Sodium salicylate potentiates the GABAB-GIRK pathway to suppress rebound depolarization in neurons of the rat's medial geniculate body.
Abstract Rebound depolarization (RD) is a voltage response to the offset from pre-hyperpolarization of neuronal membrane potential, which manifests a particular form of the postsynaptic membrane potential response to inhibitory presynaptic inputs. We previously demonstrated that sodium salicylate (NaSal), a tinnitus inducer, can drastically suppress the RD in neurons of rat medial geniculate body (MGB) (Su et al, 2012, PLoS ONE 7, e46969). The purpose of the present study was to investigate the underlying cellular mechanism by using whole-cell patch-clamp recordings in rat MGB slices. NaSal (1.4 mM) had no effects...
Source: Hearing Research - December 11, 2015 Category: Audiology Authors: Wang XX, Jin Y, Luo B, Sun JW, Zhang J, Wang M, Chen L Tags: Hear Res Source Type: research

PMID: 26643448 [PubMed - in process] (Source: Hearing Research)
Source: Hearing Research - December 1, 2015 Category: Audiology Authors: Ito J Tags: Hear Res Source Type: research

Assessment of thermal treatment via irrigation of external ear to reduce cisplatin-induced hearing loss.
Abstract Systemic and local changes in body temperature can have a profound effect on traumatic injuries including those to the inner ear. Therefore, we investigated the effects of acutely increasing or decreasing the temperature of the external ear canal on cisplatin-induced hearing loss. The external auditory canals of male guinea pigs were acutely irrigated with warm (44 °C), euthermic (37 °C), or cool (30 °C) water and subsequently injected with cisplatin (12 mg/kg, i.p.). Hearing was assessed by the auditory brainstem response and cochleograms were prepared to determine loss of hair cells. Ear can...
Source: Hearing Research - November 27, 2015 Category: Audiology Authors: Spankovich C, Lobarinas E, Ding D, Salvi R, Le Prell CG Tags: Hear Res Source Type: research

FGF22 protects hearing function from gentamycin ototoxicity by maintaining ribbon synapse number.
Abstract Inner hair cell (IHC) ribbon synapses of cochlea play important role in transmitting sound signal into auditory nerve and are sensitive to ototoxicity. However, ototoxic damage of ribbon synapses is not understood clearly. Roles of fibroblast growth factor 22 (FGF22) on synapse formation were explored under gentamycin ototoxicity. 6-week-old mice were injected intraperitoneally once daily with 50-150 mg/kg gentamicin for 10 days. Immunostaining with anti- GluR2&3/CtBP2 was used to estimate the number of ribbon synapses in the cochlea. Expression of FGF22 and myocyte enhancer factor 2D (MEF2D) was assa...
Source: Hearing Research - November 27, 2015 Category: Audiology Authors: Li S, Hang L, Ma Y Tags: Hear Res Source Type: research

A DPOAE assessment of outer hair cell integrity in ears with age-related hearing loss.
Abstract Distortion product otoacoustic emissions (DPOAEs) were used to assess outer hair cell (OHC) integrity in human ears with age-related hearing loss. Sound pressure measurements were made in the ear canal over the stimulus range 40 to 90 dB SPL (L2), with L1=0.45*L2+44 with F2 = 2 and 3 or 4 kHz. Model-generated DPOAE I/O functions were fit to DPOAE data to quantify the contribution of loss of nonlinearity (OHC loss) to the hearing loss. Results suggest OHC loss as a contributing cause of age-related hearing, regardless of audiogram configuration. It seems likely that OHC and strial pathology co-exist in ear...
Source: Hearing Research - November 27, 2015 Category: Audiology Authors: Ueberfuhr MA, Fehlberg H, Goodman SS, Withnell RH Tags: Hear Res Source Type: research

Cooling of the auditory cortex modifies neuronal activity in the inferior colliculus in rats.
nko K, Chumak T, Syka J Abstract There are powerful pathways descending from the auditory cortex (AC) to the inferior colliculus (IC), yet their function is not fully understood. The aim of this study is to examine the effects of a reversible cortical inactivation, achieved by cooling of the AC, on the responses of neurons in the rat IC. Extracellular single-unit or multi-unit activity was recorded in the IC of anaesthetized rats with a 16-channel multielectrode probe introduced along the IC dorso-ventral axis through the dorsal cortex (DCIC) to the central nucleus of the IC (CIC). Cooling of the AC produced an in...
Source: Hearing Research - November 26, 2015 Category: Audiology Authors: Popelář J, Šuta D, Lindovský J, Bureš Z, Pysanenko K, Chumak T, Syka J Tags: Hear Res Source Type: research

Biomechanics of the incudo-malleolar-joint - Experimental investigations for quasi-static loads.
Eiber A Abstract Under large quasi-static loads, the incudo-malleolar joint (IMJ), connecting the malleus and the incus, is highly mobile. It can be classified as a mechanical filter decoupling large quasi-static motions while transferring small dynamic excitations. This is presumed to be due to the complex geometry of the joint inducing a spatial decoupling between the malleus and incus under large quasi-static loads. Spatial Laser Doppler Vibrometer (LDV) displacement measurements on isolated malleus-incus-complexes (MICs) were performed. With the malleus firmly attached to a probe holder, the incus was excited ...
Source: Hearing Research - November 25, 2015 Category: Audiology Authors: Ihrle S, Gerig R, Dobrev I, Röösli C, Sim JH, Huber AM, Eiber A Tags: Hear Res Source Type: research

The response of guinea pig primary utricular and saccular irregular neurons to bone-conducted vibration (BCV) and air-conducted sound (ACS).
CONCLUSION: These results are in accord with the hypothesis put forward by Young et al. (1977) that each individual cycle of the waveform, either BCV or ACS, is the effective stimulus to the receptor hair cells on either macula. We suggest that each cycle of the BCV or ACS stimulus causes fluid displacement which deflects the short, stiff, hair bundles of type I receptors at the striola and so triggers the phase-locked neural response of primary otolithic afferents. PMID: 26626360 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - November 25, 2015 Category: Audiology Authors: Curthoys IS, Vulovic V, Burgess AM, Sokolic L, Goonetilleke SC Tags: Hear Res Source Type: research

Quantitative PCR Analysis and Protein Distribution of Drug Transporter Genes in the Rat Cochlea.
In this study, we examined the levels of endogenous membrane transporters in rat cochlea by targeted PCR array analysis of 84 transporter genes, followed by validation and localization in tissues by immunohistochemistry. Our studies indicate that several members of the SLC, VDAC and ABC membrane transporter families show high levels of expression, both at the RNA and protein levels in the rat cochlea. Identification and characterization of these membrane transporters in the inner ear have clinical implications for both therapeutic and cytotoxic mechanisms that may aid in the preservation of auditory function. PMID: 26...
Source: Hearing Research - November 25, 2015 Category: Audiology Authors: Manohar S, Jamesdaniel S, Ding D, Salvi R, Seigel GM, Roth JA Tags: Hear Res Source Type: research

A method to measure sound transmission via the malleus-incus complex.
CONCLUSION: The transfer function of the human MIC, based on motion of the umbo and lenticularis, has been visualized and analyzed. While the magnitude of the transfer function decreases with frequency, its spatio-temporal complexity increases significantly. PMID: 26626362 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - November 25, 2015 Category: Audiology Authors: Dovrev I, Ihrle S, Röösli C, Gerig R, Eiber A, Huber AM, Sim JH Tags: Hear Res Source Type: research

Corticofugal modulation of DPOAEs in gerbils.
l;ssl M Abstract Efferent auditory feedback on cochlear hair cells is well studied regarding olivocochlear brainstem mechanisms. Less is known about how the descending corticofugal system may shape efferent feedback and modulate cochlear mechanics. Distortion-product otoacoustic emissions (DPOAEs) are a suitable tool to assess outer hair cell function, as they are by-products of the nonlinear cochlear amplification process. The present project investigates the effects of cortical activity on cubic and quadratic DPOAEs in mongolian gerbils, Meriones unguiculatus, through cortical deactivation using the sodium-chann...
Source: Hearing Research - November 24, 2015 Category: Audiology Authors: Jäger K, Kössl M Tags: Hear Res Source Type: research

Mandarin Chinese vowel-plus-tone identification in noise: effects of language experience.
In conclusion, the native English experience may improve native Chinese listeners' capacity to use temporal glimpses in TM noise, possibly depending on the modulation frequency and depth, while it may not improve their ability to resist the informational masking of babble when perceiving their native speech. PMID: 26611794 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - November 20, 2015 Category: Audiology Authors: Li M, Wang W, Tao S, Dong Q, Guan J, Liu C Tags: Hear Res Source Type: research

Whole scalp resting state EEG of oscillatory brain activity shows no parametric relationship with psychoacoustic and psychosocial assessment of tinnitus: a repeated measures study.
Abstract Tinnitus is a perception of sound that can occur in the absence of an external stimulus. A brief review of electroencephalography (EEG) and magnetoencephalography (MEG) literature demonstrates that there is no clear relationship between tinnitus presence and frequency band power in whole scalp or source oscillatory activity. Yet a preconception persists that such a relationship exists and that resting state EEG could be utilised as an outcome measure for clinical trials of tinnitus interventions, e.g. as a neurophysiological marker of therapeutic benefit. To address this issue, we first examined the test-...
Source: Hearing Research - November 13, 2015 Category: Audiology Authors: Pierzycki RH, McNamara AJ, Hoare DJ, Hall DA Tags: Hear Res Source Type: research

Effects of Noise Exposure on Development of Tinnitus and Hyperacusis: Prevalence rates 12 months after exposure in Middle-Aged Rats.
Abstract Fischer Brown Norway (FBN) rats (n=233) were unilaterally exposed to 12 different combinations of noise intensity, duration, and spectrum, while 46 rats served as sham-exposed controls. Rats were behaviorally tested for tinnitus and hyperacusis using gap-induced inhibition of the acoustic startle reflex (Gap) and prepulse inhibition (PPI) using 60-dB SPL before noise-exposure and at regular intervals for 12 mo. 12-mo after noise exposure the middle-aged rats were then tested again for tinnitus and hyperacusis before collecting Auditory Brainstem Response (ABR) thresholds. Collapsing across all noise expos...
Source: Hearing Research - November 13, 2015 Category: Audiology Authors: Turner JG, Larsen D Tags: Hear Res Source Type: research

Auditory system of fruit flies.
Abstract The fruit fly, Drosophila melanogaster, is an invaluable model for auditory research. Advantages of using the fruit fly include its stereotyped behavior in response to a particular sound, and the availability of molecular-genetic tools to manipulate gene expression and cellular activity. Although the receiver type in fruit flies differs from that in mammals, the auditory systems of mammals and fruit flies are strikingly similar with regard to the level of development, transduction mechanism, mechanical amplification, and central projections. These similarities strongly support the use of the fruit fly to ...
Source: Hearing Research - November 8, 2015 Category: Audiology Authors: Ishikawa Y, Kamikouchi A Tags: Hear Res Source Type: research

Attentional Modulation of Informational Masking on Early Cortical Representations of Speech Signals.
Abstract To recognize speech in a noisy auditory scene, listeners need to perceptually segregate the target talker's voice from other competing sounds (stream segregation). A number of studies have suggested that the attentional demands placed on listeners increase as the acoustic properties and informational content of the competing sounds become more similar to that of the target voice. Hence we would expect attentional demands to be considerably greater when speech is masked by speech than when it is masked by steady-state noise. To investigate the role of attentional mechanisms in the unmasking of speech sound...
Source: Hearing Research - November 8, 2015 Category: Audiology Authors: Zhang C, Arnott SR, Rabaglia C, Avivi-Reich M, Qi J, Wu X, Li L, Schneider BA Tags: Hear Res Source Type: research

High doses of salicylate reduces glycinergic inhibition in the dorsal cochlear nucleus of the rat.
;o RM Abstract High doses of salicylate induce reversible tinnitus in experimental animals and humans, and is a common tinnitus model. Salicylate probably acts centrally and induces hyperactivity in specific auditory brainstem areas like the dorsal cochlear nucleus (DCN). However, little is known about the effect of high doses of salicylate in synapses and neurons of the DCN. Here we investigated the effects of salicylate on the excitability and evoked and spontaneous neurotransmission in the main neurons (fusiform, cartwheel and tuberculoventral) and synapses of the DCN using whole cell recordings in slices conta...
Source: Hearing Research - November 5, 2015 Category: Audiology Authors: Zugaib J, Ceballos CC, Leão RM Tags: Hear Res Source Type: research

Binaural beats increase interhemispheric alpha-band coherence between auditory cortices.
rg AG Abstract Binaural beats (BBs) are an auditory illusion occurring when two tones of slightly different frequency are presented separately to each ear. BBs have been suggested to alter physiological and cognitive processes through synchronization of the brain hemispheres. To test this, we recorded electroencephalograms (EEG) at rest and while participants listened to BBs or a monaural control condition during which both tones were presented to both ears. We calculated for each condition the interhemispheric coherence, which expressed the synchrony between neural oscillations of both hemispheres. Compared to mo...
Source: Hearing Research - November 2, 2015 Category: Audiology Authors: Solcà M, Mottaz A, Guggisberg AG Tags: Hear Res Source Type: research

Duration sensitivity of neurons in the primary auditory cortex of albino mouse.
Abstract Many neurons in the central auditory system of a number of species have been found to be sensitive to the duration of sound stimuli. While previous studies have shown that γ-aminobutyric acid (GABA)-ergic inhibitory input is important for duration sensitivity in the inferior colliculus (IC), it is still unknown whether (GABA)-ergic inhibitory input plays an important role in generating duration sensitivity in the cortex. Using free-field sound stimulation and in vivo extracellular recording, we investigated duration sensitivity in primary auditory cortical (AI) neurons of the Nembutal anesthetized a...
Source: Hearing Research - October 31, 2015 Category: Audiology Authors: Wang X, Qi Q, Huang C, Chomiak T, Luo F Tags: Hear Res Source Type: research

Animal models of tinnitus.
Abstract Presented is a thematic review of animal tinnitus models from a functional perspective. Chronic tinnitus is a persistent subjective sound sensation, emergent typically after hearing loss. Although the sensation is experientially simple, it appears to have central a nervous system substrate of unexpected complexity that includes areas outside of those classically defined as auditory. Over the past 27 years animal models have significantly contributed to understanding tinnitus' complex neurophysiology. In that time, a diversity of models have been developed, each with its own strengths and limitations. None...
Source: Hearing Research - October 30, 2015 Category: Audiology Authors: Brozoski TJ, Bauer CA Tags: Hear Res Source Type: research

The consequences of tinnitus and tinnitus severity on cognition: a review of the behavioural evidence.
Abstract People with tinnitus report anecdotal difficulties in mental concentration and psychological treatments for tinnitus advise on concentration difficulties and how to manage them. Yet the literature lacks any coherent discussion about what precise theoretical cognitive constructs might be mediating reported concentration problems. This review addresses this gap by describing and critically appraising the behavioural evidence for the effects of tinnitus on cognitive performance (namely working memory and attention). Empirical evidence is somewhat limited, but there is some support that tinnitus interferes wi...
Source: Hearing Research - October 30, 2015 Category: Audiology Authors: Mohamad N, Hoare D, Hall DA Tags: Hear Res Source Type: research

The immediate effects of acoustic trauma on excitation and inhibition in the inferior colliculus: a Wiener-kernel analysis.
Abstract Noise-induced tinnitus and hyperacusis are thought to correspond to a disrupted balance between excitation and inhibition in the central auditory system. Excitation and inhibition are often studied using pure tones; however, these responses do not reveal inhibition within the excitatory pass band. Therefore, we used a Wiener-kernel analysis, complemented with singular value decomposition (SVD), to investigate the immediate effects of acoustic trauma on excitation and inhibition in the inferior colliculus (IC). Neural responses were recorded from the IC of three anesthetized albino guinea pigs before and i...
Source: Hearing Research - October 30, 2015 Category: Audiology Authors: Heeringa AN, van Dijk P Tags: Hear Res Source Type: research

Untangling the effects of tinnitus and hypersensitivity to sound (hyperacusis) in the gap detection test.
Abstract In recent years, there has been increasing use of the gap detection reflex test to demonstrate induction of tinnitus in animals. Animals with tinnitus show weakened gap detection ability for background noise that matches the pitch of the tinnitus. The usual explanation is that the tinnitus 'fills in the gap'. It has recently been shown, however, that tinnitus is commonly associated with hyperacusis-like enhancements of the acoustic startle response, a change which might potentially alter responses in the gap detection test. We hypothesized that such enhancements could lead to an apparent reduction of gap ...
Source: Hearing Research - October 28, 2015 Category: Audiology Authors: Salloum RH, Sandridge S, Patton DJ, Stillitano G, Dawson G, Niforatos J, Santiago L, Kaltenbach JA Tags: Hear Res Source Type: research

The hidden dysfunction of otolithic organs in patients with profound sensorineural hearing loss.
Abstract OBJECTIVE: To define the profiles of ocular and cervical vestibular-evoked myogenic potentials (oVEMP and cVEMP, respectively) in patients with profound sensorineural hearing loss (PSHL). METHODS: Twenty-nine patients with PSHL and 20 healthy volunteers were investigated. The patients' medical records were collected and analyzed. The ACS-evoked oVEMPs and cVEMPs and caloric test were tested and analyzed. RESULTS: The oVEMP and cVEMP response rates in the patients with PSHL were 38.9% and 44.4%, respectively, and these values were significantly less than those in the healthy volunteers (both were...
Source: Hearing Research - October 28, 2015 Category: Audiology Authors: Xu XD, Ding CR, Yu J, Han Z, Gu J, Gao N, Jia XH, Luo X, Wang J, Chi FL Tags: Hear Res Source Type: research

Immune defense is the primary function associated with the differentially expressed genes in the cochlea following acoustic trauma.
Abstract Our previous RNA-sequencing analysis of the rat cochlear genes identified multiple biological processes and molecular pathways in the cochlear response to acoustic overstimulation. However, the biological processes and molecular pathways that are common to other species have not been documented. The identification of these common stress processes is pivotal for a better understanding of the essential response of the cochlea to acoustic injury. Here, we compared the RNA-sequencing data collected from mice and rats that sustained a similar, but not identical, acoustic injury. The transcriptome analysis of c...
Source: Hearing Research - October 28, 2015 Category: Audiology Authors: Yang S, Cai Q, Vethanayagam RR, Wang J, Yang W, Hu BH Tags: Hear Res Source Type: research

High-frequency hearing in seals and sea lions.
Abstract Existing evidence suggests that some pinnipeds (seals, sea lions, and walruses) can detect underwater sound at frequencies well above the traditional high-frequency hearing limits for their species. This phenomenon, however, is not well studied: Sensitivity patterns at frequencies beyond traditional high-frequency limits are poorly resolved, and the nature of the auditory mechanism mediating hearing at these frequencies is unknown. In the first portion of this study, auditory sensitivity patterns in the 50-180 kHz range were measured for one California sea lion (Zalophus californianus), one harbor seal (P...
Source: Hearing Research - October 27, 2015 Category: Audiology Authors: Cunningham KA, Reichmuth C Tags: Hear Res Source Type: research

Temporal pattern of acoustic imaging noise asymmetrically modulates activation in the auditory cortex.
This study investigated the hemisphere-specific effects of the temporal pattern of imaging related acoustic noise on auditory cortex activation. Hemodynamic responses (HDRs) to five temporal patterns of imaging noise corresponding to noise generated by unique combinations of imaging volume and effective repetition time (TR), were obtained using a stroboscopic event-related paradigm with extra-long (≥27.5s) TR to minimize inter-acquisition effects. In addition to confirmation that fMRI responses in auditory cortex do not behave in a linear manner, temporal patterns of imaging noise were found to modulate both the shape a...
Source: Hearing Research - October 27, 2015 Category: Audiology Authors: Ranaweera RD, Kwon M, Hu S, Tamer GG, Luh WM, Talavage TM Tags: Hear Res Source Type: research

Synaptic Mechanisms Shaping Delay-Tuned Combination-Sensitivity in The Auditory Thalamus of Mustached Bats.
Abstract For the processing of target-distance information, delay-tuned auditory neurons of the mustached bat show facilitative responses to a combination of signal elements of a biosonar pulse-echo pair with a specific echo delay. They are initially produced in the inferior colliculus by facilitative responses based on the coincidence of the rebound response following glycinergic inhibition to the first harmonic of the pulse and a short-latency response to the 2nd-4th harmonics of its echo. Here, we report that further facilitative responses to pulse-echo pairs of thalamic delay-tuned neurons are mediated by glut...
Source: Hearing Research - October 27, 2015 Category: Audiology Authors: Butman JA, Suga N Tags: Hear Res Source Type: research

High frequency bone conduction auditory evoked potentials in the guinea pig: Assessing cochlear injury after ossicular chain manipulation.
The objectives of the present study were firstly to evaluate a novel high frequency bone conduction transducer with evoked auditory potentials in a guinea pig model, and secondly to use this model to investigate the impact of middle ear surgical manipulation on cochlear function. We modified a magnetostrictive device as a high frequency BC transducer and evaluated its performance by comparison with a calibrated AC transducer at frequencies up to 32 kHz using the auditory brainstem response (ABR), compound action potential (CAP) and summating potential (SP). To mimic a middle ear traumatising stimulus, a rotating bur w...
Source: Hearing Research - October 19, 2015 Category: Audiology Authors: Bergin MJ, Bird PA, Vlajkovic SM, Thorne PR Tags: Hear Res Source Type: research

Thin-film micro-electrode stimulation of the cochlea in rats exposed to aminoglycoside induced hearing loss.
Abstract The multi-channel cochlear implant (CI) provides sound and speech perception to thousands of individuals who would otherwise be deaf. Broad activation of auditory nerve fibres when using a CI results in poor frequency discrimination. The CI also provides users with poor amplitude perception due to elicitation of a narrow dynamic range. Provision of more discrete frequency perception and a greater control over amplitude may allow users to better distinguish speech in noise and to segregate sound sources. In this research, thin-film (TF) high density micro-electrode arrays and conventional platinum ring ele...
Source: Hearing Research - October 14, 2015 Category: Audiology Authors: Allitt BJ, Harris AR, Morgan SJ, Clark GM, Paolini AG Tags: Hear Res Source Type: research

Suprathreshold auditory processing deficits in noise: Effects of hearing loss and age.
Abstract People with sensorineural hearing loss generally suffer from a reduced ability to understand speech in complex acoustic listening situations, particularly when background noise is present. In addition to the loss of audibility, a mixture of suprathreshold processing deficits is possibly involved, like altered basilar membrane compression and related changes, as well as a reduced ability of temporal coding. A series of 6 monaural psychoacoustic experiments at 0.5, 2, and 6 kHz was conducted with 18 subjects, divided equally into groups of young normalhearing, older normal-hearing and older hearing-impaired...
Source: Hearing Research - October 14, 2015 Category: Audiology Authors: Kortlang S, Mauermann M, Ewert SD Tags: Hear Res Source Type: research

Prenatal low dosage dioxin (TCDD) exposure impairs cochlear function resulting in auditory neuropathy.
Abstract 2,3,7,8-tetrachorodibenzo-p-dioxin (TCDD), a ubiquitous and persistent environmental contaminant, is a potent teratogen. Whereas developmental TCDD toxicity is mediated by the aryl hydrocarbon receptor (AhR), the normal function of the AhR is poorly understood. We tested whether dioxin exposure during a critical period of hair cell development disrupts cochlear function in three mouse strains, (C57BL6, BalbC, and CBA) that contain high affinity AhR-b alleles. C57BL/6, BalbC, and CBA dams were exposed to 500 ng/kg TCDD or olive oil (vehicle) on embryonic day 12 by gavage. Cochlear function was analyze...
Source: Hearing Research - October 11, 2015 Category: Audiology Authors: Safe TM, Luebke AE Tags: Hear Res Source Type: research

Novel in vivo imaging analysis of an inner ear drug delivery system: drug availability in inner ear following different dose of systemic drug injections.
This study provides a better understanding of in vivo drug delivery dynamics measured in the inner ear. Further studies will show whether a high dosage of drug is effective or not. PMID: 26435094 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 1, 2015 Category: Audiology Authors: Kanzaki S, Watanabe K, Fujioka M, Shibata S, Nakamura M, Okano HJ, Okano H, Ogawa K Tags: Hear Res Source Type: research

Blind people are more sensitive than sighted people to binaural sound-location cues, particularly inter-aural level differences.
Abstract Blind people use auditory information to locate sound sources and sound-reflecting objects (echolocation). Sound source localization benefits from the hearing system's ability to suppress distracting sound reflections, whereas echolocation would benefit from "unsuppressing" these reflections. To clarify how these potentially conflicting aspects of spatial hearing interact in blind versus sighted listeners, we measured discrimination thresholds for two binaural location cues: inter-aural level differences (ILDs) and inter-aural time differences (ITDs). The ILDs or ITDs were present in single clic...
Source: Hearing Research - September 30, 2015 Category: Audiology Authors: Nilsson ME, Schenkman BN Tags: Hear Res Source Type: research

Cochlear Implantation as a Long-Term Treatment for Ipsilateral Incapacitating Tinnitus in Subjects with Unilateral Hearing Loss up to 10 years.
CONCLUSION: This is the first study to report on LT results in a large number of UHL CI users, up to 10 years. Structured interviews shows that 100% of the subjects wears their CI seven days a week. The tinnitus reduces significantly up to three months after the first-fitting and the tinnitus reduction remain stable up to the LT test interval. The SSD group report tinnitus reduction as the primary benefit, whereas the majority of the AHL group report improved hearing as the primary benefit, eight (3-10) years after implantation. In addition to the tinnitus reduction, the CI provides also a benefit regarding reported. ...
Source: Hearing Research - September 30, 2015 Category: Audiology Authors: Mertens G, De Bodt M, Van de Heyning P Tags: Hear Res Source Type: research

Cannabinoids, cannabinoid receptors and tinnitus.
Abstract One hypothesis suggests that tinnitus is a form of sensory epilepsy, arising partly from neuronal hyperactivity in auditory regions of the brain such as the cochlear nucleus and inferior colliculus. Although there is currently no effective drug treatment for tinnitus, anti-epileptic drugs are used in some cases as a potential treatment option. There is increasing evidence to suggest that cannabinoid drugs, i.e. cannabinoid receptor agonists, can also have anti-epileptic effects, at least in some cases and in some parts of the brain. It has been reported that cannabinoid CB1 receptors and the endogenous ca...
Source: Hearing Research - September 30, 2015 Category: Audiology Authors: Smith PF, Zheng Y Tags: Hear Res Source Type: research

Audiograms, gap detection thresholds, and frequency difference limens in cannabinoid receptor 1 knockout mice.
Abstract The cannabinoid receptor 1 (CB1R) is found at several stages in the auditory pathway, but its role in hearing is unknown. Hearing abilities were measured in CB1R knockout mice and compared to those of wild-type mice. Operant conditioning and the psychophysical Method of Constant Stimuli were used to measure audiograms, gap detection thresholds, and frequency difference limens in trained mice using the same methods and stimuli as in previous experiments. CB1R knockout mice showed deficits at frequencies above 8 kHz in their audiograms relative to wild-type mice. CB1R knockouts showed enhancements for ...
Source: Hearing Research - September 28, 2015 Category: Audiology Authors: Toal KL, Radziwon KE, Holfoth DP, Xu-Friedman MA, Dent ML Tags: Hear Res Source Type: research

Neural networks of tinnitus in humans: Elucidating severity and habituation.
Abstract The article reviews current data about the neural correlates of an individual's reaction to tinnitus, primarily from studies that employ magnetic resonance imaging (MRI). Human studies employing brain imaging remain the most commonly used method to understand neural biomarkers of the reaction to tinnitus, a subjective hearing disorder. Evidence from anatomical and functional MRI studies is reviewed to better understand the large-scale neural networks implicated in tinnitus habituation and severity. These networks are concerned with attention, audition, and emotion, both during tasks and at 'rest' when no ...
Source: Hearing Research - September 25, 2015 Category: Audiology Authors: Husain FT Tags: Hear Res Source Type: research

Psychometric properties of the Tinnitus Functional Index (TFI): assessment in a UK research volunteer population.
CONCLUSION: Even though the proposed 8-factor structure was not fully confirmed for this population, the TFI appears to cover multiple symptom domains, and to measure the construct of tinnitus with an excellent reliability in distinguishing between patients. While the TFI may discriminate those whose tinnitus is not a problem, floor effects in many items means it is less appropriate as a measure of change in this subgroup. Further investigation is needed to determine whether these effects are relevant in other populations. PMID: 26415998 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - September 25, 2015 Category: Audiology Authors: Fackrell K, Hall DA, Barry JG, Hoare DJ Tags: Hear Res Source Type: research

Information Theoretic Evaluation of a Noiseband-Based Cochlear Implant Simulator.
This study assessed the similarity in vowel identification of CI subjects and NH subjects using an 8-channel noise-band vocoder simulator configured to match input and output frequencies or to mimic output after a basalward shift of input frequencies. Under each stimulus condition, NH subjects performed the task both with and without feedback/training. Similarity of NH subjects to CI users was evaluated using correct identification rates and information theoretic approaches. Feedback/training produced higher rates of correct identification, as expected, but also resulted in error patterns that were closer to those of the C...
Source: Hearing Research - September 23, 2015 Category: Audiology Authors: Aguiar DE, Taylor NE, Li J, Gazanfari DK, Talavage TM, Laflen JB, Neuberger H, Svirsky MA Tags: Hear Res Source Type: research

Synaptic Studies Inform the Functional Diversity of Cochlear Afferents.
Abstract Type I and type II cochlear afferents differ markedly in number, morphology and innervation pattern. The predominant type I afferents transmit the elemental features of acoustic information to the central nervous system. Excitation of these large diameter myelinated neurons occurs at a single ribbon synapse of a single inner hair cell. This solitary transmission point depends on efficient vesicular release that can produce large, rapid, suprathreshold excitatory postsynaptic potentials. In contrast, the many fewer, thinner, unmyelinated type II afferents cross the tunnel of Corti, turning basally for hund...
Source: Hearing Research - September 21, 2015 Category: Audiology Authors: Fuchs PA, Glowatzki E Tags: Hear Res Source Type: research

Hearing aid validation based on 40 Hz auditory steady-state response thresholds.
This study aimed to compare characteristics of aided and unaided auditory steady-state responses (ASSRs). METHODS: A total of 30 moderate to profoundly hearing-impaired subjects participated in this study. The subjects underwent acoustic immittance, behavioral audiometry, and ASSR with the modulation rate of 40 Hz, first without a hearing aid and then with a hearing aid. Sixteen people with normal hearing and 17 people with severe hearing loss were included in biological calibration of the sound field. RESULTS: There was a significant difference between unaided behavioral and ASSR thresholds in all test freq...
Source: Hearing Research - September 16, 2015 Category: Audiology Authors: Sardari S, Jafari Z, Haghani H, Talebi H Tags: Hear Res Source Type: research

Induction of single sided deafness in the newborn rat and its consequence for cochlear nucleus volume development.
Abstract Aim of this study was to induce a single sided deafness (SSD) in rats before hearing onset. Rats were operated at postnatal day 10 by approaching the tympanic cavity along a retroauricular path without manipulating ossicles or tympanic membrane. The ototoxic aminoglycoside neomycin was injected intracochlearly through the round window membrane on one side. When the animals have reached young adult stages, their hearing threshold was determined by their auditory brainstem response (ABR). Monaural deafening was considered successful when the hearing threshold was at least 95 dB above the threshold of the no...
Source: Hearing Research - September 16, 2015 Category: Audiology Authors: Jakob TF, Rosskothen-Kuhl N, Illing RB Tags: Hear Res Source Type: research

Otoacoustic emissions in young adults: Effects of blood group [R.1].
Abstract Previous research findings have suggested that individuals with different blood groups demonstrate varied haematological risk factors for a wide range of disorders, including noise-induced hearing loss. The present study investigated the effects of blood group on several features of otoacoustic emissions (OAEs) including magnitude, as OAE status is indicative of cochlear function. A total of 60 normal hearing females aged between 18 to 26 years were included in the study. Measurements of spontaneous otoacoustic emissions (SOAEs), transient-evoked emissions (TEOAEs) and distortion-product otoacoustic emiss...
Source: Hearing Research - September 13, 2015 Category: Audiology Authors: Chow KT, McPherson B, Fuente A Tags: Hear Res Source Type: research

Ischemia as a potential etiologic factor in idiopathic unilateral sudden sensorineural hearing loss: Analysis of posterior circulation arteries.
Abstract The association between idiopathic sudden sensorineural hearing loss (ISSNHL) and the radiologic characteristics of the vertebrobasilar artery is unclear. We hypothesized that the degree and direction of vertebrobasilar artery curvature in the posterior circulation contribute to the occurrence of ISSNHL. We consecutively enrolled patients diagnosed with unilateral ISSNHL in two tertiary hospitals. Magnetic resonance images were performed in all patients to exclude specific causes of ISSNHL, such as vestibular schwannoma, chronic mastoiditis, and anterior inferior cerebellar artery infarct. We measured the...
Source: Hearing Research - September 11, 2015 Category: Audiology Authors: Kim C, Sohn JH, Jang MU, Hong SK, Lee JS, Kim HJ, Choi HC, Lee JH Tags: Hear Res Source Type: research

Speech-evoked ABR: Effects of age and simulated neural temporal jitter.
Abstract The speech-evoked auditory brainstem response (sABR) provides a measure of encoding complex stimuli in the brainstem, and this study employed the sABR to better understand the role of neural temporal jitter in the response patterns from older adults. In experiment 1, sABR recordings were used to investigate age-related differences in periodicity encoding of the temporal envelope and fine structure components of the response to a/da/speech token. A group of younger and a group of older adults (n=22 per group) participated. The results demonstrated reduced amplitude of the fundamental frequency and harmonic...
Source: Hearing Research - September 11, 2015 Category: Audiology Authors: Mamo SK, Grose JH, Buss E Tags: Hear Res Source Type: research

Medial Olivocochlear Efferent Reflex Inhibition of Human Cochlear Nerve Responses.
Abstract Inhibition of cochlear amplifier gain by the medial olivocochlear (MOC) efferent system has several putative roles: aiding listening in noise, protection against damage from acoustic overexposure, and slowing age-induced hearing loss. The human MOC reflex has been studied almost exclusively by measuring changes in otoacoustic emissions. However, to help understand how the MOC system influences what we hear, it is important to have measurements of the MOC effect on the total output of the organ of Corti, i.e., on cochlear nerve responses that couple sounds to the brain. In this work we measured the inhibit...
Source: Hearing Research - September 10, 2015 Category: Audiology Authors: Lichtenhan JT, Wilson US, Hancock KE, Guinan JJ Tags: Hear Res Source Type: research

Tinnitus and anxiety disorders: a review.
CONCLUSION: Comorbidity is high and screening for and treatment of anxiety disorders is recommended in moderate to severe tinnitus, as, given the overlap in the structural and functional brain circuitries involved, theoretically, their management could improve (subjective) levels of tinnitus although further empirical research on this topic is required. PMID: 26342399 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - September 2, 2015 Category: Audiology Authors: Pattyn T, Van Den Eede F, Vanneste S, Cassiers L, Veltman DJ, Van De Heyning P, Sabbe BC Tags: Hear Res Source Type: research

Dunnione ameliorates cisplatin ototoxicity through modulation of NAD(+) metabolism.
Abstract Ototoxicity is an important issue in patients receiving cisplatin chemotherapy. Numerous studies have demonstrated that cisplatin-induced ototoxicity is related to oxidative stress and DNA damage. However, the precise mechanism underlying cisplatin-associated ototoxicity is still unclear. The cofactor nicotinamide adenine dinucleotide (NAD(+)) has emerged as an important regulator of energy metabolism and cellular homeostasis. Here, we demonstrate that the levels and activities of sirtuin-1 (SIRT1) are suppressed by the reduction of intracellular NAD(+) levels in cisplatin-mediated ototoxicity. We provide...
Source: Hearing Research - September 1, 2015 Category: Audiology Authors: Kim HJ, Pandit A, Oh GS, Shen A, Lee SB, Khadka D, Lee S, Shim H, Yang SH, Cho EY, Kwak TH, Choe SK, Park R, So HS Tags: Hear Res Source Type: research

Delayed loss of hearing after hearing preservation cochlear implantation: human temporal bone pathology and implications for etiology.
Abstract After initially successful preservation of residual hearing with cochlear implantation, some patients experience subsequent delayed hearing loss. The etiology of such delayed hearing loss is unknown. Human temporal bone pathology is critically important in investigating the etiology, and directing future efforts to maximize long term hearing preservation in cochlear implant patients. Here we present the temporal bone pathology from a patient implanted during life with an Iowa/Nucleus Hybrid S8 implant, with initially preserved residual hearing and subsequent hearing loss. Both temporal bones were removed ...
Source: Hearing Research - September 1, 2015 Category: Audiology Authors: Quesnel AM, Nakajima HH, Rosowski JJ, Hansen MR, Gantz BJ, Nadol JB Tags: Hear Res Source Type: research