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Recent studies have highlighted the anatomy of the cochlear partition (CP), revealing insights into the flexible nature of the osseous spiral lamina (OSL) and the existence of a flexible cochlear partition bridge (CPB) between the OSL and the basilar membrane (BM). However, most existing inner ear models treat the OSL as a rigid structure and ignore the CPB, neglecting their potential impact on intracochlear sound pressure and motion of the BM. In this paper, we investigate the effect of the CP's flexibility by including the OSL and CPB as either rigid or flexible structures in a numerical anatomical model of the human inner ear. Our findings demonstrate that the flexibility of the OSL and the presence of the CPB significantly affect cochlear macro mechanisms, including differential intracochlear sound pressure, resistive behavior in cochlear impedances, CP stiffness, and BM velocity. These results emphasize the importance of considering the flexibility of the entire CP to enhance our understanding of cochlear function and to accurately interpret experimental data on inner ear mechanics. • A flexible osseous spiral lamina (OSL) explains resistivity in cochlear impedances. • A flexible OSL predominantly influences the cochlear partition stiffness towards the base. • The cochlear partition bridge increases the effective width of the basilar membrane. • Consequently, both the OSL and the bridge affect the motion of the basilar membrane. [ABSTRACT FROM AUTHOR]

• A subject-independent model is proposed for auditory spatial attention detection. • Mutual information-based EEG graph modeling captures brain functional connectivity. • Domain generalization enhances the generalizability of our model to unseen subjects. • The proposed model has potential applications in "neuro-steered hearing devices". Auditory spatial attention detection (ASAD) seeks to determine which speaker in a surround sound field a listener is focusing on based on the one's brain biosignals. Although existing studies have achieved ASAD from a single-trial electroencephalogram (EEG), the huge inter-subject variability makes them generally perform poorly in cross-subject scenarios. Besides, most ASAD methods do not take full advantage of topological relationships between EEG channels, which are crucial for high-quality ASAD. Recently, some advanced studies have introduced graph-based brain topology modeling into ASAD, but how to calculate edge weights in a graph to better capture actual brain connectivity is worthy of further investigation. To address these issues, we propose a new ASAD method in this paper. First, we model a multi-channel EEG segment as a graph, where differential entropy serves as the node feature, and a static adjacency matrix is generated based on inter-channel mutual information to quantify brain functional connectivity. Then, different subjects' EEG graphs are encoded into a shared embedding space through a total variation graph neural network. Meanwhile, feature distribution alignment based on multi-kernel maximum mean discrepancy is adopted to learn subject-invariant patterns. Note that we align EEG embeddings of different subjects to reference distributions rather than align them to each other for the purpose of privacy preservation. A series of experiments on open datasets demonstrate that the proposed model outperforms state-of-the-art ASAD models in cross-subject scenarios with relatively low computational complexity, and feature distribution alignment improves the generalizability of the proposed model to a new subject. [ABSTRACT FROM AUTHOR]

Abstract Compared with machine audition, the human auditory system can recognize speech accurately and quickly. This paper proposes a new developmental network (DN) that simulates the human auditory system and constructs an artificial auditory model for speech recognition. The new model simulates each key element of the human auditory pathway as a deep network; in particular, an additional layer in the network is considered to simulate the function of the superior colliculus in the thalamus for speech context integration. The mel-frequency cepstral coefficient (MFCC) is used to extract the features of the speech signal as the sensory input of the DN. The emergent feature of DN model provides an explanation of how such internal neurons represent the short speech context when they are not supervised by the external world. The experimental results show that the recognition rates of English words and phrases can be improved significantly compared to those reported in the existing literature. The proposed DN model provides a new method to solve difficult problems, such as universal speech recognition, in traditional machine audition systems. Meanwhile, the same learning principle can potentially be used in or adapted to other computational contexts and applications. Highlights • This paper proposes a new developmental network that simulates human auditory system for speech recognition. • The new model simulates each key element of the human auditory pathway as a deep network. • An additional layer in the network is considered to simulate the function of the superior colliculus in the thalamus for speech context integration. • Mel Frequency Cepstrum Coefficient is used to extract the features of the speech signal. [ABSTRACT FROM AUTHOR]

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 the listening experiences of older adults with mild hearing impairment and concluded that ecological momentary assessment provided group and individual data which highlighted the between-subject variability in this clinical population. The second study investigated the difference that the provision of hearing aids could make for older adults with mild hearing impairment. The pilot study indicated that ecological momentary assessment could be successfully used in intervention studies to measure, for example, individual hearing aid benefit, which may extend beyond improved speech understanding. The study also revealed the potential for ecological momentary assessment as a tool for clinical practice and decision-making. Ecological momentary assessment can result in a rich array of research data if specific study design guidelines, presented in this paper, are followed. The development of a clinical ecological momentary assessment tool would provide clinicians an individualized outcome measure and facilitate the adoption of a greater degree of client- and family-centeredness, thereby improving rehabilitation outcomes. Highlights • Ecological momentary assessment (EMA) is a methodological approach proven to be suitable for hearing research. • When designing an EMA study, adherence to the suggested guidelines is important. • EMA also shows promise for use in intervention studies. • Further development of EMA into a clinical practice tool could facilitate improved rehabilitation outcomes. [ABSTRACT FROM AUTHOR]

• Cochlear implants benefit different vestibular schwannoma scenarios. • The Auditory Nerve Test System aids the decision for cochlear implant placement. • A positive response ensures sound detection with a cochlear implant. The use of cochlear implants (CIs) is on the rise for patients with vestibular schwannoma (VS). Besides CI following tumor resection, new scenarios such as implantation in observed and/or irradiated tumors are becoming increasingly common. A significant emerging trend is the need of intraoperative evaluation of the functionality of the cochlear nerve in order to decide if a CI would be placed. The purpose of this paper is to explore the experience of a tertiary center with the application of the Auditory Nerve Test System (ANTS) in various scenarios regarding VS patients. The results are compared to that of the studies that have previously used the ANTS in this condition. Patients with unilateral or bilateral VS (NF2) who were evaluated with the ANTS prior to considering CI in a tertiary center between 2021 and 2023 were analyzed. The presence of a robust wave V was chosen to define a positive electrical auditory brainstem response (EABR). Two patients underwent promontory stimulation (PromStim) EABR previous to ANTS evaluation. Seven patients, 2 NF-2 and 5 with sporadic VS were included. The initial scenario was simultaneous translabyrinthine (TL) tumor resection and CI in 3 cases while a CI placement without tumor resection was planned in 4 cases. The ANTS was positive in 4 cases, negative in 2 cases, and uncertain in one case. Two patients underwent simultaneous TL and CI, 1 patient simultaneous TL and auditory brainstem implant, 3 patients posterior tympanotomy with CI, and 1 patient had no implant placement. In the 5 patients undergoing CI, sound detection was present. There was a good correlation between the PromStim and ANTS EABR. The literature research yielded 35 patients with complete information about EABR response. There was one false negative and one false positive case; that is, the 28 implanted cases with a present wave V following tumor resection had some degree of auditory perception in all but one case. The ANTS is a useful intraoperative tool to asses CI candidacy in VS patients undergoing observation, irradiation or surgery. A positive strongly predicts at least sound detection with the CI. [ABSTRACT FROM AUTHOR]

Introduction There is no standard diagnostic criterion for tinnitus, although some clinical assessment instruments do exist for identifying patient complaints. Within epidemiological studies the presence of tinnitus is determined primarily by self-report, typically in response to a single question. Using these methods prevalence figures vary widely. Given the variety of published estimates worldwide, we assessed and collated published prevalence estimates of tinnitus and tinnitus severity, creating a narrative synthesis of the data. The variability between prevalence estimates was investigated in order to determine any barriers to data synthesis and to identify reasons for heterogeneity. Methods and analysis: A systematic review included all adult population studies reporting the prevalence of tinnitus from January 1980 to July 2015. We searched five databases (Embase, Medline, PsychInfo, CINAHL and Web Of Science), using a combination of medical subject headings (MeSH) and relevant text words. Observational studies including cross-sectional studies were included, but studies estimating the incidence of tinnitus (e.g. cohort studies) were outside the scope of this systematic review. Results The databases identified 875 papers and a further 16 were identified through manual searching. After duplicates were removed, 515 remained. On the basis of the title, abstract and full-text screening, 400, 48 and 27 papers respectively were removed. This left 40 papers, reporting 39 different studies, for data extraction. Sixteen countries were represented, with the majority of the studies from the European region (38.5%). Publications since 2010 represented half of all included studies (48.7%). Overall prevalence figures for each study ranged from 5.1% to 42.7%. For the 12 studies that used the same definition of tinnitus, prevalence ranged from 11.9% to 30.3%. Twenty-six studies (66.7%) reported tinnitus prevalence by different age groups, and generally showed an increase in prevalence as age increases. Half the studies reported tinnitus prevalence by gender. The pattern generally showed higher tinnitus prevalence among males than females. There were 8 different types of definitions of tinnitus, the most common being “tinnitus lasting for more than five minutes at a time” (34.3%). Only seven studies gave any justification for the question that was used, or acknowledged the lack of standard questions for tinnitus. There is widespread inconsistency in defining and reporting tinnitus, leading to variability in prevalence estimates among studies. Nearly half of the included studies had a high risk of bias and this limits the generalisability of prevalence estimates. In addition, the available prevalence data is heterogeneous thereby preventing the ability to pool the data and perform meta-analyses. Sources of heterogeneity include different diagnostic criteria, different age groups, different study focus and differences in reporting and analysis of the results. Heterogeneity thus made comparison across studies impracticable. Conclusion Deriving global estimates of the prevalence of tinnitus involves combining results from studies which are consistent in their definition and measurement of tinnitus, survey methodology and in the reporting and analysis of the results. Ultimately comparison among studies is unachievable without such consistency. The strength of this systematic review is in providing a record of all the available, recent epidemiological data in each global region and in making recommendations for promoting standardisation. [ABSTRACT FROM AUTHOR]

Background The most common form of tinnitus is a subjective, auditory, and distressing phantom phenomenon. Comorbidity with depression is high but other important psychiatric disorders such as anxiety disorders have received less attention. The current paper reviews the literature on the associations between tinnitus and anxiety disorders and the underlying pathophysiology, and discusses the clinical implications. Methodology PubMed and Web of Science were searched for all articles published up until October 2014 using combinations of the following search strings “Tinnitus”, ”Anxiety disorder”, “Panic Disorder”, “Generalized Anxiety Disorder”, “Post traumatic stress disorder”, “PTSD” “Social Phobia”, “Phobia Disorder”, “Obsessive Compulsive Disorder”, “Agoraphobia”. Results A total of 117 relevant papers were included. A 45% lifetime prevalence of anxiety disorders is reported in tinnitus populations, while an important overlap in associated (sub)cortical brain areas and cortico-subcortical networks involved in attention, distress, and memory functions is suggested. A disturbed hypothalamic-pituitary-adrenal axis function can be found in tinnitus and in anxiety disorders but, in comorbidity, the direction of the dysfunction is unclear. Conclusion Comorbidity is high and screening for and treatment of anxiety disorders is recommended in moderate to severe tinnitus, as, given the overlap in the structural and functional brain circuitries involved, theoretically, their management could improve (subjective) levels of tinnitus although further empirical research on this topic is required. [ABSTRACT FROM AUTHOR]

The recording of auditory evoked potentials (AEPs) at fast rates allows the study of neural adaptation, improves accuracy in estimating hearing threshold and may help diagnosing certain pathologies. Stimulation sequences used to record AEPs at fast rates require to be designed with a certain jitter, i.e., not periodical. Some authors believe that stimuli from wide-jittered sequences may evoke auditory responses of different morphology, and therefore, the time-invariant assumption would not be accomplished. This paper describes a methodology that can be used to analyze the time-invariant assumption in jittered stimulation sequences. The proposed method [Split-IRSA] is based on an extended version of the iterative randomized stimulation and averaging (IRSA) technique, including selective processing of sweeps according to a predefined criterion. The fundamentals, the mathematical basis and relevant implementation guidelines of this technique are presented in this paper. The results of this study show that Split-IRSA presents an adequate performance and that both fast and slow mechanisms of adaptation influence the evoked-response morphology, thus both mechanisms should be considered when time-invariance is assumed. The significance of these findings is discussed. [ABSTRACT FROM AUTHOR]

Objective This paper aims to provide a review of studies using neuroimaging to measure functional-structural reorganisation of the neuronal network for auditory perception after unilateral hearing loss. Design A literature search was performed in PubMed. Search criterions were peer reviewed original research papers in English completed by the 11th of March 2015. Study sample Twelve studies were found to use neuroimaging in subjects with unilateral hearing loss. An additional five papers not identified by the literature search were provided by a reviewer. Thus, a total of 17 studies were included in the review. Results Four different neuroimaging methods were used in these studies: Functional magnetic resonance imaging (fMRI) ( n = 11), diffusion tensor imaging (DTI) ( n = 4), T1/T2 volumetric images ( n = 2), magnetic resonance spectroscopy (MRS) ( n = 1). One study utilized two imaging methods (fMRI and T1 volumetric images). Conclusion Neuroimaging techniques could provide valuable information regarding the effects of unilateral hearing loss on both auditory and non-auditory performance. fMRI-studies showing a bilateral BOLD-response in patients with unilateral hearing loss have not yet been followed by DTI studies confirming their microstructural correlates. In addition, the review shows that an auditory modality-specific deficit could affect multi-modal brain regions and their connections. [ABSTRACT FROM AUTHOR]

• Popper and Fay (Hearing Research , 2011) argued that the terms "hearing specialist" and "non-specialist" (or "generalist") be dropped from use with fishes. • The terms were used to focus on mechanisms thought to enhance detection of sound pressure to increase hearing bandwidth and sensitivity. • In this review, we revisit the words and argue for their "reintroduction" of the terms and propose that "specialization" be used with specific anatomical adaptations. • We propose that specializations may be related to auditory functions beyond just detection of sound pressure. Investigators working with fish bioacoustics used to refer to fishes that have a narrow hearing bandwidth and poor sensitivity as "hearing generalists" (or "non-specialists"), while fishes that could detect a wider hearing bandwidth and had greater sensitivity were referred to as specialists. However, as more was learned about fish hearing mechanism and capacities, these terms became hard to apply since it was clear there were gradations in hearing capabilities. Popper and Fay, in a paper in Hearing Research in 2011, proposed that these terms be dropped because of the gradation. While this was widely accepted by investigators, it is now apparent that the lack of relatively concise terminology for fish hearing capabilities makes it hard to discuss fish hearing. Thus, in this paper we resurrect the terms specialist and non-specialist but use them with modifiers to express the specific structure of function that is considered a specialization. Moreover, this resurrection recognizes that hearing specializations in fishes may not only be related to increased bandwidth and/or sensitivity, but to other, perhaps more important, aspects of hearing such as sound source localization, discrimination between sounds, and detection of sounds in the presence of masking signals. [ABSTRACT FROM AUTHOR]

• First study to use NSS and HQ concurrently in large community and clinical samples. • Pioneering report of normative data using the newly translated 21-item French NSS. • Noise sensitivity and hyperacusis are multidimensional constructs. Noise sensitivity and hyperacusis are decreased sound tolerance conditions that are not well delineated or defined. This paper presents the correlations and distributions of the Noise Sensitivity Scale (NSS) and the Hyperacusis Questionnaire (HQ) scores in two distinct large samples. In Study 1, a community-based sample of young healthy adults (n = 103) exhibited a strong correlation (r = 0.74) between the two questionnaires. The mean NSS and HQ scores were 54.4 ± 16.9 and 12.5 ± 7.5, respectively. NSS scores displayed a normal distribution, whereas HQ scores showed a slight positive skew. In Study 2, a clinical sample of Veterans with or without clinical comorbidities (n = 95) showed a moderate correlation (r = 0.58) between the two questionnaires. The mean scores were 66.6 ± 15.6 and 15.3 ± 7.3 on the NSS and HQ, respectively. Both questionnaires' scores followed a normal distribution. In both samples, participants who self-identified as having decreased sound tolerance scored higher on both questionnaires. These findings provide reference data from two diverse sample groups. The moderate to strong correlations observed in both studies suggest a significant overlap between noise sensitivity and hyperacusis. The results underscore that NSS and HQ should not be used interchangeably, as they aim to measure distinct constructs, however to what extent they actually do remains to be determined. Further investigation should distinguish between these conditions through a comprehensive psychometric analysis of the questionnaires and a thorough exploration of psychoacoustic, neurological, and physiological differences that set them apart. [ABSTRACT FROM AUTHOR]

• The neural processing of temporal envelopes in aging and hearing loss is reviewed. • High-frequency (>100 Hz) envelope encoding is degraded in aging and hearing loss. • Low-frequency envelope encoding is inconsistently altered in aging and hearing loss. • Amplified envelope encoding may be present at the midbrain as well as at the cortex. • Disinhibition and cochlear dysfunction may lead to exaggerated envelope processing. Temporal modulations are ubiquitous features of sound signals that are important for auditory perception. The perception of temporal modulations, or temporal processing, is known to decline with aging and hearing loss and negatively impact auditory perception in general and speech recognition specifically. However, neurophysiological literature also provides evidence of exaggerated or enhanced encoding of specifically temporal envelopes in aging and hearing loss, which may arise from changes in inhibitory neurotransmission and neuronal hyperactivity. This review paper describes the physiological changes to the neural encoding of temporal envelopes that have been shown to occur with age and hearing loss and discusses the role of disinhibition and neural hyperactivity in contributing to these changes. Studies in both humans and animal models suggest that aging and hearing loss are associated with stronger neural representations of both periodic amplitude modulation envelopes and of naturalistic speech envelopes, but primarily for low-frequency modulations (<80 Hz). Although the frequency dependence of these results is generally taken as evidence of amplified envelope encoding at the cortex and impoverished encoding at the midbrain and brainstem, there is additional evidence to suggest that exaggerated envelope encoding may also occur subcortically, though only for envelopes with low modulation rates. A better understanding of how temporal envelope encoding is altered in aging and hearing loss, and the contexts in which neural responses are exaggerated/diminished, may aid in the development of interventions, assistive devices, and treatment strategies that work to ameliorate age- and hearing-loss-related auditory perceptual deficits. [ABSTRACT FROM AUTHOR]

• The BCI provides effective and safe rehabilitation for indicated patients. • The audiological results of BCI are comparable with similar devices. • After accumulated time of 113 years, no serious adverse events have occurred. Active transcutaneous bone conduction devices are a type of bone conduction device developed to keep the skin intact and provide direct bone conduction stimulation. The Bone Conduction Implant (BCI) is such a device and has been implanted in 16 patients. The objective of this paper is to give a broad overview of the BCI development to the final results of 13 patients at 5-year follow-up. Follow-up of these patients included audiological performance investigations, questionnaires, as well as safety evaluation and objective functionality testing of the device. Among those audiological measurements were sound field warble tone thresholds, speech recognition threshold (SRT), speech recognition score (SRS) and signal to noise ratio threshold (SNR-threshold). The accumulated implant time for all 16 patients was 113 years in February 2022. During this time, no serious adverse events have occurred. The functional improvement for the 13 patients reported in this paper was on average 29.5 dB (average over 0.5, 1, 2 and 4 kHz), while the corresponding effective gain was -12.4 dB. The SRT improvement was 24.5 dB and the SRS improvement was 38.1%, while the aided SNR-threshold was on average –6.4 dB. It was found that the BCI can give effective and safe hearing rehabilitation for patients with conductive and mild-to-moderate mixed hearing loss. [ABSTRACT FROM AUTHOR]

Novel hearing therapeutics are rapidly progressing along the innovation pathway and into the clinical trial domain. Because these trials are new to the hearing community, they come with challenges in terms of trial design, regulation and delivery. In this paper, we address the key scientific and operational issues and outline the opportunities for interdisciplinary and international collaboration these trials offer. Vital to the future successful implementation of these therapeutics is to evaluate their potential for adoption into healthcare systems, including consideration of their health economic value. This requires early engagement with all stakeholder groups along the hearing innovation pathway. • Novel hearing loss therapies are rapidly progressing along the translational pathway. • To develop precision medicine for inner ear disorders, precision diagnosis is needed. • There is an urgent need for large-scale genotype–phenotype studies. • Clinical trials capability and capacity must increase in line with this growing field. • For implementation, it is vital to consider health economics and service impact. [ABSTRACT FROM AUTHOR]

This paper presents evidence for a strong connection between the development of speech and language skills and musical activities of children and adolescents with hearing impairment and/or cochlear implants. This conclusion is partially based on findings for typically hearing children and adolescents, showing better speech and language skills in children and adolescents with musical training, and importantly, showing increases of speech and language skills in children and adolescents taking part in musical training. Further, studies of hearing-impaired children show connections between musical skills, involvement in musical hobbies, and speech and language skills. Even though the field is still lacking large-scale randomised controlled trials on the effects of musical interventions on the speech and language skills of children and adolescents with hearing impairments and cochlear implants, the current evidence seems enough to urge speech therapists, music therapists, music teachers, parents, and children and adolescents with hearing impairments and/or cochlear implants to start using music for enhancing speech and language skills. For this reason, we give our recommendations on how to use music for language skill enhancement in this group. • Musical activities enhance language skills in children with impaired hearing. • Similar effects are shown in typically-hearing children. • We urge the use of music with children and adolescents with impaired hearing. • We give recommendations on how to use music for language enhancement. [ABSTRACT FROM AUTHOR]

Hearing damage caused by blast waves is a frequent and common injury for Service members. However, most studies have focused on high-intensity blast exposures that are known to cause moderate to severe traumatic brain injury (TBI), and fewer studies have investigated the progressive hearing damage caused by low-intensity blast exposures (below mild TBI). In this paper, we report our recent study in chinchillas to investigate the auditory function changes over the time course after repetitive exposures to low-intensity blast. Two groups of chinchillas (N = 7 each) were used in this study. Group 1 was for an acute study with 2 blasts and Group 2 for progressive study with 3 blasts on Day 1 and observed for 7 days. Animals in both groups were exposed to blast overpressures of 21–35 kPa (3–5 psi or 180–185 dB SPL) at which the eardrum was usually not ruptured. One ear was left open while another ear was protected with an earplug. Blast overpressures were monitored at the entrance of the ear canal (P0) and near the eardrum in the canal (P1). Auditory brainstem responses (ABRs), distortion product otoacoustic emissions (DPOAEs), and middle latency responses (MLRs) were measured after each blast series in the acute group and on Days 1, 4, and 7 in the progressive group. Results show that hearing damage was induced in both ears after blast exposure on Day 1 and more damage was observed in open ears than plugged ears. Seven days after the three-blast series, the ABR threshold in open ears was still 7–20 dB higher on average than prior to the blasts. The MLR wave amplitude shifts were observed in both open and protected ears, which indicated central auditory damage. With the protection of an earplug, hearing thresholds had recovered to the pre-blast level by Day 7. Using this chinchilla blast model, acute and progressive hearing damages were quantified in both open and protected ears following repeated low-intensity blast exposures. • Hearing damages after exposure to repeated low-intensity blasts are observed. • Auditory injury assessed with auditory brainstem response, distortion product otoacoustic emission, and mid-latency response. • Acute and progressive hearing impairment over time course are investigated in chinchillas. • Auditory injury in protected ears with earplugs is assessed when exposed to blasts. [ABSTRACT FROM AUTHOR]

Hearing damage is one of most prevalent injuries in military personnel and civilians exposed to a blast. However, the mechanism of how the blast overpressure interacts with the tympanic membrane (TM) and impairs the peripheral auditory system still remains unclear. A 3D finite element (FE) model of the human ear has been developed to predict the blast overpressure transmission through the ear (Leckness et al., 2018), but the model needs to be further validated in TM response to blast pressure. This paper reports the first-ever approach using two laser Doppler vibrometers (LDVs) to measure the motion of the TM when the ear was exposed to a blast. Five fresh human temporal bones were used in this study with a pressure sensor inserted near the TM to measure the pressure reaching the TM (P1). The temporal bone was mounted in a "head block" and exposed to blast at the overpressure around 35 kPa measured at the entrance of the ear canal (P0). The movements of the TM at the umbo and the "head block" were measured simultaneously by two LDVs and the exact motion of the TM was determined by subtracting the head block motion from the TM data. Results include that the maximum TM velocity was 12.62 ± 3.63 m/s (mean ± SD) and the displacement was 0.78 ± 0.26 mm. The peak-to-peak displacement normalized by the P0 pressure was 22.9 ± 6.6 μm/kPa. The frequency domain analysis indicated that the spectrum peaks were located at frequencies below 3 kHz. The TM motion was then compared with that calculated from the FE model of the human ear with the measured P0 pressure wave applied at the ear canal entrance. The FE model-derived TM displacement under blast overpressure was consistent with the experimental results. This study provides a new methodology to determine the behavior of the middle ear in response to blast overpressure. The experimental data are critical for validating the FE model of the human ear for blast wave transduction and understanding the TM damage induced by blast exposure. • Movements of human tympanic membrane (TM) under blast exposure are measured. • Dual-laser Doppler vibrometers are established to measure TM vibration under blast. • Delayed movement of the TM with respect to blast overpressure has been observed. • Frequency components of the TM movement induced by blast are below 3 kHz. • The FE model was validated with the TM movement in response to blast in temporal bones. [ABSTRACT FROM AUTHOR]

The human tympanic membrane (TM, or eardrum) is composed primarily of layers of collagen fibers oriented in the radial and circumferential directions, as well as epidermal and mucosal layers at the lateral and medial surfaces. The mechanical properties of the TM depend on the microstructures of the collagen fibers, which vary with location, resulting in a spatial variation of Young's modulus. In this study, the Young's modulus of the human TM is measured using microindentation. A 10 μm diameter spherical nanoindenter tip is used to indent the TM at different locations in the lateral and medial surfaces. Through a viscoelastic contact analysis, the steady state out-of-plane (through thickness) Young's modulus at a constant strain rate for the TM is determined from the uniaxial relaxation modulus. The measured spatial distribution of Young's modulus is reported for the entire TM pars tensa on both lateral and medial surfaces. The Young's modulus, for the four TM quadrants, is analyzed statistically using a normal quantile-quantile (Q-Q) plot. The obtained S-shaped curve indicates a bi-modal Gaussian distribution in the Q-Q plot. The spatial distribution of the Young's modulus is modeled by a bivariate Gaussian function in the polar coordinates over the entire TM on both the lateral and medial surfaces. It is shown that the anterior-superior quadrant has the smallest value of Young's modulus. Differences are observed in the spatial distribution of the Young's modulus for both the lateral and medial surfaces. For the medial surface, Young's modulus varies mainly along the radial direction following a small-large-small trend, emanating from the umbo. For the lateral surface, the modulus at the anterior-superior quadrant shows the smallest modulus; the modulus decreases gradually along the radial directions. The quantitative results presented in this paper will help improve future simulation models of the middle ear by using spatial dependence of Young's modulus over the entire TM. • Microindentation was used to measure the out-of-plane Young's modulus of the entire human TM. • The Young's modulus distribution is reported for the entire TM pars tensa on both lateral and medial sides. • The Young's modulus mapping was accurately modeled by a bivariate Gaussian function in polar coordinates. [ABSTRACT FROM AUTHOR]

Abstract This paper investigates the salience of speech contrasts in noise, in relation to how listening attention affects scalp-recorded cortical responses. The contrasts that were examined with consonant-vowel syllables, were place of articulation, vowel length and voice-onset time (VOT) and our analysis focuses on the correspondence between the effect of attention on the electrophysiology and the decrement in behavioral results when noise was added to the stimuli. Normal-hearing subjects (n = 20) performed closed-set syllable identification in no noise, 0, 4 and 8 dB signal-noise ratio (SNR). Identification in noise decreased markedly for place of articulation, moderately for vowel length and marginally for VOT. The same syllables were used in two electrophysiology conditions, where subjects attended to the stimuli, and also while their attention was diverted to a visual discrimination task. Differences in global field power between the attention conditions from each contrast showed that that the effect of attention was negligible for place of articulation. They implied offset encoding of vowel length and were early (starting at 117 ms), and of high amplitude (>3 μV) for VOT. There were significant correlations between the difference in syllable identification in no noise and 0 dB SNR and the electrophysiology results between attention conditions for the VOT contrast. Comparison of the two attention conditions with microstate analysis showed a significant difference in the duration of microstate class D. These results show differential integration of attention and syllable processing according to speech contrast and they suggest that there is correspondence between the salience of a contrast in noise and the effect of attention on the evoked electrical response. Highlights • Electrophysiological attention differences for VOT and perception are correlated. • VOT perception is robust to noise and affected by the attention of the listener. • EEG measures of place of articulation are little affected by listening attention. • Clustered microstate analysis reveals differences in listening attention. [ABSTRACT FROM AUTHOR]

Abstract The estimated incidence of sensorineural hearing impairment (>40 dB HL) at birth is 1.86 per 1000 newborns in developed countries and 30–40% of these are unilateral. Profound sensorineural unilateral hearing impairment or single sided deafness (SSD) can be treated with a cochlear implant. However, this treatment is costly and invasive and unnecessary in the eyes of many. Very young children with SSD often do not exhibit language and cognitive delays and it is hard to imagine that neurocognitive skills will present difficulties with one good ear. In the current paper we review the most recent evidence on the consequences of unilateral hearing impairment for auditory and neurocognitive factors. While data of both adults and children are discussed, we focus on developmental factors, congenital deafness and a window of opportunity for intervention. We discuss which etiologies qualify for a cochlear implant and present our multi-center prospective study on cochlear implants in infants with one deaf ear. The large, state-of-the art body of research allows for evidence-based decisions regarding management of unilateral hearing loss in children. Highlights • Persons with single sided deafness (SSD) demonstrate deficiencies in several domains. • Children with SSD have difficulty mastering complex skills for spoken language. • Neurocognitive deficiencies do not appear to resolve with age without intervention. • The reviewed factors due to congenital deafness strongly support early rehabilitation. • 5 to 10 newborns with SSD qualify for a cochlear implant (CI) each year in Flanders. [ABSTRACT FROM AUTHOR]

Abstract One of the tenets of mammalian auditory physiology is that the frequency selectivity at the cochlear base decreases as a function of stimulus level. Changes in frequency selectivity have been shown to be accompanied by changes in response phases as a function of stimulus level. The existence of such nonlinear properties has been revealed by the analysis of either direct or indirect recordings of mechanical vibrations of the cochlea. Direct measurements of cochlear mechanical vibrations, however, have been carried out with success primarily in cochlear regions that are tuned to frequencies >7 kHz, but not in regions sensitive to lower frequencies. In this paper we continue to analyze recently published data from measurements of sound-induced vibrations at four locations near the apex of the intact guinea pig cochlea, in a region encompassing approximately 25% of its total length. Analysis of the responses at all locations reveal level-dependent phase properties that are rather different from those usually reported at the base of the cochlea of laboratory animals such as the chinchilla. Cochlear group delays, for example, increase or remain constant with increasing stimulus. Similarly, frequency selectivity at all the regions increases as a function of stimulus level. Highlights • The base and the apex of the cochlea process sounds in a different fashion. • Nonlinear amplification of vibrations at the apex is smaller than at the base. • Nonlinear phase changes at the apex and at the base are different. • Group delays increase or remain constant with stimulus level at the apex. • Frequency selectivity increases with stimulus level at the apex. [ABSTRACT FROM AUTHOR]

Abstract Although human speech recognition is often experienced as relatively effortless, a number of common challenges can render the task more difficult. Such challenges may originate in talkers (e.g., unfamiliar accents, varying speech styles), the environment (e.g. noise), or in listeners themselves (e.g., hearing loss, aging, different native language backgrounds). Each of these challenges can reduce the intelligibility of spoken language, but even when intelligibility remains high, they can place greater processing demands on listeners. Noisy conditions, for example, can lead to poorer recall for speech, even when it has been correctly understood. Speech intelligibility measures, memory tasks, and subjective reports of listener difficulty all provide critical information about the effects of such challenges on speech recognition. Eye tracking and pupillometry complement these methods by providing objective physiological measures of online cognitive processing during listening. Eye tracking records the moment-to-moment direction of listeners' visual attention, which is closely time-locked to unfolding speech signals, and pupillometry measures the moment-to-moment size of listeners' pupils, which dilate in response to increased cognitive load. In this paper, we review the uses of these two methods for studying challenges to speech recognition. Highlights • Reviews the uses of eye tracking and pupillometry for studying challenges to speech recognition. [ABSTRACT FROM AUTHOR]

Abstract Hearing helps us know where we are relative to important events and objects in our environment and it allows us to track our changing position dynamically over space and time. Auditory cues are used in combination with other sensory inputs (visual, vestibular, proprioceptive) to help us perceive our own movements through space, known as self-motion perception. Whether we are maintaining standing balance, walking, or driving, audition can provide unique and important information to help optimize self-motion perception, and consequently to support safe mobility. Recent epidemiological and experimental studies have provided evidence that hearing loss is associated with greater walking difficulties, poorer overall physical functioning, and a significantly increased risk of falling in older adults. Importantly, the mechanisms underlying the associations between hearing status and mobility are poorly understood. It is also critical to consider that age-related hearing loss is often concomitant with declines in other sensory, motor, and cognitive functions and that these declines may interact, particularly during realistic, everyday tasks. Overall, exploring the role of auditory cues and the effects of hearing loss on self-motion perception specifically, and mobility more generally, are important to both building fundamental knowledge about the perceptual processes underlying the ability to perceive our movements through space, as well as to optimizing mobility-related interventions for those with hearing loss so that they can function better when confronted by everyday, real-world, sensory-motor challenges. The goal of this paper is to explore the role of hearing in self-motion perception across a range of mobility-related behaviors. First, we briefly review the ways in which auditory cues are used to perceive self-motion and how sound inputs affect behaviors such as standing balance, walking, and driving. Next, we consider age-related changes in auditory self-motion perception and the potential consequences to performance on mobility-related tasks. We then describe how hearing loss is associated with declines in mobility-related abilities and increased adverse outcomes such as falls. We describe age-related changes to other sensory and cognitive functions and how these may interact with hearing loss in ways that affect mobility. Finally, we briefly consider the implications of the hearing-mobility associations with respect to applied domains such as screening for mobility problems and falls risk in those with hearing loss and developing interventions and training approaches targeting safe and independent mobility throughout the lifespan. Highlights • Auditory cues can be used to perceive self-motion and can affect mobility-related behaviors (balance, walking, driving). • Age-related hearing loss affects the processing of auditory inputs that are used to perceive self-motion. • Hearing loss in older adults is associated with mobility problems and increased incidence of falls. • Poorer self-motion perception, increased cognitive load, vestibular loss, social isolation may underlie these associations. • It remains unclear how/whether hearing interventions such as hearing aids result in safer mobility. [ABSTRACT FROM AUTHOR]

Abstract In a relatively short period of time, modern societies have been transformed by the ubiquitous uptake of advanced and portable mobile communication, computation, and sensors available on smartphones. Looking forward, it is anticipated that smartphones will have an increasingly important role in health management including the delivery of hearing healthcare and operation of hearing instruments. Objective : This paper provides a brief overview of the role of smartphones in audiologic rehabilitation and hearing research and reports on the findings of a survey assessing attitudes of audiologists towards smartphone integration in hearing healthcare. Design: A total of 258 audiologists working in the United States completed the 10-item survey. Results: The key finding from the survey is that practitioners generally expressed a high willingness to integrate smartphone technology in patient care. Counterintuitively, it was observed that clinicians with the least number of years of experience had relatively more negative attitudes toward smartphone integration in hearing healthcare than clinicians with comparatively more years of experience. Conclusions: The findings suggest that the attitudes of audiologists likely do not represent a barrier regarding smartphone integration in audiologic rehabilitation. Highlights • Audiologists are generally open to the use of smartphone connectivity as a new element of hearing care provision. • Seasoned audiologists were more apt to embrace the use of smartphones to aid in patient communication and device adjustment. • Smartphones could play a key role in audiologic rehabilitation. • Many smartphone apps already exist for audiological purposes and many more are possible. [ABSTRACT FROM AUTHOR]

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 the displacement field induced by the IED insertion, which has to be known for a better understanding of perceived discomfort. Thus, this paper proposes to validate a method based on medical images to estimate the displacement field of the ear canal walls due to the insertion of an IED. The approach is validated on a human-like artificial ear with canal geometry deformed using two custom molded IEDs with controlled shapes. These geometries are obtained using computed tomography imaging and the displacement field is computed using a registration method. The errors due to the ear canal segmentation and to the registration steps are small enough to compute a relevant estimation of the expected displacement field. Results show that the amplitude of the displacement and its location into the ear canal can be evaluated with an accuracy of ± 0.2 mm and ± 0.4 mm respectively. Preliminary results on images with a degraded resolution indicate that the proposed approach used to assess the displacement field of the ear canal walls using computed tomography images could be applied on magnetic resonance images, which is a preferred method to image human subject ear canals for future investigations. [ABSTRACT FROM AUTHOR]

For the validation of modelling results or the comparison of middle ear interventions, such as prostheses placement, average responses of middle ear vibrations are needed. One such response is the amplitude and phase of the vibration of the stapes footplate as a function of frequency. Average responses and their standard deviation are commonly obtained by calculating the mean of a number of measured responses at each frequency. A typical middle ear magnitude response curve shows a number of distinct peaks, and the location of these peaks varies between ears. By simply taking an average along the magnitude or phase response axis, the typical fine structure of the response curve is flattened out, delivering an average curve which no longer has the typical morphology of an individual response curve. This paper introduces methods to avoid this problem by first aligning the typical curve features along the frequency axis prior to calculating the average along the magnitude or phase axis, resulting in average magnitude and phase curves which maintain the typical morphology of the curve obtained for an individual ear. In the method, landmark points on the response magnitude curves are defined and the frequencies at which these points occur are averaged. Next, these average frequencies are used to align the landmark points between curves, prior to averaging values along the magnitude or phase axes. Methods for semi-automatic and manual assignment of landmark points and curve alignment are presented. After alignment, the correspondence between the original landmark frequencies and aligned frequencies is obtained together with the warping function which maps each original magnitude curve to its aligned version. The phase curves are aligned using the warping functions determined from the corresponding magnitude curves. Finally, a method is proposed to compare the data set of an individual measurement or model result to an aligned average curve in terms of magnitude and frequency by applying the alignment procedure to the individual curve. [ABSTRACT FROM AUTHOR]

Peterson and Heil [Hear. Res., In Press] have argued that the statistics of spontaneous spiking in auditory nerve fibers (ANFs) can be best explained by a model with a limited number of synaptic vesicle docking (release) sites ( ∼ 4 ) and a relatively-long average redocking time ( ∼ 16–17 ms) for each of the sites. In this paper we demonstrate how their model can be: i) generalized to also describe sound-driven ANF responses and ii) incorporated into a well-established and widely-used model of the entire auditory periphery [Zilany et al., J. Acoust. Soc. Am. 135, 283–286, 2014]. The responses of the new model exhibit substantial improvement in several measures of ANF spiking statistics, and predicted physiological forward-masking and rate-level functions from the new model structure are shown to also better match published physiological data. [ABSTRACT FROM AUTHOR]

The effort required to listen to and understand noisy speech is an important factor in the evaluation of noise reduction schemes. This paper introduces a model for Listening Effort prediction from Acoustic Parameters (LEAP). The model is based on methods from automatic speech recognition, specifically on performance measures that quantify the degradation of phoneme posteriorgrams produced by a deep neural net: Noise or artifacts introduced by speech enhancement often result in a temporal smearing of phoneme representations, which is measured by comparison of phoneme vectors. This procedure does not require a priori knowledge about the processed speech, and is therefore single-ended. The proposed model was evaluated using three datasets of noisy speech signals with listening effort ratings obtained from normal hearing and hearing impaired subjects. The prediction quality was compared to several baseline models such as the ITU-T standard P.563 for single-ended speech quality assessment, the American National Standard ANIQUE+ for single-ended speech quality assessment, and a single-ended SNR estimator. In all three datasets, the proposed new model achieved clearly better prediction accuracies than the baseline models; correlations with subjective ratings were above 0.9. So far, the model is trained on the specific noise types used in the evaluation. Future work will be concerned with overcoming this limitation by training the model on a variety of different noise types in a multi-condition way in order to make it generalize to unknown noise types. [ABSTRACT FROM AUTHOR]

The auditory system processes temporal information at multiple scales, and disruptions to this temporal processing may lead to deficits in auditory tasks such as detecting and discriminating sounds in a noisy environment. Here, a modelling approach is used to study the temporal regularity of firing by chopper cells in the ventral cochlear nucleus, in both the normal and impaired auditory system. Chopper cells, which have a strikingly regular firing response, divide into two classes, sustained and transient, based on the time course of this regularity. Several hypotheses have been proposed to explain the behaviour of chopper cells, and the difference between sustained and transient cells in particular. However, there is no conclusive evidence so far. Here, a reduced mathematical model is developed and used to compare and test a wide range of hypotheses with a limited number of parameters. Simulation results show a continuum of cell types and behaviours: chopper-like behaviour arises for a wide range of parameters, suggesting that multiple mechanisms may underlie this behaviour. The model accounts for systematic trends in regularity as a function of stimulus level that have previously only been reported anecdotally. Finally, the model is used to predict the effects of a reduction in the number of auditory nerve fibres (deafferentation due to, for example, cochlear synaptopathy). An interactive version of this paper in which all the model parameters can be changed is available online. [ABSTRACT FROM AUTHOR]

· Rabbit eardrum prestrain was measured using an automated setup. · A pulsed laser perforated the eardrum at seven predefined locations. · Clear signs of prestrain were found. · Holes made inferior to the umbo had the most consistent prestrain values. · The laser setup allows faster and more consistent measurements than in previous work. · The laser setup minimizes dehydration artefacts by shortening the measurement time. While the presence of residual stress (also called prestress) in the tympanic membrane (TM) was hypothesized more than 150 years ago by von Helmholtz (1869), little experimental data exists to date. In this paper, a novel approach to study residual stress is presented. Using a pulsed laser, the New Zealand white rabbit TM is perforated at seven predefined locations. The subsequent retraction of the membrane around the holes is computed using digital image correlation (DIC). The amount of retraction is the so-called prestrain, which is caused by the release of prestress due to the perforation. By measuring the prestrain using DIC, we show that residual stress is clearly present over the entire rabbit TM surface. In total, fourteen TMs have been measured in this work. An automated approach allows tracking the holes' deformation during the measurement process and enables a more robust analysis than was previously possible. We find similar strains (around 5%) as reported in previous work, in which slits were created manually using flattened surgical needles. However, the new approach greatly reduces measurement time, which minimizes dehydration artifacts. To investigate the effect of perforation location on the TM, the spatial decrease of the prestrain (α) around the perforation was quantified. Perforations inferior to the umbo showed the least negative α values, i.e., the most gradual decrease around the hole, and were the most consistent. Perforations on other locations showed more negative α values, i.e., steeper decrease in strain, but were less consistent across samples. We also investigated the effect of the holes' creation sequence but did not observe a significant change in the results. Overall, the presented method allows for consistent residual stress measurements over the TM surface. The findings contribute to our fundamental knowledge of the mechanics of the rabbit TM and provide a basis for future work on human TMs. [ABSTRACT FROM AUTHOR]

Background The scientific understanding of tinnitus and its etiology has transitioned from thinking of tinnitus as solely a peripheral auditory problem to an increasing awareness that cortical networks may play a critical role in tinnitus percept or bother. With this change, studies that seek to use structural brain imaging techniques to better characterize tinnitus patients have become more common. These studies include using voxel-based morphometry (VBM) to determine if there are differences in regional gray matter volume in individuals who suffer from tinnitus and those who do not. However, studies using VBM in patients with tinnitus have produced inconsistent and sometimes contradictory results. Objective This paper is a systematic review of all of the studies to date that have used VBM to study regional gray matter volume in people with tinnitus, and explores ways in which methodological differences in these studies may account for their heterogeneous results. We also aim to provide guidance on how to conduct future studies using VBM to produce more reproducible results to further our understanding of disease processes such as tinnitus. Methods Studies about tinnitus and VBM were searched for using PubMed and Embase. These returned 15 and 25 results respectively. Of these, nine met the study criteria and were included for review. An additional 5 studies were identified in the literature as pertinent to the topic at hand and were added to the review, for a total of 13 studies. Results There was significant heterogeneity among the studies in several areas, including inclusion and exclusion criteria, software programs, and statistical analysis. We were not able to find publicly shared data or code for any study. Discussion The differences in study design, software analysis, and statistical methodology make direct comparisons between the different studies difficult. Especially problematic are the differences in the inclusion and exclusion criteria of the study, and the statistical design of the studies, both of which could radically alter findings. Thus, heterogeneity has complicated efforts to explore the etiology of tinnitus using structural MRI. Conclusion There is a pressing need to standardize the use of VBM when evaluating tinnitus patients. While some heterogeneity is expected given the rapid advances in the field, more can be done to ensure that there is internal validity between studies. [ABSTRACT FROM AUTHOR]

The rupture of tympanic membrane (TM) has long been viewed as an indicator of blast injury, especially for hearing loss. However, little is known about damage to the TM caused by blast with pressure lower than the rupture threshold. In this paper, we present our study on the effect of blast overpressure on the static mechanical properties of TM. Chinchilla was used as the animal model and exposed to multiple blasts with pressures lower than the rupture threshold of the TM. Using a micro-fringe projection method, we observed the alteration of the static mechanical properties of post-blast chinchilla's TMs as compared to those of control TMs. Specifically, after exposing to multiple blasts, the Young's modulus of chinchilla TM decreased by ∼53% while the ultimate failure pressure decreased by ∼33%. Scanning Electron Microscope (SEM) images show the damage formation in the post-blast TM as compared with its control counterpart. [ABSTRACT FROM AUTHOR]

Deformation of the tympanic membrane is known to contribute to the pressure regulation processes in the middle ear cleft. In this paper we investigated pressure variations in the rabbit middle ear in response to sinusoidal varying pressures applied to the ear canal, with frequencies ranging from 0.5 Hz to 50 Hz and pressure amplitudes ranging between 0.25 kPa and 1 kPa. The transtympanic pressure difference was found to be smallest in the quasi-static range, and quickly increased as a function of frequency. The response curves showed asymmetry, with larger transtympanic pressures when positive pressures were applied in the ear canal. Normalized transtympanic pressure amplitudes remained fairly constant as a function of input pressure, with values in the range of 60%–70% relative to the applied pressure. The total harmonic distortion of the middle ear pressure signal was calculated and was found to be very small ( ≤ 2%) for low-pressure amplitudes and low frequencies. For pressure amplitudes in the order of 0.25 kPa–0.5 kPa, it increased to about 10% at 50 Hz. When a 1 kPa pressure amplitude was applied, variation between animals became large and distortion values up to 30% at 50 Hz were observed. The results showed that pressure buffering due to tympanic membrane displacement was most effective for compensating small transtympanic pressure loads at low frequencies. [ABSTRACT FROM AUTHOR]

Recently, there has been growing evidence that development and maturation of the auditory system depends substantially on the afferent activity supplying inputs to the developing centers. In cases when this activity is altered during early ontogeny as a consequence of, e.g., an unnatural acoustic environment or acoustic trauma, the structure and function of the auditory system may be severely affected. Pathological alterations may be found in populations of ribbon synapses of the inner hair cells, in the structure and function of neuronal circuits, or in auditory driven behavioral and psychophysical performance. Three characteristics of the developmental impairment are of key importance: first, they often persist to adulthood, permanently influencing the quality of life of the subject; second, their manifestations are different and sometimes even contradictory to the impairments induced by noise trauma in adulthood; third, they may be ‘hidden’ and difficult to diagnose by standard audiometric procedures used in clinical practice. This paper reviews the effects of early interventions to the auditory system, in particular, of sound exposure during ontogeny. We summarize the results of recent morphological, electrophysiological, and behavioral experiments, discuss the putative mechanisms and hypotheses, and draw possible consequences for human neonatal medicine and noise health. [ABSTRACT FROM AUTHOR]

Cochlear implants encode speech information by stimulating the auditory nerve with amplitude-modulated pulse trains. A computer model of the auditory nerve's response to electrical stimulation can be used to evaluate different approaches to improving CI patients' perception. In this paper a computationally efficient stochastic and adaptive auditory nerve model was used to investigate full nerve responses to amplitude-modulated electrical pulse trains. The model was validated for nerve responses to AM pulse trains via comparison with animal data. The influence of different parameters, such as adaptation and stochasticity, on long-term adaptation and modulation-following behavior was investigated. Responses to pulse trains with different pulse amplitudes, amplitude modulation frequencies, and modulation depths were modeled. Rate responses as well as period histograms, Vector Strength and the fundamental frequency were characterized in different time bins. The response alterations, including frequency following behavior, observed over the stimulus duration were similar to those seen in animal experiments. The tested model can be used to predict complete nerve responses to arbitrary input, and thus to different sound coding strategies. [ABSTRACT FROM AUTHOR]

Hearing is an extremely complex phenomenon, involving a large number of interrelated variables that are difficult to measure in vivo. In order to investigate such process under simplified and well-controlled conditions, models of sound transmission have been developed through many decades of research. The value of modeling the hearing system is not only to explain the normal function of the hearing system and account for experimental and clinical observations, but to simulate a variety of pathological conditions that lead to hearing damage and hearing loss, as well as for development of auditory implants, effective ear protections and auditory hazard countermeasures. In this paper, we provide a review of the strategies used to model the auditory function of the external, middle, inner ear, and the micromechanics of the organ of Corti, along with some of the key results obtained from such modeling efforts. Recent analytical and numerical approaches have incorporated the nonlinear behavior of some parameters and structures into their models. Few models of the integrated hearing system exist; in particular, we describe the evolution of the Auditory Hazard Assessment Algorithm for Human (AHAAH) model, used for prediction of hearing damage due to high intensity sound pressure. Unlike the AHAAH model, 3D finite element models of the entire hearing system are not able yet to predict auditory risk and threshold shifts. It is expected that both AHAAH and FE models will evolve towards a more accurate assessment of threshold shifts and hearing loss under a variety of stimuli conditions and pathologies. [ABSTRACT FROM AUTHOR]

Since 1992, the Speech Recognition in Noise Test, or SPRINT, has been the standard speech-in-noise test for assessing auditory fitness-for-duty of US Army Soldiers with hearing loss. The original SPRINT test consisted of 200 monosyllabic words presented at a Signal-to-Noise Ratio (SNR) of +9 dB in the presence of a six-talker babble noise. Normative data for the test was collected on 319 hearing impaired Soldiers, and a procedure for making recommendations about the disposition of military personnel on the basis of their SPRINT score and their years of experience was developed and implemented as part of US Army policy. In 2013, a new 100-word version of the test was developed that eliminated words that were either too easy or too hard to make meaningful distinctions among hearing impaired listeners. This paper describes the development of the original 200-word SPRINT test, along with a description of the procedure used to reduce the 200-word test to 100 words and the results of a validation study conducted to evaluate how well the shortened 100-word test is able to capture the results from the full 200-word version of the SPRINT. [ABSTRACT FROM AUTHOR]

The Federal Food and Drug Administration, or FDA is generally considered a powerful gatekeeper, able to deliver or withhold life-saving cures and create or destroy economic windfalls. As the decades go by, and technologies, diseases, public health demands, and politics evolve, we can identify patterns of change, action and inter-action among some of these traditional stakeholders in the FDA's policy sphere. A careful examination of this agency's colorful history can shed light on central features of the agency's policy process, which has been quite receptive to its stakeholders and adaptive to change over the decades and, in turn, show the way for development in lanes which do not fit neatly into the current paradigms offered by the agency. This paper will explore the history of FDA policy process, through examination of seminal moments in FDA history, the prominent actors and focusing events within them, and the outcomes of those events, in an attempt to illuminate a pattern of behavior or processes by which a struggling field of pharmaceutical development such as interventions for hearing loss can advance. [ABSTRACT FROM AUTHOR]

Exposure to intense sound or noise can result in purely temporary threshold shift (TTS), or leave a residual permanent threshold shift (PTS) along with alterations in growth functions of auditory nerve output. Recent research has revealed a number of mechanisms that contribute to noise-induced hearing loss (NIHL). The principle cause of NIHL is damage to cochlear hair cells and associated synaptopathy. Contributions to TTS include reversible damage to hair cell (HC) stereocilia or synapses, while moderate TTS reflects protective purinergic hearing adaptation. PTS represents permanent damage to or loss of HCs and synapses. While the substrates of HC damage are complex, they include the accumulation of reactive oxygen species and the active stimulation of intracellular stress pathways, leading to programmed and/or necrotic cell death. Permanent damage to cochlear neurons can also contribute to the effects of NIHL, in addition to HC damage. These mechanisms have translational potential for pharmacological intervention and provide multiple opportunities to prevent HC damage or to rescue HCs and spiral ganglion neurons that have suffered injury. This paper reviews advances in our understanding of cellular mechanisms that contribute to NIHL and their potential for therapeutic manipulation. [ABSTRACT FROM AUTHOR]

Understanding the biology of the previously underappreciated sensitivity of cochlear synapses to noise insult, and its clinical consequences, is becoming a mission for a growing number of auditory researchers. In addition, several research groups have become interested in developing therapeutic approaches that can reverse synaptopathy and restore hearing function. One of the major challenges to realizing the potential of synaptopathy rodent models is that current clinical audiometric approaches cannot yet reveal the presence of this subtle cochlear pathology in humans. This has catalyzed efforts, both from basic and clinical perspectives, to investigate novel means for diagnosing synaptopathy and to determine the main functional consequences for auditory perception and hearing abilities. Such means, and a strong concordance between findings in pre-clinical animal models and clinical studies in humans, are important for developing and realizing therapeutics. This paper frames the key outstanding translational questions that need to be addressed to realize this ambitious goal. [ABSTRACT FROM AUTHOR]