Speech Discrimination Outcomes in Adult Cochlear Implant Recipients by Primary Language and Bilingual Hispanic Patients.

OBJECTIVE: Compare cochlear implant (CI) outcomes in English speakers, Spanish speakers, and bilingual Hispanics. STUDY DESIGN: Retrospective review. SETTING: Academic tertiary care center. METHODS: Eighty-five postlingually deafened adults unilaterally implanted between January 2014 and December 2018 were stratified by primary language. Primary outcomes were: (1) English consonant-nucleus-consonant and Spanish bisyllables word tests in quiet, and (2) English AzBio and Latin American Hearing In Noise Test (LA-HINT) sentence tests in quiet and in noise at multiple time-intervals postactivation. RESULTS: In the respective languages, primary Spanish speakers (n = 24), and English speakers (n = 61) experienced the greatest increases in average scores for word and sentence tests in quiet during the first 6 months postactivation, with gradual increases in average scores over time. English speakers performed significantly worse on AzBio tests in noise, compared to quiet, while the addition of noise did not significantly affect average LA-HINT scores in Spanish speakers across multiple time intervals. An early ceiling effect was also demonstrated for LA-HINT. Although not significant, bilingual Hispanics (n = 12) had lower average AzBio in quiet scores than English speakers and higher average LA-HINT in quiet scores than the Spanish speakers across multiple time intervals. CONCLUSION: English and Spanish CI users experienced the greatest increases in speech understanding in quiet the first few months after implant activation. An early ceiling effect is demonstrated with LA-HINT, indicating LA-HINT is not appropriate for evaluating longitudinal CI outcomes in Spanish speakers. Bilingual Hispanics represent a unique group, and further investigations are necessary to understand speech perception patterns in both languages and develop the best CI test strategies for these individuals.

Single Fraction and Hypofractionated Radiation Cause Cochlear Damage, Hearing Loss, and Reduced Viability of Merlin-Deficient Schwann Cells.

BACKGROUND: Vestibular schwannomas (VS) are benign intracranial tumors caused by loss of function of the merlin tumor suppressor. We tested three hypotheses related to radiation, hearing loss (HL), and VS cell survival: (1) radiation causes HL by injuring auditory hair cells (AHC), (2) fractionation reduces radiation-induced HL, and (3) single fraction and equivalent appropriately dosed multi-fractions are equally effective at controlling VS growth. We investigated the effects of single fraction and hypofractionated radiation on hearing thresholds in rats, cell death pathways in rat cochleae, and viability of human merlin-deficient Schwann cells (MD-SC). METHODS: Adult rats received cochlear irradiation with single fraction (0 to 18 Gray [Gy]) or hypofractionated radiation. Auditory brainstem response (ABR) testing was performed for 24 weeks. AHC viabilities were determined using immunohistochemistry. Neonatal rat cochleae were harvested after irradiation, and gene- and cell-based assays were conducted. MD-SCs were irradiated, and viability assays and immunofluorescence for DNA damage and cell cycle markers were performed. RESULTS: Radiation caused dose-dependent and progressive HL in rats and AHC losses by promoting expression of apoptosis-associated genes and proteins. When compared to 12 Gy single fraction, hypofractionation caused smaller ABR threshold and pure tone average shifts and was more effective at reducing MD-SC viability. CONCLUSIONS: Investigations into the mechanisms of radiation ototoxicity and VS radiobiology will help determine optimal radiation regimens and identify potential therapies to mitigate radiation-induced HL and improve VS tumor control.

Genotype-phenotype associations in paragangliomas of the temporal bone in a multi-ethnic cohort.

BACKGROUND: Temporal bone paragangliomas are rare tumours with variable presentation that can be hereditary. Identification of clinical and genetic factors of aggressive tumour behaviour is important. OBJECTIVE: To determine the underlying genetic mutations and genotype/phenotype correlations in a multi-ethnic population of South Florida with sporadic temporal bone paragangliomas. METHODS: In a cohort of glomus tympanicum (GT) and glomus jugulare (GJ) cases, we assessed the frequency of pathogenic single nucleotide variants, insertions, deletions, and duplications in coding exons of genes that have been associated with paragangliomas (SDHB, SDHC, SDHD, SDHA, SDHAF2, RET, NF1, VHL, TMEM127, and MAX). RESULTS: None of the 12 GT cases had mutations. Among 13 GJ cases, we identified four mutation carriers (31%); two in SDHC, one in SDHB, and one in SDHD. All patients with pathogenic mutations were of Hispanic ethnicity, presented at a younger age (mean 27.5 versus 52.11 years), and with more advanced disease when compared to mutation-negative GJ cases.Conclusions and Significance: Mutations in the SDH genes are found in 31% of sporadic GJ. SDH-associated GJ had advanced disease and a 50% risk of metastasis. Our data supports emerging recommendations for genetic screening in all populations with GJ tumours as the genetic status informs management.

Transient decrease in sound tolerance levels following hearing deprivation in normal-hearing subjects.

Objective: To determine the circadian influence on sound sensitivity produced by temporal hearing deprivation in healthy normal human subjects. Design: Participants underwent bilateral earplugging before completion of anthropometry, the author's developed questionnaire, the Hamilton Anxiety and Depression Inventory, pure tone audiometry (PTA), stapedial reflex thresholds (SRT), distortion products otoacoustic emissions input/output (DPOAE-I/O), and uncomfortable loudness levels (ULLs). Afterward, the participants were randomly divided into group A, starting at 8:00 a.m. and finishing at 8:00 p.m., and group B, starting at 4:00 p.m. and ending at 4:00 a.m. Serum cortisol levels and audiological test results were obtained at the beginning and end of the session and 24-h free urinary cortisol levels were measured. Study sample: Thirty healthy volunteers. Results: PTA was 2.68 and 3.33 dB HL in groups A and B, respectively, with no statistical difference between them. ULLs were significantly lower in group A compared to group B, with an average of 8.1 dB SPL in group A and 3.3 dB SPL in group B (p < 0.0001). A SRT shift was observed in group A, with no difference in group B, and a night shift in DPOAE-I/O in group B. Conclusions: Reduced loudness tolerance is demonstrated during daytime hearing deprivation in contrast to nighttime; this may be due to increased central gain in the awake cortex.

Merlin-Deficient Schwann Cells Are More Susceptible to Radiation Injury than Normal Schwann Cells In Vitro.

Objectives Vestibular schwannomas (VS) are intracranial tumors, which are caused by NF2 gene mutations that lead to loss of merlin protein. A treatment for VS is stereotactic radiosurgery, a form of radiation. To better understand the radiobiology of VS and radiation toxicity to adjacent structures, our main objectives were (1) investigate effects of single fraction (SF) radiation on viability, cytotoxicity, and apoptosis in normal Schwann cells (SCs) and merlin-deficient Schwann cells (MD-SCs) in vitro, and (2) analyze expression of double strand DNA breaks (γ-H2AX) and DNA repair protein Rad51 following irradiation. Study Design This is a basic science study. Setting This study is conducted in a research laboratory. Participants Patients did not participate in this study. Main Outcome Measures In irradiated normal SCs and MD-SCs (0-18 Gy), we measured (1) viability, cytotoxicity, and apoptosis using cell-based assays, and (2) percentage of cells with γ-H2AX and Rad51 on immunofluorescence. Results A high percentage of irradiated MD-SCs expressed γ-H2AX, which may explain the dose-dependent losses in viability in rodent and human cell lines. In comparison, the viabilities of normal SCs were only compromised at higher doses of radiation (>12 Gy, human SCs), which may be related to less Rad51 repair. There were no further reductions in viability in human MD-SCs beyond 9 Gy, suggesting that <9 Gy may be insufficient to initiate maximal tumor control. Conclusion The MD-SCs are more susceptible to radiation than normal SCs, in part through differential expression of γ-H2AX and Rad51. Understanding the radiobiology of MD-SCs and normal SCs is important for optimizing radiation protocols to maximize tumor control while limiting radiation toxicity in VS patients.

Comparison of Speech Test Outcomes After Cochlear Implantation in Patients With and Without Asymmetric Hearing Loss.

OBJECTIVES: Determine whether asymmetric hearing loss (AHL) affects postoperative speech outcomes in cochlear implant (CI) patients. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary care hospital. PATIENTS: Adult English-speaking patients with unilateral CIs implanted between 2014 and 2018 were stratified into NonAHL and AHL groups based on preoperative AzBio scores in quiet from the nonimplanted ear (0-50% vs. 51-100%, respectively). INTERVENTIONS: CI surgery in the poorer performing ear. MAIN OUTCOME MEASURES: Postoperative consonant-nucleusconsonant (CNC) word and AzBio sentence test scores in quiet and/or noise at +5 dB signal-to-noise ratio (SNR). RESULTS: Of 512 patients, 33 non-AHL and 27 AHL patients were included. Average ages were 65.6 and 63.6 years, respectively. As expected, preoperative AzBio scores in quiet from the nonimplanted ear were higher in the AHL group (95% confidence interval [95%CI]: 66.4-76.4%) than the non-AHL group at baseline (95%CI: 12.3-23.6%). In both cohorts, AzBio scores in quiet from the implanted ear improved from baseline, with 24-month scores (95%CI: 73.8 - 84.9%) being higher than preoperative scores (95%CI: 13.2-23.1%). There were also significant differences in AzBio scores in quiet between cohorts overall (p  = 0.0120) on mixed model analysis, with the AHL group performing ∼6.4% better than the non-AHL group; however, differences were not significant when scores were stratified by time. In addition, there were no significant differences in CNC in quiet and AzBio scores in noise at +5 dB SNR between cohorts (p  = 0.1786 and p  = 0.6215, respectively). CONCLUSIONS: After CI, patients with AHL can achieve scores on word and sentence tests at least comparable to traditional CI candidates, supporting the expansion of CI candidacy to include patients with AHL.

Mesenchymal Stem Cells for Treatment of Delayed-Healing Tympanic Membrane Perforations Using Hyaluronate-based Laminas as a Delivery System: An Animal Model With Histopathologic Study.

HYPOTHESIS: Bone marrow derived-mesenchymal stem cells (BM-MSCs) improve the healing of chronic tympanic membrane perforations (cTMPs) in an animal model. BACKGROUND: cTMPs generate significant morbidity and reduced quality of life, usually requiring surgical assistance. With growing interest in alternative therapies, we sought to evaluate the effect of BM-MSC-therapy on the healing of cTMPs. METHODS: Sixty cTMPs were established in C57Bl/6 mice and randomized into four groups: hyaluronate scaffold as graft plus BM-MSCs (n = 19 ears), scaffold plus cell culture media (n = 16), scaffold plus phosphate-buffered saline (PBS, n = 12), and no intervention (n = 13). Hyaluronate scaffolds with or without BM-MSCs were applied on 8-week perforated eardrums. After a blinded assessment of perforation sizes at baseline and 2 weeks after treatment, mean perforation reduction rates (%) were compared. Histology characterization was then performed. RESULTS: Mean perforation size reduction rates were significantly higher for cTMPs that received scaffolds plus BM-MSCs (Student's t test, p = 0.0207, 12.3% [95% CI: 7.8-16.7]) and scaffolds plus cell culture media (p = 0.0477, 11.3% [95% CI: 4.4-18.2]) when compared with no intervention (4.2% [95% CI: 1.2-7.2]). This was not observed when treating eardrums with scaffolds plus PBS (7.3% [95% CI: 2.7-11.9]). On histology, BM-MSC-treated eardrums demonstrated restoration of the trilaminar configuration and reduced inflammatory changes, while other groups developed tissue architecture disorganization and hypercellular infiltrates surrounding the perforation site. CONCLUSIONS: BM-MSCs and cell culture media equivalently increased cTMP healing rates. Cell-based therapy conferred a restoration of the trilaminar configuration of the eardrum with relatively compact and organized fibrous layers.

Tumor-Associated Macrophages in Vestibular Schwannoma and Relationship to Hearing.

OBJECTIVE: (1) Characterize the distribution of M1 and M2 macrophages in vestibular schwannomas by hearing status. (2) Develop assays to assess monocyte migration and macrophage polarization in cocultures with vestibular schwannoma cells. STUDY DESIGN: Basic and translational science. SETTING: Tertiary care center. METHODS: A retrospective chart review of 30 patients with vestibular schwannoma (VS) was performed. Patients were stratified into serviceable and unserviceable hearing groups. Immunohistochemistry for CD80+ M1 and CD163+ M2 macrophages was conducted. Primary VS cultures (n = 4) were developed and cocultured with monocytes. Immunohistochemistry for macrophage markers was performed to assess monocyte migration and macrophage polarization. RESULTS: Although tumors associated with unserviceable hearing had higher levels of CD80 and CD163 than those with serviceable hearing, the relationship was only significant with CD163 (P = .0161). However, CD163 level did not remain a significant predictor variable associated with unserviceable hearing on multivariate analysis when adjusted for other variables. In vitro assays show that VS cells induced monocyte migration and polarization toward CD80+ M1 or CD163+ M2 macrophage phenotypes, with qualitative differences in CD163+ macrophage morphologies between serviceable and unserviceable hearing groups. CONCLUSION: Vestibular schwannomas express varying degrees of CD80+ M1 and CD163+ M2 macrophages. We present evidence that higher expression of CD163+ may contribute to poorer hearing outcomes in patients with VS. We also describe in vitro assays in a proof-of-concept investigation that VS cells can initiate monocyte migration and macrophage polarization. Future investigations are warranted to explore the relationships between tumor, macrophages, secreted cytokines, and hearing outcomes in patients with VS.

Needle Fracture During Injection Medialization Laryngoplasty.

OBJECTIVES: Awake injection medialization laryngoplasty is one of the most common therapeutic procedures done by laryngologists in the office or at the bedside. Complications of injection needle fracture are rarely reported. METHODS: This is a case report of a 59-year-old male inpatient who developed left vocal fold immobility with significant glottic insufficiency after pneumonectomy for a large left-sided lung cancer. During bedside injection medialization using thyrohyoid approach, the 25 G needle fractured at the hub and was embedded partly in pre-epiglottic space and partly extending over rima glottidis. RESULTS: Fractured needle was successfully retrieved at the bedside with an endoscopic biopsy forcep using flexible bronchoscope. CONCLUSION: It is imperative to be aware of rare complications of routine procedures like injection laryngoplasty so they can be managed timely and effectively.

Understanding the Radiobiology of Vestibular Schwannomas to Overcome Radiation Resistance.

Vestibular schwannomas (VS) are benign tumors arising from cranial nerve VIII that account for 8-10% of all intracranial tumors and are the most common tumors of the cerebellopontine angle. These tumors are typically managed with observation, radiation therapy, or microsurgical resection. Of the VS that are irradiated, there is a subset of tumors that are radioresistant and continue to grow; the mechanisms behind this phenomenon are not fully understood. In this review, the authors summarize how radiation causes cellular and DNA injury that can activate (1) checkpoints in the cell cycle to initiate cell cycle arrest and DNA repair and (2) key events that lead to cell death. In addition, we discuss the current knowledge of VS radiobiology and how it may contribute to clinical outcomes. A better understanding of VS radiobiology can help optimize existing treatment protocols and lead to new therapies to overcome radioresistance.

Primary Vestibular Schwannoma Cells Activate p21 and RAD51-Associated DNA Repair Following Radiation-Induced DNA Damage.

HYPOTHESIS: Vestibular Schwannoma (VS) can avoid cell death following radiation injury by entering cell cycle arrest and activating RAD51-related DNA repair. BACKGROUND: Although the radiobiology of various cancers is well-studied, the radiobiological effects in VS are poorly understood. In this study, we describe how VS cells enter cell cycle arrest (through p21 expression), activate DNA repair (through RAD51 upregulation), and avoid cell death after radiation-induced double-stranded breaks (DSB) in DNA (as measured by γ-H2AX). METHODS: Primary human VS cells were cultured on 96-well plates and 16-well culture slides at 10,000 cells/well and exposed to either 0 or 18 Gray of radiation. Viability assays were performed at 96 h in vitro. Immunofluorescence for γ-H2AX, RAD51, and p21 was performed at 6 h. RESULTS: Radiation (18 Gy) induced the expression of γ-H2AX, p21, and RAD51 in six cultured VS, suggesting that irradiated VS acquire DSBs, enter cell cycle arrest, and initiate RAD51 DNA repair to evade cell death. However, viability studies demonstrate variable responses in individual VS cells with 3 of 6 VS showing radiation resistance to 18 Gy. On further analyses, radiation-resistant VS cells expressed significantly more p21 than radiation-responsive tumors. CONCLUSIONS: In response to radiation-induced DNA damage, primary VS cells can enter cell cycle arrest and express RAD51 DNA repair mechanisms to avoid cell death. Radioresistant VS cells may mount a more robust p21 response to ensure sufficient time for DNA repair. Further investigation into DNA repair proteins and cell cycle checkpoints may provide important insight on the radiobiology of VS and mechanisms for resistance.

On the in vivo origin of human nasal mesenchymal stem cell cultures.

OBJECTIVES: Mesenchymal stem cells (MSCs), classically expanded in culture from bone marrow, are of broad interest to the regenerative medicine community. Human nasal turbinate mesenchymal-like stem cell cultures have also been described, defined by an in vitro phenotype similar to bone marrow MSCs. Nonetheless, the identity in vivo of the cells that give rise to nasal MSC-like cultures remains unclear, and these cells are often suggested to be related to olfactory lineages. Here, we sought to define the in vivo phenotype of human nasal MSC-like cells. METHODS: Human turbinate tissue samples were used for RNA and immunohistochemical analysis. We also analyzed a recently published single cell RNA-sequencing dataset from adult human olfactory and respiratory mucosa samples from our lab, to focus on cell populations expressing MSC markers. Immunochemistry was performed to stain turbinate sections and nasal MSC cultures for selected markers. RESULTS: While there is no single MSC-specific gene, we identified a human nasal mucosal cell population in vivo that uniquely expressed transcripts characteristic of typical MSC cultures, including ENG (CD105), NES, and CD34, and lacked expression of other transcripts associated with surface epithelia. The expression of transcription factors such as SOX17, EBF1, and FOXP1 suggests cells in the MSC-like cluster maintain an ability to direct cell fate, consistent with the behavior of nasal MSC-like cells in vitro. SOX17 was found to be uniformly expressed by nasal MSC cultures, consistent with the in vivo data. Immunohistochemistry of human nasal tissue samples indicated that ENG, CD34, and SOX17 expression localized selectively to cells surrounding blood vessels in the lamina propria. CONCLUSION: Our findings provide evidence that the in vivo origin of nasal MSC-like cultures is likely a vascular or pericyte population, rather than cells related to the olfactory neuronal lineage. LEVEL OF EVIDENCE: NA.

COVID-19 Infection and Its Influence in Otorhinolaryngology-Head and Neck Surgery.

Introduction The novel coronavirus disease 2019 pandemic has rapidly spread worldwide, challenging healthcare resources and communities to an unprecedent degree. Simultaneously, the amount of clinical and scientific information released has overwhelmed journal platforms. Objectives This review aims to summarize the available diagnostic tools and current guidelines to safely assist patients while limiting the exposure of otolaryngologists during this pandemic. Data Synthesis Key articles were retrieved from the following databases: PubMed, Lancet, Springer Nature, BioMed Central, JAMA network and MEDLINE, as well as updated documents from the Spanish Ministry of Health, World Health Organization, Centers for Disease Control and Prevention, Spanish Association of Surgeons, ENT-UK, American College of Surgeons, and American Academy of Otolaryngology-Head and Neck Surgery. The terms used for the search were: COVID-19 , Test COVID , Surgery in COVID , 2019-nCoV , ' coronavirus' , and SARS-CoV-2 . A total of 10,245 papers were retrieved. The inclusion criteria for the review included: COVID-19 testing ( n = 531), society guidelines for otolaryngology-head and neck surgery patient care in the outpatient clinic ( n = 10) and surgical ( n = 18) settings. Studies not related to COVID-19 diagnosis were excluded. Conclusion Healthcare institutions around the world are outlining their own protocols regarding laboratory testing and personnel protective equipment usage based upon medical societies recommendations during the COVID-19 pandemic. We have summarized the available laboratory tests and their respective sensitivity and specificity. Moreover, clinical guidelines from different societies were reviewed and summarized to facilitate guidance for otolaryngologists in the operating room and in the clinical settings.

Effect of age, electrode array, and time on cochlear implant impedances.

Objectives: To determine the impact of age, electrode array, and time on impedance patterns in cochlear implant (CI) patients. Methods: A retrospective case review was performed on 98 patients implanted with the CI24RE perimodiolar (PM) and CI422 lateral wall (LW) arrays between 2010 and 2014 to assess impedances at the 1 week and 3-6 month visit after initial stimulation (IS). Results: With respect to age, impedances were higher in young patients compared to older patients in the middle and apical turns. With time, there were significant reductions in impedances across most electrodes. Electrode array type also had a significant impact on impedance measurements with PM and LW arrays having higher impedances in the basal turn and apical turns, respectively. Furthermore, PM arrays demonstrated significantly lower impedances in the middle and apical turn with time, when compared to LW arrays. Conclusions: Age, electrode array, and time can independently affect CI impedances. Moreover, we show that PM arrays may be advantageous to LW arrays, due to demonstrated lower impedances in the middle and apical turns long term. Understanding the impact of impedance on speech discrimination and determining the intracochlear processes that contribute to differences in impedance are future research directions.

Acute N-Acetylcysteine Administration Ameliorates Loss of Olfactory Neurons Following Experimental Injury In Vivo.

The olfactory epithelium (OE) is the peripheral organ for the sense of smell, housing primary sensory neurons that project axons from the nose to the brain. Due to the presence of a basal stem cell niche, the adult mammalian OE is a dynamic tissue capable of replacing neurons following their loss. Nonetheless, certain conditions, such as blunt head trauma, can result in persistent olfactory loss, thought to be due to shearing of olfactory nerve filaments at the skull base, degeneration, and failures in proper regeneration/reinnervation. The identification of new treatment strategies aimed at preventing degeneration of olfactory neurons is, therefore, needed. In considering potential therapies, we have focused on N-acetylcysteine (NAC), a glutathione substrate shown to be neuroprotective, with a record of safe clinical use. Here, we have tested the use of NAC in an animal model of olfactory degeneration. Administered acutely, we found that NAC (100 mg/kg, twice daily) resulted in a reduction of olfactory neuronal loss from the OE of the nose following surgical ablation of the olfactory bulb. At 1 week postlesion, we identified 54 ± 8.1 mature neurons per 0.5 mm epithelium in NAC-treated animals vs. 28 ± 4.2 in vehicle-treated controls (P = 0.02). Furthermore, in an olfactory cell culture model, we have identified significant alterations in the expression of several genes involved in oxidative stress pathways following NAC exposure. Our results provide evidence supporting the potential therapeutic utility for NAC acutely following head trauma-induced olfactory loss. Anat Rec, 303:626-633, 2020. © 2019 American Association for Anatomy.

Animal Model of Chronic Tympanic Membrane Perforation.

Chronic tympanic membrane perforations (TMP) can be a source of significant morbidity from hearing loss, recurrent middle ear infections, changes in lifestyle, and risk of cholesteatoma formation. Laboratory experiments of TMP have been fraught by the rapid and high rate of spontaneous healing observed in animal models. There is controversy on the minimal time that perforations in animal models must have in order to be considered chronic TMP and thus have clinical relevance, with authors suggesting time periods of perforation patency of 8-12 weeks. In this article, we sought to create a clinically significant experimental model that could yield a high rate of perforation patency for at least 8 weeks. Animals undergoing acute TMP were exposed to three different experimental situations to delay the healing of the perforation: fractionated radiation, topical lipopolysaccharide application, and a combined dexamethasone and mitomycin C (DXM/MC) solution. In our study, the use of DXM/MC reliably produced TMP lasting at least 8 weeks in 86.48% of the cases without the need to reopen the perforation, infolding the edges of the membrane, or using physical barriers to prevent TMP closure. Histologically, the resulting perforated tympanum showed hyaline changes of the remnant tympanum and hyperkeratosis of the squamous epithelia of the external auditory canal. We believe that this model is reproducible and has potential use in experiments of delayed healing of TMP. Anat Rec, 303:619-625, 2020. © 2019 American Association for Anatomy.

Cervical VEMP tuning changes by Meniere's disease stages.

OBJECTIVE: To determine if changes in cervical vestibular-evoked myogenic potential (cVEMP) testing reflect the different stages of cochlea-saccular hydrops in Meniere's disease (MD). METHODS: This is a case-control retrospective series. Forty-seven patients with unilateral MD by American Academy of Otolaryngology-Head and Neck Surgery diagnostic and staging criteria, and 30 with non-MD vertigo as control. Meniere patients were further classified based on symptoms at the time of testing as active or stable. Subsequently, patients underwent cVEMP testing by tone-burst stimuli at 500 and 1,000 Hz. The main outcome measure was to compare the cVEMP 1,000 and 500 Hz amplitude ratio in ears with MD and non-MD vertigo, and in active versus stable MD. RESULTS: The cVEMP 1,000/500 Hz amplitude ratio was higher in Meniere's ears (mean = 1.14 µV, SD = 0.25) than in non-Meniere's ears (mean = 0.96 µV, SD = 0.2) (Student's t test, P = .001), and higher in active (mean = 1.22 µV, SD = 0.25) than in stable MD (mean = 1.00 µV, SD = 0.18) (P = .0035). The diagnostic value of cVEMP 1,000/500 Hz amplitude ratio to differentiate MD versus non-MD vertigo was evaluated with a receiver-operating characteristics (ROC) curve and the area under the curve (AUC) was 0.716 (95% confidence interval [CI] [0.591, 0.829]). The ideal cutoff point was 0.9435 with sensitivity and specificity values of 83% and 53%, respectively. The sensitivity and specificity values for this test to differentiate active versus stable MD were 68% and 81%, respectively, with AUC 0.746 (95% CI [0.607, 0.885]) and cutoff value of 1.048. In all ears, the 1,000/500 Hz amplitude ratio increased by a decrease of the 500 Hz amplitude with increasing age. CONCLUSION: The cVEMP 1,000/500 Hz amplitude ratio is elevated in ears with MD but not in those with non-MD vertigo. After corrected by age, this ratio is higher in active but not in stable MD, probably reflecting dynamic changes in saccular membrane motion mechanics in hydrops, and may be a useful marker of disease progression and the effect of therapy. LEVEL OF EVIDENCE: IV.

Cell-Based Therapy Restores Olfactory Function in an Inducible Model of Hyposmia.

Stem cell-based therapies have been proposed as a strategy to replace damaged tissues, especially in the nervous system. A primary sensory modality, olfaction, is impaired in 12% of the US population, but lacks treatment options. We report here the development of a novel mouse model of inducible hyposmia and demonstrate that purified tissue-specific stem cells delivered intranasally engraft to produce olfactory neurons, achieving recovery of function. Adult mice were rendered hyposmic by conditional deletion of the ciliopathy-related IFT88 gene in the olfactory sensory neuron lineage and following experimentally induced olfactory injury, received either vehicle or stem cell infusion intranasally. Engraftment-derived olfactory neurons were identified histologically, and functional improvements were measured via electrophysiology and behavioral assay. We further explored mechanisms in culture that promote expansion of engraftment-competent adult olfactory basal progenitor cells. These findings provide a basis for translational research on propagating adult tissue-specific sensory progenitor cells and testing their therapeutic potential.

Laminin-coated electrodes improve cochlear implant function and post-insertion neuronal survival.

The benefits of Cochlear implant (CI) technology depend among other factors on the proximity of the electrode array to the spiral ganglion neurons. Laminin, a component of the extracellular matrix, regulates Schwann cell proliferation and survival as well as reorganization of actin fibers within their cytoskeleton, which is necessary for myelination of peripheral axons. In this study we explore the effectiveness of laminin-coated electrodes in promoting neuritic outgrowth from auditory neurons towards the electrode array and the ability to reduce acoustic and electric auditory brainstem response (i.e. aABR and eABR) thresholds. In vitro: Schwann cells and neurites are attracted towards laminin-coated surfaces with longer neuritic processes in laminin-coated dishes compared to uncoated dishes. In vivo: Animals implanted with laminin-coated electrodes experience significant decreases in eABR and aABR thresholds at selected frequencies compared to the results from the uncoated electrodes group. At 1 month post implantation there were a greater number of spiral ganglion neurons and neuritic processes projecting into the scala tympani of animals implanted with laminin-coated electrodes compared to animals with uncoated electrodes. These data suggest that Schwann cells are attracted towards laminin-coated electrodes and promote neuritic outgrowth/ guidance and promote the survival of spiral ganglion neurons following electrode insertion trauma.

Middle ear irrigation using a hydrodebrider decreases biofilm surface area in an animal model of otitis media.

OBJECTIVE: To compare the safety and efficacy of manual and powered irrigation of the middle ear using saline or 1% baby shampoo to treat biofilm-forming bacterial middle ear infections. BACKGROUND: Biofilms play a major role in recalcitrant otitis media and are challenging to treat. Many therapeutic strategies have been attempted and the role of topical therapies is still being investigated. Topical irrigation using saline or 1% baby shampoo and the use of a hydrodebrider have been investigated in biofilms involved in chronic rhinosinusitis and their role within the middle ear is yet to be determined. METHODS: Twenty-two adult chinchillas underwent bilateral trans-bullar inoculation of non-typable biofilm forming Haemophilus influenza followed by unilateral middle ear irrigation 5 days later using saline administered via a powered hydrodebrider or manual irrigation of saline or 1% baby shampoo. Contralateral inoculated ears served as control and were not irrigated. Two days following irrigation, the bullae were harvested and processed for scanning electron microscopy to assess biofilm surface area. Auditory brainstem responses were performed before bacterial inoculation and prior to euthanasia. RESULTS: Manual and powered irrigation were effective in reducing the surface area of biofilm when compared to the control group. The hydrodebrider demonstrated to be more effective at eradicating biofilm than manual irrigation, especially in areas of difficult access, such as the ventral portion of the chinchillas' bullae. There was no difference in manual irrigation of saline when compared to 1% baby shampoo. Irrigations either manually or using the hydrodebrider did not affect hearing, the vestibular system or facial function. CONCLUSION: Middle ear biofilms can be treated safely and effectively with rinses using either normal saline or 1% baby shampoo administered manually or with a powered hydrodebrider. LEVEL OF EVIDENCE: NA.