Development of intra-operative assessment system for ossicular mobility and middle ear transfer function.
In this study, a new system with a hand-held probe which enables intraoperative quantitative measurements of ossicular mobility has been developed. This system not only measures the ossicular mobility, but also investigates "local" transmission characteristics of the middle ear by directly applying vibration to the ossicles and measuring cochlear microphonic. The basic performance of this system was confirmed by measuring the mobility of artificial ossicles and cochlear microphonics in an animal experiment. Our system may contribute to selection of a better surgical method and reducing the risks of revision surge...
Source: Hearing Research - November 22, 2018 Category: Audiology Authors: Koike T, Irie Y, Ebine R, Fujishiro T, Kanzaki S, Keat CS, Higo T, Ohoyama K, Hayashi M, Ikegami H Tags: Hear Res Source Type: research

Investigating peripheral sources of speech-in-noise variability in listeners with normal audiograms.
In this study, we present a retrospective investigation of these peripheral sources and their relationship with SIN performance variability in one of the largest datasets of young normal-hearing listeners presented to date. 194 participants completed detailed case history questionnaires assessing noise exposure, SIN complaints, tinnitus, and hyperacusis. Standard and extended high frequency audiograms, distortion product otoacoustic emissions, click-evoked auditory brainstem responses, and SIN performance measures were also collected. We found that: 1) the prevalence of SIN deficits in normal hearing listeners was 42% when...
Source: Hearing Research - November 22, 2018 Category: Audiology Authors: Smith SB, Krizman J, Liu C, White-Schwoch T, Nicol T, Kraus N Tags: Hear Res Source Type: research

Differential responses to spectrally degraded speech within human auditory cortex: An intracranial electrophysiology study.
This study investigated electrocorticographic (ECoG) responses to noise-vocoded speech and related these responses to behavioral performance in a phonemic identification task. Subjects were neurosurgical patients undergoing chronic invasive monitoring for medically refractory epilepsy. Stimuli were utterances /aba/ and /ada/, spectrally degraded using a noise vocoder (1-4 bands). ECoG responses were obtained from Heschl's gyrus (HG) and superior temporal gyrus (STG), and were examined within the high gamma frequency range (70-150 Hz). All subjects performed at chance accuracy with speech degraded to 1 and 2 spectral band...
Source: Hearing Research - November 22, 2018 Category: Audiology Authors: Nourski KV, Steinschneider M, Rhone AE, Kovach CK, Kawasaki H, Howard MA Tags: Hear Res Source Type: research

Tonotopy in calcium homeostasis and vulnerability of cochlear hair cells.
Abstract Ototoxicity, noise overstimulation, or aging, can all produce hearing loss with similar properties, in which outer hair cells (OHCs), principally those at the high-frequency base of the cochlea, are preferentially affected. We suggest that the differential vulnerability may partly arise from differences in Ca2+ balance among cochlear locations. Homeostasis is determined by three factors: Ca2+ influx mainly via mechanotransducer (MET) channels; buffering by calcium-binding proteins and organelles like mitochondria; and extrusion by the plasma membrane CaATPase pump. We review quantification of these parame...
Source: Hearing Research - November 16, 2018 Category: Audiology Authors: Fettiplace R, Nam JH Tags: Hear Res Source Type: research

Neural crest contributions to the ear: Implications for congenital hearing disorders.
Abstract Congenital hearing disorders affect millions of children worldwide and can significantly impact acquisition of speech and language. Efforts to identify the developmental genetic etiologies of conductive and sensorineural hearing losses have revealed critical roles for cranial neural crest cells (NCCs) in ear development. Cranial NCCs contribute to all portions of the ear, and defects in neural crest development can lead to neurocristopathies associated with profound hearing loss. The molecular mechanisms governing the development of neural crest derivatives within the ear are partially understood, but man...
Source: Hearing Research - November 14, 2018 Category: Audiology Authors: Ritter KE, Martin DM Tags: Hear Res Source Type: research

Intracochlear near infrared stimulation: Feasibility of optoacoustic stimulation in  vivo.
This study investigated the properties of a near infrared laser (NIR) induced optoacoustic effect. Pressure recordings were performed at the external meatus of anaesthetized guinea pigs during intracochlear NIR stimulation. The sound pressure and power spectra were determined. The results were compared to multi unit responses in the inferior colliculus (IC). Additionally, the responses to NIR stimulation were compared to IC responses induced by intracochlear electric stimulation at the same cochlear position to investigate a potentially confounding contribution of direct neural NIR stimulation. The power spectra of the sou...
Source: Hearing Research - November 12, 2018 Category: Audiology Authors: Baumhoff P, Kallweit N, Kral A Tags: Hear Res Source Type: research

The frequency-following response (FFR) to speech stimuli: A  normative dataset in healthy newborns.
The frequency-following response (FFR) to speech stimuli: A normative dataset in healthy newborns. Hear Res. 2018 Nov 09;371:28-39 Authors: Ribas-Prats T, Almeida L, Costa-Faidella J, Plana M, Corral MJ, Gómez-Roig MD, Escera C Abstract The Frequency-Following Response (FFR) is a neurophonic auditory evoked potential that reflects the efficient encoding of speech sounds and is disrupted in a range of speech and language disorders. This raises the possibility to use it as a potential biomarker for literacy impairment. However, reference values for comparison with the normal population are n...
Source: Hearing Research - November 9, 2018 Category: Audiology Authors: Ribas-Prats T, Almeida L, Costa-Faidella J, Plana M, Corral MJ, Gómez-Roig MD, Escera C Tags: Hear Res Source Type: research

Pulse-rate discrimination deficit in cochlear implant users: is the upper limit of pitch peripheral or central?
Abstract Cochlear implant (CI) users do not reliably associate an increase in pulse rate above 300 pulses per second (pps) with an increase in pitch. The locus of this upper limit of pitch remains unknown. The present study tested the hypothesis that this deficit resides at least initially at the auditory nerve. The hypothesis was tested by comparing pulse rate discrimination in different neural excitation patterns, in which a large versus small population of auditory nerve fibers was activated. If poorer pulse rate discrimination was found under conditions where narrower spread of neural excitation (SOE) was anti...
Source: Hearing Research - November 3, 2018 Category: Audiology Authors: Zhou N, Mathews J, Dong L Tags: Hear Res Source Type: research

Hot topics in Aging and Speech Communication: Current trends and future directions in basic, clinical and audiological research fields.
PMID: 30342726 [PubMed - in process] (Source: Hearing Research)
Source: Hearing Research - October 23, 2018 Category: Audiology Authors: Frisina RD Tags: Hear Res Source Type: research

Performance evaluation of a novel piezoelectric subcutaneous bone conduction device.
CONCLUSION: The sound transfer function efficacy of a novel subcutaneous bone conduction device has been quantified, and the influence of stimulation location and mastoidectomy have been analyzed based on promontory motion in Thiel-preserved cadaver heads. PMID: 30343248 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 6, 2018 Category: Audiology Authors: Dobrev I, Sim JH, Pfiffner F, Huber AM, Röösli C Tags: Hear Res Source Type: research

Spatial variation in signal and sensory precision both constrain auditory acuity at high frequencies.
Abstract Sensory performance is constrained by the information in the stimulus and the precision of the involved sensory system(s). Auditory spatial acuity is robust across a broad range of sound frequencies and source locations, but declines at eccentric lateral angles. The basis of such variation is not fully understood. Low-frequency auditory spatial acuity is mediated by sensitivity to interaural time difference (ITD) cues. While low-frequency spatial acuity varies across azimuth and some physiological models predict strong medial bias in the precision of ITD sensitivity, human psychophysical ITD sensitivity a...
Source: Hearing Research - October 4, 2018 Category: Audiology Authors: Brown AD, Benichoux V, Jones HG, Anbuhl KL, Tollin DJ Tags: Hear Res Source Type: research

Subtypes of GABAergic cells in the inferior colliculus.
Abstract The inferior colliculus occupies a central position in ascending and descending auditory pathways. A substantial proportion of its neurons are GABAergic, and these neurons contribute to intracollicular circuits as well as to extrinsic projections to numerous targets. A variety of types of evidence - morphology, physiology, molecular markers - indicate that the GABAergic cells can be divided into at least four subtypes that serve different functions. However, there has yet to emerge a unified scheme for distinguishing these subtypes. The present review discusses these criteria and, where possible, relates ...
Source: Hearing Research - October 4, 2018 Category: Audiology Authors: Schofield BR, Beebe NL Tags: Hear Res Source Type: research

In-vivo assessment of osseous versus non-osseous transmission pathways of vibratory stimuli applied to the bone and the dura in humans.
CONCLUSION: We demonstrate a proof-of-concept comparison of DPOAEs and teeth acceleration levels elicited by a bone vibrator placed either against the skin-covered temporal bone, as in audiometry, or directly against the dura mater in patients undergoing a craniotomy. It was demonstrated that DPOAEs could be elicited via non-osseous pathways within the skull contents and that the required measurements could be performed intra-operatively. PMID: 30292958 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - September 28, 2018 Category: Audiology Authors: Stump R, Dobrev I, Krayenbühl N, Probst R, Röösli C Tags: Hear Res Source Type: research

Cortical correlates of speech intelligibility measured using functional near-infrared spectroscopy (fNIRS).
Abstract Functional neuroimaging has identified that the temporal, frontal and parietal cortex support core aspects of speech processing. An objective measure of speech intelligibility based on cortical activation in these brain regions would be extremely useful to speech communication and hearing device applications. In the current study, we used noise-vocoded speech to examine cortical correlates of speech intelligibility in normally-hearing listeners using functional near-infrared spectroscopy (fNIRS), a non-invasive, neuroimaging technique that is fully-compatible with hearing devices, including cochlear impla...
Source: Hearing Research - September 25, 2018 Category: Audiology Authors: Lawrence RJ, Wiggins IM, Anderson CA, Davies-Thompson J, Hartley DEH Tags: Hear Res Source Type: research

Chronotolerance for cisplatin ototoxicity in the rat.
The objective of the study was to determine the sensitivity of cisplatin ototoxicity to circadian time. Fifty-seven Fischer 344/NHsd rats were exposed to 12 mg/kg cisplatin by intra-peritoneal injection at one of six time points on a 12 h light-12 h dark cycle: 2, 6, or 10 h after light onset or 2, 6, or 10 h after light offset. Cochlear injury was evaluated using auditory brainstem response threshold shifts and postmortem outer hair cell counts. All animals experienced threshold shift in the highest frequencies tested (30 and 40 kHz). The animals exposed to cisplatin at 6 h after light onset (the inactive pe...
Source: Hearing Research - September 18, 2018 Category: Audiology Authors: Bielefeld EC, Markle A, DeBacker JR, Harrison RT Tags: Hear Res Source Type: research

Rapamycin but not acarbose decreases age-related loss of outer hair cells in the mouse Cochlea.
Abstract Adding rapamycin or acarbose to diet at 9-10 months of age has been shown to significantly increase life span in both male and female UM-HET3 mice. The current study examined cochleae of male and female UM-HET3 mice at 22 months of age to determine if either treatment also influenced age-related loss of cochlear hair cells. A large loss of cochlear outer hair cells was observed at 22 months of age in untreated mice in both apical and basal halves of the cochlear spiral. Addition of acarbose to diet had no significant effect on the amount of outer hair cell loss at 22 months of age or in its pattern, with ...
Source: Hearing Research - September 7, 2018 Category: Audiology Authors: Altschuler RA, Kanicki A, Martin C, Kohrman DC, Miller RA Tags: Hear Res Source Type: research

A comparison of systemic and local dexamethasone administration: From perilymph/cochlea concentration to cochlear distribution.
Abstract Different types of inner ear diseases can damage different cochlear subsites by different mechanisms. Steroids administered by different methods are commonly used for treating inner ear diseases. There is reason to believe that dexamethasone (Dex) may reach cochlear subsite targets via different pathways after administration by different methods: Intratympanic (IT), postaural (PA), and intraperitoneal (IP). The purpose of this study was to explore the cochlear concentration and distribution of Dex after administration by different methods. High-performance liquid chromatography-mass spectrometry and immun...
Source: Hearing Research - September 7, 2018 Category: Audiology Authors: Wang Y, Han L, Diao T, Jing Y, Wang L, Zheng H, Ma X, Qi J, Yu L Tags: Hear Res Source Type: research

Dimension-selective attention as a possible driver of dynamic, context-dependent re-weighting in speech processing.
Abstract The contribution of acoustic dimensions to an auditory percept is dynamically adjusted and reweighted based on prior experience about how informative these dimensions are across the long-term and short-term environment. This is especially evident in speech perception, where listeners differentially weight information across multiple acoustic dimensions, and use this information selectively to update expectations about future sounds. The dynamic and selective adjustment of how acoustic input dimensions contribute to perception has made it tempting to conceive of this as a form of non-spatial auditory selec...
Source: Hearing Research - August 24, 2018 Category: Audiology Authors: Holt LL, Tierney AT, Guerra G, Laffere A, Dick F Tags: Hear Res Source Type: research

Input-output curves of low and high spontaneous rate auditory nerve fibers are exponential near threshold.
Abstract Input-output (IO) properties of cochlear transduction are frequently determined by analyzing the average discharge rates of auditory nerve fibers (ANFs) in response to relatively long tonal stimulation. The ANFs in cats have spontaneous discharge rates (SRs) that are bimodally distributed, peaking at low (
Source: Hearing Research - August 24, 2018 Category: Audiology Authors: Horst JW, McGee J, Walsh EJ Tags: Hear Res Source Type: research

Editorial introduction: The 6th International Conference on Auditory Cortex.
PMID: 30126551 [PubMed - in process] (Source: Hearing Research)
Source: Hearing Research - August 23, 2018 Category: Audiology Authors: Butler BE, Cohen YE, Lomber SG Tags: Hear Res Source Type: research

Human frequency following responses to iterated rippled noise with positive and negative gain: Differential sensitivity to waveform envelope and temporal fine-structure.
Abstract The perceived pitch of iterated rippled noise (IRN) with negative gain (IRNn) is an octave lower than that of IRN with positive gain (IRNp). IRNp and IRNn have identical waveform envelopes (ENV), but differing stimulus waveform fine structure (TFS), which likely accounts for this perceived pitch difference. Here, we examine whether differences in the temporal pattern of phase-locked activity reflected in the human brainstem Frequency Following Response (FFR) elicited by IRNp and IRNn can account for the differences in perceived pitch for the two stimuli. FFRs using a single onset polarity were measured in...
Source: Hearing Research - July 29, 2018 Category: Audiology Authors: Ananthakrishnan S, Krishnan A Tags: Hear Res Source Type: research

Detection of single mRNAs in individual cells of the auditory system.
Abstract Gene expression analysis is essential for understanding the rich repertoire of cellular functions. With the development of sensitive molecular tools such as single-cell RNA sequencing, extensive gene expression data can be obtained and analyzed from various tissues. Single-molecule fluorescence in situ hybridization (smFISH) has emerged as a powerful complementary tool for single-cell genomics studies because of its ability to map and quantify the spatial distributions of single mRNAs at the subcellular level in their native tissue. Here, we present a detailed method to study the copy numbers and spatial ...
Source: Hearing Research - July 29, 2018 Category: Audiology Authors: Salehi P, Nelson CN, Chen Y, Lei D, Crish SD, Nelson J, Zuo H, Bao J Tags: Hear Res Source Type: research

Age-related changes in Na, K-ATPase expression, subunit isoform selection and assembly in the stria vascularis lateral wall of mouse cochlear.
Abstract Due to the critical role of cochlear ion channels for hearing, the focus of the present study was to examine age-related changes of Na, K-ATPase (NKA) subunits in the lateral wall of mouse cochlea. We combined qRT-PCR, western blot and immunocytochemistry methodologies in order to determine gene and protein expression levels in the lateral wall of young and aged CBA/CaJ mice. Of the seven NKA subunits, only the mRNA expressions of α1, β1 and β2 subunit isoforms were detected in the lateral wall of CBA/CaJ mice. Aging was accompanied by dys-regulation of gene and protein expression of all t...
Source: Hearing Research - July 10, 2018 Category: Audiology Authors: Ding B, Walton JP, Zhu X, Frisina RD Tags: Hear Res Source Type: research

Neuroanatomical characterization of perineuronal net components in the human cochlear nucleus and superior olivary complex.
In conclusion, the present study demonstrates that PNs form a prominent extracellular structure on CN and SOC neurons in the human brain, potentially stabilizing synaptic contacts, which is in agreement with many other mammalian species. PMID: 30025262 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - July 10, 2018 Category: Audiology Authors: Weinrich L, Sonntag M, Arendt T, Morawski M Tags: Hear Res Source Type: research

Hearing preservation at low frequencies by insulin-like growth factor 1 in a guinea pig model of cochlear implantation.
In this study, the effects of IGF1 on hearing preservation were examined after cochlear implantation to a normal-hearing guinea pig model. The electrode was inserted in an atraumatic way through the round window membrane of guinea pigs with the application of a gelatin-sponge soaked with IGF1 or saline. The auditory brainstem response (ABR) was recorded pre-operatively, immediately after cochlear implantation, and 7, 14, 28, and 56 days after electrode insertion. In comparison to the control group, the IGF1-treated group showed better hearing preservation at low frequencies, 7 days after surgery. IGF1 application was effec...
Source: Hearing Research - July 6, 2018 Category: Audiology Authors: Yamahara K, Nishimura K, Ogita H, Ito J, Nakagawa T, Furuta I, Kita T, Omori K, Yamamoto N Tags: Hear Res Source Type: research

Perception of noise-vocoded tone complexes: A time domain analysis based on an auditory filterbank model.
Abstract When a wideband harmonic tone complex (wHTC) is passed through a noise vocoder, the resulting sounds can have spectra with large peak-to-valley ratios, but little or no periodicity strength in the autocorrelation functions. We measured judgments of pitch strength for normal-hearing listeners for noise-vocoded wideband harmonic tone complexes (NV-wHTCs) relative to standard and anchor stimuli. The standard was a 1-channel NV-wHTC and the anchor was either the unprocessed wHTC or an infinitely-iterated rippled noise (IIRN). Although there is variability among individuals, the magnitude judgment functions ob...
Source: Hearing Research - July 4, 2018 Category: Audiology Authors: Shofner WP, Morris H, Mills M Tags: Hear Res Source Type: research

Local drug delivery to the inner ear: Principles, practice, and future challenges.
PMID: 30006112 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - June 28, 2018 Category: Audiology Authors: Plontke SK, Salt AN Tags: Hear Res Source Type: research

Familiarity with social sounds alters c-Fos expression in auditory cortex and interacts with estradiol in locus coeruleus.
Abstract When a social sound category initially gains behavioral significance to an animal, plasticity events presumably enhance the ability to recognize that sound category in the future. In the context of learning natural social stimuli, neuromodulators such as norepinephrine and estrogen have been associated with experience-dependent plasticity and processing of newly salient social cues, yet continued plasticity once stimuli are familiar could disrupt the stability of sensorineural representations. Here we employed a maternal mouse model of natural sensory cortical plasticity for infant vocalizations to ask wh...
Source: Hearing Research - June 28, 2018 Category: Audiology Authors: Moreno A, Gumaste A, Adams GK, Chong KK, Nguyen M, Shepard KN, Liu RC Tags: Hear Res Source Type: research

Electric and acoustic harmonic integration predicts speech-in-noise performance in hybrid cochlear implant users.
CONCLUSIONS: We demonstrate integration of acoustic and electric information in H-CI users for complex pitch sensation. The correlation with speech scores in H-CI users might be associated with the ability to segregate a target speaker from background noise using the speaker's fundamental frequency. PMID: 29980380 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - June 28, 2018 Category: Audiology Authors: Bonnard D, Schwalje A, Gantz B, Choi I Tags: Hear Res Source Type: research

Neuroplastic change of cytoskeleton in inferior colliculus after auditory deafferentation.
In this study, we evaluated the dynamic status of neurofilament (NF) phosphorylation in the IC after hearing loss. We induced auditory deafferentation via unilateral or bilateral cochlear ablation in rats, aged 4 weeks. To evaluate cytoskeletal changes in neurons, we evaluated mRNA fold changes in NF heavy chain expression, non-phosphorylated NF protein fold changes using SMI-32 antibody, and the ratio of SMI-32 immunoreactive (SMI-32-ir) neurons to the total neuronal population in the IC at 4 and 12 weeks after deafness. In the bilateral deafness (BD) group, the ratios of SMI-32-ir neurons significantly increased at 4 wee...
Source: Hearing Research - June 23, 2018 Category: Audiology Authors: Han JJ, Lee HS, Park MH Tags: Hear Res Source Type: research

Microenvironmental support for cell delivery to the inner ear.
In this study, we demonstrate that MSC delivered to the inner ear of guinea pigs or to decellularized cochleae preferentially bind to areas of high heparin concentration. This presents an opportunity for modulating cell behaviour ex vivo. We evaluated the effect of carboxymethylglucose sulfate (Cacicol®), a heparan sulfate analogue on spiral ganglion cells and MSC and demonstrated support of neuronal survival and support of stem cell proliferation. PMID: 29945803 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - June 21, 2018 Category: Audiology Authors: Schulze J, Sasse S, Prenzler N, Staecker H, Mellott AJ, Roemer A, Durisin M, Lenarz T, Warnecke A Tags: Hear Res Source Type: research

Intracochlear pressure in response to high intensity, low frequency sounds in chinchilla.
Abstract Exposure to high intensity (blast) sounds can result in both conductive and sensorineural damage to hearing. This includes rupture of the tympanic membrane and dislocation of the middle ear ossicles, as well as damage to the inner and outer hair cells in the cochlea. A clearer understanding of how the hearing system responds to blast could help us better prevent auditory trauma, and support those who have been exposed to such sounds. Chinchillas are often used in studies of hearing due to the similarity between the chinchilla and human audiograms. The suitability of their use in research on auditory traum...
Source: Hearing Research - June 21, 2018 Category: Audiology Authors: Peacock J, Al Hussaini M, Greene NT, Tollin DJ Tags: Hear Res Source Type: research

Comorbidities of hearing loss and the implications of multimorbidity for audiological care.
Abstract With increasing age, the risk of developing chronic health conditions also increases, and many older people suffer from multiple co-existing health conditions, i.e., multimorbidity. One common health condition at older age is hearing loss (HL). The current article reflects on the implications for audiological care, when HL is one of several health conditions in a multimorbidity. An overview of health conditions often co-existing with HL, so called comorbidities, is provided, including indications for the strength of the associations. The overview is based on a literature study examining cohort studies tha...
Source: Hearing Research - June 19, 2018 Category: Audiology Authors: Besser J, Stropahl M, Urry E, Launer S Tags: Hear Res Source Type: research

Implications and attitudes of audiologists towards smartphone integration in hearing healthcare.
CONCLUSIONS: The findings suggest that the attitudes of audiologists likely do not represent a barrier regarding smartphone integration in audiologic rehabilitation. PMID: 29945802 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - June 19, 2018 Category: Audiology Authors: Kimball SH, Singh G, John AB, Jenstad LM Tags: Hear Res Source Type: research

The use of ecological momentary assessment in hearing research and future clinical applications.
Abstract To obtain real-world insights into the hearing difficulties of individuals, the field of hearing research has recently started to adopt ecological momentary assessment. Using this approach, study participants describe their experiences in real time, in their own natural environment. This paper describes the use of ecological momentary assessment in hearing research to date. Several studies have shown the approach is feasible and has good construct validity for use with adults with hearing impairment and/or tinnitus. Two recent studies conducted by the authors are described. The first study investigated th...
Source: Hearing Research - June 19, 2018 Category: Audiology Authors: Timmer BHB, Hickson L, Launer S Tags: Hear Res Source Type: research

Frequency specificity of amplitude envelope patterns in noise-vocoded speech.
We examined the frequency specificity of amplitude envelope patterns in 4 frequency bands, which universally appeared through factor analyses applied to power fluctuations of critical-band filtered speech sounds in 8 different languages/dialects [Ueda and Nakajima (2017). Sci. Rep., 7 (42468)]. A series of 3 perceptual experiments with noise-vocoded speech of Japanese sentences was conducted. Nearly perfect (92-94%) mora recognition was achieved, without any extensive training, in a control condition in which 4-band noise-vocoded speech was employed (Experiments 1-3). Blending amplitude envelope patterns of the frequency b...
Source: Hearing Research - June 15, 2018 Category: Audiology Authors: Ueda K, Araki T, Nakajima Y Tags: Hear Res Source Type: research

Effect of sound level on virtual and free-field localization of brief sounds in the anterior median plane.
da EA Abstract The detection of high-frequency spectral notches has been shown to be worse at 70-80 dB sound pressure level (SPL) than at higher levels up to 100 dB SPL. The performance improvement at levels higher than 70-80 dB SPL has been related to an 'ideal observer' comparison of population auditory nerve spike trains to stimuli with and without high-frequency spectral notches. Insofar as vertical localization partly relies on information provided by pinna-based high-frequency spectral notches, we hypothesized that localization would be worse at 70-80 dB SPL than at higher levels. Results from a firs...
Source: Hearing Research - June 14, 2018 Category: Audiology Authors: Marmel F, Marrufo-Pérez MI, Heeren J, Ewert S, Lopez-Poveda EA Tags: Hear Res Source Type: research

Estimation of the ear canal displacement field due to in-ear device insertion using a registration method on a human-like artificial ear.
Abstract Passive and active in-ear devices (IED) occluding the ear canal are commonly used to (i) protect people from high noise levels (earplugs), (ii) assist people suffering from hearing impairment (hearing aids) or (iii) help people in listening from their sound systems (earbuds). However, the usability and/or efficiency of IEDs can be greatly affected by several discomfort components (physical, acoustical and functional). The mechanical pressure exerted by the IED onto the ear canal walls is greatly suspected to affect the aforementioned comfort components. This physical characteristic is closely related to t...
Source: Hearing Research - June 2, 2018 Category: Audiology Authors: Benacchio S, Doutres O, Le Troter A, Varoquaux A, Wagnac E, Callot V, Sgard F Tags: Hear Res Source Type: research

COMT and the neurogenetic architecture of hearing loss induced tinnitus.
Abstract As the COMT polymorphism is especially prominent in the prefrontal cortex and has been associated with auditory gating, we hypothesize that tinnitus patients with this polymorphism have altered activity in the ventromedial prefrontal/anterior cingulate areas that modulates the tinnitus percept. To test this, we recruited a total of 40 tinnitus subjects and 20 healthy controls for an EEG study. A comparison between tinnitus subjects and healthy controls and their frequency of being Val/Val genotype or Met carriers (including Val/Met and Met/Met genotype) shows no significant effect, suggesting that the dis...
Source: Hearing Research - June 1, 2018 Category: Audiology Authors: Vanneste S, Alsalman O, De Ridder D Tags: Hear Res Source Type: research

Brainstem-cortical functional connectivity for speech is differentially challenged by noise and reverberation.
Abstract Everyday speech perception is challenged by external acoustic interferences that hinder verbal communication. Here, we directly compared how different levels of the auditory system (brainstem vs. cortex) code speech and how their neural representations are affected by two acoustic stressors: noise and reverberation. We recorded multichannel (64 ch) brainstem frequency-following responses (FFRs) and cortical event-related potentials (ERPs) simultaneously in normal hearing individuals to speech sounds presented in mild and moderate levels of noise and reverb. We matched signal-to-noise and direct-to-reverbe...
Source: Hearing Research - May 26, 2018 Category: Audiology Authors: Bidelman GM, Davis MK, Pridgen MH Tags: Hear Res Source Type: research

Topography of sound level representation in the FM sweep selective region of the pallid bat auditory cortex.
Abstract Sound level processing is a fundamental function of the auditory system. To determine how the cortex represents sound level, it is important to quantify how changes in level alter the spatiotemporal structure of cortical ensemble activity. This is particularly true for echolocating bats that have control over, and often rapidly adjust, call level to actively change echo level. To understand how cortical activity may change with sound level, here we mapped response rate and latency changes with sound level in the auditory cortex of the pallid bat. The pallid bat uses a 60-30 kHz downward frequency modula...
Source: Hearing Research - May 26, 2018 Category: Audiology Authors: Measor K, Yarrow S, Razak KA Tags: Hear Res Source Type: research

Neural representation of interaural correlation in human auditory brainstem: Comparisons between temporal-fine structure and envelope.
Abstract Central processing of interaural correlation (IAC), which depends on the precise representation of acoustic signals from the two ears, is essential for both localization and recognition of auditory objects. A complex soundwave is initially filtered by the peripheral auditory system into multiple narrowband waves, which are further decomposed into two functionally distinctive components: the quickly-varying temporal-fine structure (TFS) and the slowly-varying envelope. In rats, a narrowband noise can evoke auditory-midbrain frequency-following responses (FFRs) that contain both the TFS component (FFRTFS) a...
Source: Hearing Research - May 23, 2018 Category: Audiology Authors: Wang Q, Lu H, Wu Z, Li L Tags: Hear Res Source Type: research

The effects of aging on auditory cortical function.
Abstract Age-related hearing loss is a prominent deficit, afflicting approximately half of the geriatric population. In many cases, the person may have no deficits in detecting sounds, but nonetheless suffers from a reduced ability to understand speech, particularly in a noisy environment. While rodent models have shown that there are a variety of age-related changes throughout the auditory neuraxis, far fewer studies have investigated the effects at the cortical level. Here I review recent evidence from a non-human primate model of age-related hearing loss at the level of the core (primary auditory cortex, A1) an...
Source: Hearing Research - May 23, 2018 Category: Audiology Authors: Recanzone G Tags: Hear Res Source Type: research

Intracochlear pressure measurements during acoustic shock wave exposure.
Abstract INTRODUCTION: Injuries to the peripheral auditory system are among the most common results of high intensity impulsive acoustic exposure. Prior studies of high intensity sound transmission by the ossicular chain have relied upon measurements in animal models, measurements at more moderate sound levels (i.e. 
Source: Hearing Research - May 19, 2018 Category: Audiology Authors: Greene NT, Alhussaini MA, Easter JR, Argo TF, Walilko T, Tollin DJ Tags: Hear Res Source Type: research

Investigation of the 2f1-f2 and 2f2-f1 distortion product otoacoustic emissions using a computational model of the gerbil ear.
Abstract In this work, a three-dimensional computational model of the gerbil ear is used to investigate the generation of the 2f1-f2 and 2f2-f1 distortion product otoacoustic emissions (DPOAEs). In order to predict both the distortion and reflection sources, cochlear roughness is modeled by introducing random inhomogeneities in the outer hair cell properties. The model was used to simulate the generation of DPOAEs in response to a two-tone stimulus for various primary stimulus levels and frequency ratios. As in published experiments, the 2f1-f2 DPOAEs are mostly dominated by the distortion component while the 2f2-...
Source: Hearing Research - May 19, 2018 Category: Audiology Authors: Wen H, Bowling T, Meaud J Tags: Hear Res Source Type: research

Eardrum and columella displacement in single ossicle ears under quasi-static pressure variations.
Abstract Although most birds encounter large pressure variations during flight, motion of the middle ear components as a result of changing ambient pressure are not well known or described. In the present study, motion of the columella footplate and tympanic membrane (extrastapedius) in domestic chickens (Gallus gallus domesticus) under quasi-static pressure conditions are provided. Micro-CT scans were made of cadaveric heads of chickens under positive (0.25 kPa, 0.5 kPa, 1 kPa, and 1.5 kPa) and negative (-0.25 kPa, -0.5 kPa, -1 kPa, and -1.5 kPa) middle ear pressure. Both extrastape...
Source: Hearing Research - May 19, 2018 Category: Audiology Authors: Claes R, Muyshondt PGG, Van Assche F, Van Hoorebeke L, Aerts P, Dirckx JJJ Tags: Hear Res Source Type: research

A circuit mechanism of time-to-space conversion for perception.
Abstract Sensory information in a temporal sequence is processed as a collective unit by the nervous system. The cellular mechanisms underlying how sequential inputs are incorporated into the brain has emerged as an important subject in neuroscience. Here, we hypothesize that information-bearing (IB) signals can be entrained and amplified by a clock signal, allowing them to efficiently propagate along in a feedforward circuit. IB signals can remain latent on individual dendrites of the receiving neurons until they are read out by an oscillatory clock signal. In such a way, the IB signals pass through the next neur...
Source: Hearing Research - May 17, 2018 Category: Audiology Authors: Yang S, Chung J, Jin SH, Bao S, Yang S Tags: Hear Res Source Type: research

Outlook and future of inner ear therapy.
Abstract Drug delivery to the inner ear is an ideal method to treat a wide variety of otologic conditions. A broad range of potential applications is just beginning to be explored. New approaches combine principles of inner ear pharmacokinetics with emerging technologies of drug delivery including novel delivery systems, drug-device combinations, and new categories of drugs. Strategies include cell-specific targeting, manipulation of gene expression, local activation following systemic delivery, and use of stem cells, viral vectors, and gene editing systems. Translation of these therapies to the clinic remains cha...
Source: Hearing Research - May 17, 2018 Category: Audiology Authors: Devare J, Gubbels S, Raphael Y Tags: Hear Res Source Type: research

Human medial efferent activity elicited by dynamic versus static contralateral noises.
Abstract The medial olivocochlear reflex (MOCR) modifies cochlear amplifier function to improve encoding of signals in static noise, but conflicting results have been reported regarding how the MOCR responds to dynamic, temporally-complex noises. The current study utilized three MOCR elicitors with identical spectral content but different temporal properties: broadband noise, amplitude-modulated noise, and speech envelope-modulated noise. MOCR activity was assessed using contralateral inhibition of transient-evoked otoacoustic emissions in 27 normal-hearing young adults. Elicitors were presented contralaterally at...
Source: Hearing Research - May 16, 2018 Category: Audiology Authors: Mertes IB Tags: Hear Res Source Type: research

Differential fates of tissue macrophages in the cochlea during postnatal development.
Abstract The cochlea contains macrophages. These cells participate in inflammatory responses to cochlear pathogenesis. However, it is not clear how and when these cells populate the cochlea during postnatal development. The current study aims to determine the postnatal development of cochlear macrophages with the focus on macrophage development in the organ of Corti and the basilar membrane. Cochleae were collected from C57BL/6J mice at ages of postnatal day (P) 1 to P21, as well as from mature mice (1-4 months). Macrophages were identified based on their expression of F4/80 and Iba1, as well as their unique morph...
Source: Hearing Research - May 16, 2018 Category: Audiology Authors: Dong Y, Zhang C, Frye M, Yang W, Ding D, Sharma A, Guo W, Hu BH Tags: Hear Res Source Type: research