Correction to: An Alternative Explanation for Difficulties with Speech in Background Talkers: Abnormal Fusion of Vowels Across Fundamental Frequency and Ears
A correction to this paper has been published: https://doi.org/10.1007/s10162-021-00802-6 (Source: JARO - Journal of the Association for Research in Otolaryngology)
Source: JARO - Journal of the Association for Research in Otolaryngology - July 16, 2021 Category: ENT & OMF Source Type: research

Aging Effects on Cortical Responses to Tones and Speech in Adult Cochlear-Implant Users
This study recorded cortical auditory evoked potentials from younger to middle-aged (
Source: JARO - Journal of the Association for Research in Otolaryngology - July 6, 2021 Category: ENT & OMF Source Type: research

Examining the Factors that Contribute to Non-Monotonic Growth of the $$2f_1 - f_2$$ 2 f 1 - f 2  Otoacoustic Emission in Humans
AbstractCubic distortion product otoacoustic emission input –output functions in humans show a complex pattern of growth. To further investigate the growth of the\(2f_1-f_2\) otoacoustic emission, magnitude and phase input –output functions were obtained from human subjects using a range of stimulus levels, frequencies, and frequency ratios. Three factors related to cochlear nonlinearity may produce non-monotonic input–output functions: a two-component interaction, an operating point shift, and two-tone suppressio n. To complement data interpretation, a local model of distortion product otoacoustic emissi...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 1, 2021 Category: ENT & OMF Source Type: research

Visual Influences on Auditory Behavioral, Neural, and Perceptual Processes: A Review
AbstractIn a naturalistic environment, auditory cues are often accompanied by information from other senses, which can be redundant with or complementary to the auditory information. Although the multisensory interactions derived from this combination of information and that shape auditory function are seen across all sensory modalities, our greatest body of knowledge to date centers on how vision influences audition. In this review, we attempt to capture the state of our understanding at this point in time regarding this topic. Following a general introduction, the review is divided into 5 sections. In the first section, ...
Source: JARO - Journal of the Association for Research in Otolaryngology - May 20, 2021 Category: ENT & OMF Source Type: research

Effects of Several Therapeutic Agents on Mammalian Vestibular Function: Meclizine, Diazepam, and JNJ7777120
In this study, two commonly prescribed medications, meclizine and diazepam, and a candidate for future clinical use, JNJ7777120, were evaluated for their effects on short latency compound action potentials generated by the peripheral vestibular system and corresponding central neural relays (i.e., vestibular sensory-evoked potentials, VsEPs). The effects of the selected drugs developed slowly over the course of two hours in the mouse. Findings indicate that meclizine (600  mg/kg) and diazepam (>  60 mg/kg) can act on peripheral elements of the vestibular maculae whereas diazepam also acts most effective...
Source: JARO - Journal of the Association for Research in Otolaryngology - May 19, 2021 Category: ENT & OMF Source Type: research

Hearing Impairment and Cognition in an Aging World
AbstractWith the increasing number of older adults around the world, the overall number of dementia cases is expected to rise dramatically in the next 40  years. In 2020, nearly 6 million individuals in the USA were living with Alzheimer’s disease, the most common type of dementia, with anticipated growth to nearly 14 million by year 2050. This increasing prevalence, coupled with high societal burden, makes prevention and intervention of dementia a medical and public health priority. As clinicians and researchers, we will continue to see more individuals with hearing loss with other comorbidities including demen...
Source: JARO - Journal of the Association for Research in Otolaryngology - May 18, 2021 Category: ENT & OMF Source Type: research

Otoconia Structure After Short- and Long-Duration Exposure to Altered Gravity
This study provides a purely descriptive account of otoconia remodeling after exposures to altered gravity. The mechanism(s) underlying these processes must be identified and quantitatively validated to develop countermeasures to altered gravity levels during exploration missions. (Source: JARO - Journal of the Association for Research in Otolaryngology)
Source: JARO - Journal of the Association for Research in Otolaryngology - May 18, 2021 Category: ENT & OMF Source Type: research

Examining the Factors that Contribute to Non-Monotonic Growth of the $$2f_1 - f_2$$ 2 f 1 - f 2  Otoacoustic Emission in Humans
AbstractCubic distortion product otoacoustic emission input –output functions in humans show a complex pattern of growth. To further investigate the growth of the\(2f_1-f_2\) otoacoustic emission, magnitude and phase input –output functions were obtained from human subjects using a range of stimulus levels, frequencies, and frequency ratios. Three factors related to cochlear nonlinearity may produce non-monotonic input–output functions: a two-component interaction, an operating point shift, and two-tone suppressio n. To complement data interpretation, a local model of distortion product otoacoustic emissi...
Source: JARO - Journal of the Association for Research in Otolaryngology - May 11, 2021 Category: ENT & OMF Source Type: research

Reweighting of Binaural Localization Cues Induced by Lateralization Training
This study investigated whether binaural-cue reweighting can be induced by lateralization training in a virtual audio-visual environment. Twenty normal-hearing participants, divided into two groups, completed the experiment consisting of 7 days of lateralization training, preceded and followed by a test measuring the binaural-cue weights. Participants ’ task was to lateralize 500-ms bandpass-filtered (2–4 kHz) noise bursts containing various combinations of spatially consistent and inconsistent binaural cues. During training, additional visual cues reinforced the azimuth corresponding to ITDs in one group ...
Source: JARO - Journal of the Association for Research in Otolaryngology - May 6, 2021 Category: ENT & OMF Source Type: research

Development of Auditory Cortex Circuits
AbstractThe ability to process and perceive sensory stimuli is an essential function for animals. Among the sensory modalities, audition is crucial for communication, pleasure, care for the young, and perceiving threats. The auditory cortex (ACtx) is a key sound processing region that combines ascending signals from the auditory periphery and inputs from other sensory and non-sensory regions. The development of ACtx is a protracted process starting prenatally and requires the complex interplay of molecular programs, spontaneous activity, and sensory experience. Here, we review the development of thalamic and cortical audit...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 28, 2021 Category: ENT & OMF Source Type: research

How Zebrafish Can Drive the Future of Genetic-based Hearing and Balance Research
AbstractOver the last several decades, studies in humans and animal models have successfully identified numerous molecules required for hearing and balance. Many of these studies relied on unbiased forward genetic screens based on behavior or morphology to identify these molecules. Alongside forward genetic screens, reverse genetics has further driven the exploration of candidate molecules. This review provides an overview of the genetic studies that have established zebrafish as a genetic model for hearing and balance research. Further, we discuss how the unique advantages of zebrafish can be leveraged in future genetic s...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 28, 2021 Category: ENT & OMF Source Type: research

The Panoramic ECAP Method: Estimating Patient-Specific Patterns of Current Spread and Neural Health in Cochlear Implant Users
AbstractThe knowledge of patient-specific neural excitation patterns from cochlear implants (CIs) can provide important information for optimizing efficacy and improving speech perception outcomes. The Panoramic ECAP ( ‘PECAP’) method (Cosentino et al.2015) uses forward-masked electrically evoked compound action-potentials (ECAPs) to estimate neural activation patterns of CI stimulation. The algorithm requires ECAPs be measured for all combinations of probe and masker electrodes, exploiting the fact that ECAP amplitudes reflect the overlapping excitatory areas of both probesand maskers. Here we present an impro...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 23, 2021 Category: ENT & OMF Source Type: research

Rate and Temporal Coding of Regular and Irregular Pulse Trains in Auditory Midbrain of Normal-Hearing and Cochlear-Implanted Rabbits
AbstractAlthough pitch is closely related to temporal periodicity, stimuli with a degree of temporal irregularity can evoke a pitch sensation in human listeners. However, the neural mechanisms underlying pitch perception for irregular sounds are poorly understood. Here, we recorded responses of single units in the inferior colliculus (IC) of normal hearing (NH) rabbits to acoustic pulse trains with different amounts of random jitter in the inter-pulse intervals and compared with responses to electric pulse trains delivered through a cochlear implant (CI) in a different group of rabbits. In both NH and CI animals, many IC n...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 23, 2021 Category: ENT & OMF Source Type: research

An Alternative Explanation for Difficulties with Speech in Background Talkers: Abnormal Fusion of Vowels Across Fundamental Frequency and Ears
In this study, using dichotic speech stimuli, we examined the relationship between speech fusion and vowel identification. Dichotic vowel perception was measured in NH and HI listeners, with across-ear fundamental frequency differences varied. Synthetic vowels /i/, /u/, /a/, and /ae/ were generated with three fundamental frequencies (F0) of 106.9, 151.2, and 201.8  Hz and presented dichotically through headphones. For HI listeners, stimuli were shaped according to NAL-NL2 prescriptive targets. Although the dichotic vowels presented were always different across ears, listeners were not informed that there were no singl...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 20, 2021 Category: ENT & OMF Source Type: research

Phosphorylation of MYL12 by Myosin Light Chain Kinase Regulates Cellular Shape Changes in Cochlear Hair Cells
In conclusion, MYL12 phosphorylation by smMLCK contributed to the apical constriction-like cellular shape change of HCs possibly relating to the development of auditory epithelia and hearing function. (Source: JARO - Journal of the Association for Research in Otolaryngology)
Source: JARO - Journal of the Association for Research in Otolaryngology - April 20, 2021 Category: ENT & OMF Source Type: research

Super-enhancer Acquisition Drives FOXC2 Expression in Middle Ear Cholesteatoma
In this study, we examined the localization of variously modified histone H3 acetylation at lysine 9, 14, 18, 23, and 27 in paraffin-embedded sections of human middle ear cholesteatoma (cholesteatoma) tissues and the temporal bones of an animal model of cholesteatoma immunohistochemically. As a result, we found that there was a significant increase of the expression levels of H3K27ac both in human cholesteatoma tissues and the animal model. In genetics, super-enhancers are clusters of enhancers that drive the transcription of genes involved in cell identity. Super-enhancers were originally defined using the H3K27ac signal,...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 16, 2021 Category: ENT & OMF Source Type: research

Auditory Brainstem Models: Adapting Cochlear Nuclei Improve Spatial Encoding by the Medial Superior Olive in Reverberation
AbstractListeners typically perceive a sound as originating from the direction of its source, even as direct sound is followed milliseconds later by reflected sound from multiple different directions. Early-arriving sound is emphasised in the ascending auditory pathway, including the medial superior olive (MSO) where binaural neurons encode the interaural-time-difference (ITD) cue for spatial location. Perceptually, weighting of ITD conveyed during rising sound energy is stronger at 600 Hz than at 200 Hz, consistent with the minimum stimulus rate for binaural adaptation, and with the longer reverberation times at 600 Hz, c...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 16, 2021 Category: ENT & OMF Source Type: research

A Bridge over Troubled Listening: Improving Speech-in-Noise Perception by Children with Dyslexia
AbstractDevelopmental dyslexia is most commonly associated with phonological processing difficulties. However, children with dyslexia may experience poor speech-in-noise perception as well. Although there is an ongoing debate whether a speech perception deficit is inherent to dyslexia or acts as an aggravating risk factor compromising learning to read indirectly, improving speech perception might boost reading-related skills and reading acquisition. In the current study, we evaluated advanced speech technology as applied in auditory prostheses, to promote and eventually normalize speech perception of school-aged children w...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 16, 2021 Category: ENT & OMF Source Type: research

Speech Perception with Noise Vocoding and Background Noise: An EEG and Behavioral Study
This study explored the physiological response of the human brain to degraded speech syllables. The degradation was introduced using noise vocoding and/or background noise. The goal was to identify physiological features of auditory-evoked potentials (AEPs) that may explain speech intelligibility. Ten human subjects with normal hearing participated in syllable-detection tasks, while their AEPs were recorded with 32-channel electroencephalography. Subjects were presented with six syllables in the form of consonant-vowel-consonant or vowel-consonant-vowel. Noise vocoding with 22 or 4 frequency channels was applied to the syl...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 13, 2021 Category: ENT & OMF Source Type: research

Examining the Factors that Contribute to Non-Monotonic Growth of the $$2f_1 - f_2$$ 2 f 1 - f 2  Otoacoustic Emission in Humans
AbstractCubic distortion product otoacoustic emission input –output functions in humans show a complex pattern of growth. To further investigate the growth of the\(2f_1-f_2\) otoacoustic emission, magnitude and phase input –output functions were obtained from human subjects using a range of stimulus levels, frequencies, and frequency ratios. Three factors related to cochlear nonlinearity may produce non-monotonic input–output functions: a two-component interaction, an operating point shift, and two-tone suppressio n. To complement data interpretation, a local model of distortion product otoacoustic emissi...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 12, 2021 Category: ENT & OMF Source Type: research

Forward and Reverse Middle Ear Transmission in Gerbil with a Normal or Spontaneously Healed Tympanic Membrane
AbstractTympanic membranes (TM) that have healed spontaneously after perforation present abnormalities in their structural and mechanical properties; i.e., they are thickened and abnormally dense. These changes result in a deterioration of middle ear (ME) sound transmission, which is clinically presented as a conductive hearing loss (CHL). To fully understand the ME sound transmission under TM pathological conditions, we created a gerbil model with a controlled 50% pars tensa perforation, which was left to heal spontaneously for up to 4  weeks (TM perforations had fully sealed after 2 weeks). After the recovery p...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 16, 2021 Category: ENT & OMF Source Type: research

Transient Delivery of a  KCNQ2/3-Specific Channel Activator 1 Week After Noise Trauma Mitigates Noise-Induced Tinnitus
AbstractExposure to loud noise can cause hearing loss and tinnitus in mice and humans. In mice, one major underlying mechanism of noise-induced tinnitus is hyperactivity of auditory brainstem neurons, due at least in part, to decreased Kv7.2/3 (KCNQ2/3) potassium channel activity. In our previous studies, we used a reflex-based mouse model of tinnitus and showed that administration of a non-specific KCNQ channel activator, immediately after noise trauma, prevented the development of noise-induced tinnitus, assessed 1  week after trauma. Subsequently, we developed RL-81, a very potent and highly specific activator of K...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 11, 2021 Category: ENT & OMF Source Type: research

Sensitivity to Pulse Phase Duration as a Marker of Neural Health Across Cochlear Implant Recipients and Electrodes
In this study, we examined the across-site variation of charge integration in recipients of Cochlear© devices. PPD and PA dynamic ranges were measured relative to two threshold anchors with either a 25- or 50-microse cond PPD. Strength-duration functions, previously shown to relate to survival of spiral ganglion cells and peripheral processes, were compared to charge integration efficiency on selected electrodes. Results showed no significant or systematic relationship between the across-site variation in charge integration efficiency and electrode position or threshold levels. Charge integration efficiency was poorer...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 8, 2021 Category: ENT & OMF Source Type: research

Residual Hair Cell Responses in Electric-Acoustic Stimulation Cochlear Implant Users with Complete Loss of Acoustic Hearing After Implantation
AbstractChanges in cochlear implant (CI) design and surgical techniques have enabled the preservation of residual acoustic hearing in the implanted ear. While most Nucleus Hybrid L24 CI users retain significant acoustic hearing years after surgery, 6 –17 % experience a complete loss of acoustic hearing (Roland et al. Laryngoscope. 126(1):175-81. (2016), Laryngoscope. 128(8):1939-1945 (2018); Scheperle et al. Hear Res. 350:45-57 (2017)). Electrocochleography (ECoG) enables non-invasive monitoring of peripheral auditory function and may provide insight into the pathophysiology of hearing loss. The ECoG response is evok...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 4, 2021 Category: ENT & OMF Source Type: research

Stem Cells and Gene Therapy in Progressive Hearing Loss: the State of the Art
AbstractProgressive non-syndromic sensorineural hearing loss (PNSHL) is the most common cause of sensory impairment, affecting more than a third of individuals over the age of 65. PNSHL includes noise-induced hearing loss (NIHL) and inherited forms of deafness, among which is delayed-onset autosomal dominant hearing loss (AD PNSHL). PNSHL is a prime candidate for genetic therapies due to the fact that PNSHL has been studied extensively, and there is a potentially wide window between identification of the disorder and the onset of hearing loss. Several gene therapy strategies exist that show potential for targeting PNSHL, i...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 28, 2021 Category: ENT & OMF Source Type: research

Using Interleaved Stimulation to Measure the Size and Selectivity of the Sustained Phase-Locked Neural Response to Cochlear Implant Stimulation
AbstractWe measured the sustained neural response to electrical stimulation by a cochlear implant (CI). To do so, we interleaved two stimuli with frequencies F1 and F2  Hz and recorded a neural distortion response (NDR) at F2-F1 Hz. We show that, because any one time point contains only the F1 or F2 stimulus, the instantaneous nonlinearities typical of electrical artefact should not produce distortion at this frequency. However, if the stimulus is smoothed, such as by charge integration at the nerve membrane, subsequent (neural) nonlinearities can produce a component at F2-F1 Hz. We stimulated a single CI el...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 25, 2021 Category: ENT & OMF Source Type: research

Self-Reported Sense of Direction and Vestibular Function in the Baltimore Longitudinal Study of Aging (BLSA)
In this study, we evaluated whether vestibular function is associated with self-reported sense of direction. Participants for this cross-sectional study were recruited from the Baltimore Longitudinal Study of Aging, a longstanding cohort study of healthy aging. In a modified version of the Santa Barbara Sense-of-Direction (SBSOD) Scale, participants rated statements about spatial and navigational abilities. A lower average score indicates poorer self-reported sense of direction. Vestibular function testing inclu ded cervical vestibular-evoked myogenic potential (VEMP) to assess saccular function, ocular VEMP to assess utri...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 15, 2021 Category: ENT & OMF Source Type: research

Early Physiological and Cellular Indicators of Cisplatin-Induced Ototoxicity
AbstractCisplatin chemotherapy often causes permanent hearing loss, which leads to a multifaceted decrease in quality of life. Identification of early cisplatin-induced cochlear damage would greatly improve clinical diagnosis and provide potential drug targets to prevent cisplatin ’s ototoxicity. With improved functional and immunocytochemical assays, a recent seminal discovery revealed that synaptic loss between inner hair cells and spiral ganglion neurons is a major form of early cochlear damage induced by noise exposure or aging. This breakthrough discovery prompted the current study to determine early functional,...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 7, 2021 Category: ENT & OMF Source Type: research

Characterization of the Sheep Round Window Membrane
AbstractIntratympanic injection is a clinically used approach to locally deliver therapeutic molecules to the inner ear. Drug diffusion, at least in part, is presumed to occur through the round window membrane (RWM), one of the two openings to the inner ear. Previous studies in human temporal bones have identified a three-layered structure of the RWM with a thickness of 70 –100 μm. This is considerably thicker than the RWM in rodents, which are mostly used to model RWM permeability and assess drug uptake. The sheep has been suggested as a large animal model for inner ear research given the similarities in str...
Source: JARO - Journal of the Association for Research in Otolaryngology - November 30, 2020 Category: ENT & OMF Source Type: research

Noninvasive Measures of Distorted Tonotopic Speech Coding Following Noise-Induced Hearing Loss
AbstractAnimal models of noise-induced hearing loss (NIHL) show a dramatic mismatch between cochlear characteristic frequency (CF, based on place of innervation) and the dominant response frequency in single auditory-nerve-fiber responses to broadband sounds (i.e., distorted tonotopy, DT). This noise trauma effect is associated with decreased frequency-tuning-curve (FTC) tip-to-tail ratio, which results from decreased tip sensitivity and enhanced tail sensitivity. Notably, DT is more severe for noise trauma than for metabolic (e.g., age-related) losses of comparable degree, suggesting that individual differences in DT may ...
Source: JARO - Journal of the Association for Research in Otolaryngology - November 13, 2020 Category: ENT & OMF Source Type: research

Acoustic Trauma Increases Ribbon Number and Size in Outer Hair Cells of the Mouse Cochlea
AbstractOuter hair cells (OHCs) in the mouse cochlea are contacted by up to three type II afferent boutons. On average, only half of these are postsynaptic to presynaptic ribbons. Mice of both sexes were subjected to acoustic trauma that produced a threshold shift of 44.2  ± 9.1 dB 7 days after exposure. Ribbon synapses of OHCs were quantified in post-trauma and littermate controls using immunolabeling of CtBP2. Visualization with virtual reality was used to determine 3-D cytoplasmic localization of CtBP2 puncta to the synaptic pole of OHCs. Acoustic trauma was associated with a statistically sig...
Source: JARO - Journal of the Association for Research in Otolaryngology - November 5, 2020 Category: ENT & OMF Source Type: research

Evaluating and Comparing Behavioural and Electrophysiological Estimates of Neural Health in Cochlear Implant Users
AbstractVariations in neural health along the cochlea can degrade the spectral and temporal representation of sounds conveyed by cochlear implants (CIs). We evaluated and compared one electrophysiological measure and two behavioural measures that have been proposed as estimates of neural health patterns, in order to explore the extent to which the different measures provide converging and consistent neural health estimates. All measures were obtained from the same 11 users of the Cochlear Corporation CI. The two behavioural measures were multipulse integration (MPI) and the polarity effect (PE), both measured on each of se...
Source: JARO - Journal of the Association for Research in Otolaryngology - November 4, 2020 Category: ENT & OMF Source Type: research

Interpreting the Effect of Stimulus Parameters on the Electrically Evoked Compound Action Potential and on Neural Health Estimates
We present a simple theoretical model for the effect of IPG on ECAP AGFs, along with a re-analysis of both animal and human data that measured the IPG effect. Both the theoretical model and the re-analysis of the animal data suggest that the IPG effect on ECAP AGF slope (IPG slope effect), measured using either a linear or logarithmic input-output scale, does not successfully control for the effects of non-neural factors. Both the model and the data suggest that the appropriate method to estimate neural health is by measuring the IPG offset effect, defined as the dB offset between the linear portions of ECAP AGFs for two s...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 27, 2020 Category: ENT & OMF Source Type: research

The Temporal Fine Structure of Background Noise Determines the Benefit of Bimodal Hearing for Recognizing Speech
In this study, we investigated whether the use of a CI alone provides access to only envelope cues and whether acoustic amplification can provide additional access to TFS cues. To this end, we evaluated speech recognition in bimodal listeners, using SS noise and two amplitude-modulated noise types, namely babble noise and amplitude-modulated steady-state (AMSS) noise. We hypothesized that speech recognition in noise depends on the envelope of the noise, but not on its TFS when listening with a CI. Secondly, we hypothesized that the amount of benefit gained by the addition of a contralateral hearing aid depends on both the ...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 26, 2020 Category: ENT & OMF Source Type: research

Human Vestibulo-Ocular Reflex Adaptation Reduces when Training Demand Variability Increases
In this study, head rotation frequency during training incrementally increased 0.5–2 Hz over 20 min. Active and passive (imposed, unpredictable) sinusoidal (1.3-Hz rotations) and head impulse VOR gains were measured before and after training. We show that for controls, manual × 2 training resulted in significant sinusoidal and impulse VOR adaptation of ~ 6 % and ~ 3 %, respectively, though this w as ~two-thirds lower than increases after computer-controlled × 2 training (non-variable) reported in a prior study. In contrast, for patients, there was an increas...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 22, 2020 Category: ENT & OMF Source Type: research

Effects of Kainic Acid-Induced Auditory Nerve Damage on Envelope-Following Responses in the Budgerigar ( Melopsittacus undulatus )
AbstractSensorineural hearing loss is a prevalent problem that adversely impacts quality of life by compromising interpersonal communication. While hair cell damage is readily detectable with the clinical audiogram, this traditional diagnostic tool appears inadequate to detect lost afferent connections between inner hair cells and auditory nerve (AN) fibers, known as cochlear synaptopathy. The envelope-following response (EFR) is a scalp-recorded response to amplitude modulation, a critical acoustic feature of speech. Because EFRs can have greater amplitude than wave I of the auditory brainstem response (ABR; i.e., the AN-...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 19, 2020 Category: ENT & OMF Source Type: research

Does the “Reticular Lamina Nonlinearity” Contribute to the Basal DPOAE Source?
AbstractThe spatial extent of the cochlear region that actually contributes to the DPOAE signal measured in the ear canal may be evaluated experimentally using interference tones or computed numerically using nonlinear cochlear models. A nonlinear transmission-line cochlear model is used in this study to evaluate whether the recently reported nonlinear behavior of the reticular lamina (RL) over a wide basal region may be associated with generation of a significant distortion product otoacoustic emission (DPOAE) component. A two-degrees-of-freedom 1-D nonlinear model was used as discussed by Sisto et al. (2019), in which ea...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 20, 2020 Category: ENT & OMF Source Type: research

Perceptual Weighting of Binaural Lateralization Cues across Frequency Bands
AbstractThe auditory system uses interaural time and level differences (ITD and ILD) as cues to localize and lateralize sounds. The availability of ITDs and ILDs in the auditory system is limited by neural phase-locking and by the head size, respectively. Although the frequency-specific limitations are well known, the relative contribution of ITDs and ILDs in individual frequency bands in broadband stimuli is unknown. To determine these relative contributions, or spectral weights, listeners were asked to lateralize stimuli consisting of eleven simultaneously presented 1-ERB-wide noise bands centered between 442 and 5544 &n...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 10, 2020 Category: ENT & OMF Source Type: research

Correlating Cochlear Morphometrics from Parnell ’s Mustached Bat ( Pteronotus parnellii ) with Hearing
AbstractMorphometric analysis of the inner ear of mammals can provide information for cochlear frequency mapping, a species-specific designation of locations in the cochlea at which different sound frequencies are encoded. Morphometric variation occurs in the hair cells of the organ of Corti along the cochlea, with the base encoding the highest frequency sounds and the apex encoding the lowest frequencies. Changes in cell shape and spacing can yield additional information about the biophysical basis of cochlear tuning mechanisms. Here, we investigate how morphometric analysis of hair cells in mammals can be used to predict...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 8, 2020 Category: ENT & OMF Source Type: research

Effect of the Relative Timing between Same-Polarity Pulses on Thresholds and Loudness in Cochlear Implant Users
AbstractThe effect of the relative timing between pairs of same-polarity monophasic pulses has been studied extensively in single-neuron animal studies and has revealed fundamental properties of the neurons. For human cochlear implant listeners, the requirement to use charge-balanced stimulation and the typical use of symmetric, biphasic pulses limits such measures, because currents of opposite polarities interact at the level of the neural membrane. Here, we propose a paradigm to study same-polarity summation of currents while keeping the stimulation charge-balanced within a short time window. We used pairs of mirrored ps...
Source: JARO - Journal of the Association for Research in Otolaryngology - August 23, 2020 Category: ENT & OMF Source Type: research

The Effect of Phantom Stimulation and Pseudomonophasic Pulse Shapes on Pitch Perception by Cochlear Implant Listeners
AbstractIt has been suggested that a specialized high-temporal-acuity brainstem pathway can be activated by stimulating more apically in the cochlea than is achieved by cochlear implants (CIs) when programmed with contemporary clinical settings. We performed multiple experiments to test the effect on pitch perception of phantom stimulation and asymmetric current pulses, both supposedly stimulating beyond the most apical electrode of a CI. The two stimulus types were generated using a bipolar electrode pair, composed of the most apical electrode of the array and a neighboring, more basal electrode. Experiment 1 used a pitch...
Source: JARO - Journal of the Association for Research in Otolaryngology - August 16, 2020 Category: ENT & OMF Source Type: research

Gap Detection Deficits in Chinchillas with Selective Carboplatin-Induced Inner Hair Cell Loss
AbstractTemporal resolution is essential for processing complex auditory information such as speech. In hearing impaired persons, temporal resolution, often assessed by detection of brief gaps in continuous sound stimuli, is typically poorer than in individuals with normal hearing. At low stimulus presentation levels, hearing impaired individuals perform poorly but the deficits are greatly reduced when the sensation level of the stimuli are adjusted to match their normal hearing peers. In the present study, we evaluated the effect of selective inner hair cell loss on gap detection in chinchillas treated with carboplatin, a...
Source: JARO - Journal of the Association for Research in Otolaryngology - August 16, 2020 Category: ENT & OMF Source Type: research

Vibration Measurements of the Gerbil Eardrum Under Quasi-static Pressure Steps
In this study, we measured in vivo vibration responses in 11 gerbils while varying the middle-ear pressure quasi-statically, with the ear canal at ambient pressure. Vibrations were recorded using a single-point laser Doppler vibrometer with five glass-coated reflective beads (diameter ~  40 μm) as targets. The locations were the umbo, mid-manubrium, posterior pars tensa, anterior pars tensa and pars flaccida. As described in earlier studies, the unpressurized vibration magnitude was flat at low frequencies, increased until a resonance frequency at around 1.8–2.5 kHz, and bec ame complex at higher ...
Source: JARO - Journal of the Association for Research in Otolaryngology - August 10, 2020 Category: ENT & OMF Source Type: research

Mechanical Properties of Baboon Tympanic Membrane from Young to Adult
AbstractMechanical properties of the tympanic membrane (TM) play an important role in sound transmission through the middle ear. While numerous studies have investigated the mechanical properties of the adult human TM, the effects of age on the TM ’s properties remain unclear because of the limited published data on the TM of young children. To address this deprivation, we used baboons in this study as an animal model for investigating the effect of age on the mechanical properties of the TM. Temporal bones were harvested from baboons (Papio anubis) of four different age groups: less than 1  year, 1–3 ...
Source: JARO - Journal of the Association for Research in Otolaryngology - August 10, 2020 Category: ENT & OMF Source Type: research

Utricular Sensitivity during Hydrodynamic Displacements of the Macula
AbstractTo explore the effects of cochlear hair cell displacement, researchers have previously monitored functional and mechanical responses during low-frequency (LF) acoustic stimulation of the cochlea. The induced changes are believed to result from modulation of the conductance of mechano-electrical transduction (MET) channels on cochlear hair cells, along with receptor potential modulation. It is less clear how, or if, vestibular hair cell displacement affects vestibular function. Here, we have used LF (
Source: JARO - Journal of the Association for Research in Otolaryngology - August 10, 2020 Category: ENT & OMF Source Type: research

Effects of Tonic Muscle Activation on Amplitude-Modulated Cervical Vestibular Evoked Myogenic Potentials (AMcVEMPs) in Young Females: Preliminary Findings
AbstractCervical vestibular evoked myogenic potentials (cVEMPs) are usually elicited by transient tonebursts, but when elicited by amplitude-modulated (AM) tones, they can provide new information about cVEMPs. Previous reports of cVEMPs elicited by AM tones, or AMcVEMPs, have not systematically examined the effects of tonic EMG activation on their response properties. Fourteen young, healthy female adults (ages 20 –24) with clinically normal audiograms participated in this study. AMcVEMPs were elicited with bone-conducted 500 Hz tones amplitude modulated at a rate of 37 Hz and recorded for five different EM...
Source: JARO - Journal of the Association for Research in Otolaryngology - August 4, 2020 Category: ENT & OMF Source Type: research

The Genetics of Variation of the Wave 1 Amplitude of the Mouse Auditory Brainstem Response
AbstractThis is the first genome-wide association study with the Hybrid Mouse Diversity Panel (HDMP) to define the genetic landscape of the variation in the suprathreshold wave 1 amplitude of the auditory brainstem response (ABR) both pre- and post-noise exposure. This measure is correlated with the density of the auditory neurons (AN) and/or the compliment of synaptic ribbons within the inner hair cells of the mouse cochlea. We analyzed suprathreshold ABR for 635 mice from 102 HMDP strains pre- and post-noise exposure (108  dB 10 kHz octave band noise exposure for 2 h) using auditory brainstem response (ABR...
Source: JARO - Journal of the Association for Research in Otolaryngology - August 4, 2020 Category: ENT & OMF Source Type: research

Correction to: Speech Perception with Spectrally Non-overlapping Maskers as Measure of Spectral Resolution in Cochlear Implant Users
An error in interpreting the statistical analysis output led to reporting errors in some of the effect sizes for the three-way repeated-measures ANOVAs in Experiment 1. (Source: JARO - Journal of the Association for Research in Otolaryngology)
Source: JARO - Journal of the Association for Research in Otolaryngology - July 19, 2020 Category: ENT & OMF Source Type: research

Relationships between Intrascalar Tissue, Neuron Survival, and Cochlear Implant Function
In this study, we investigated the relationship between intrascalar tissue and 5 measures of implant function in guinea pigs. Variation in both spiral ganglion neuron (SGN) survival and intrascalar tissue was produced by implanting hearing ears, ears deafened with neomycin, and neomycin-deafened ears treated with a neurotrophin. We found significant effects of SGN density on 4 functional measures but adding intrascalar tissue level to the analysis did not explain more variation in any measure than was explained by SGN density alone. These results suggest that effects of intrascalar tissue on electrical hearing are relative...
Source: JARO - Journal of the Association for Research in Otolaryngology - July 19, 2020 Category: ENT & OMF Source Type: research

Optimizing Auditory Brainstem Response Acquisition Using Interleaved Frequencies
AbstractAuditory brainstem responses (ABRs) require averaging responses to hundreds or thousands of repetitions of a stimulus (e.g., tone pip) to obtain a measurable evoked response at the scalp. Fast repetition rates lead to changes in ABR amplitude and latency due to adaptation. To minimize the effect of adaptation, stimulus rates are sometimes as low as 10 to 13.3 stimuli per second, requiring long acquisition times. The trade-off between reducing acquisition time and minimizing the effect of adaptation on ABRs is an especially important consideration for studies of cochlear synaptopathy, which use the amplitude of shor...
Source: JARO - Journal of the Association for Research in Otolaryngology - July 8, 2020 Category: ENT & OMF Source Type: research