence from functional neuroimaging studies suggests that the auditory cortex can become more responsive to visual and somatosensory stimulation following deafness, and that this occurs predominately in the right hemisphere. Extensive cross-modal plasticity in prospective cochlear implant recipients is correlated with poor speech outcomes following implantation, highlighting the potential impact of central auditory plasticity on subsequent aural rehabilitation. Conversely, the effects of hearing restoration with a cochlear implant on cortical plasticity are less well understood, since the use of most ne...
Source: Hearing Research - March 24, 2015 Category: Audiology Authors: Dewey RS, Hartley DE Tags: Hear Res Source Type: research

A novel method for selectively labelling olivocochlear collaterals in the rat.
Abstract Axons of olivocochlear neurons originate from the brainstem and project to the cochlea. A subpopulation, medial olivocochlear (MOC) neurons, also projects collateral branches to the cochlear nucleus. The precise targets of these collaterals are as yet unknown. Previous methods for labelling these collaterals include firstly, cochlear injections of retrograde tracers, but this is technically demanding and can also label afferent projections or secondly, labelling by injecting tracers into the nuclei of origin of MOC neurons. However, this latter method is non-specific because it also labels non-MOC project...
Source: Hearing Research - March 23, 2015 Category: Audiology Authors: Baashar A, Robertson D, Mulders WH Tags: Hear Res Source Type: research

Biomark as electrophysiological tool for assessing children at risk for (central) auditory processing disorders without reading deficits.
Abstract Biological Marker of auditory processing (BioMARK) is an electrophysiological test tool widely known as Speech-evoked ABR. Several previous investigations have shown the utility of speech-evoked ABR in the diagnosis of language based processing deficits like learning disability and specific language impairment; however missing from literature is a study that has ruled out the existence of comorbidity of such conditions and carefully delineated the efficacy of speech-evoked ABR in children with children with auditory processing disorders sans reading deficits. Hence, the present study aimed at investigatin...
Source: Hearing Research - March 21, 2015 Category: Audiology Authors: Kumar P, Singh NK Tags: Hear Res Source Type: research

Infrared neural stimulation fails to evoke neural activity in the deaf guinea pig cochlea.
Abstract At present there is some debate as to the processes by which infrared neural stimulation (INS) activates neurons in the cochlea, as the lasers used for INS can potentially generate a range of secondary stimuli e.g. an acoustic stimulus is produced when the light is absorbed by water. To clarify whether INS in the cochlea requires functioning hair cells and to explore the potential relevance to cochlear implants, experiments using INS were performed in the cochleae of both normal hearing and profoundly deaf guinea pigs. A response to laser stimulation was readily evoked in normal hearing cochlea. However, ...
Source: Hearing Research - March 18, 2015 Category: Audiology Authors: Thompson AC, Fallon JB, Wise AK, Wade SA, Shepherd RK, Stoddart PR Tags: Hear Res Source Type: research

Aminoglycoside ototoxicity and hair cell ablation in the adult gerbil: a simple model to study hair cell loss and regeneration.
Abstract The Mongolian gerbil, Meriones unguiculatus, has been widely employed as a model for studies of the inner ear. In spite of its established use for auditory research, no robust protocols to induce ototoxic hair cell damage have been developed for this species. In this paper, we demonstrate the development of an aminoglycoside-induced model of hair cell loss, using kanamycin potentiated by the loop diuretic furosemide. Interestingly, we show that the gerbil is relatively insensitive to gentamicin compared to kanamycin, and that bumetanide is ineffective in potentiating the ototoxicity of the drug. We also e...
Source: Hearing Research - March 14, 2015 Category: Audiology Authors: Abbas L, Rivolta MN Tags: Hear Res Source Type: research

Binaural interaction in human auditory brainstem response compared for tone-pips and rectangular clicks under conditions of auditory and visual attention.
Abstract Binaural interaction in the auditory brainstem response (ABR) represents the discrepancy between the binaural waveform and the sum of monaural ones. A typical ABR binaural interaction in humans is a reduction of the binaural amplitude compared to the monaural sum at the wave-V latency, i.e., the DN1 component. It has been considered that the DN1 is mainly elicited by high frequency components of stimuli whereas some studies have shown the contribution of low-to-middle frequency components to the DN1. To examine this issue, the present study compared the ABR binaural interaction elicited by tone pips (1 kH...
Source: Hearing Research - March 13, 2015 Category: Audiology Authors: Ikeda K Tags: Hear Res Source Type: research

High-field fMRI reveals tonotopically-organized and core auditory cortex in the cat.
Abstract As frequency is one of the most basic elements of sound, it is not surprising that the earliest stages of auditory cortical processing are tonotopically organized. In cats, there are four known tonotopically organized cortical areas: the anterior (AAF), posterior (PAF), and ventral posterior (VPAF) auditory fields and primary auditory cortex (A1). Electrophysiological and anatomical evidence have suggested that AAF and A1 form core auditory cortex. The purpose of this investigation was to determine if high-field functional magnetic resonance imaging (fMRI) could be used to define the borders of all four t...
Source: Hearing Research - March 13, 2015 Category: Audiology Authors: Hall AJ, Lomber SG Tags: Hear Res Source Type: research

Synaptopathy in the noise-exposed and aging cochlea: primary neural degeneration in acquired sensorineural hearing loss.
Abstract The classic view of sensorineural hearing loss (SNHL) is that the "primary" targets are hair cells, and that cochlear-nerve loss is "secondary" to hair cell degeneration. Our recent work in mouse and guinea pig has challenged that view. In noise-induced hearing loss, exposures causing only reversible threshold shifts (and no hair cell loss) nevertheless cause permanent loss of>50% of cochlear-nerve / hair-cell synapses. Similarly, in age-related hearing loss, degeneration of cochlear synapses precedes both hair cell loss and threshold elevation. This primary neural degeneration has ...
Source: Hearing Research - March 10, 2015 Category: Audiology Authors: Kujawa SG, Liberman MC Tags: Hear Res Source Type: research

Neural Processing of Auditory Signals in the Time Domain: Delay-Tuned Coincidence Detectors in the Mustached Bat.
Abstract The central auditory system produces combination-sensitive neurons tuned to a specific combination of multiple signal elements. Some of these neurons act as coincidence detectors with delay lines for the extraction of spectro-temporal information from sounds. "Delay-tuned" neurons of mustached bats are tuned to a combination of up to four signal elements with a specific delay between them and form a delay map. They are produced in the inferior colliculus by the coincidence of the rebound response following glycinergic inhibition to the first harmonic of a biosonar pulse with the short-latency re...
Source: Hearing Research - March 6, 2015 Category: Audiology Authors: Suga N Tags: Hear Res Source Type: research

Assessing Temporal Modulation Sensitivity Using Electrically Evoked Auditory Steady State Responses.
In this study we evaluate the use of EASSRs as a tool for assessing temporal modulation sensitivity. Modulation sensitivity was assessed behaviourally using modulation detection thresholds (MDTs) for a 20 Hz rate. On the same stimulation sites, EASSRS were measured using sinusoidally amplitude modulated pulse trains at 4 and 40 Hz. Measurements were taken using a bipolar configuration on 12 electrode pairs over 5 participants. Results showed that EASSR amplitudes and signal-to-noise ratios (SNRs) were significantly related to the MDTs. Larger EASSRs corresponded with sites of improved modulation sensitivity. This relation ...
Source: Hearing Research - March 5, 2015 Category: Audiology Authors: Luke R, Van Deun L, Hofmann M, van Wieringen A, Wouters J Tags: Hear Res Source Type: research

Modulation frequency discrimination with single and multiple channels in cochlear implant users.
In this study, single- and multi-channel AMFD thresholds were measured in CI users. Multi-channel component electrodes were either widely or narrowly spaced to vary the degree of overlap between neural populations. The reference amplitude modulation (AM) frequency was 100 Hz, and coherent modulation was applied to all channels. In Experiment 1, single- and multi-channel AMFD thresholds were measured at similar loudness. In this case, current levels on component channels were higher for single-than for multi-channel AM stimuli, and the modulation depth was approximately 100% of the perceptual dynamic range (i.e., between th...
Source: Hearing Research - March 5, 2015 Category: Audiology Authors: Galvin JJ, Oba S, Başkent D, Fu QJ Tags: Hear Res Source Type: research

Audio-vocal responses of vocal fundamental frequency and formant during sustained vowel vocalizations in different noises.
Abstract Sustained vocalizations of vowels [a], [i], and syllable [mə] were collected in twenty normal-hearing individuals. On vocalizations, five conditions of different audio-vocal feedback were introduced separately to the speakers including no masking, wearing supra-aural headphones only, speech-noise masking, high-pass noise masking, and broad-band-noise masking. Power spectral analysis of vocal fundamental frequency (F0) was used to evaluate the modulations of F0 and linear-predictive-coding was used to acquire first two formants. The results showed that while the formant frequencies were not significantly ...
Source: Hearing Research - March 4, 2015 Category: Audiology Authors: Lee SH, Hsiao TY, Lee GS Tags: Hear Res Source Type: research

The pupil response reveals increased listening effort when it is difficult to focus attention.
Abstract Recent studies have shown that prior knowledge about where, when, and who is going to talk improves speech intelligibility. How related attentional processes affect cognitive processing load has not been investigated yet. In the current study, three experiments investigated how the pupil dilation response is affected by prior knowledge of target speech location, target speech onset, and who is going to talk. A total of 56 young adults with normal hearing participated. They had to reproduce a target sentence presented to one ear while ignoring a distracting sentence simultaneously presented to the other ea...
Source: Hearing Research - February 27, 2015 Category: Audiology Authors: Koelewijn T, de Kluiver H, Shinn-Cunningham BG, Zekveld AA, Kramer SE Tags: Hear Res Source Type: research

Neural representation of dynamic frequency is degraded in older adults.
Abstract Older adults, even with clinically normal hearing sensitivity, often report difficulty understanding speech in the presence of background noise. Part of this difficulty may be related to age-related degradations in the neural representation of speech sounds, such as formant transitions. Frequency-following responses (FFRs), which are dependent on phase-locked neural activity, were elicited using sounds consisting of linear frequency sweeps, which may be viewed as simple models of formant transitions. Eighteen adults (ten younger, 22 - 24 years old, and nine older, 51 - 67 years old) were tested. FFRs were...
Source: Hearing Research - February 24, 2015 Category: Audiology Authors: Clinard CG, Cotter CM Tags: Hear Res Source Type: research

Electrocochleographic findings in superior canal dehiscence syndrome.
This study evaluated the electrocochleographic findings of patients with superior canal dehiscence (SCD) syndrome and determined their diagnostic values and relationships with audiometric parameters. Thirteen symptomatic SCD patients (1 bilateral) confirmed by temporal bone computed tomography (TBCT) and cervical vestibular evoked myogenic potentials (cVEMP) were recruited. SCD sizes were measured on reformatted images in the plane of the superior canal (SC). Results of audiologic tests (audiometry, cVEMP, electrocochleography (ECoG)) for 14 affected and 12 contralateral unaffected ears were evaluated. Relationships betwee...
Source: Hearing Research - February 12, 2015 Category: Audiology Authors: Park JH, Lee SY, Song JJ, Choi BY, Koo JW Tags: Hear Res Source Type: research

Forward acoustic masking enhances the auditory brainstem response in a diotic, but not dichotic, paradigm in salicylate-induced tinnitus.
Abstract We recently reported that forward acoustic masking can enhance the auditory brainstem response (ABR) in rats treated with a high dose of sodium salicylate (NaSal), a tinnitus inducer, when tested in open acoustic field (Liu & Chen, 2012, Brain Research 1485, 88-94). In the present study, we first replicated this experiment in closed acoustic field under two conditions: (1) the forward masker and the probe were presented to both ears (diotic paradigm); (2) the forward masker was presented to one ear and the probe to the other ear (dichotic paradigm). We found that only when the stimuli were presented b...
Source: Hearing Research - February 7, 2015 Category: Audiology Authors: Liu XP, Chen L Tags: Hear Res Source Type: research

Human cortical sensitivity to interaural time difference in high-frequency sounds.
In conclusion, our findings show that the human auditory cortex is sensitive to ITD in the envelope of high-frequency sounds and this sensitivity may have behavioral relevance. PMID: 25668126 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - February 7, 2015 Category: Audiology Authors: Salminen NH, Altoè A, Takanen M, Santala O, Pulkki V Tags: Hear Res Source Type: research

Multichannel recordings of the human brainstem frequency-following response: Scalp topography, source generators, and distinctions from the transient ABR.
Abstract Brainstem frequency-following responses (FFRs) probe the neural transcription of speech/music, auditory disorders, and plasticity in subcortical auditory function. Despite clinical and empirical interest, the response's neural basis remains poorly understood. The current study aimed to more fully characterize functional properties of the human FFR (topography, source locations, generation). Speech-evoked FFRs were recorded using a high-density (64 channel) electrode montage. Source dipole modeling and 3-channel Lissajous analysis was used to localize the most likely FFR generators and their orientation tr...
Source: Hearing Research - February 5, 2015 Category: Audiology Authors: Bidelman GM Tags: Hear Res Source Type: research

Use of binaural and monaural cues to identify the lateral position of a virtual object using echoes.
Abstract Under certain conditions, sighted and blind humans can use echoes to discern characteristics of otherwise silent objects. Previous research concluded that robust horizontal-place object localisation ability, without using head movement, depends on information above 2 kHz. While a strong interaural level difference (ILD) cue is available, it was not clear if listeners were using that or the monaural level cue that necessarily accompanies ILD. In this experiment, 13 sighted and normal-hearing listeners were asked to identify the right-vs.-left position of an object in virtual auditory space. Sounds were man...
Source: Hearing Research - February 5, 2015 Category: Audiology Authors: Rowan D, Papadopoulos T, Edwards D, Allen R Tags: Hear Res Source Type: research

Diffusion tensor imaging of the auditory nerve in patients with long-term single-sided deafness.
Abstract A cochlear implant (CI) can restore hearing in patients with profound sensorineural hearing loss by direct electrical stimulation of the auditory nerve. Therefore, the viability of the auditory nerve is vitally important in successful hearing recovery. However, the nerve typically degenerates following cochlear hair cell loss, and the amount of degeneration may considerably differ between the two ears, also in patients with bilateral deafness. A measure that reflects the nerve's condition would help to assess the best of both nerves and decide accordingly which ear should be implanted for optimal benefit ...
Source: Hearing Research - February 2, 2015 Category: Audiology Authors: Vos SB, Haakma W, Versne H, Froeling M, Speleman L, Dik P, Viergever MA, Leemans A, Grolman W Tags: Hear Res Source Type: research

Deletion of Shank1 has minimal effects on the molecular composition and function of glutamatergic afferent postsynapses in the mouse inner ear.
Abstract Shank proteins (1-3) are considered the master organizers of glutamatergic postsynaptic densities in the central nervous system, and the genetic deletion of either Shank1, 2, or 3 results in altered composition, form, and strength of glutamatergic postsynapses. To investigate the contribution of Shank proteins to glutamatergic afferent synapses of the inner ear and especially cochlea, we used immunofluorescence and quantitative real time PCR to determine the expression of Shank1, 2, and 3 in the cochlea. Because we found evidence for expression of Shank1 but not 2 and 3, we investigated the morphology, co...
Source: Hearing Research - January 28, 2015 Category: Audiology Authors: Braude JP, Vijayakumar S, Baumgarner K, Laurine R, Jones TA, Jones SM, Pyott SJ Tags: Hear Res Source Type: research

Subcortical representation of musical dyads: individual differences and neural generators.
Abstract When two notes are played simultaneously they form a musical dyad. The sensation of pleasantness, or "consonance", of a dyad is likely driven by the harmonic relation of the frequency components of the combined spectrum of the two notes. Previous work has demonstrated a relation between individual preference for consonant over dissonant dyads, and the strength of neural temporal coding of the harmonicity of consonant relative to dissonant dyads as measured using the electrophysiological "frequency-following response" (FFR). However, this work also demonstrated that both these variables...
Source: Hearing Research - January 27, 2015 Category: Audiology Authors: Bones O, Plack CJ Tags: Hear Res Source Type: research

Efficacy and safety of N-acetylcysteine in prevention of noise induced hearing loss: A randomized clinical trial.
This study provides a prospective, randomized, double-blinded, placebo-controlled clinical trial investigating the safety profile and the efficacy of NAC to prevent hearing loss in a military population after weapons training. Of the 566 total study subjects, 277 received NAC while 289 were given placebo. The null hypothesis for the rate of STS was not rejected based on the measured results. While no significant differences were found for the primary outcome, rate of threshold shifts, the right ear threshold shift rate difference did approach significance (p = 0.0562). No significant difference was found in the s...
Source: Hearing Research - January 22, 2015 Category: Audiology Authors: Kopke R, Slade MD, Jackson R, Hammill T, Fausti S, Lonsbury-Martin B, Sanderson A, Dreisbach L, Rabinowitz P, Torre P, Balough B Tags: Hear Res Source Type: research

The verbal transformation effect and the perceptual organization of speech: Influence of formant transitions and F0-contour continuity.
This study explored the role of formant transitions and F0-contour continuity in binding together speech sounds into a coherent stream. Listening to a repeating recorded word produces verbal transformations to different forms; stream segregation contributes to this effect and so it can be used to measure changes in perceptual coherence. In experiment 1, monosyllables with strong formant transitions between the initial consonant and following vowel were monotonized; each monosyllable was paired with a weak-transitions counterpart. Further stimuli were derived by replacing the consonant-vowel transitions with samples from ad...
Source: Hearing Research - January 22, 2015 Category: Audiology Authors: Stachurski M, Summers RJ, Roberts B Tags: Hear Res Source Type: research

The regulation of gene expression in hair cells.
Abstract No genes have been discovered for which expression is limited only to inner ear hair cells. This is hardly surprising, since the number of mammalian genes is estimated to be 20-25,000, and each gene typically performs many tasks in various locations. Many genes are expressed in inner ear sensory cells and not in other cells of the labyrinth. However, these genes are also expressed in other locations, often in other sensory or neuronal cell types. How gene transcription is directed specifically to hair cells is unclear. Key transcription factors that act during development can specify cell phenotypes, and ...
Source: Hearing Research - January 20, 2015 Category: Audiology Authors: Ryan AF, Ikeda R, Masuda M Tags: Hear Res Source Type: research

Auditory Midbrain Implant: Research and Development Towards a Second Clinical Trial.
Abstract The cochlear implant is considered one of the most successful neural prostheses to date, which was made possible by visionaries who continued to develop the cochlear implant through multiple technological and clinical challenges. However, patients without a functional auditory nerve or implantable cochlea cannot benefit from a cochlear implant. The focus of the paper is to review the development and translation of a new type of central auditory prosthesis for this group of patients, which is known as the auditory midbrain implant (AMI) and is designed for electrical stimulation within the inferior collicu...
Source: Hearing Research - January 19, 2015 Category: Audiology Authors: Lim HH, Lenarz T Tags: Hear Res Source Type: research

Auditory deficits of Kcna1 deletion are similar to those of a monaural hearing impairment.
Abstract Kv1.1 subunits of low voltage-activated (Kv) potassium channels are encoded by the Kcna1 gene and crucially determine the synaptic integration window to control the number and temporal precision of action potentials in the auditory brainstem of mammals and birds. Prior electrophysiological studies showed that auditory signaling is compromised in monaural as well as in binaural neurons of the auditory brainstem in Kv1.1 knockout mice (Kcna1(-/-)). Here we examine the behavioral effects of Kcna1 deletion on sensory tasks dependent on either binaural processing (detecting the movement of a sound source acros...
Source: Hearing Research - January 17, 2015 Category: Audiology Authors: Karcz A, Allen PD, Walton J, Ison JR, Kopp-Scheinpflug C Tags: Hear Res Source Type: research

Considering optogenetic stimulation for cochlear implants.
This article is part of a Special Issue entitled . PMID: 25601298 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - January 16, 2015 Category: Audiology Authors: Jeschke M, Moser T Tags: Hear Res Source Type: research

Superior Temporal Resolution of Chronos versus Channelrhodopsin-2 in an Optogenetic Model of the Auditory Brainstem Implant.
Abstract Contemporary auditory brainstem implant (ABI) performance is limited by reliance on electrical neurostimulation with its accompanying channel cross talk and current spread to non-auditory neurons. A new generation ABI based on optogenetic-technology may ameliorate limitations fundamental to electrical stimulation. The most widely studied opsin is channelrhodopsin-2 (ChR2); however, its relatively slow kinetic properties may prevent the encoding of auditory information at high stimulation rates. In the present study, we compare to ChR2 the temporal resolution of light-evoked responses of a recently develop...
Source: Hearing Research - January 15, 2015 Category: Audiology Authors: Edward Hight A, Kozin ED, Darrow K, Lehmann A, Boyden E, Brown MC, Lee DJ Tags: Hear Res Source Type: research

Recovery characteristics of the electrically stimulated auditory nerve in deafened guinea pigs: Relation to neuronal status.
Abstract Successful cochlear implant performance requires adequate responsiveness of the auditory nerve to prolonged pulsatile electrical stimulation. Degeneration of the auditory nerve as a result of severe hair cell loss could considerably compromise this ability. The main objective of this study was to characterize the recovery of the electrically stimulated auditory nerve, as well as to evaluate possible changes caused by deafness-induced degeneration. To this end we studied temporal responsiveness of the auditory nerve in a guinea pig model of sensorineural hearing loss. Using masker-probe and pulse train par...
Source: Hearing Research - January 9, 2015 Category: Audiology Authors: Ramekers D, Versnel H, Strahl SB, Klis SF, Grolman W Tags: Hear Res Source Type: research

Comparison of the sensitivity of prepulse inhibition of the startle reflex and operant conditioning in an auditory intensity difference limen paradigm.
Abstract Reward-based operant conditioning (OC) procedures and reflex-based prepulse inhibition (PPI) procedures are used in mouse psychoacoustics. Therefore it is important to know whether both procedures provide comparable results for perceptual measurements. Here we evaluate the sensitivity of the C57BL/6N mouse in both procedures by testing the same individuals in the same Intensity Difference Limen (IDL(1)) task. Level increments of a 10 kHz tone were presented in a train of 10 kHz reference tones. Objective analysis based on signal-detection theory was applied to compare the results of OC and PPI p...
Source: Hearing Research - January 8, 2015 Category: Audiology Authors: Behrens D, Klump GM Tags: Hear Res Source Type: research

Perineuronal nets in the auditory system.
i M Abstract Perineuronal nets (PNs) are a unique and complex meshwork of specific extracellular matrix molecules that ensheath a subset of neurons in many regions of the central nervous system (CNS). PNs appear late in development and are supposed to restrict synaptic plasticity and to stabilize functional neuronal connections. PNs were further hypothesized to create a charged milieu around the neurons and thus, might directly modulate synaptic activity. Although PNs were first described more than 120 years ago, their exact functions still remain elusive. The purpose of the present review is to propose the nuclei...
Source: Hearing Research - January 8, 2015 Category: Audiology Authors: Sonntag M, Blosa M, Schmidt S, Rübsamen R, Morawski M Tags: Hear Res Source Type: research

Nanogrooved Surface-Patterns induce cellular organization and axonal outgrowth in neuron-like PC12-Cells.
In conclusion, surface nanopatterns have the potential to be utilized as an electrode modification for a stronger separation of cells, and can be used to direct cells towards the electrode contacts of cochlear implants. PMID: 25576787 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - January 7, 2015 Category: Audiology Authors: Klymov A, Rodrigues Neves CT, Riet JT, Agterberg MJ, Mylanus EA, Snik AF, Jansen JA, Walboomers XF Tags: Hear Res Source Type: research

Morphological and morphometric characterization of direct transdifferentiation of support cells into hair cells in ototoxin-exposed postnatal utricular explants.
Abstract We have studied aminoglycoside-induced vestibular hair-cell renewal using long-term culture of utricular macula explants from 4-day-old rats. Explanted utricles were exposed to 1 mM of gentamicin for 48 h, during 2(nd) and 3(rd) days in vitro (DIV), and then recovering in unsupplemented medium. Utricles were harvested at specified time points from the 2(nd) through the 28(th) DIV. The cellular events that occurred within hair cell epithelia during the culture period were documented from serial sectioned specimens. Vestibular hair cells (HCs) and supporting cells (SCs) were systematically counted using lig...
Source: Hearing Research - January 7, 2015 Category: Audiology Authors: Werner M, Van De Water TR, Hammarsten P, Arnoldsson G, Berggren D Tags: Hear Res Source Type: research

Usher syndrome: An effective sequencing approach to establish a genetic and clinical diagnosis.
Abstract Usher syndrome is an autosomal recessive disorder characterized by retinitis pigmentosa, sensorineural hearing loss and, in some cases, vestibular dysfunction. The disorder is clinically and genetically heterogeneous and, to date, mutations in 11 genes have been described. This finding makes difficult to get a precise molecular diagnosis and offer patients accurate genetic counselling. To overcome this problem and to increase our knowledge of the molecular basis of Usher syndrome, we designed a targeted resequencing custom panel. In a first validation step a series of 16 Italian patients with known molecu...
Source: Hearing Research - January 6, 2015 Category: Audiology Authors: Lenarduzzi S, Vozzi D, Morgan A, Rubinato E, D'Eustacchio A, Osland TM, Rossi C, Graziano C, Castorina P, Ambrosetti U, Morgutti M, Girotto G Tags: Hear Res Source Type: research

Cochlear implant users move in time to the beat of drum music.
Abstract Cochlear implant users show a profile of residual, yet poorly understood, musical abilities. An ability that has received little to no attention in this population is entrainment to a musical beat. We show for the first time that a heterogeneous group of cochlear implant users is able to find the beat and move their bodies in time to Latin Merengue music, especially when the music is presented in unpitched drum tones. These findings not only reveal a hidden capacity for feeling musical rhythm through the body in the deaf and hearing impaired population, but illuminate promising avenues for designing early...
Source: Hearing Research - January 6, 2015 Category: Audiology Authors: Phillips-Silver J, Toiviainen P, Gosselin N, Turgeon C, Lepore F, Peretz I Tags: Hear Res Source Type: research

Early UCSF Contributions to the Development of Multiple-Channel Cochlear Implants.
Abstract The early contributions of the UCSF cochlear implant (CI) research team to the development of multiple-channel cochlear implants from about 1971 through the mid-1980s are briefly summarized. Scientists at UCSF conducted fundamental studies related to device safety, the control of patterned electrical stimulation, and the designs of intracochlear electrode arrays, coders, and implanted multiple-channel electrode drivers. They conducted many original studies documenting parameters of hearing with cochlear implants relevant to next-generation CI designs. On these bases, the UCSF team constructed early models...
Source: Hearing Research - January 2, 2015 Category: Audiology Authors: Merzenich MM Tags: Hear Res Source Type: research

Unilateral spectral and temporal compression reduces binaural fusion for normal hearing listeners with cochlear implant simulations.
Abstract Patients with single sided deafness have recently begun receiving cochlear implants in their deaf ear. These patients gain a significant benefit from having a cochlear implant. However, despite this benefit, they are considerably slower to develop binaural abilities such as summation compared to bilateral cochlear implant patients. This suggests that these patients have difficulty fusing electric and acoustic signals. Although this may reflect inherent differences between electric and acoustic stimulation, it may also reflect properties of the processor and fitting system, which result in spectral and tem...
Source: Hearing Research - December 27, 2014 Category: Audiology Authors: Aronoff JM, Shayman C, Prasad A, Suneel D, Stelmach J Tags: Hear Res Source Type: research

Eye color as a risk factor for acquired sensorineural hearing loss: A review.
CONCLUSIONS: Eye color does not appear to play a role in hearing loss in non-exposed individuals or presbycusis. It is possible that dark-eyed individuals, with greater inner ear melanin content, are better protected against noise-induced hearing loss. Evidence suggests that melanin can be protective against radiation-induced sensorineural hearing loss, but may predispose individuals to cisplatin ototoxicity. Future studies are required to support these conclusions. PMID: 25529530 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - December 19, 2014 Category: Audiology Authors: Mujica-Mota MA, Schermbrucker J, Daniel SJ Tags: Hear Res Source Type: research

A behavioral audiogram of the red fox (Vulpes vulpes).
Abstract We determined the absolute hearing sensitivity of the red fox (Vulpes vulpes) using an adapted standard psychoacoustic procedure. The animals were tested in a reward-based go/no-go procedure in a semi-anechoic chamber. At 60 dB sound pressure level (SPL) (re 20 μPa) red foxes perceive pure tones between 51 Hz and 48 kHz, spanning 9.84 octaves with a single peak sensitivity of -15 dB at 4 kHz. The red foxes' high-frequency cutoff is comparable to that of the domestic dog while the low-frequency cutoff is comparable to that of the domestic cat and the absolute sensitivi...
Source: Hearing Research - December 18, 2014 Category: Audiology Authors: Malkemper EP, Topinka V, Burda H Tags: Hear Res Source Type: research

Current focusing in cochlear implants: An analysis of neural recruitment in a computational model.
Abstract Several multipolar current focusing strategies are examined in a computational model of the implanted human cochlea. The model includes a realistic spatial distribution of cell bodies of the auditory neurons throughout Rosenthal's canal. Simulations are performed of monopolar, (partial) tripolar and phased array stimulation. Excitation patterns, estimated thresholds, electrical dynamic range, excitation density and neural recruitment curves are determined and compared. The main findings are: (I) current focusing requires electrical field interaction to induce spatially restricted excitation patterns. For ...
Source: Hearing Research - December 17, 2014 Category: Audiology Authors: Kalkman RK, Briaire JJ, Frijns JH Tags: Hear Res Source Type: research

Inner ear contribution to bone conduction hearing in the human.
Abstract Bone conduction (BC) hearing relies on sound vibration transmission in the skull bone. Several clinical findings indicate that in the human, the skull vibration of the inner ear dominates the response for BC sound. Two phenomena transform the vibrations of the skull surrounding the inner ear to an excitation of the basilar membrane, (1) inertia of the inner ear fluid and (2) compression and expansion of the inner ear space. The relative importance of these two contributors were investigated using an impedance lumped element model. By dividing the motion of the inner ear boundary in common and differential...
Source: Hearing Research - December 17, 2014 Category: Audiology Authors: Stenfelt S Tags: Hear Res Source Type: research

The early days of the multi channel cochlear implant: Efforts and achievement in France.
This article is part of a Special Issue entitled . PMID: 25499127 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - December 10, 2014 Category: Audiology Authors: Chouard CH Tags: Hear Res Source Type: research

Sensitivity of envelope following responses to vowel polarity.
Abstract Envelope following responses (EFRs) elicited by stimuli of opposite polarities are often averaged due to their insensitivity to polarity when elicited by amplitude modulated tones. A recent report illustrates that individuals exhibit varying degrees of polarity-sensitive differences in EFR amplitude when elicited by vowel stimuli (Aiken and Purcell, 2013). The aims of the current study were to evaluate the incidence and degree of polarity-sensitive differences in EFRs recorded in a large group of individuals, and to examine potential factors influencing the polarity-sensitive nature of EFRs. In Experiment...
Source: Hearing Research - December 8, 2014 Category: Audiology Authors: Easwar V, Beamish L, Aiken S, Choi JM, Scollie S, Purcell D Tags: Hear Res Source Type: research

Getting a decent (but sparse) signal to the brain for users of cochlear implants.
Abstract The challenge in getting a decent signal to the brain for users of cochlear implants (CIs) is described. A breakthrough occurred in 1989 that later enabled most users to understand conversational speech with their restored hearing alone. Subsequent developments included stimulation in addition to that provided with a unilateral CI, either with electrical stimulation on both sides or with acoustic stimulation in combination with a unilateral CI, the latter for persons with residual hearing at low frequencies in either or both ears. Both types of adjunctive stimulation produced further improvements in perfo...
Source: Hearing Research - December 8, 2014 Category: Audiology Authors: Wilson BS Tags: Hear Res Source Type: research

Familial hemiplegic migraine type-1 mutated cav2.1 calcium channels alter inhibitory and excitatory synaptic transmission in the lateral superior olive of mice.
Abstract CaV2.1 Ca(2+) channels play a key role in triggering neurotransmitter release and mediating synaptic transmission. Familial hemiplegic migraine type-1 (FHM-1) is caused by missense mutations in the CACNA1A gene that encodes the α1A pore-forming subunit of CaV2.1 Ca(2+) channels. We used knock-in (KI) transgenic mice harbouring the pathogenic FHM-1 mutation R192Q to study inhibitory and excitatory neurotransmission in the principle neurons of the lateral superior olive (LSO) in the auditory brainstem. We tested if the R192Q FHM-1 mutation differentially affects excitatory and inhibitory synaptic tran...
Source: Hearing Research - December 4, 2014 Category: Audiology Authors: Inchauspe CG, Pilati N, Di Guilmi MN, Urbano FJ, Ferrari MD, van den Maagdenberg AM, Forsythe ID, Uchitel OD Tags: Hear Res Source Type: research

Biological correlates of tinnitus-related distress: An exploratory study.
Abstract During the process of tinnitus diagnostics, various psychometric instruments are used to measure tinnitus-related distress. The aim of present work was to explore whether candidates for biological correlates of the tinnitus-related distress could be found in peripheral blood of patients and if so, whether there was association between them and psychometric scores that reflect tinnitus-related distress. The concentrations of interleukin-1β (IL1β), interleukin-6 (IL6), tumor necrosis factor-α (TNFα) and a brain-derived neutrotrophic factor (BDNF) were measured in serum of 30 patients d...
Source: Hearing Research - December 1, 2014 Category: Audiology Authors: Szczepek AJ, Haupt H, Klapp BF, Olze H, Mazurek B Tags: Hear Res Source Type: research

Attentional modulation of medial olivocochlear inhibition: Evidence for immaturity in children.
Abstract Efferent feedback shapes afferent auditory processing. Auditory attention has been shown to modulate medial olivocochlear (MOC) efferent activity in human adults. Since auditory attention continues to develop throughout childhood, the present study explored whether attentional control of medial-efferent inhibition in 5-10 year-old children is adult-like. MOC inhibition was measured in adults (n = 14) and children (n = 12) during no-task (contralateral broadband noise), passive (contralateral noise with tone-pips) and active listening conditions (attended tone-pips embedded in contralat...
Source: Hearing Research - December 1, 2014 Category: Audiology Authors: Mishra SK Tags: Hear Res Source Type: research

Turtle utricle dynamic behavior using a combined anatomically accurate model and experimentally measured hair bundle stiffness.
Abstract Anatomically correct turtle utricle geometry was incorporated into two finite element models. The geometrically accurate model included appropriately shaped macular surface and otoconial layer, compact gel and column filament (or shear) layer thicknesses and thickness distributions. The first model included a shear layer where the effects of hair bundle stiffness was included as part of the shear layer modulus. This solid model's undamped natural frequency was matched to an experimentally measured value. This frequency match established a realistic value of the effective shear layer Young's modulus of 16&...
Source: Hearing Research - December 1, 2014 Category: Audiology Authors: Davis JL, Grant JW Tags: Hear Res Source Type: research

Speech perception with interaction-compensated simultaneous stimulation and long pulse durations in cochlear implant users.
Abstract Early multi-channel designs in the history of cochlear implant development were based on a vocoder-type processing of frequency channels and presented bands of compressed analog stimulus waveforms simultaneously on multiple tonotopically arranged electrodes. The realization that the direct summation of electrical fields as a result of simultaneous electrode stimulation exacerbates interactions among the stimulation channels and limits cochlear implant outcome led to the breakthrough in the development of cochlear implants, the continuous interleaved (CIS) sampling coding strategy. By interleaving stimulat...
Source: Hearing Research - November 29, 2014 Category: Audiology Authors: Schatzer R, Koroleva I, Griessner A, Levin S, Kusovkov V, Yanov Y, Zierhofer C Tags: Hear Res Source Type: research