Hair cell counts in a rat model of sound damage: Effects of tissue preparation & identification of regions of hair cell loss.
In this study we quantify changes in HC number following exposure to one of four sound damage paradigms. We exposed adult, anesthetized Sprague Dawley rats to a unilateral 16 kHz pure tone that varied in intensity (114 dB or 118 dB) and duration (1, 2, or 4 h) and sacrificed animals 2-4 weeks later. We compared two different methods of tissue preparation, plastic embedding/sectioning and whole mount dissection, for quantifying hair cell loss as a function of frequency We found that the two methods of tissue preparation produced largely comparable cochleograms, with whole mount dissections allowing a mor...
Source: Hearing Research - August 20, 2015 Category: Audiology Authors: Neal C, Kennon-McGill S, Freemyer A, Shum A, Staecker H, Durham D Tags: Hear Res Source Type: research

Analysis of plasma microRNA expression profiles in male textile workers with noise-induced hearing loss.
Abstract BACKGROUND: Circulating microRNAs (miRNAs) have attracted interests as non-invasive biomarkers of physiological and pathological conditions, which may be applied in noise-induced hearing loss (NIHL). However, no epidemiology studies have yet examined the potential effects of NIHL or noise exposure on miRNA expression profiles. OBJECTIVES: We sought to identify permanent NIHL-related miRNAs and to predict the biological functions of the putative genes encoding the indicated miRNAs. METHODS: In the discovery stage, we used a microarray assay to detect the miRNA expression profiles between pooled p...
Source: Hearing Research - August 13, 2015 Category: Audiology Authors: Ding L, Liu J, Shen HX, Pan LP, Liu QD, Zhang HD, Han L, Shuai LG, Ding EM, Zhao QN, Wang BS, Zhu BL Tags: Hear Res Source Type: research

Protective role of edaravone against cisplatin-induced ototoxicity in an auditory cell line.
Abstract Edaravone is a neuroprotective agent with a potent free radical scavenging and antioxidant actions. In the present study we investigated the influence of edaravone on cisplatin ototoxicity in auditory cells. Cell viability was determined using a 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide cell proliferation assay. Oxidative stress and apoptosis were assessed by reactive oxygen species (ROS) measurement, Hoechst 33258 staining, caspase-3 activity assay, and immunoblotting of PARP. Pretreatment with 100 μM of edaravone prior to application of 15 μM of cisplatin increased cel...
Source: Hearing Research - August 13, 2015 Category: Audiology Authors: Im GJ, Chang J, Lee S, Choi J, Jung HH, Lee HM, Ryu SH, Park SK, Kim JH, Kim HJ Tags: Hear Res Source Type: research

The pathophysiology of otosclerosis: Review of current research.
Abstract Otosclerosis is a complex disease of the human otic capsule with highest incidence in adult Caucasians. So far, many possible etiological factors like genetics, HLA, autoimmunity, viruses, inflammation, and hormones have been investigated but still the development of the disease remains unclear. Currently, the surgical replacement of stapes (stapedotomy) remains the best possible treatment option. In this review, we analyze different etiological factors studied so far in otosclerosis pathophysiology and discuss most recent findings and possible new research pathways. PMID: 26276418 [PubMed - as suppl...
Source: Hearing Research - August 11, 2015 Category: Audiology Authors: Rudic M, Keogh I, Wagner R, Wilkinson E, Kiros N, Ferrary E, Sterkers O, Bozorg Grayeli A, Zarkovic K, Zarkovic N Tags: Hear Res Source Type: research

Effects of background noise on inter-trial phase coherence and auditory N1-P2 responses to speech stimulus.
This study investigated the effects of a speech-babble background noise on inter-trial phase coherence (ITPC, also referred to as phase locking value (PLV)) and auditory event-related responses (AERP) to speech sounds. Specifically, we analyzed EEG data from 11 normal hearing subjects to examine whether ITPC can predict noise-induced variations in the obligatory N1-P2 complex response. N1-P2 amplitude and latency data were obtained for the syllable/bu/in quiet and noise listening conditions. ITPC data in delta, theta, and alpha frequency bands were calculated for the N1-P2 responses in the two passive listening conditions....
Source: Hearing Research - August 11, 2015 Category: Audiology Authors: Koerner TK, Zhang Y Tags: Hear Res Source Type: research

Brief bursts of infrasound may improve cognitive function - an fMRI study.
Kühn S Abstract At present, infrasound (sound frequency
Source: Hearing Research - August 7, 2015 Category: Audiology Authors: Weichenberger M, Kühler R, Bauer M, Hensel J, Brühl R, Ihlenfeld A, Ittermann B, Gallinat J, Koch C, Sander T, Kühn S Tags: Hear Res Source Type: research

Age-regulated function of autophagy in the mouse inner ear.
We report that autophagy-related genes (ATG) Becn1, Atg4g and Atg5 are expressed in the mouse cochlea, vestibular system and brainstem cochlear nuclei from late developmental stages to adulthood. Atg9 was studied in the mouse cochlea and showed a similar pattern. The presence of autophagic flux was confirmed by decreased sequestosome 1 (SQSTM1/p62) and increased relative levels of microtubule-associated protein light chain 3-II (LC3-II). Inner ear autophagy flux is developmentally regulated and is lower at perinatal stages than in the adult mouse, where an expression plateau is reached at the age of two-months, coinciding ...
Source: Hearing Research - July 30, 2015 Category: Audiology Authors: de Iriarte Rodríguez R, Pulido S, Rodríguez-de la Rosa L, Marta Magariños, Varela-Nieto I Tags: Hear Res Source Type: research

The Paracrine Effect of Mesenchymal Human Stem Cells Restored Hearing in β Tubulin Induced Autoimmune Sensorineural Hearing Loss.
The Paracrine Effect of Mesenchymal Human Stem Cells Restored Hearing in β Tubulin Induced Autoimmune Sensorineural Hearing Loss. Hear Res. 2015 Jul 30; Authors: Yoo TJ, Du X, Zhou B Abstract The aim of this study was to examine the activities of hASCs (Human Adipose tissue Derived Stem Cells) on autoimmune hearing loss (EAHL) and how human stem cells regenerated mouse cochlea cells. We have restored hearing in 19 years old white female with autoimmune hearing loss with autologous adipose tissue derived stem cells and we wish to understand the mechanism of restoration of hearing in animal model. ...
Source: Hearing Research - July 30, 2015 Category: Audiology Authors: Yoo TJ, Du X, Zhou B Tags: Hear Res Source Type: research

Abnormal fast fluctuations of electrocochleography and otoacoustic emissions in Menière's disease.
Abnormal fast fluctuations of electrocochleography and otoacoustic emissions in Menière's disease. Hear Res. 2015 Jul 29; Authors: Gerenton G, Giraudet F, Djennaoui I, Pavier Y, Gilain L, Mom T, Avan P Abstract The responses of cochlear hair cells to sound stimuli depend on the resting position of their stereocilia bundles, which is sensitive to the chemical and mechanical environment. Cochlear hydrops, a hallmark of Menière's disease (MD), which is likely to come with disruption of this environment, results in hearing symptoms and electrophysiological signs, such as excessive changes in...
Source: Hearing Research - July 29, 2015 Category: Audiology Authors: Gerenton G, Giraudet F, Djennaoui I, Pavier Y, Gilain L, Mom T, Avan P Tags: Hear Res Source Type: research

Mice with conditional deletion of Cx26 exhibit no vestibular phenotype despite secondary loss of Cx30 in the vestibular end organs.
Abstract Connexins are components of gap junctions which facilitate transfer of small molecules between cells. One member of the connexin family, Connexin 26 (Cx26), is prevalent in gap junctions in sensory epithelia of the inner ear. Mutations of GJB2, the gene encoding Cx26, cause significant hearing loss in humans. The vestibular system, however, does not usually show significant functional deficits in humans with this mutation. Mouse models for loss of Cx26 function demonstrate hearing loss and cochlear pathology but the extent of vestibular dysfunction and organ pathology are less well characterized. To under...
Source: Hearing Research - July 29, 2015 Category: Audiology Authors: Lee MY, Takada T, Takada Y, Kappy MD, Beyer LA, Swiderski DL, Godin AL, Brewer S, King WM, Raphael Y Tags: Hear Res Source Type: research

Speech quality evaluation of a sparse coding shrinkage noise reduction algorithm with normal hearing and hearing impaired listeners.
Abstract Although there are numerous papers describing single-channel noise reduction strategies to improve speech perception in a noisy environment, few studies have comprehensively evaluated the effects of noise reduction algorithms on speech quality for hearing impaired (HI). A model-based sparse coding shrinkage (SCS) algorithm has been developed, and has shown previously (Sang et al., 2014) that it is as competitive as a state-of-the-art Wiener filter approach in speech intelligibility. Here, the analysis is extended to include subjective quality ratings and a method called Interpolated Paired Comparison...
Source: Hearing Research - July 29, 2015 Category: Audiology Authors: Sang J, Hu H, Zheng C, Li G, Lutman ME, Bleeck S Tags: Hear Res Source Type: research

Age-related Shifts in Distortion Product Otoacoustic Emissions Peak-ratios and Amplitude Modulation Spectra.
In this study, we measured DPOAEs to reveal age-related changes in peak f2/f1 ratio and degradation in AM detection by basilar membrane vibration. Two tones (f1 and f2, f2>f1) at various f2/f1 ratios and simultaneous presentation of one AM and one pure tone were used as stimuli to evoke DPOAEs. In addition of observing reduced DPOAE amplitudes and steeper slopes in the input-output DPOAE functions, higher peak f2/f1 ratios and broader f2/f1 tuning were also observed in aged animals. Aged animals generally had lower distortion product (DP) and first sideband (SB 1) responses evoked by an f1 pure tone and an f2 AM tone, r...
Source: Hearing Research - July 29, 2015 Category: Audiology Authors: Lai J, Bartlett EL Tags: Hear Res Source Type: research

Cochlear afferent innervation development.
Abstract Sound signal is detected by sensory hair cells located in the cochlear region of the inner ear, and transmitted to the central nervous system by the spiral ganglion neurons (SGNs). These bipolar neurons develop long peripheral processes to connect hair cells, forming ribbon synapses, specialised for the precision and speed required to process auditory information. The establishment of a complex innervation pattern relies on specific signals, intrinsic to SGNs or provided by neighbouring cells, which are tightly controlled in time and space. In this paper, we review recent advances about stepwise developme...
Source: Hearing Research - July 28, 2015 Category: Audiology Authors: Delacroix L, Malgrange B Tags: Hear Res Source Type: research

The development of a fast method for recording Schroeder-phase masking functions.
Abstract Schroeder-phase masking complexes have been used in many psychophysical experiments to examine the phase curvature of cochlear filtering at characteristic frequencies, and other aspects of cochlear nonlinearity. In a normal nonlinear cochlea, changing the "scalar factor" of the Schroeder-phase masker from -1 through 0 to +1 results in a marked difference in the measured masked thresholds, whereas this difference is reduced in ears with damaged outer hair cells. Despite the valuable information it may give, one disadvantage of the Schroeder-phase masking procedure is the length of the test - usin...
Source: Hearing Research - July 22, 2015 Category: Audiology Authors: Rahmat S, O'Beirne GA Tags: Hear Res Source Type: research

In Vivo Overactivation of the Notch Signaling Pathway in the Developing Cochlear Epithelium.
Abstract Notch signaling is thought to play important roles in both prosensory domain specification and cell fate determination during inner ear development. Inhibition of the Notch signaling pathway in prosensory cells results in excessive hair cell formation, while activation of the Notch signaling pathway by overexpression of activated Notch1 (Notch1-intercellular domain, NICD) in the cochlear epithelium results in ectopic sensory patches where NICD is expressed. However, the effect of Notch activation on the prosensory domain is not fully understood. To elucidate the precise roles of Notch signaling in cochlea...
Source: Hearing Research - July 22, 2015 Category: Audiology Authors: Tateya T, Sakamoto S, Imayoshi I, Kageyama R Tags: Hear Res Source Type: research

Insertion trauma and recovery of function after cochlear implantation: Evidence from objective functional measures.
Abstract Partial loss and subsequent recovery of cochlear implant function in the first few weeks following cochlear implant surgery has been observed in previous studies using psychophysical detection thresholds. In the current study, we explored this putative manifestation of insertion trauma using objective functional measures: electrically-evoked compound action potential (ECAP) amplitude-growth functions (ECAP amplitude as a function of stimulus level). In guinea pigs implanted in a hearing ear with good post-implant hearing and good spiral ganglion neuron (SGN) survival, consistent patterns of ECAP functions...
Source: Hearing Research - July 21, 2015 Category: Audiology Authors: Pfingst BE, Hughes AP, Colesa DJ, Watts MM, Strahl SB, Raphael Y Tags: Hear Res Source Type: research

Contribution of the Incudo-Malleolar Joint to Middle-Ear Sound Transmission.
In this study, spatial stapes motions were measured during acoustic stimulation (0.25-8 kHz) in six fresh human temporal bones for two conditions of the IMJ: (1) normal IMJ and (2) IMJ with experimentally-reduced mobility. Stapes velocity was measured at multiple points on the footplate using a scanning laser Doppler vibrometry (SLDV) system, and the 3D motion components were calculated under both conditions of the IMJ. The artificial reduction of the IMJ mobility was confirmed by measuring the relative motion between the malleus and the incus. The magnitudes of the piston-like motion of the stapes increased with the reduc...
Source: Hearing Research - July 21, 2015 Category: Audiology Authors: Gerig R, Ihrle S, Röösli C, Dalbert A, Dobrev I, Pfiffner F, Eiber A, Huber AM, Sim JH Tags: Hear Res Source Type: research

Audibility, Speech perception and processing of temporal cues in ribbon synaptic disorders due to OTOF mutations.
Abstract Mutations in the OTOF gene encoding otoferlin result in a disrupted function of the ribbon synapses with an impaired multivesicular glutamate release. Most affected subjects present with congenital hearing loss and abnormal auditory brainstem potentials associated with preserved cochlear hair cell activities (otoacoustic emissions, cochlear microphonics [CMs]). Transtympanic electrocochleography (ECochG) has recently been proposed for defining the details of potentials arising in both the cochlea and auditory nerve in this disorder, and with a view to shedding light on the pathophysiological mechanisms un...
Source: Hearing Research - July 15, 2015 Category: Audiology Authors: Santarelli R, Del Castillo I, Cama E, Scimemi P, Starr A Tags: Hear Res Source Type: research

Vestibular function and temporal bone imaging in DFNB1.
Abstract DFNB1 is the most prevalent type of hereditary hearing impairment known nowadays and the audiometric phenotype is very heterogeneous. There is, however, no consensus in literature on vestibular and imaging characteristics. Vestibular function and imaging results of 44 DFNB1 patients were evaluated in this retrospective study. All patients displayed a response during rotational velocity step testing. In 65% of the cases, the caloric results were within normal range bilaterally. The video head impulse test was normal in all patients. In 34.4% of the CT scans one or more temporal bone anomalies were found. T...
Source: Hearing Research - July 15, 2015 Category: Audiology Authors: Oonk AM, Beynon AJ, Peters TA, Kunst HP, Admiraal RJ, Kremer H, Verbist B, Pennings RJ Tags: Hear Res Source Type: research

Reliable encoding and processing of auditory information is mediated by different types of synapses employing distinct molecular and structural mechanisms.
Abstract Hearing impairment is the most common human sensory deficit. Considering the sophisticated anatomy and physiology of the auditory system, disease-related failures frequently occur. To meet the demands of the neuronal circuits responsible for processing auditory information, the synapses of the lower auditory pathway are anatomically and functionally specialized to indefatigably process acoustic information with utmost temporal precision. However, while sharing some functional properties, the afferent synapses of the cochlea and of auditory brainstem differ greatly in their morphology and employ distinct m...
Source: Hearing Research - July 15, 2015 Category: Audiology Authors: Wichmann C Tags: Hear Res Source Type: research

Central auditory processing in patients with spinocerebellar ataxia.
CONCLUSIONS: A majority of patients exhibited SSW test deficits, with a predominance of bilateralism, and three-fourths had impaired RGDT performance, pointing to difficulties with binaural integration and temporal resolution. Assessment of CAPD is important for therapeutic follow ups in patients with SCA. PMID: 26183435 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - July 13, 2015 Category: Audiology Authors: Zeigelboim BS, de Carvalho HA, Teive HA, Liberalesso PB, Jurkiewicz AL, da Silva Abdulmassih EM, Marques JM, Cordeiro ML Tags: Hear Res Source Type: research

Proteomic identification of hair cell repair proteins in the model sea anemone Nematostella vectensis.
In this study, several polypeptides of RPs were isolated from mucus using blue native PAGE and then sequenced using LC-MS/MS. Thirty-seven known polypeptides were identified, including Hsp70s, as well as many polypeptide subunits of the 20S proteasome. Other identified polypeptides included those involved in cellular stress responses, protein folding, and protein degradation. Specific inhibitors of Hsp70s and the 20S proteasome were employed in experiments to test their involvement in hair bundle repair. The results of those experiments suggested that repair requires biologically active Hsp70s and 20S proteasomes. A model ...
Source: Hearing Research - July 13, 2015 Category: Audiology Authors: Tang PC, Watson GM Tags: Hear Res Source Type: research

Stream segregation in the anesthetized auditory cortex.
Abstract Auditory stream segregation describes the way that sounds are perceptually segregated into groups or streams on the basis of perceptual attributes such as pitch or spectral content. For sequences of pure tones, segregation depends on the tones' proximity in frequency and time. In the auditory cortex (and elsewhere) responses to sequences of tones are dependent on stimulus conditions in a similar way to the perception of these stimuli. However, although highly dependent on stimulus conditions, perception is also clearly influenced by factors unrelated to the stimulus, such as attention. Exactly how 'bottom...
Source: Hearing Research - July 9, 2015 Category: Audiology Authors: Scholes C, Palmer AR, Sumner CJ Tags: Hear Res Source Type: research

Subcortical processing in auditory communication.
z S Abstract The voice is a rich source of information, which the human brain has evolved to decode and interpret. Empirical observations have shown that the human auditory system is especially sensitive to the human voice, and that activity within the voice-sensitive regions of the primary and secondary auditory cortex is modulated by the emotional quality of the vocal signal, and may therefore subserve, with frontal regions, the cognitive ability to correctly identify the speaker's affective state. So far, the network involved in the processing of vocal affect has been mainly characterised at the cortical level....
Source: Hearing Research - July 8, 2015 Category: Audiology Authors: Pannese A, Grandjean D, Frühholz S Tags: Hear Res Source Type: research

Hyperinsulinemia/diabetes, hearing, and aging in the University of Wisconsin calorie restriction monkeys.
Abstract The purpose of this study was to determine the effects of hyperinsulinemia/Type 2 diabetes mellitus (HI-T2DM) on hearing impairment using rhesus monkeys to obtain control over diet and lifestyle factors that confound human studies. The study is a retrospective evaluation of rhesus monkeys from the Wisconsin National Primate Research Center (WNPRC) study on caloric restriction and aging. The research questions were the following: 1. Is HI-T2DM related to hearing impairment? 2. If so, what is the site of lesion in the auditory system? and 3. What physiological factors affect the risk of hearing loss in HI-T...
Source: Hearing Research - July 7, 2015 Category: Audiology Authors: Fowler CG, Chiasson KB, Colman R, Kemnitz JW, Beasley TM, Weindruch R Tags: Hear Res Source Type: research

Canertinib induces ototoxicity in three preclinical models.
In this study, a significant dose-dependent canertinib ototoxicity was observed in a zebrafish model. Canertinib ototoxicity was further confirmed in two mouse models with different genetic backgrounds. The data strongly suggested an evolutionally preserved ERBB molecular mechanism underlying canertinib ototoxicity. Thus, these results imply that clinical monitoring of hearing loss should be considered for clinical testing of canertinib or other pan-ERBB inhibitors. PMID: 26163095 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - July 7, 2015 Category: Audiology Authors: Tang J, Yi Q, Li H, Kopecky BJ, Ding D, Ou HC, DeCook R, Chen X, Sun Z, Kobel M, Bao J Tags: Hear Res Source Type: research

Auditory cortex directs the input-specific remodeling of thalamus.
Abstract Input-specific remodeling is observed both in the primary auditory cortex (AI) and the ventral division of the medial geniculate body of the thalamus (MGBv) through motivation such as learning. Here, we show the role of AI in the MGBv remodeling induced by the electrical stimulation (ES) of the central division of the inferior colliculus (ICc). For the MGBv neurons with frequency tunings different from those of electrically stimulated ICc neurons, their frequency tunings shifted towards the tunings of the ICc neurons. AI neurons also showed this input-specific remodeling after ES of the ICc (ESICc). Inter...
Source: Hearing Research - July 2, 2015 Category: Audiology Authors: Nelson S, Kong L, Liu X, Yan J Tags: Hear Res Source Type: research

Putative role of border cells in generating spontaneous morphological activity within Kölliker's organ.
Putative role of border cells in generating spontaneous morphological activity within Kölliker's organ. Hear Res. 2015 Jun 26; Authors: Nishani Dayaratne MW, Vlajkovic SM, Lipski J, Thorne PR Abstract Kölliker's organ is a transient epithelial structure, comprising a major part of the organ of Corti during pre-hearing stages of development. The auditory system is spontaneously active during development, which serves to retain and refine neural connections. Kölliker's organ is considered a key candidate for generating such spontaneous activity, most likely through purinergic (P2 receptor...
Source: Hearing Research - June 26, 2015 Category: Audiology Authors: Nishani Dayaratne MW, Vlajkovic SM, Lipski J, Thorne PR Tags: Hear Res Source Type: research

Restoration of middle-ear input in fluid-filled middle ears by controlled introduction of air or a novel air-filled implant.
In this study, air bubbles or air-filled implants were introduced into saline-filled human cadaveric MEs. Umbo velocity, a convenient measure of ME response, served as an indicator of hearing sensitivity. Filling the ME with saline reduced umbo velocity by 25-30 dB at low frequencies and more at high frequencies, consistent with earlier work (Ravicz et al., Hear. Res. 195: 103-130 (2004)). Small amounts of air (∼30 μl) in the otherwise saline-filled ME increased umbo velocity substantially, to levels only 10-15 dB lower than in the dry ME, in a frequency- and location-dependent manner: air in contact with the tympan...
Source: Hearing Research - June 26, 2015 Category: Audiology Authors: Ravicz ME, Chien WW, Rosowski JJ Tags: Hear Res Source Type: research

Decreased temporal precision of neuronal signaling as a candidate mechanism of auditory processing disorder.
Abstract The sense of hearing is the fastest of our senses and provides the first all-or-none action potential in the auditory nerve in less than four milliseconds. Short stimulus evoked latencies and their minimal variability are hallmarks of auditory processing from spiral ganglia to cortex. Here, we review how even small changes in first spike latencies (FSL) and their variability (jitter) impact auditory temporal processing. We discuss a number of mouse models with degraded FSL/jitter whose mutations occur exclusively in the central auditory system and therefore might serve as candidates to investigate the cel...
Source: Hearing Research - June 25, 2015 Category: Audiology Authors: Kopp-Scheinpflug C, Tempel BL Tags: Hear Res Source Type: research

Synaptic encoding and processing of auditory information in physiology and disease.
PMID: 26119179 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - June 25, 2015 Category: Audiology Authors: Moser T, Strenzke N Tags: Hear Res Source Type: research

The effect of visual cues on top-down restoration of temporally interrupted speech, with and without further degradations.
In this study we investigated if an accompanying video of the speaker can enhance the intelligibility of interrupted sentences, and the phonemic restoration benefit, measured by an increase in intelligibility when the silent intervals are filled with noise. Similar to previous studies, restoration benefit was observed with interrupted speech without spectral degradations (experiment 1), but was absent in acoustic simulations of CIs (experiment 2) and was present again in simulations of Electric Acoustic Stimulation (experiment 3). In all experiments, the additional speech information provided by the complementary visual cu...
Source: Hearing Research - June 24, 2015 Category: Audiology Authors: Benard MR, Başkent D Tags: Hear Res Source Type: research

The role of extended preoperative steroids in hearing preservation cochlear implantation.
Abstract INTRODUCTION: Steroids have been shown to reduce the hearing threshold shifts associated with cochlear implantation. Previous studies have examined only the administration of steroids just prior to surgery. The aim of this study is to examine the role of extended preoperative systemic steroids in hearing preservation cochlear implantation. METHODS: An animal model of cochlear implantation was used. 24 Hartley strain guinea pigs with a mean weight of 768 g and normal hearing were randomised into a control group, a second group receiving a single dose of systemic dexamethasone one day prior to surgery,...
Source: Hearing Research - June 24, 2015 Category: Audiology Authors: Kuthubutheen J, Coates H, Rowsell C, Nedzelski J, Chen JM, Lin V Tags: Hear Res Source Type: research

Theta, beta and gamma rate modulations in the developing auditory system.
ers J Abstract In the brain, the temporal analysis of many important auditory features relies on the synchronized firing of neurons to the auditory input rhythm. These so-called neural oscillations play a crucial role in sensory and cognitive processing and deviances in oscillatory activity have shown to be associated with neurodevelopmental disorders. Given the importance of neural auditory oscillations in normal and impaired sensory and cognitive functioning, there has been growing interest in their developmental trajectory from early childhood on. In the present study, neural auditory processing was investigate...
Source: Hearing Research - June 24, 2015 Category: Audiology Authors: Vanvooren S, Hofmann M, Poelmans H, Ghesquière P, Wouters J Tags: Hear Res Source Type: research

Auditory-neurophysiological responses to speech during early childhood: Effects of background noise.
Abstract Early childhood is a critical period of auditory learning, during which children are constantly mapping sounds to meaning. But learning rarely occurs under ideal listening conditions-children are forced to listen against a relentless din. This background noise degrades the neural coding of these critical sounds, in turn interfering with auditory learning. Despite the importance of robust and reliable auditory processing during early childhood, little is known about the neurophysiology underlying speech processing in children so young. To better understand the physiological constraints these adverse listen...
Source: Hearing Research - June 22, 2015 Category: Audiology Authors: White-Schwoch T, Davies EC, Thompson EC, Carr KW, Nicol T, Bradlow AR, Kraus N Tags: Hear Res Source Type: research

History of the tinnitus research consortium.
This article describes the creation and accomplishments of the Tinnitus Research Consortium (TRC), founded and supported through philanthropy and intended to enrich the field of tinnitus research. Bringing together a group of distinguished auditory researchers, most of whom were not involved in tinnitus research, over the fifteen years of its life it developed novel research approaches and recruited a number of new investigators into the field. The purpose of this special issue is to highlight some of the significant accomplishments of the investigators supported by the TRC. PMID: 26096056 [PubMed - as supplied by pub...
Source: Hearing Research - June 18, 2015 Category: Audiology Authors: Snow JB Tags: Hear Res Source Type: research

Morphological Correlates of Hearing Loss after Cochlear Implantation and Electro-Acoustic Stimulation in a Hearing-Impaired Guinea Pig Model.
The objective of this study was to determine the mechanisms of EAS-induced hearing loss in an animal model with high-frequency hearing loss. Guinea pigs were exposed to 24 hours of noise (12-24 kHz at 116 dB) to induce a high-frequency hearing loss. After recovery, two groups of animals were implanted (n=6 per group), with one group receiving chronic acoustic and electric stimulation for 10 weeks, and the other group receiving no stimulation during this time frame. A third group (n=6) was not implanted, but received chronic acoustic stimulation. Auditory brainstem responses were recorded biweekly to monitor changes in hear...
Source: Hearing Research - June 15, 2015 Category: Audiology Authors: Reiss LA, Stark G, Nguyen-Huynh AT, Spear KA, Zhang H, Tanaka C, Li H Tags: Hear Res Source Type: research

Integrated processing of spatial cues in human auditory cortex.
kki V Abstract Human sound source localization relies on acoustical cues, most importantly, the interaural differences in time and level (ITD and ILD). For reaching a unified representation of auditory space the auditory nervous system needs to combine the information provided by these two cues. In search for such a unified representation, we conducted a magnetoencephalography (MEG) experiment that took advantage of the location-specific adaptation of the auditory cortical N1 response. In general, the attenuation caused by a preceding adaptor sound to the response elicited by a probe depends on their spatial arran...
Source: Hearing Research - June 11, 2015 Category: Audiology Authors: Salminen NH, Takanen M, Santala O, Lamminsalo J, Altoè A, Pulkki V Tags: Hear Res Source Type: research

The effect of the resistive properties of bone on neural excitation and electric fields in cochlear implant models.
This study investigated the effect that bone resistivity has on modelled neural thresholds and intracochlear potentials using user-specific volume conduction models of implanted cochleae applying monopolar stimulation. The complexity of the description of the head volume enveloping the cochlea was varied between a simple infinite bone volume and a detailed skull containing a brain volume, scalp and accurate return electrode position. It was found that, depending on the structure of the head model and implementation of the return electrode, different bone resistivity values are necessary to match model predictions to data f...
Source: Hearing Research - June 11, 2015 Category: Audiology Authors: Malherbe TK, Hanekom T, Hanekom JJ Tags: Hear Res Source Type: research

Tinnitus Functional Index: Development, Validation, Outcomes Research, and Clinical Application.
Abstract The Tinnitus Research Consortium (TRC) issued a Request for Proposals in 2003 to develop a new tinnitus outcome measure that would: (1) be highly sensitive to treatment effects (validated for "responsiveness"); (2) address all major dimensions of tinnitus impact; and (3) be validated for scaling the negative impact of tinnitus. A grant was received by M. Meikle to conduct the study. In that observational study, all of the TRC objectives were met, with the final 25-item Tinnitus Functional Index (TFI) containing eight subscales. The study was published in 2012, and since then the TFI has received...
Source: Hearing Research - June 11, 2015 Category: Audiology Authors: Henry JA, Griest S, Thielman E, McMillan G, Kaelin C, Carlson KF Tags: Hear Res Source Type: research

Tinnitus: Maladaptive Auditory-Somatosensory Plasticity.
Abstract Tinnitus, the phantom perception of sound, is physiologically characterized by an increase in spontaneous neural activity in the central auditory system. However, as tinnitus is often associated with hearing impairment, it is unclear how a decrease of afferent drive can result in central hyperactivity. In this review, we first assess methods for tinnitus induction and objective measures of the tinnitus percept in animal models. From animal studies, we discuss evidence that tinnitus originates in the cochlear nucleus (CN), and hypothesize mechanisms whereby hyperactivity may develop in the CN after periphe...
Source: Hearing Research - June 11, 2015 Category: Audiology Authors: Wu C, Stefanescu RA, Martel DT, Shore SE Tags: Hear Res Source Type: research

Effects of Basilar Membrane Arch and Radial Tension on the Travelling Wave in Gerbil Cochlea.
Abstract The basilar membrane velocity of gerbil cochlea showed discrepancy between theoretical model and experimental measurements. We hypothesize that the reasons of such discrepancies are due to the arch towards the scala tympani and radial tension present in the basilar membrane of the gerbil cochlea. The arch changes the bending stiffness in the basilar membrane, reduces the effective fluid force on the membrane and increases the basilar membrane's inertia. The existence of the radial tension also dampens the acoustic travelling wave. In this paper, the wave number functions along the gerbil basilar membrane ...
Source: Hearing Research - June 9, 2015 Category: Audiology Authors: Chan WX, Yoon YJ Tags: Hear Res Source Type: research

Cortical Development and Neuroplasticity in Auditory Neuropathy Spectrum Disorder.
Abstract Cortical development is dependent to a large extent on stimulus-driven input. Auditory Neuropathy Spectrum Disorder (ANSD) is a recently described form of hearing impairment where neural dys-synchrony is the predominant characteristic. Children with ANSD provide a unique platform to examine the effects of asynchronous and degraded afferent stimulation on cortical auditory neuroplasticity and behavioral processing of sound. In this review, we describe patterns of auditory cortical maturation in children with ANSD. The disruption of cortical maturation that leads to these various patterns includes high leve...
Source: Hearing Research - June 9, 2015 Category: Audiology Authors: Sharma A, Cardon G Tags: Hear Res Source Type: research

The tip-link molecular complex of the auditory mechano-electrical transduction machinery.
Abstract Sound waves are converted into electrical signals by a process of mechano-electrical transduction (MET), which takes place in the hair bundle of cochlear hair cells. In response to the mechanical stimulus of the hair bundle, the tip-links, key components of the MET machinery, are tensioned and the MET channels open, which results in the generation of the cell receptor potential. Tip-links are composed of cadherin-23 (Cdh23) and protocadherin-15 (Pcdh15), both non-conventional cadherins, that form the upper and the lower part of these links, respectively. Here, we review the various Pcdh15 isoforms present...
Source: Hearing Research - June 3, 2015 Category: Audiology Authors: Pepermans E, Petit C Tags: Hear Res Source Type: research

Sound Localization in the Alligator.
Abstract In early tetrapods, it is assumed that the tympana were acoustically coupled through the pharynx and therefore inherently directional, acting as pressure difference receivers. The later closure of the middle ear cavity in turtles, archosaurs, and mammals is a derived condition, and would have changed the ear by decoupling the tympana. Isolation of the middle ears would then have led to selection for structural and neural strategies to compute sound source localization in both archosaurs and mammalian ancestors. In the archosaurs (birds and crocodilians) the presence of air spaces in the skull provided con...
Source: Hearing Research - June 2, 2015 Category: Audiology Authors: Bierman HS, Carr CE Tags: Hear Res Source Type: research

Vasopressin induces endolymphatic hydrops in mouse inner ear, as evaluated with repeated 9.4 T MRI.
In this study we evaluate the effect of vasopressin administration in vivo in longitudinal studies using two mouse strains. High resolution MRI at 9.4 T in combination with intraperitoneally delivered Gadolinium contrast, was performed before and after chronic subcutaneous administration of vasopressin via mini-osmotic pumps in the same mouse. A development of endolymphatic hydrops over time could be demonstrated in C57BL6 mice (5 mice, 2 and 4 weeks of administration) as well as in CBA/J mice (4 mice, 2 weeks of administration; 6 mice, 3 and 4 weeks of administration). In most C57BL6 mice hydrops developed first after mor...
Source: Hearing Research - June 2, 2015 Category: Audiology Authors: Degerman E, In 't Zandt R, Pålbrink A, Magnusson M Tags: Hear Res Source Type: research

Noninvasive scalp recording of cortical auditory evoked potentials in the alert macaque monkey.
Abstract Scalp-recorded evoked potentials (EP) provide researchers and clinicians with irreplaceable means for recording stimulus-related neural activities in the human brain, due to its high temporal resolution, handiness, and, perhaps more importantly, non-invasiveness. This work recorded the scalp cortical auditory EP (CAEP) in unanesthetized monkeys by using methods that are essentially identical to those applied to humans. Young adult rhesus monkeys (Macaca mulatta, 5-7 years old) were seated in a monkey chair, and their head movements were partially restricted by polystyrene blocks and tension poles placed a...
Source: Hearing Research - May 29, 2015 Category: Audiology Authors: Itoh K, Nejime M, Konoike N, Nakada T, Nakamura K Tags: Hear Res Source Type: research

Variation analysis of transcriptome changes reveals cochlear genes and their associated functions in cochlear susceptibility to acoustic overstimulation.
This study revealed that the constitutive expressions of cochlear genes displayed diverse levels of gene-specific variation. These variation patterns were altered by acoustic trauma; approximately one-third of the examined genes displayed marked increases in their expression variation. Bioinformatics analyses revealed that the genes that exhibited increased variation were functionally related to cell death, biomolecule metabolism, and membrane function. In contrast, the stable genes were primarily related to basic cellular processes, including protein and macromolecular syntheses and transport. There was no functional over...
Source: Hearing Research - May 26, 2015 Category: Audiology Authors: Yang S, Cai Q, Bard J, Jamison J, Wang J, Yang W, Hu BH Tags: Hear Res Source Type: research

Attenuation of hearing loss in DBA/2J mice by anti-apoptotic treatment.
Abstract DBA/2J mice are characterized by early onset hearing loss at about 3 to 4 weeks of age. Mutations in cadherin 23 (Cdh23) and fascin-2 (Fscn2) are responsible for the phenotypes, but the underlying mechanism is unknown. In the present study, DBA/2J mice displayed progressive hair cell loss and degeneration of spiral ganglion neurons (SGNs) after 2 weeks of age; however, the mRNA level of Caspase-3 in the inner ears was much higher at 2 weeks of age than that at 4 or 8 weeks of age. Moreover, transcriptional levels of Caspase-3 and Caspase-9 in the inner ears of DBA/2J mice were significantly higher than th...
Source: Hearing Research - May 20, 2015 Category: Audiology Authors: Yang L, Zhang H, Han X, Zhao X, Hu F, Li P, Xie G, Gao L, Cheng L, Song X, Han F Tags: Hear Res Source Type: research

Cochlear neuropathy in human presbycusis: confocal analysis of hidden hearing loss in post-mortem tissue.
Abstract Recent animal work has suggested that cochlear synapses are more vulnerable than hair cells in both noise-induced and age-related hearing loss. This synaptopathy is invisible in conventional histopathological analysis, because cochlear nerve cell bodies in the spiral ganglion survive for years, and synaptic analysis requires special immunostaining or serial-section electron microscopy. Here, we show that the same quadruple-immunostaining protocols that allow synaptic counts, hair cell counts, neuronal counts and differentiation of afferent and efferent fibers in mouse can be applied to human temporal bone...
Source: Hearing Research - May 19, 2015 Category: Audiology Authors: Viana LM, O'Malley JT, Burgess BJ, Jones DD, Oliveira CA, Santos F, Merchant SN, Liberman LD, Liberman MC Tags: Hear Res Source Type: research