Otolaryngology - Research Publications

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    Effectiveness of Intranasal Mometasone Furoate vs Saline for Sleep-Disordered Breathing in Children A Randomized Clinical Trial
    Baker, A ; Grobler, A ; Davies, K ; Griffiths, A ; Hiscock, H ; Kubba, H ; Peters, RL ; Ranganathan, S ; Rimmer, J ; Rose, E ; Rowe, K ; Simpson, CM ; Davidson, A ; Nixon, G ; Perrett, KP (AMER MEDICAL ASSOC, 2023-03)
    IMPORTANCE: Obstructive sleep-disordered breathing (SDB) in children is characterized by snoring and difficulty breathing during sleep. SDB affects at least 12% of otherwise healthy children and is associated with significant morbidity. Evidence from small clinical trials suggests that intranasal corticosteroids improve SDB as measured by polysomnography; however, the effect on symptoms and quality of life is unclear. OBJECTIVE: To determine whether intranasal mometasone furoate is more effective than intranasal saline for improving symptoms and quality of life in children with SDB. DESIGN, SETTING, AND PARTICIPANTS: The MIST trial was a multicenter, randomized, double-blind, placebo-controlled trial, recruiting participants from June 8, 2018, to February 13, 2020. Children aged 3 to 12 years who were referred to a specialist for significant SDB symptoms were included; exclusions were previous adenotonsillectomy, body mass index greater than the 97th percentile, and severe SDB. Randomization was stratified by site, and data were analyzed on an intention-to-treat basis from October 28, 2020, to September 25, 2022. INTERVENTIONS: Participants were randomly assigned to receive mometasone furoate, 50 μg, or sodium chloride (saline), 0.9%, 1 spray per nostril daily, dispensed in identical bottles. MAIN OUTCOMES AND MEASURES: The primary outcome was resolution of significant SDB symptoms (ie, reduction to a level no longer requiring referral to a specialist as per the American Academy of Pediatrics guidelines) at 6 weeks, measured by parental report of symptoms using the SDB Score. RESULTS: A total of 276 participants (mean [SD] age, 6.1 [2.3] years; 146 male individuals [53%]) were recruited, 138 in each treatment arm. Resolution of significant SDB symptoms occurred in 56 of 127 participants (44%) in the mometasone group and 50 of 123 participants (41%) in the saline group (risk difference, 4%; 95% CI, -8% to 16%; P = .51) with 26 participants lost to follow-up and missing values managed by multiple imputation. The main adverse effects were epistaxis, affecting 12 of 124 participants (9.7%) in the mometasone group and 18 of 120 participants (15%) in the saline group, and nasal itch/irritation, affecting 12 of 124 participants (9.7%) in the mometasone group and 22 of 120 participants (18%) in the saline group. CONCLUSIONS AND RELEVANCE: Results of this randomized clinical trial suggest that there was no difference in treatment effect between intranasal mometasone and saline for the management of SDB symptoms. The results suggest that almost one-half of children with SDB could be initially managed in the primary care setting and may not require referral to specialist services, as is currently recommended. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ANZCTRN12618000448246.
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    Characteristics of the Summating Potential Measured Across a Cochlear Implant Array as an Indicator of Cochlear Function.
    Panario, J ; Bester, C ; O'Leary, SJ (Ovid Technologies (Wolters Kluwer Health), 2023-09)
    OBJECTIVES: The underlying state of cochlear and neural tissue function is known to affect postoperative speech perception following cochlear implantation. The ability to assess these tissues in patients can be performed using intracochlear electrocochleography (IC ECochG). One component of ECochG is the summating potential (SP) that appears to be generated by multiple cochlear tissues. Its qualities may be able to detect the presence of functional inner hair cells, but evidence for this is limited in human cochleae. This study aimed to examine the IC SP characteristics in cochlear implantation recipients, its relationship to preoperative speech perception and audiometric thresholds, and to other IC ECochG components. DESIGN: This is a retrospective analysis of 113 patients' IC ECochG recordings across the array in response to a 500 Hz tone burst stimulus. Responses to condensation and rarefaction stimuli were then subtracted from one another to emphasize the cochlear microphonic and added to one another to emphasize the SP, auditory nerve neurophonic, and compound action potential. Patients were grouped based on their maximum SP deflection being large and positive (+SP), large and negative (-SP), or minimal (0 SP) to further investigate these relationships. RESULTS: Patients in the +SP group had better preoperative speech perception (mean consonant-vowel-consonant phoneme score 46%) compared to the -SP and 0 SP groups (consonant-vowel-consonant phoneme scores 34% and 36%, respectively, difference to +SP: p < 0.05). Audiometric thresholds were lowest for +SP (mean pure-tone average 50 dB HL), then -SP (65 dB HL), and highest for 0 SP patients (70 dB HL), but there was not a statistical significance between +SP and -SP groups ( p > 0.1). There were also distinct differences between SP groups in the qualities of their other ECochG components. These included the +SP patients having larger cochlear microphonic maximum amplitude, more apical SP peak electrode locations, and a more spatially specific SP magnitude growth pattern across the array. CONCLUSIONS: Patients with large positive SP deflection in IC ECochG have preoperatively better speech perception and lower audiometric thresholds than those without. Patterns in other ECochG components suggest its positive deflection may be an indicator of cochlear function.
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    Intra-cochlear Flushing Reduces Tissue Response to Cochlear Implantation
    Razmovski, T ; Brody, KM ; Stathopoulos, D ; Zhang, D ; Cho, E ; Hampson, AJ ; Collins, A ; Bester, C ; O'Leary, S (WILEY, 2024-03)
    INTRODUCTION: Intraoperative trauma leading to bleeding during cochlear implantation negatively impacts residual hearing of cochlear implant recipients. There are no clinical protocols for the removal of blood during implantation, to reduce the consequential effects such as inflammation and fibrosis which adversely affect cochlear health and residual hearing. This preclinical study investigated the implementation of an intra-cochlear flushing protocol for the removal of blood. METHODS: Three groups of guinea pigs were studied for 28 days after cochlear implantation; cochlear implant-only (control group); cochlear implant with blood injected into the cochlea (blood group); and cochlear implant, blood injection, and flushing of the blood from the cochlea intraoperatively (flush group). Auditory brainstem responses (ABRs) in addition to tissue response volumes were analyzed and compared between groups. RESULTS: After implantation, the blood group exhibited the highest ABR thresholds when compared to the control and flush group, particularly in the high frequencies. On the final day, the control and blood group had similar ABR thresholds across all frequencies tested, whereas the flush group had the lowest thresholds, significantly lower at 24 kHz than the blood and control group. Analysis of the tissue response showed the flush group had significantly lower tissue responses in the basal half of the array when compared with the blood and control group. CONCLUSIONS: Flushing intra-cochlear blood during surgery resulted in better auditory function and reduced subsequent fibrosis in the basal region of the cochlea. This finding prompts the implementation of a flushing protocol in clinical cochlear implantation. LEVEL OF EVIDENCE: N/A Laryngoscope, 134:1410-1416, 2024.
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    Hybrid optogenetic and electrical stimulation for greater spatial resolution and temporal fidelity of cochlear activation
    Thompson, AC ; Wise, AK ; Hart, WL ; Needham, K ; Fallon, JB ; Gunewardene, N ; Stoddart, PR ; Richardson, RT (IOP PUBLISHING LTD, 2020-10)
    OBJECTIVE: Compared to electrical stimulation, optogenetic stimulation has the potential to improve the spatial precision of neural activation in neuroprostheses, but it requires intense light and has relatively poor temporal kinetics. We tested the effect of hybrid stimulation, which is the combination of subthreshold optical and electrical stimuli, on spectral and temporal fidelity in the cochlea by recording multiunit activity in the inferior colliculus of channelrhodopsin (H134R variant) transgenic mice. APPROACH: Pulsed light or biphasic electrical pulses were delivered to cochlear spiral ganglion neurons of acutely deafened mice, either as individual stimuli or as hybrid stimuli for which the timing of the electrical pulse had a varied delay relative to the start of the optical pulse. Response thresholds, spread of activation and entrainment data were obtained from multi-unit recordings from the auditory midbrain. MAIN RESULTS: Facilitation occurred when subthreshold electrical stimuli were applied at the end of, or up to 3.75 ms after subthreshold optical pulses. The spread of activation resulting from hybrid stimulation was significantly narrower than electrical-only and optical-only stimulation (p < 0.01), measured at equivalent suprathreshold levels of loudness that are relevant to cochlear implant users. Furthermore, temporal fidelity, measured as maximum following rates to 300 ms pulse trains bursts up to 240 Hz, was 2.4-fold greater than optical-only stimulation (p < 0.05). SIGNIFICANCE: By significantly improving spectral resolution of electrical- and optical-only stimulation and the temporal fidelity of optical-only stimulation, hybrid stimulation has the potential to increase the number of perceptually independent stimulating channels in a cochlear implant.
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    Tissue Characterization Using Synchrotron Radiation at 0.7 THz to 10.0 THz with Extended ATR Apparatus Techniques
    Vilagosh, Z ; Appadoo, D ; Foroughimehr, N ; Shams, R ; Sly, D ; Juodkazis, S ; Ivanova, E ; Wood, AW (MDPI, 2022-11)
    The attenuated total reflection (ATR) apparatus, with an added partial reflection/partial transmission mode, was used to demonstrate a novel way of characterizing water-based substances at 0.7 to 10.0 THz at the Australian Synchrotron THz-far infrared beamline. The technique utilized a diamond-crystal-equipped ATR to track temperature-dependent changes in reflectance. A "crossover flare" feature in the spectral scan was noted, which appeared to be a characteristic of water and water-dominated compounds. A "quiet zone" feature was also seen, where no temperature-dependent variation in reflectance exists. The variation in these spectral features can be used as a signature for the presence of bound and bulk water. The method can also potentially identify the presence of fats and oils in a biological specimen. The technique requires minimal sample preparation and is non-destructive. The presented method has the promise to provide a novel, real-time, low-preparation, analytical method for investigating biological material, which offers avenues for rapid medical diagnosis and industrial analysis.
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    Electrocochleography triggered intervention successfully preserves residual hearing during cochlear implantation: Results of a randomised clinical trial
    Bester, C ; Collins, A ; Razmovski, T ; Weder, S ; Briggs, RJ ; Wei, B ; Zakaria, AF ; Gerard, J-M ; Mitchell-Innes, A ; Tykocinski, M ; Kennedy, R ; Iseli, C ; Dahm, M ; Ellul, S ; O'Leary, S (ELSEVIER, 2022-12)
    BACKGROUND: Preservation of natural hearing during cochlear implantation is associated with improved speech outcomes, however more than half of implant recipients lose this hearing. Real-time electrophysiological monitoring of cochlear output during implantation, made possible by recording electrocochleography using the electrodes on the cochlear implant, has shown promise in predicting hearing preservation. Sudden drops in the amplitude of the cochlear microphonic (CM) have been shown to predict more severe hearing losses. Here, we report on a randomized clinical trial investigating whether immediate surgical intervention triggered by these drops can save residual hearing. METHODS: A single-blinded placebo-controlled trial of surgical intervention triggered when CM amplitude dropped by at least 30% of a prior maximum amplitude during cochlear implantation. Intraoperative electrocochleography was recorded in 60 adults implanted with Cochlear Ltd's Thin Straight Electrode, half randomly assigned to a control group and half to an interventional group. The surgical intervention was to withdraw the electrode in ½-mm steps to recover CM amplitude. The primary outcome was hearing preservation 3 months following implantation, with secondary outcomes of speech-in-noise reception thresholds by group or CM outcome, and depth of implantation. RESULTS: Sixty patients were recruited; neither pre-operative audiometry nor speech reception thresholds were significantly different between groups. Post-operatively, hearing preservation was significantly better in the interventional group. This was the case in absolute difference (median of 30 dB for control, 20 dB for interventional, χ² = 6.2, p = .013), as well as for relative difference (medians of 66% for the control, 31% for the interventional, χ² = 5.9, p = .015). Speech-in-noise reception thresholds were significantly better in patients with no CM drop at any point during insertion compared with patients with a CM drop; however, those with successfully recovered CMs after an initial drop were not significantly different (median gain required for speech reception score of 50% above noise of 6.9 dB for no drop, 8.6 for recovered CM, and 9.8 for CM drop, χ² = 6.8, p = .032). Angular insertion depth was not significantly different between control and interventional groups. CONCLUSIONS: This is the first demonstration that surgical intervention in response to intraoperative hearing monitoring can save residual hearing during cochlear implantation.
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    Dynamic optical clamp: A novel electrophysiology tool and a technique for closed-loop stimulation
    Hart, WL ; Needham, K ; Richardson, RT ; Stoddart, PR ; Kameneva, T (ELSEVIER SCI LTD, 2023-08)
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    Monitoring Cochlear Health With Intracochlear Electrocochleography During Cochlear Implantation: Findings From an International Clinical Investigation
    O'Leary, S ; Mylanus, E ; Venail, F ; Lenarz, T ; Birman, C ; Di Lella, F ; Roland Jr, JT ; Gantz, B ; Beynon, A ; Sicard, M ; Buechner, A ; Lai, WK ; Boccio, C ; Choudhury, B ; Tejani, VD ; Plant, K ; English, R ; Arts, R ; Bester, C (LIPPINCOTT WILLIAMS & WILKINS, 2023-03)
    OBJECTIVES: Electrocochleography (ECochG) is emerging as a tool for monitoring cochlear function during cochlear implant (CI) surgery. ECochG may be recorded directly from electrodes on the implant array intraoperatively. For low-frequency stimulation, its amplitude tends to rise or may plateau as the electrode is inserted. The aim of this study was to explore whether compromise of the ECochG signal, defined as a fall in its amplitude of 30% or more during insertion, whether transient or permanent, is associated with poorer postoperative acoustic hearing, and to examine how preoperative hearing levels may influence the ability to record ECochG. The specific hypotheses tested were threefold: (a) deterioration in the pure-tone average of low-frequency hearing at the first postoperative follow-up interval (follow-up visit 1 [FUV1], 4 to 6 weeks) will be associated with compromise of the cochlear microphonic (CM) amplitude during electrode insertion (primary hypothesis); (b) an association is observed at the second postoperative follow-up interval (FUV2, 3 months) (secondary hypothesis 1); and (c) the CM response will be recorded earlier during electrode array insertion when the preoperative high-frequency hearing is better (secondary hypothesis 2). DESIGN: International, multi-site prospective, observational, between groups design, targeting 41 adult participants in each of two groups, (compromised CM versus preserved CM). Adult CI candidates who were scheduled to receive a Cochlear Nucleus CI with a Slim Straight or a Slim Modiolar electrode array and had a preoperative audiometric low-frequency average thresholds of ≤80 dB HL at 500, 750, and 1000 Hz in the ear to be implanted, were recruited from eight international implant sites. Pure tone audiometry was measured preoperatively and at postoperative visits (FUV1 and follow-up visit 2 [FUV2]). ECochG was measured during and immediately after the implantation of the array. RESULTS: From a total of 78 enrolled individuals (80 ears), 77 participants (79 ears) underwent surgery. Due to protocol deviations, 18 ears (23%) were excluded. Of the 61 ears with ECochG responses, amplitudes were < 1 µV throughout implantation for 18 ears (23%) and deemed "unclear" for classification. EcochG responses >1 µV in 43 ears (55%) were stable throughout implantation for 8 ears and compromised in 35 ears. For the primary endpoint at FUV1, 7/41 ears (17%) with preserved CM had a median hearing loss of 12.6 dB versus 34/41 ears (83%) with compromised CM and a median hearing loss of 26.9 dB ( p < 0.014). In assessing the practicalities of measuring intraoperative ECochG, the presence of a measurable CM (>1 µV) during implantation was dependent on preoperative, low-frequency thresholds, particularly at the stimulus frequency (0.5 kHz). High-frequency, preoperative thresholds were also associated with a measurable CM > 1 µV during surgery. CONCLUSIONS: Our data shows that CM drops occurring during electrode insertion were correlated with significantly poorer hearing preservation postoperatively compared to CMs that remained stable throughout the electrode insertion. The practicality of measuring ECochG in a large cohort is discussed, regarding the suggested optimal preoperative low-frequency hearing levels ( < 80 dB HL) considered necessary to obtain a CM signal >1 µV.
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    Acoustic Analysis of Slag Foaming in the BOF
    Heenatimulla, J ; Brooks, GA ; Dunn, M ; Sly, D ; Snashall, R ; Leung, W (MDPI, 2022-07)
    The control of slag foam that is produced during the Basic Oxygen Furnace (BOF) process has been the subject of significant research. The behaviour of slag foams is complex. Hence, the control of slag foam in the dynamic process of the BOF is challenging. Acoustic analysis of the BOF is one of the most promising methods for the indirect measurement of slag foam height. This paper reviews different studies on the fundamental behaviour of acoustics in liquid foams and various acoustic studies related to determining the slag foam height during the BOF process. Studies on the BOF have been carried out using both cold water models and plant trials, where acoustic measurements taken directly from the process were analysed. These studies showed that the attenuation of sound through liquid foam was influenced mainly by factors such as viscosity, bubble size, and foam height. Current systems are said to be 70 to 87 per cent accurate in detecting and/or predicting slopping events in the BOF, though there is a lack of systematic data in the literature to fully quantify this accuracy. There have been various attempts to combine sound with vibration and image signals to improve the prediction of slopping events in BOFs. The review substantiates the lack of accuracy of the current systems in determining the slag foam height using acoustic analysis and the need to address fundamental questions about the behaviour of sound in dynamic foam, its reliance on different factors, and the relatability of comparing cold model data to industrial data.
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    Comparison of Quality of Life between Patients Undergoing Submental Endoscopic Thyroidectomy and Conventional Thyroidectomy: A Prospective Controlled Clinical Trial
    Piromchai, P (MDPI, 2022-08)
    The objectives of this study were to compare the surgical outcomes and quality of life between patients undergoing submental endoscopic thyroidectomy and those undergoing conventional thyroidectomy. The surgical outcomes and quality of life were recorded. Forty-eight patients were included in the study. Their ages ranged from 20 to 60 years. All patients underwent lobectomy, isthmectomy, or the combination of lobectomy and isthmectomy. Most histological diagnoses were benign (85.42%). The submental endoscopic thyroidectomy group showed better scores in the energy/fatigue, emotional wellbeing, and general health domains (p = 0.006, 0.041, and 0.004, respectively). There were no statistically significant differences in surgical outcomes between the submental endoscopic thyroidectomy and conventional thyroidectomy groups (p > 0.05). Submental endoscopic thyroidectomy is feasible, and permits a better quality of life in terms of the energy/fatigue, emotional wellbeing, and general health domains.