Human Click-Based Echolocation of Distance: Superfine Acuity and Dynamic Clicking Behaviour
AbstractSome people who are blind have trained themselves in echolocation using mouth clicks. Here, we provide the first report of psychophysical and clicking data during echolocation of distance from a group of 8 blind people with experience in mouth click-based echolocation (daily use for>  3 years). We found that experienced echolocators can detect changes in distance of 3 cm at a reference distance of 50 cm, and a change of 7 cm at a reference distance of 150 cm, regardless of object size (i.e. 28.5 cm vs. 80 cm diameter disk). Participants made mouth clicks that were more i...
Source: JARO - Journal of the Association for Research in Otolaryngology - July 8, 2019 Category: ENT & OMF Source Type: research

Pre-operative Brain Imaging Using Functional Near-Infrared Spectroscopy Helps Predict Cochlear Implant Outcome in Deaf Adults
AbstractCurrently, it is not possible to accurately predict how well a deaf individual will be able to understand speech when hearing is (re)introduced via a cochlear implant. Differences in brain organisation following deafness are thought to contribute to variability in speech understanding with a cochlear implant and may offer unique insights that could help to more reliably predict outcomes. An emerging optical neuroimaging technique, functional near-infrared spectroscopy (fNIRS), was used to determine whether a pre-operative measure of brain activation could explain variability in cochlear implant (CI) outcomes and of...
Source: JARO - Journal of the Association for Research in Otolaryngology - July 8, 2019 Category: ENT & OMF Source Type: research

Osteoclasts Modulate Bone Erosion in Cholesteatoma via RANKL Signaling
In this study, we found that a significantly larger number of osteoclasts were observed on the eroded bone adjacent to choles teatomas than in unaffected areas, and that fibroblasts in the cholesteatoma perimatrix expressed RANKL. We also investigated upstream transcription factors of RANKL using RNA sequencing results obtained via Ingenuity Pathways Analysis, a tool that identifies relevant targets in molecular biology sy stems. The concentrations of four candidate factors, namely interleukin-1β, interleukin-6, tumor necrosis factor α, and prostaglandin E2, were increased in cholesteatomas compared with normal ...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 28, 2019 Category: ENT & OMF Source Type: research

Rapamycin Protects Spiral Ganglion Neurons from Gentamicin-Induced Degeneration In Vitro
AbstractGentamicin, one of the most widely used aminoglycoside antibiotics, is known to have toxic effects on the inner ear. Taken up by cochlear hair cells and spiral ganglion neurons (SGNs), gentamicin induces the accumulation of reactive oxygen species (ROS) and initiates apoptosis or programmed cell death, resulting in a permanent and irreversible hearing loss. Since the survival of SGNs is specially required for cochlear implant, new procedures that prevent SGN cell loss are crucial to the success of cochlear implantation. ROS modulates the activity of the mammalian target of rapamycin (mTOR) signaling pathway, which ...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 24, 2019 Category: ENT & OMF Source Type: research

AAV-Mediated Neurotrophin Gene Therapy Promotes Improved Survival of Cochlear Spiral Ganglion Neurons in Neonatally Deafened Cats: Comparison of AAV2-hBDNF and AAV5-hGDNF
In this study, we explored the potential for two adeno-associated viral vectors (AAV) to elicit targeted neurotrophic factor expression in the cochlea and promote improved SG and radial nerve fiber survival. Juvenile cats were deafened prior to hearing onset by systemic aminoglycoside injections. Auditory brainstem responses showed profound hearing loss by 16 –18 days postnatal. At ~ 4 weeks of age, AAV2-GFP (green fluorescent protein), AAV5-GFP, AAV2-hBDNF, or AAV5-hGDNF (glial-derived neurotrophic factor) was injected through the round window unilaterally. For GFP immunofluorescence, animals were s...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 20, 2019 Category: ENT & OMF Source Type: research

Cortical Auditory Evoked Potentials in Response to Frequency Changes with Varied Magnitude, Rate, and Direction
In conclusion, the ACC is most strongly affected by magnitude and also substantially by rate and direction of the change. These stimulus dependencies should be considered in choosing stimuli for ACCs as objective clinical measure of hearing performance. (Source: JARO - Journal of the Association for Research in Otolaryngology)
Source: JARO - Journal of the Association for Research in Otolaryngology - June 5, 2019 Category: ENT & OMF Source Type: research

Virtual Rhesus Labyrinth Model Predicts Responses to Electrical Stimulation Delivered by a Vestibular Prosthesis
AbstractTo better understand the spread of prosthetic current in the inner ear and to facilitate design of electrode arrays and stimulation protocols for a vestibular implant system intended to restore sensation after loss of vestibular hair cell function, we created a model of the primate labyrinth. Because the geometry of the implanted ear is complex, accurately modeling effects of prosthetic stimuli on vestibular afferent activity required a detailed representation of labyrinthine anatomy. Model geometry was therefore generated from three-dimensional (3D) reconstructions of a normal rhesus temporal bone imaged using mic...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 4, 2019 Category: ENT & OMF Source Type: research

A Site-Selection Strategy Based on Polarity Sensitivity for Cochlear Implants: Effects on Spectro-Temporal Resolution and Speech Perception
ABSTRACTThresholds of asymmetric pulses presented to cochlear implant (CI) listeners depend on polarity in a way that differs across subjects and electrodes. It has been suggested that lower thresholds for cathodic-dominant compared to anodic-dominant pulses reflect good local neural health. We evaluated the hypothesis that this polarity effect (PE) can be used in a site-selection strategy to improve speech perception and spectro-temporal resolution. Detection thresholds were measured in eight users of Advanced Bionics CIs for 80-pps, triphasic, monopolar pulse trains where the central high-amplitude phase was either anodi...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 3, 2019 Category: ENT & OMF Source Type: research

Exploring the Role of Medial Olivocochlear Efferents on the Detection of Amplitude Modulation for Tones Presented in Noise
AbstractThe medial olivocochlear reflex has been hypothesized to improve the detection and discrimination of dynamic signals in noisy backgrounds. This hypothesis was tested here by comparing behavioral outcomes with otoacoustic emissions. The effects of a precursor on amplitude-modulation (AM) detection were measured for a 1- and 6-kHz carrier at levels of 40, 60, and 80  dB SPL in a two-octave-wide noise masker with a level designed to produce poor, but above-chance, performance. Three types of precursor were used: a two-octave noise band, an inharmonic complex tone, and a pure tone. Precursors had the same overall ...
Source: JARO - Journal of the Association for Research in Otolaryngology - May 28, 2019 Category: ENT & OMF Source Type: research

Investigating the Effect of Cochlear Synaptopathy on Envelope Following Responses Using a Model of the Auditory Nerve
AbstractThe healthy auditory system enables communication in challenging situations with high levels of background noise. Yet, despite normal sensitivity to pure tones, many listeners complain about having difficulties in such situations. Recent animal studies demonstrated that noise overexposure that produces temporary threshold shifts can cause the loss of auditory nerve (AN) fiber synapses (i.e., cochlear synaptopathy, CS), which appears to predominantly affect medium- and low-spontaneous rate (SR) fibers. In the present study, envelope following response (EFR) magnitude-level functions were recorded in normal hearing (...
Source: JARO - Journal of the Association for Research in Otolaryngology - May 17, 2019 Category: ENT & OMF Source Type: research

The fMRI Data of Thompson et al. (2006) Do Not Constrain How the Human Midbrain Represents Interaural Time Delay
AbstractThis commentary provides an alternate interpretation of the fMRI data that were presented in a communication to the journalNature Neuroscience(Thompson et al., Nat. Neurosci. 9: 1096 –1098,2006). The authors argued that their observations demonstrated that traditional models of binaural hearing which incorporate “internal delays,” such as the coincidence-counting mechanism proposed by Jeffress and quantified by Colburn, are invalid, and that a new model for human interaural time delay processing must be developed. We argue that the fMRI data presented do not strongly favor either the refutation or...
Source: JARO - Journal of the Association for Research in Otolaryngology - May 14, 2019 Category: ENT & OMF Source Type: research

Neural Encoding of Amplitude Modulations in the Human Efferent System
The objective o f this study was to investigate the encoding of AM signals in the medial olivocochlear system by measuring the modulation transfer functions of the efferent response in humans. A secondary goal was to replicate the controversial findings from the literature that efferent stimulation produces larger effects for the AM elicitor with 100 Hz modulation frequency in comparison with the unmodulated elicitor. The efferent response was quantified by measuring changes in stimulus-frequency otoacoustic emission magnitude due to various modulated and unmodulated elicitors. Unmodulated, broadband noise e licitors ...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 29, 2019 Category: ENT & OMF Source Type: research

Early Hearing Loss upon Disruption of Slc4a10 in C57BL/6 Mice
In this study, we show that in mice the expression of the bicarbonate transporter Slc4a10/Ncbe/Nbcn2 in spiral ligament fibrocytes starts shortly before hearing onset. Its disruption in a C57BL/6 background results in early onset progressive hearing loss. This hearing loss is characterized by a reduced endocochlear potential from hearing onset onward and progressive degeneration of outer hair cells. Notably, the expression of a related bicarbonate transporter, i.e., Slc4a7/Nbcn1, is also lost in spiral ligament fibrocytes of Slc4a10 knockout mice. The histological analysis of the spiral ligament of Slc4a10 knockout mice do...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 18, 2019 Category: ENT & OMF Source Type: research

Evaluating Psychophysical Polarity Sensitivity as an Indirect Estimate of Neural Status in Cochlear Implant Listeners
AbstractThe physiological integrity of spiral ganglion neurons is presumed to influence cochlear implant (CI) outcomes, but it is difficult to measure neural health in CI listeners. Modeling data suggest that, when peripheral processes have degenerated, anodic stimulation may be a more effective neural stimulus than cathodic stimulation. The primary goal of the present study was to evaluate the emerging theory that polarity sensitivity reflects neural health in CI listeners. An ideal in vivo estimate of neural integrity should vary independently of other factors known to influence the CI electrode-neuron interface, such as...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 4, 2019 Category: ENT & OMF Source Type: research

The Estimated Electrode-Neuron Interface in Cochlear Implant Listeners Is Different for Early-Implanted Children and Late-Implanted Adults
This study examined whether ENI quality differed between early-implanted children and late-implanted adults. Auditory detection thresholds and most comfortable levels (MCLs) were obtained with monopolar and focused electrode configurations. Channel-to-channel variability and dynamic range were calculated for both types of stimulation. Electrical field imaging data were also acquired to estimate levels of intracochlear resistance. Children exhibited lower average auditory perception thresholds and MCLs compared with adults, particularly with focused stimulation. However, neither dynamic range nor channel-to-channel threshol...
Source: JARO - Journal of the Association for Research in Otolaryngology - March 25, 2019 Category: ENT & OMF Source Type: research

Towards a Mechanistic-Driven Precision Medicine Approach for Tinnitus
AbstractIn this position review, we propose to establish a path for replacing the empirical classification of tinnitus with a taxonomy from precision medicine. The goal of a classification system is to understand the inherent heterogeneity of individuals experiencing and suffering from tinnitus and to identify what differentiates potential subgroups. Identification of different patient subgroups with distinct audiological, psychophysical, and neurophysiological characteristics will facilitate the management of patients with tinnitus as well as the design and execution of drug development and clinical trials, which, for the...
Source: JARO - Journal of the Association for Research in Otolaryngology - March 1, 2019 Category: ENT & OMF Source Type: research

A Randomized Controlled Crossover Study of the Impact of Online Music Training on Pitch and Timbre Perception in Cochlear Implant Users
In conclusion, auditory training (with either acute participation in an online music training program or audiobook listening) may improve performance on untrained tasks of pitch discrimination and timbre identification. These findings demonstrate a potential role for music training in perceptual auditory appraisal of complex stimuli. Furthermore, this study highlights the importance and the need for more tightly controlled training studies in order to accurat ely evaluate the impact of rehabilitation training protocols on auditory processing. (Source: JARO - Journal of the Association for Research in Otolaryngology)
Source: JARO - Journal of the Association for Research in Otolaryngology - February 27, 2019 Category: ENT & OMF Source Type: research

Inhibition of Histone Methyltransferase G9a Attenuates Noise-Induced Cochlear Synaptopathy and Hearing Loss
In this study, we investigated the effect of G9a (KMT1C, EHMT2), a major histone lysine methyltransferase encoded by the humanEHMT2 gene and responsible for histone H3 lysine 9 dimethylation (H3K9me2) on noise-induced permanent hearing loss (NIHL) in adult CBA/J mice. The conditions of noise exposure used in this study led to losses of cochlear synapses and outer hair cells (OHCs) and permanent auditory threshold shifts. Inhibition of G9a with its specific inhibitor BIX 01294 or with siRNA significantly attenuated these pathological features. Treatment with BIX 01294 also prevented the noise-induced decrease of KCNQ4 immun...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 1, 2019 Category: ENT & OMF Source Type: research

The Effect of Stimulus Polarity on the Relation Between Pitch Ranking and ECAP Spread of Excitation in Cochlear Implant Users
AbstractAlthough modern cochlear implants (CIs) use cathodic-leading symmetrical biphasic pulses to stimulate the auditory nerve, a growing body of evidence suggests that anodic-leading pulses may be more effective. The positive polarity has been shown to produce larger electrically evoked compound action potential (ECAP) amplitudes, steeper slope of the amplitude growth function, and broader spread of excitation (SOE) patterns. Polarity has also been shown to influence pitch perception. It remains unclear how polarity affects the relation between physiological SOE and psychophysical pitch perception. Using a within-subjec...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 31, 2019 Category: ENT & OMF Source Type: research

Effects of Musical Training and Hearing Loss on Fundamental Frequency Discrimination and Temporal Fine Structure Processing: Psychophysics and Modeling
AbstractSeveral studies have shown that musical training leads to improved fundamental frequency (F0) discrimination for young listeners with normal hearing (NH). It is unclear whether a comparable effect of musical training occurs for listeners whose sensory encoding ofF0 is degraded. To address this question, the effect of musical training was investigated for three groups of listeners (young NH, older NH, and older listeners with hearing impairment, HI). In a first experiment,F0 discrimination was investigated using complex tones that differed in harmonic content and phase configuration (sine, positive, or negative Schr...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 28, 2019 Category: ENT & OMF Source Type: research

Neural Switch Asymmetry in Feature-Based Auditory Attention Tasks
AbstractActive listening involves dynamically switching attention between competing talkers and is essential to following conversations in everyday environments. Previous investigations in human listeners have examined the neural mechanisms that support switching auditory attention within the acoustic featural cues of pitch and auditory space. Here, we explored the cortical circuitry underlying endogenous switching of auditory attention between pitch and spatial cues necessary to discern target from masker words. Because these tasks are of unequal difficulty, we expected an asymmetry in behavioral switch costs for hard-to-...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 23, 2019 Category: ENT & OMF Source Type: research

Water Waves to Sound Waves: Using Zebrafish to Explore Hair Cell Biology
AbstractAlthough perhaps best known for their use in developmental studies, over the last couple of decades, zebrafish have become increasingly popular model organisms for investigating auditory system function and disease. Like mammals, zebrafish possess inner ear mechanosensory hair cells required for hearing, as well as superficial hair cells of the lateral line sensory system, which mediate detection of directional water flow. Complementing mammalian studies, zebrafish have been used to gain significant insights into many facets of hair cell biology, including mechanotransduction and synaptic physiology as well as mech...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 11, 2019 Category: ENT & OMF Source Type: research

Neural ITD Sensitivity and Temporal Coding with Cochlear Implants in an Animal Model of Early-Onset Deafness
AbstractUsers of cochlear implant (CI) face challenges in everyday situations such as understanding conversations in noise, even with CIs in both ears. These challenges are related to difficulties with tasks that require fine temporal processing such as discrimination of pulse rates or interaural time differences (ITD), a major cue for sound localization. The degradation in temporal processing and ITD sensitivity are especially acute in those who lost hearing in early childhood. Here, we characterized temporal coding and ITD sensitivity of single neurons in a novel animal model of early-onset deafness. Rabbits were deafene...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 8, 2019 Category: ENT & OMF Source Type: research

Interaural Pitch-Discrimination Range Effects for Bilateral and Single-Sided-Deafness Cochlear-Implant Users
AbstractBy allowing bilateral access to sound, bilateral cochlear implants (BI-CIs) or unilateral CIs for individuals with single-sided deafness (SSD; i.e., normal or near-normal hearing in one ear) can improve sound localization and speech understanding in noise. Spatial hearing in the horizontal plane is primarily conveyed by interaural time and level differences computed from neurons in the superior olivary complex that receive frequency-matched inputs. Because BI-CIs and SSD-CIs do not necessarily convey frequency-matched information, it is critical to understand how to align the inputs to CI users. Previous studies sh...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 8, 2019 Category: ENT & OMF Source Type: research

A New Model for Congenital Vestibular Disorders
AbstractMany developmental disorders of the inner ear are manifested clinically as delayed motor development and challenges in maintaining posture and balance, indicating involvement of central vestibular circuits. How the vestibular circuitry is rewired in pediatric cases is poorly understood due to lack of a suitable animal model. Based on this, our lab designed and validated a chick embryo model to study vestibular development in congenital vestibular disorders. The developing inner ear or “otocyst” on the right side of 2-day-old chick embryos (E2) was surgically rotated 180° in the anterior–poster...
Source: JARO - Journal of the Association for Research in Otolaryngology - December 18, 2018 Category: ENT & OMF Source Type: research

Effect of Chronic Stimulation and Stimulus Level on Temporal Processing by Cochlear Implant Listeners
AbstractA series of experiments investigated potential changes in temporal processing during the months following activation of a cochlear implant (CI) and as a function of stimulus level. Experiment 1 tested patients on the day of implant activation and 2 and 6  months later. All stimuli were presented using direct stimulation of a single apical electrode. The dependent variables were rate discrimination ratios (RDRs) for pulse trains with rates centred on 120 pulses per second (pps), obtained using an adaptive procedure, and a measure of the upper limit of temporal pitch, obtained using a pitch-ranking procedure. Al...
Source: JARO - Journal of the Association for Research in Otolaryngology - December 12, 2018 Category: ENT & OMF Source Type: research

Time-Compressed Speech Identification Is Predicted by Auditory Neural Processing, Perceptuomotor Speed, and Executive Functioning in Younger and Older Listeners
AbstractOlder adults typically have difficulty identifying speech that is temporally distorted, such as reverberant, accented, time-compressed, or interrupted speech. These difficulties occur even when hearing thresholds fall within a normal range. Auditory neural processing speed, which we have previously found to predict auditory temporal processing (auditory gap detection), may interfere with the ability to recognize phonetic features as they rapidly unfold over time in spoken speech. Further, declines in perceptuomotor processing speed and executive functioning may interfere with the ability to track, access, and proce...
Source: JARO - Journal of the Association for Research in Otolaryngology - November 19, 2018 Category: ENT & OMF Source Type: research

Speech Perception with Spectrally Non-overlapping Maskers as Measure of Spectral Resolution in Cochlear Implant Users
AbstractPoor spectral resolution contributes to the difficulties experienced by cochlear implant (CI) users when listening to speech in noise. However, correlations between measures of spectral resolution and speech perception in noise have not always been found to be robust. It may be that the relationship between spectral resolution and speech perception in noise becomes clearer in conditions where the speech and noise are not spectrally matched, so that improved spectral resolution can assist in separating the speech from the masker. To test this prediction, speech intelligibility was measured with noise or tone maskers...
Source: JARO - Journal of the Association for Research in Otolaryngology - November 19, 2018 Category: ENT & OMF Source Type: research

Vestibular Evoked Myographic Correlation
AbstractThis work started from the hypothesis that the physiological processes giving rise to the vestibular evoked myogenic potential (VEMP) can be induced not only by transient sounds but also by a continuous stimulation with a stochastic signal. The hypothesis is based on the idea that the number of motor unit action potentials (MUAPs) decreases after a momentary amplitude increase of the effective stimulus, whereas a momentary amplitude decrease has the opposite effect. This concept was theoretically analyzed by assuming that the effective stimulus is closely related to the envelope of the stimulus actually presented. ...
Source: JARO - Journal of the Association for Research in Otolaryngology - November 12, 2018 Category: ENT & OMF Source Type: research

Interaction Between Pitch and Timbre Perception in Normal-Hearing Listeners and Cochlear Implant Users
This study tested the interaction between pitch and sharpness (an aspect of timbre) perception related to the fundamental frequency (F0) and spectral slope of harmonic complex tones, respectively, in both NH listeners and CI users. In experiment 1, the F0 (and spectral slope) difference limens (DLs) were measured with a fixed spectral slope (and F0) and 20-dB amplitude roving. Then, the F0 and spectral slope were varied congruently or incongruently by the same multiple of individual DLs to assess the pitch and sharpness ranking sensitivity. Both NH and CI subjects had significantly higher pitch and sharpness ranking sensit...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 30, 2018 Category: ENT & OMF Source Type: research

Study of the Mechanisms by Which Aminoglycoside Damage Is Prevented in Chick Embryonic Hair Cells
AbstractA major side effect of aminoglycoside antibiotics is mammalian hair cell death. It is thus intriguing that embryonic chick hair cells treated with aminoglycosides at embryonic day (E) 12 are insensitive to ototoxicity. To exclude some unknown factors in vivo that might be involved in preventing aminoglycoside damage to embryonic hair cells, we first cultured chick embryonic basilar papilla (BP) with an aminoglycoside antibiotic in vitro. The results indicated that the hair cells were almost intact at E12 and E14 and were only moderately damaged in most parts of the BP at E16 and E18. Generally, hair cells residing ...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 18, 2018 Category: ENT & OMF Source Type: research

Amplitude Modulation Detection in Children with a History of Temporary Conductive Hearing Loss Remains Impaired for Years After Restoration of Normal Hearing
AbstractOtitis media with effusion (OME) is considered a form of relative sensory deprivation that often occurs during a critical period of language acquisition in children. Animal studies have demonstrated that hearing loss during early development can impair behavioral sensitivity to amplitude modulation (AM), critical for speech understanding, even after restoration of normal hearing thresholds. AM detection in humans with a history of OME-associated conductive hearing loss (CHL) has not been previously investigated. Our objective was to determine whether OME-associated CHL in children ages 6  months to 3 year...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 17, 2018 Category: ENT & OMF Source Type: research

Interaural Time Difference Perception with a Cochlear Implant and a Normal Ear
AbstractCurrently there is a growing population of cochlear-implant (CI) users with (near) normal hearing in the non-implanted ear. This configuration is often called SSD (single-sided deafness) CI. The goal of the CI is often to improve spatial perception, so the question raises to what extent SSD CI listeners are sensitive to interaural time differences (ITDs). In a controlled lab setup, sensitivity to ITDs was investigated in 11 SSD CI listeners. The stimuli were 100-pps pulse trains on the CI side and band-limited click trains on the acoustic side. After determining level balance and the delay needed to achieve synchro...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 27, 2018 Category: ENT & OMF Source Type: research

Human Vestibulo-Ocular Reflex Adaptation Training: Time Beats Quantity
AbstractThe vestibulo-ocular reflex (VOR) is the main gaze stabilising system during rapid head movements. The VOR is highly plastic and its gain (eye/head velocity) can be increased via training that induces an incrementally increasing retinal image slip error signal to drive VOR adaptation. Using the unilateral incremental VOR adaptation technique and horizontal active head impulses as the vestibular stimulus, we sought to determine the factors important for VOR adaptation including: the total training time, ratio and number of head impulses to each side (adapting and non-adapting sides; the adapting side was pseudo-rand...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 24, 2018 Category: ENT & OMF Source Type: research

The Masked ABR (mABR): a New Measurement Method for the Auditory Brainstem Response
AbstractThe auditory brainstem response (ABR) is relatively non-invasive, and in many species, the only practical way to assess auditory sensitivity. The two main methods for measuring ABR are using either transients or tone bursts as a stimulus. The transient stimulus produces strong neural responses that contain no frequency information. In contrast, tone bursts stimulate only a small part of the auditory system, eliciting weaker neural responses but supplying frequency information. Furthermore, short tone bursts become less and less frequency specific with increasing stimulus wavelength, making them unsuitable for testi...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 20, 2018 Category: ENT & OMF Source Type: research

Evaluation of Possible Effects of a Potassium Channel Modulator on Temporal Processing by Cochlear Implant Listeners
We report the results of a randomised placebo-controlled double-blind study on psychophysical tests of the effects of AUT00063 on temporal processing by CI listeners. The study measured the upper limit of temporal pitch, gap detection, and discrimination of low rates (centred on 120  pps) for monopolar pulse trains presented to an apical electrode. The upper limit was measured using the optimally efficient midpoint comparison (MPC) pitch-ranking procedure; thresholds were obtained for the other two measures using an adaptive procedure. Twelve CI users (MedEl and Cochlear) were tested before and after two periods of AU...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 19, 2018 Category: ENT & OMF Source Type: research

Surface Motion of Tympanic Membrane in a Chinchilla Model of Acute Otitis Media
In this study, the TM surface motion was determined using scanning laser Doppler vibrometry (SLDV) in a chinchilla model of AOM. The AOM was established by transbullar injection of nontypeableHaemophilus influenzae. The TM surface vibration was measured in control (uninfected) animals and two AOM groups of animals: 4  days (4D) and 8 days (8D) post inoculation. To quantify the effect of middle ear pressure in those infected ears, the SLDV measurement was first conducted in unopened AOM ears and then in middle ear pressure released ears. Results showed that middle ear infection generally reduced the TM displace me...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 6, 2018 Category: ENT & OMF Source Type: research

Noise-Induced Hypersensitization of the Acoustic Startle Response in Larval Zebrafish
ABSTRACTOverexposure to loud noise is known to lead to deficits in auditory sensitivity and perception. We studied the effects of noise exposure on sensorimotor behaviors of larval (5 –7 days post-fertilization) zebrafish (Danio rerio), particularly the auditory-evoked startle response and hearing sensitivity to acoustic startle stimuli. We observed a temporary 10 –15 dB decrease in startle response threshold after 18 h of flat-spectrum noise exposure at 20 dB re·1 ms−2. Larval zebrafish also exhibited decreased habituation to startle-inducing stimuli following noise exposure. T...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 6, 2018 Category: ENT & OMF Source Type: research

The Stress Response in the Non-sensory Cells of the Cochlea Under Pathological Conditions —Possible Role in Mediating Noise Vulnerability
AbstractVarious stressors, such as loud sounds and the effects of aging, impair the function and viability of the cochlear sensory cells, the hair cells. Stressors trigger pathophysiological changes in the cochlear non-sensory cells as well. We have here studied the stress response mounted in the lateral wall of the cochlea during acute noise stress and during age-related chronic stress. We have used the activation of JNK/c-Jun, ERK, and NF- κB pathways as a readout of the stress response, and the expression of the FoxO3 transcription factor as a possible additional player in cellular stress. In the aging cochlea, NF...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 6, 2018 Category: ENT & OMF Source Type: research

Improved Neural Coding of ITD with Bilateral Cochlear Implants by Introducing Short Inter-pulse Intervals
AbstractBilateral cochlear implant (CI) users have poor perceptual sensitivity to interaural time differences (ITDs), which limits their ability to localize sounds and understand speech in noisy environments. This is especially true for high-rate (>  300 pps) periodic pulse trains, which are used as carriers in CI processors. Here, we investigate a novel stimulation strategy in which extra pulses are added to high-rate periodic pulse trains to introduce short inter-pulse intervals (SIPIs). We hypothesized that SIPIs can improve neural ITD se nsitivity similarly to the effect observed by randomly jittering IP...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 6, 2018 Category: ENT & OMF Source Type: research

Surface Motion of Tympanic Membrane in a Chinchilla Model of Acute Otitis Media
In this study, the TM surface motion was determined using scanning laser Doppler vibrometry (SLDV) in a chinchilla model of AOM. The AOM was established by transbullar injection of nontypeableHaemophilus influenzae. The TM surface vibration was measured in control (uninfected) animals and two AOM groups of animals: 4  days (4D) and 8 days (8D) post inoculation. To quantify the effect of middle ear pressure in those infected ears, the SLDV measurement was first conducted in unopened AOM ears and then in middle ear pressure released ears. Results showed that middle ear infection generally reduced the TM displace me...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 6, 2018 Category: ENT & OMF Source Type: research

Noise-Induced Hypersensitization of the Acoustic Startle Response in Larval Zebrafish
ABSTRACTOverexposure to loud noise is known to lead to deficits in auditory sensitivity and perception. We studied the effects of noise exposure on sensorimotor behaviors of larval (5 –7 days post-fertilization) zebrafish (Danio rerio), particularly the auditory-evoked startle response and hearing sensitivity to acoustic startle stimuli. We observed a temporary 10 –15 dB decrease in startle response threshold after 18 h of flat-spectrum noise exposure at 20 dB re·1 ms−2. Larval zebrafish also exhibited decreased habituation to startle-inducing stimuli following noise exposure. T...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 6, 2018 Category: ENT & OMF Source Type: research

The Stress Response in the Non-sensory Cells of the Cochlea Under Pathological Conditions —Possible Role in Mediating Noise Vulnerability
AbstractVarious stressors, such as loud sounds and the effects of aging, impair the function and viability of the cochlear sensory cells, the hair cells. Stressors trigger pathophysiological changes in the cochlear non-sensory cells as well. We have here studied the stress response mounted in the lateral wall of the cochlea during acute noise stress and during age-related chronic stress. We have used the activation of JNK/c-Jun, ERK, and NF- κB pathways as a readout of the stress response, and the expression of the FoxO3 transcription factor as a possible additional player in cellular stress. In the aging cochlea, NF...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 6, 2018 Category: ENT & OMF Source Type: research

Improved Neural Coding of ITD with Bilateral Cochlear Implants by Introducing Short Inter-pulse Intervals
AbstractBilateral cochlear implant (CI) users have poor perceptual sensitivity to interaural time differences (ITDs), which limits their ability to localize sounds and understand speech in noisy environments. This is especially true for high-rate (>  300 pps) periodic pulse trains, which are used as carriers in CI processors. Here, we investigate a novel stimulation strategy in which extra pulses are added to high-rate periodic pulse trains to introduce short inter-pulse intervals (SIPIs). We hypothesized that SIPIs can improve neural ITD se nsitivity similarly to the effect observed by randomly jittering IP...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 6, 2018 Category: ENT & OMF Source Type: research

Otoprotective Effects of Stephania tetrandra S. Moore Herb Isolate against Acoustic Trauma
AbstractNoise is the most common occupational and environmental hazard, and noise-induced hearing loss (NIHL) is the second most common form of sensorineural hearing deficit. Although therapeutics that target the free-radical pathway have shown promise, none of these compounds is currently approved against NIHL by the United States Food and Drug Administration. The present study has demonstrated that tetrandrine (TET), a traditional Chinese medicinal alkaloid and the main chemical isolate of theStephania tetrandra S. Moore herb, significantly attenuated NIHL in CBA/CaJ mice. TET is known to exert antihypertensive and antia...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 5, 2018 Category: ENT & OMF Source Type: research