The effects of extended-wear hearing aids on the localization accuracy of listeners with normal audiometric thresholds.

Extended-wear hearing aids (EWHAs) are small broadband analog amplification devices placed deeply enough in the ear canal to preserve most of the cues in the head-related transfer function. However, little is known about how EWHAs affect localization accuracy for normal hearing threshold (NHT) listeners. In this study, eight NHT participants were fitted with EWHAs and localized broadband sounds of different durations (250 ms and 4 s) and stimulus intensities (40, 50, 60, 70, and 80 dBA) in a spherical speaker array. When the EWHAs were in the active mode, localization accuracy was only slightly degraded relative to open-ear performance. However, when the EWHAs were turned off, localization performance was substantially degraded even at the highest stimulus intensities. An electro-acoustical evaluation of the EWHAs showed minimal effects of dynamic range compression on the signals and good preservation of the signal pattern for vertical polar sound localization. Between-study comparisons suggest that EWHA active mode localization accuracy is favorable compared to conventional active earplugs, and EWHA passive mode localization accuracy is comparable to conventional passive earplugs. These results suggest that the deep-insertion analog design of the EWHA is generally better at preserving localization accuracy of NHT listeners than conventional earplug devices.

Supporting Equity and Inclusion of Deaf and Hard-of-Hearing Individuals in Professional Organizations.

Disability is an important and often overlooked component of diversity. Individuals with disabilities bring a rare perspective to science, technology, engineering, mathematics, and medicine (STEMM) because of their unique experiences approaching complex issues related to health and disability, navigating the healthcare system, creatively solving problems unfamiliar to many individuals without disabilities, managing time and resources that are limited by physical or mental constraints, and advocating for themselves and others in the disabled community. Yet, individuals with disabilities are underrepresented in STEMM. Professional organizations can address this underrepresentation by recruiting individuals with disabilities for leadership opportunities, easing financial burdens, providing equal access, fostering peer-mentor groups, and establishing a culture of equity and inclusion spanning all facets of diversity. We are a group of deaf and hard-of-hearing (D/HH) engineers, scientists, and clinicians, most of whom are active in clinical practice and/or auditory research. We have worked within our professional societies to improve access and inclusion for D/HH individuals and others with disabilities. We describe how different models of disability inform our understanding of disability as a form of diversity. We address heterogeneity within disabled communities, including intersectionality between disability and other forms of diversity. We highlight how the Association for Research in Otolaryngology has supported our efforts to reduce ableism and promote access and inclusion for D/HH individuals. We also discuss future directions and challenges. The tools and approaches discussed here can be applied by other professional organizations to include individuals with all forms of diversity in STEMM.

Attenuation characteristics of an extended-wear hearing aid: Impulse and continuous noise.

The extended-wear hearing aid (EWHA) is a hearing assistive device that combines a low-power analog amplification circuit with a soft biocompatible foam plug that allows it to remain in the ear canal for several months at a time without replacement. EWHAs fit snugly in the ear canal and are not vented and so produce insertion losses comparable to a passive earplug when inserted into the ear canal with the active circuitry turned off. However, EWHAs are not marketed as hearing protection devices, and other than a general warning to users that the device will have impaired auditory awareness when the device is inserted in the "off" mode, relatively little has been reported about the attenuation characteristics of EWHAs. In this study, commercially-available EWHAs were evaluated using the ANSI standard procedures for measuring hearing protector attenuation in impulse noise [ANSI (2010). S1242-2010, Methods for the Measurement of Insertion Loss of Hearing Protective Devices in Continuous or Impulsive Noise Using Microphone-In-Real-Ear or Acoustic Text Fixture Procedures (American National Standards Institute, New York)] and in continuous noise [ANSI (2006). S12.6, Methods for Measuring the Real-Ear Attenuation of Hearing Protectors (American National Standards Institute, New York)]. Attenuation values were also measured in double and triple protection conditions that combined EWHAs with traditional earplugs and earmuffs. The results show that properly-fit EWHAs can provide passive attenuation comparable to conventional passive earplugs, which may make it possible to use them to provide persistent protection from intermittent noise sources.

Counting or discriminating the number of voices to assess binaural fusion with single-sided vocoders.

For single-sided deafness cochlear-implant (SSD-CI) listeners, different peripheral representations for electric versus acoustic stimulation, combined with interaural frequency mismatch, might limit the ability to perceive bilaterally presented speech as a single voice. The assessment of binaural fusion often relies on subjective report, which requires listeners to have some understanding of the perceptual phenomenon of object formation. Two experiments explored whether binaural fusion could instead be assessed using judgments of the number of voices in a mixture. In an SSD-CI simulation, normal-hearing listeners were presented with one or two "diotic" voices (i.e., unprocessed in one ear and noise-vocoded in the other) in a mixture with additional monaural voices. In experiment 1, listeners reported how many voices they heard. Listeners generally counted the diotic speech as two separate voices, regardless of interaural frequency mismatch. In experiment 2, listeners identified which of two mixtures contained diotic speech. Listeners performed significantly better with interaurally frequency-matched than with frequency-mismatched stimuli. These contrasting results suggest that listeners experienced partial fusion: not enough to count the diotic speech as one voice, but enough to detect its presence. The diotic-speech detection task (experiment 2) might provide a tool to evaluate fusion and optimize frequency mapping for SSD-CI patients.

Binaural Optimization of Cochlear Implants: Discarding Frequency Content Without Sacrificing Head-Shadow Benefit.

OBJECTIVES: Single-sided deafness cochlear-implant (SSD-CI) listeners and bilateral cochlear-implant (BI-CI) listeners gain near-normal levels of head-shadow benefit but limited binaural benefits. One possible reason for these limited binaural benefits is that cochlear places of stimulation tend to be mismatched between the ears. SSD-CI and BI-CI patients might benefit from a binaural fitting that reallocates frequencies to reduce interaural place mismatch. However, this approach could reduce monaural speech recognition and head-shadow benefit by excluding low- or high-frequency information from one ear. This study examined how much frequency information can be excluded from a CI signal in the poorer-hearing ear without reducing head-shadow benefits and how these outcomes are influenced by interaural asymmetry in monaural speech recognition. DESIGN: Speech-recognition thresholds for sentences in speech-shaped noise were measured for 6 adult SSD-CI listeners, 12 BI-CI listeners, and 9 normal-hearing listeners presented with vocoder simulations. Stimuli were presented using nonindividualized in-the-ear or behind-the-ear head-related impulse-response simulations with speech presented from a 70° azimuth (poorer-hearing side) and noise from 70° (better-hearing side), thereby yielding a better signal-to-noise ratio (SNR) at the poorer-hearing ear. Head-shadow benefit was computed as the improvement in bilateral speech-recognition thresholds gained from enabling the CI in the poorer-hearing, better-SNR ear. High- or low-pass filtering was systematically applied to the head-related impulse-response-filtered stimuli presented to the poorer-hearing ear. For the SSD-CI listeners and SSD-vocoder simulations, only high-pass filtering was applied, because the CI frequency allocation would never need to be adjusted downward to frequency-match the ears. For the BI-CI listeners and BI-vocoder simulations, both low and high pass filtering were applied. The normal-hearing listeners were tested with two levels of performance to examine the effect of interaural asymmetry in monaural speech recognition (vocoder synthesis-filter slopes: 5 or 20 dB/octave). RESULTS: Mean head-shadow benefit was smaller for the SSD-CI listeners (~7 dB) than for the BI-CI listeners (~14 dB). For SSD-CI listeners, frequencies <1236 Hz could be excluded; for BI-CI listeners, frequencies <886 or >3814 Hz could be excluded from the poorer-hearing ear without reducing head-shadow benefit. Bilateral performance showed greater immunity to filtering than monaural performance, with gradual changes in performance as a function of filter cutoff. Real and vocoder-simulated CI users with larger interaural asymmetry in monaural performance had less head-shadow benefit. CONCLUSIONS: The "exclusion frequency" ranges that could be removed without diminishing head-shadow benefit are interpreted in terms of low importance in the speech intelligibility index and a small head-shadow magnitude at low frequencies. Although groups and individuals with greater performance asymmetry gained less head-shadow benefit, the magnitudes of these factors did not predict the exclusion frequency range. Overall, these data suggest that for many SSD-CI and BI-CI listeners, the frequency allocation for the poorer-ear CI can be shifted substantially without sacrificing head-shadow benefit, at least for energetic maskers. Considering the two ears together as a single system may allow greater flexibility in discarding redundant frequency content from a CI in one ear when considering bilateral programming solutions aimed at reducing interaural frequency mismatch.

The Effects of Dynamic-range Automatic Gain Control on Sentence Intelligibility With a Speech Masker in Simulated Cochlear Implant Listening.

OBJECTIVES: "Channel-linked" and "multi-band" front-end automatic gain control (AGC) were examined as alternatives to single-band, channel-unlinked AGC in simulated bilateral cochlear implant (CI) processing. In channel-linked AGC, the same gain control signal was applied to the input signals to both of the two CIs ("channels"). In multi-band AGC, gain control acted independently on each of a number of narrow frequency regions per channel. DESIGN: Speech intelligibility performance was measured with a single target (to the left, at -15 or -30°) and a single, symmetrically-opposed masker (to the right) at a signal-to-noise ratio (SNR) of -2 decibels. Binaural sentence intelligibility was measured as a function of whether channel linking was present and of the number of AGC bands. Analysis of variance was performed to assess condition effects on percent correct across the two spatial arrangements, both at a high and a low AGC threshold. Acoustic analysis was conducted to compare postcompressed better-ear SNR, interaural differences, and monaural within-band envelope levels across processing conditions. RESULTS: Analyses of variance indicated significant main effects of both channel linking and number of bands at low threshold, and of channel linking at high threshold. These improvements were accompanied by several acoustic changes. Linked AGC produced a more favorable better-ear SNR and better preserved broadband interaural level difference statistics, but did not reduce dynamic range as much as unlinked AGC. Multi-band AGC sometimes improved better-ear SNR statistics and always improved broadband interaural level difference statistics whenever the AGC channels were unlinked. Multi-band AGC produced output envelope levels that were higher than single-band AGC. CONCLUSIONS: These results favor strategies that incorporate channel-linked AGC and multi-band AGC for bilateral CIs. Linked AGC aids speech intelligibility in spatially separated speech, but reduces the degree to which dynamic range is compressed. Combining multi-band and channel-linked AGC offsets the potential impact of diminished dynamic range with linked AGC without sacrificing the intelligibility gains observed with linked AGC.

Relating interaural difference sensitivities for several parameters measured in normal-hearing and hearing-impaired listeners.

Just-noticeable differences (JNDs) in interaural time delay (ITD), interaural level difference (ILD), and interaural cross-correlation (ICC) were measured with low- and high-frequency noise bands over multiple sessions for 10 normal-hearing (NH) and 11 hearing-impaired (HI) listeners. Individual subject thresholds tended to improve with training then stabilize. Measured JNDs varied over these experienced listeners, for both subject groups and all tasks. Group JNDs were seldom predictable from hearing level. Individual listeners' JNDs were highly correlated across frequency for each task and group, except for ICC in the HI listeners. Further, ITD JNDs almost always significantly correlated with ILD JNDs within a group. Finally, although the ICC JNDs always significantly correlated with the ITD or ILD JNDs for the NH listeners, they often did not for the HI listeners. These findings suggest that little information about binaural sensitivity is added for NH listeners with multiple ITD, ILD, and ICC measures. For HI listeners, however, while ITD and ILD measures are well correlated, information is added with ICC measures. In general, the results suggest that less information is added with JND measures for NH listeners (15 significant correlations) than for HI listeners (six significant correlations).

Fuhrman Grade and Neutrophil-To-Lymphocyte Ratio Influence on Survival in Patients With Metastatic Renal Cell Carcinoma Treated With First-Line Tyrosine Kinase Inhibitors.

BACKGROUND: The present study investigated the various features that might influence the overall survival (OS) of patients with metastatic renal cell carcinoma (RCC) treated with first-line tyrosine kinase inhibitors (TKIs). PATIENTS AND METHODS: A retrospective analysis was performed of consecutive patients with metastatic RCC, in whom treatment with a first-line TKI was initiated from January 2010 to December 2014, at the Department of Oncology, Military Institute of Medicine (Warsaw, Poland). Cox proportional hazards regression was used to construct a prognostic model that included independent factors for OS. We validated the model using 2 bootstrap procedures and calculation of the bias-corrected concordance index. RESULTS: Of the 266 patients included in the study, 201, 45, and 20 received sunitinib, pazopanib, and sorafenib, respectively. The median OS for the whole cohort was 24.8 months (95% confidence interval, 20.2-29.4 months). Six factors were independently associated with poor survival: Eastern Cooperative Oncology Group performance status > 0 (P < .0001), Fuhrman grade 3 to 4 (P < .0001), hemoglobin less than the lower limit of normal (P < .0001), lactate dehydrogenase greater than the upper limit of normal (P = .0011), neutrophil-to-lymphocyte ratio ≥ 4 (P < .0001), and > 2 metastatic sites (P = .0012). The bias-corrected concordance index was 0.751. CONCLUSION: Fuhrman grade and neutrophil-to-lymphocyte ratio are potential factors that affect the survival of patients with metastatic RCC treated with first-line TKIs. The presented prognostic model demonstrated satisfactory performance but requires external validation with a larger data set.

Peptide- and collagen-based hydrogel substrates for in vitro culture of chick cochleae.

The overall goal of this work is to improve the culture of the auditory organ of birds for the dual use of developing a hair cell regeneration model and charting a pathway to the eventual replacement of the hearing organ. In doing so, we develop a protocol for removing the auditory organ from its basement membrane in the inner ear, attach the organ to a series of artificial basement membranes, and conduct qualitative and quantitative analysis of how cell morphology, viability and function change with time. Native matrix cultures, where the epithelium was floating in media with the basement membrane and accessory structures attached, were used as a basis of comparison. PuraMatrix, collagen I, collagen I/chondroitin-sulfate and Matrigel were chosen to encompass a diverse range of mechanical properties and macromolecule moieties. Surprisingly, we find that PuraMatrix outperformed the other matrices as a scaffold for sensory organ culture. PuraMatrix a self-assembled peptide hydrogel, is a biochemically specific culture substrate that contains none of the extracellular matrix (ECM) molecules and growth factors contained in the inner ear's basement membrane. Rheological measurements reveal that PuraMatrix may be a closer approximation to the stiffness of the soft tissue supporting the auditory organ. Cell density on the PuraMatrix substrate is comparable to that of the native matrix cultures, despite the absence of the basement membrane and accessory structures. Further studies show that PuraMatrix supports the culture of functional hair cells over a 72 h period, with a significant increase in the number of functional hair cells in comparison to the organ cultured without a matrix. This is the first example of adhesion of the adult auditory epithelium to a biomaterial for an extended period of time. With further optimization, this system will enable the performance of many novel biophysical and pharmacological studies involving hair cells and supporting cells.