A retrospective review of divers treated for inner ear decompression sickness at Fiona Stanley Hospital hyperbaric medicine unit 2014-2020.

Introduction: Inner ear decompression sickness (IEDCS) is increasingly recognised in recreational diving, with the inner ear particularly vulnerable to decompression sickness in divers with a right-to-left shunt, such as is possible through a persistent (patent) foramen ovale (PFO). A review of patients treated for IEDCS at Fiona Stanley Hospital Hyperbaric Medicine Unit (FSH HMU) in Western Australia was performed to examine the epidemiology, risk factors for developing this condition, the treatment administered and the outcomes of this patient population. Methods: A retrospective review of all divers treated for IEDCS from the opening of the FSH HMU on 17 November 2014 to 31 December 2020 was performed. Patients were included if presenting with vestibular or cochlear dysfunction within 24 hours of surfacing from a dive, and excluded if demonstrating features of inner ear barotrauma. Results: There were a total of 23 IEDCS patients and 24 cases of IEDCS included for analysis, with 88% experiencing vestibular manifestations and 38% cochlear. Median dive time was 40 minutes and median maximum depth was 24.5 metres. The median time from surfacing to hyperbaric oxygen treatment (HBOT) was 22 hours. Vestibulocochlear symptoms fully resolved in 67% and complete symptom recovery was achieved in 58%. A PFO was found in 6 of 10 patients who subsequently underwent investigation with bubble contrast echocardiography upon follow-up. Conclusions: IEDCS occurred predominantly after non-technical repetitive air dives and ongoing symptoms and signs were often observed after HBOT. Appropriate follow-up is required given the high prevalence of PFO in these patients.

Which stimulus should be used for auditory brainstem response in newborns; CE-Chirp® level specific versus Click stimulus.

OBJECTIVES: Auditory Brainstem Response (ABR), the electrical responses in the neuronal pathways extending from the inner ear to the auditory cortex, are evaluated with auditory stimuli. ABR analysis evaluates waves I, III and V's absolute-latencies, amplitude values, interpeak-latencies, interaural-latency differences, and morphologies. This study aims to reveal the advantages of CE-Chirp® LS stimulus and its clinical uses to increase by comparing the amplitude, latency, and interpeak-latency differences of waves I, III, and V at 80 dB nHL and wave V at 60, 40, 20 dB nHL by using click and CE-Chirp® LS stimuli. METHODS: 100 (54 boys, 46 girls) infants with normal hearing were included in the National Newborn Hearing Screening Program. With the click and CE-Chirp® LS ABR, the absolute latency and amplitude values of wave V at 20, 40, and 60 dB nHL, and the absolute-latency, interpeak-latency, and amplitude values of waves I, III, and V at 80 dB nHL are determined between stimuli and right-left ear. RESULTS: When the wave V latency and amplitudes obtained at 80, 60, 40, and 20 dB nHL levels were examined between genders, and according to the risk factor, no significant difference was found between click and CE-Chirp® LS stimuli (p > 0.05). Waves I, III, and V absolute-latency, amplitudes were compared at 80 dB nHL and wave V absolute-latency, amplitudes at 60, 40, and 20 dB nHL; the amplitudes measured with CE-Chirp® LS were significantly higher than the click stimulus (p < 0.05). When two stimuli were compared for I-III and III-V interpeak-latency values at 80 dB nHL level, no significant difference was found between the two stimuli (p > 0.05). However, the I-V interpeak-latency value was statistically significantly decreased for two stimuli, regardless of the ear (p < 0.05). CONCLUSIONS: It is suggested to increase the use of CE-Chirp® LS stimulus with better morphology and amplitude in clinics, believing that it facilitates clinicians' interpretation.

Oridonin employs interleukin 1 receptor type 2 to treat noise-induced hearing loss by blocking inner ear inflammation.

NOD-like receptor protein 3 (NLRP3) inflammasomes trigger the inflammatory cascades and participate in various inflammatory diseases, including noise-induced hearing loss (NIHL) caused by oxidative stress. Recently, the anti-inflammatory traditional medicine oridonin (Ori) has been reported to provide hearing protection in mice after noise exposure by blocking the NLRP3-never in mitosis gene A-related kinase 7 (NEK7)-inflammasome complex assembly. Using RNA sequencing analysis, we further elucidated that interleukin 1 receptor type 2 (IL1R2) may be another crucial factor regulated by Ori to protect NIHL. We observed that IL1R2 expression was localized in spiral ganglion neurons, inner and outer hair cells, in Ori-treated mouse cochleae. Additionally, we confirmed that ectopic overexpression of IL1R2 in the inner ears of healthy mice using an adeno-associated virus delivery system significantly reduced noise-induced ribbon synapse lesions and hearing loss by blocking the "cytokine storm" in the inner ear. This study provides a novel theoretical foundation for guiding the clinical treatment of NIHL.

The Diagnostic Value of 1.5T Versus 3.0T Magnetic Resonance Imaging Intratympanic Gadolinium Inner Ear Enhancement in Patients with Meniere's Disease.

BACKGROUND: A comparative study of 1.5T and 3.0T magnetic resonance imaging inner ear gadolinium enhancement was carried out to further explore the practicality and universality of 1.5T magnetic resonance imaging in the diagnosis of inner ear labyrinthine hydrops positive imaging. METHODS: This dual case-control study was conducted on 25 patients with Meniere's disease (experimental group), diagnosed by People's Hospital of Ordos Dongsheng District between April 2017 and April 2019 and 51 patients with Meniere's disease (control group), diagnosed by People's Hospital Affiliated to Fujian University of Traditional Chinese Medicine between March 2010 and February 2011 and published on Chinese Medical Journal in 2011. Both groups were injected with gadolinium diluent into bilateral tympanic chambers through the tympanic membrane, and 3 dimensional-Fluid Attenuated Inversion Recovery (FLAIR) magnetic resonance imaging scanning of the inner ear was performed 24 hours later. The results of the 2 groups were observed, calculated, and statistically processed. RESULTS: The positive rate of membranous labyrinthine hydrops was 96% (24/25) in the experimental group and 96.1% (49/51) in the control group. The results are very close. CONCLUSION: In clinical diagnoses of Meniere's disease, 1.5T magnetic resonance imaging and 3.0T magnetic resonance imaging have the same value and significance.

Otopathologic and Computed Tomography Correlation of Internal Auditory Canal Diverticula in Otosclerosis.

INTRODUCTION: Internal auditory canal (IAC) diverticula, also known as IAC cavitary lesions or anterior cupping of the IAC, observed in otopathologic specimens and high-resolution computed tomography (CT) scans of the temporal bone are thought to be related to otosclerosis. Herein, we examined the usefulness of CT scans in identifying diverticula and determined whether IAC diverticula are associated with otosclerosis on otopathology. METHODS: One hundred five consecutive specimens were identified from the National Temporal Bone Hearing and Balance Pathology Resource Registry. Inclusion criteria included the availability of histologic slides and postmortem specimen CT scans. Exclusion criteria included cases with severe postmortem changes or lesions causing bony destruction of the IAC. RESULTS: Ninety-seven specimens met criteria for study. Of these, 42% of the specimens were from male patients, and the average age of death was 77 years (SD = 18 yr). IAC diverticula were found in 48 specimens, of which 46% were identified in the CT scans. The mean area of the IAC diverticula was 0.34 mm 2 . The sensitivity and specificity of detecting IAC diverticula based on CT were 77% and 63%, respectively. Overall, 27% of specimens had otosclerosis. Histologic IAC diverticula were more common in specimens with otosclerosis than those without (37.5% versus 16%; p = 0.019). Cases with otosclerosis had a greater mean histologic diverticula area compared with nonotosclerosis cases (0.69 mm 2 versus 0.14 mm 2 ; p = 0.001). CONCLUSION: IAC diverticula are commonly found in otopathologic specimens with varied etiologies, but larger diverticula are more likely to be associated with otosclerosis. The sensitivity and specificity of CT scans to detect IAC diverticula are limited.

Migrainous Vertigo, Tinnitus, and Ear Symptoms and Alternatives.

Migraine headaches frequently coexist with vestibular symptoms such as vertigo, motion sickness, and gait instability. Migraine-related vasospasm can also damage the inner ear, which results in symptoms such as sudden sensorineural hearing loss and resultant tinnitus. The pathophysiology of these symptoms is not yet fully understood, and despite their prevalence, there is no universally approved management. This review summarizes the data on complementary and integrative medicine in treating patients with migrainous ear disorders.

Computational methodology for drug delivery to the inner ear using magnetic nanoparticle aggregates.

BACKGROUND AND OBJECTIVE: The main goal of the proposed study is to improve the efficiency of the ear treatment via targeted drug delivery to the inner ear, i.e. the cochlea. Although pharmacotherapy has been proposed as a solution to prevent damage or restore functionality to hair cells, the main challenge in such treatments is ensuring adequate drug delivery to the cells. To this end, we present a methodology for the evaluation of the magnetic forces needed to move magnetic particle nanorobots (abbreviated as MNP) and their aggregates through the cochlea round window membrane (RWM). METHODS: The FEM - Lagrangian-Eulerian approach (Abaqus software) was used to determine the specific parameters of movement of the nanoparticles crossing the RWM. This method results in a high consistency of FEM simulations and in-vivo experimental results in regards to the required magnetic force during the movement of spherical nanoparticles with a given viscosity ηave. Based on the analysis of the experimental studies found in subject literature, the sizes of the MNPs and their aggregates able to cross RWM with and without the application of magnetic force FM have been determined. RESULTS: The present work accounts for both the experimental and theoretical aspects of these investigations. Presented research confirms the definite usability of the Lagrange-Euler method for the precise determination of the required magnetic force value FM to control the accelerated motion of MNP aggregates of complex shapes through RWM. It is possible to determine the predominant parameters with a precision of less than 5% for single-layer aggregates and spatial aggregates crossing the RWM. It can be concluded that the MNPs and their aggregates should not be larger than 500-750 nm to cross the RWM with high velocities of penetration close to 800 nm/s for magnetic forces of hundreds 10-14 Newtons. CONCLUSIONS: The proposed Lagrangian-Eulerian approach is capable of accurately predicting the movement parameters of MNP aggregates of irregular shape that are close to the experimental test cases. The presented method can serve as a supplementary tool for the design of drug delivery systems to the inner ear using MNPs.

[Estradiol regulates the expression of plasma membrane Ca2+-ATPase isoform 2 in inner ear of rats].

Objective: To observe the effects of estradiol on expression of plasma membrane Ca2+-ATPase isoform 2 in inner ear of rats. Methods: Twenty-five Three-months-old female Sprague-Dawley rats were randomly and equally divided into five groups by random number table mathod,with five rats in each group. Animals in Sham group were sham-operated while others were bilateral ovariactmized. One month after modeling, the OVX groups were supplemented with estradiol (E2 group), progesterone (P group), estradiol and progesterone (E2+P group)and vehicle sesame oil (Veh group), while the Sham operation group (Sham group) was supplemented with vehicle sesame oil.All rats were sacrificed and otocysts were obtained immediately. Enzyme-linked immunosorbent assay was used to detect the changes in serum estradiol and progesterone levels of each group of rats before operation, before treatment and before sacrifice. Western blot and quantitative real-time polymerase chain reaction were used to detect the expression of total PMCA2 protein and mRNA in the inner ear of each group. Results: There was no significant difference in serum estradiol and progesterone levels among the five groups before operated(P>0.05). Before treatment, the serum estradiol and progesterone levels of rats in each group were significantly lower than those in Sham group (P<0.05). The serum estradiol level in E2 group and E2+P group was not significantly different from that in Sham group (P>0.05), while the serum estradiol level in P group and Veh group was significantly different from that in Sham group (P<0.05). The level of progesterone in P group and E2+P group was higher than that in Sham group (P<0.05), while the level of progesterone in Veh group and E2 group was lower than that in Sham group (P<0.05). Protein and mRNA expression of PMCA2 in P and Veh groups were significantly decreased compared with that of Sham group (P<0.05) while the expression levels underwent no significantly change in E2 and E2+P groups (P<0.05). Conclusion: The decrease of serum estradiol level can reduce the expression of otolith regulatory protein PMCA2 in rats, and then affect otolith metabolism, which may be an important link of estrogen affecting otolith metabolism.

Inner ear decompression sickness in a hyperbaric chamber inside tender: a case report.

Inner ear decompression sickness (IEDCS) is a rare diving complication that presents with vestibular dysfunction, cochlear dysfunction, or a combination of both. While scuba diving is a known cause, no cases have been reported in the occupational hyperbaric setting. We present the case of a 55-year-old man who developed IEDCS after working as a hyperbaric multiplace chamber inside tender. The patient was treated with seven sessions of hyperbaric oxygen therapy, resulting in resolution of the majority of his symptoms. This case illustrates a potential occupational hazard of working in a hyperbaric chamber and demonstrates successful treatment with hyperbaric oxygen therapy.

Building inner ears: recent advances and future challenges for in vitro organoid systems.

While inner ear disorders are common, our ability to intervene and recover their sensory function is limited. In vitro models of the inner ear, like the organoid system, could aid in identifying new regenerative drugs and gene therapies. Here, we provide a perspective on the status of in vitro inner ear models and guidance on how to improve their applicability in translational research. We highlight the generation of inner ear cell types from pluripotent stem cells as a particularly promising focus of research. Several exciting recent studies have shown how the developmental signaling cues of embryonic and fetal development can be mimicked to differentiate stem cells into "inner ear organoids" containing otic progenitor cells, hair cells, and neurons. However, current differentiation protocols and our knowledge of embryonic and fetal inner ear development in general, have a bias toward the sensory epithelia of the inner ear. We propose that a more holistic view is needed to better model the inner ear in vitro. Moving forward, attention should be made to the broader diversity of neuroglial and mesenchymal cell types of the inner ear, and how they interact in space or time during development. With improved control of epithelial, neuroglial, and mesenchymal cell fate specification, inner ear organoids would have the ability to truly recapitulate neurosensory function and dysfunction. We conclude by discussing how single-cell atlases of the developing inner ear and technical innovations will be critical tools to advance inner ear organoid platforms for future pre-clinical applications.

Association Between Incomplete Partition Type III and Abnormal Hypothalamic Morphology: Further Imaging Evidence.

PURPOSE: Incomplete partition III (IP-III), characterized by congenital mixed or sensorineural hearing loss, is a rare genetic disease transmitted through X-linked mode of inheritance. Inner ear findings of IP-III have been well described and allow an immediate diagnosis to be made. Recently, an association between IP-III and distinct hypothalamic malformations has been reported in some of the patients with IP-III. The purpose of this study was to investigate the morphologic abnormalities of the hypothalamus in IP-III. MATERIALS AND METHODS: Magnetic resonance imaging studies of 8 subjects, including 1 set of brothers, who were diagnosed with IP-III based on their clinical and inner ear imaging findings, were analyzed. RESULTS: Of the 8 subjects, 7 demonstrated some degree of morphologic abnormality of the hypothalamus. Of these, 2 showed asymmetrical thickening, 1 showed symmetrical thickening, and 4 showed mass-like enlargement of the hypothalamus. Six of 7 subjects with hypothalamic abnormalities showed asymmetry in caudal extension of the abnormalities, which was more discernible on coronal oblique T2-weighted images. Clinically, none of the subjects had endocrinologic or neurologic symptoms. CONCLUSIONS: This retrospective analysis presents further magnetic resonance imaging evidence on the association between the rare IP-III malformations and the presence of hypothalamic morphologic abnormalities.

Alteration of the relative vibration of the round window membrane after implantation of a direct acoustic cochlear implant.

Objective: Subjects implanted with a Direct Acoustic Cochlear Implant (DACI) show improvements in their bone conduction (BC) thresholds after surgery. We hypothesised that a new pathway for BC sound is created via the DACI. The aim of this study was to investigate the contribution of this pathway to the cochlear response via measurements of the promontory and round window membrane (RWM) velocities while stimulating with a conventional bone conductor.Design: This study was a cadaver head study with a repeated measures study design.Study Sample: Eight ears of five fresh-frozen cadaveric whole heads were investigated in this trial.Results: After DACI implantation the promontory and RWM velocities did not change significantly in the frequency range 0.5-2 kHz when the DACI was switched off.Conclusions: No significant changes in the relative vibration magnitude of the RWM after DACI implantation were observed. The improvements in BC thresholds seen in patients implanted with a DACI very likely have their origin in the changed impedance at the oval window after DACI surgery leading to a more efficient contribution from the inner ear components to BC sound.

Hypothalamic malformations in patients with X-linked deafness and incomplete partition type 3.

Patients with X-linked deafness carry mutations in the POU3F4 gene and have pathognomonic inner ear malformations characterised by symmetrical incomplete partition type 3 (absent modiolus and lamina spiralis but preserved interscalar septum in a normal-sized cochlea) and large internal auditory meatus (IAM) with an increased risk of gusher during stapes surgery. We describe a range of fairly characteristic malformations in the hypothalamus of some patients with this rare condition, ranging from subtle asymmetric appearance and thickening of the tuber cinereum to more marked hypothalamic enlargement. We discuss the role of POU3F4 in the normal development of both the inner ear and hypothalamus and the proposed pathophysiology of incomplete partition type 3.

Subclinical conductive hearing loss significantly reduces otoacoustic emission amplitude: Implications for test performance.

OBJECTIVES: Distortion product otoacoustic emissions (DPOAEs) are a time-efficient, non-invasive means of assessing the integrity of active inner ear mechanics. Unfortunately, the presence of even relatively minor conductive hearing loss (CHL) has been suggested to reduce the clinical utility of DPOAEs significantly. The primary aims of this study were to systematically evaluate the impact of CHL on DPOAE amplitude and to determine if ear-specific primary tone level manipulations can be used to mitigate CHL impact and recover DPOAE measurability. METHODS: For 30 young adults (57 ears) with normal hearing, DPOAEs were obtained for f2 = 1-6 kHz. Observed DPOAE amplitudes were used to generate ear- and frequency-specific models with the primary tone levels, L1 and L2, as inputs and predicted DPOAE amplitude, LDP, as output. These models were then used to simulate the effect of CHL (0-15 dB), as well as L1 manipulations (0-15 dB), on DPOAE measurability. RESULTS: Mean LDP for every CHL condition was significantly different from that for all other conditions (p = <.001), with a mean LDP attenuation of 8.7 dB for every 5 dB increase in CHL. Mean DPOAE measurability in response to a standard clinical stimulation paradigm of L1/L2 = 65/55 (dB SPL) was determined to be 99%, 84%, 37%, and 9% in the presence of 0, 5, 10, and 15 dB CHL, respectively. In the presence of 10 dB CHL, altering L1 resulted in an approximately 25% increase in DPOAE responses. CONCLUSION: Subclinical CHL loss is sufficient to significantly impair DPOAE measurability in a meaningful proportion of otherwise healthy ears. However, through strategic alteration of primary tone levels, the clinician can mitigate CHL impact and at least partially recover DPOAE measurability.

The Clinical Benefit of Device Therapy for Meniere's Disease in Adults: Systematic Review and Meta-Analysis.

OBJECTIVES: This study aimed to assess the clinical benefit of device therapy on controlling the symptoms of Meniere's disease (MD). MATERIALS AND METHODS: We searched PubMed, Embase, the Cochrane Library, China National Knowledge Internet, and Wanfang Data before January 13, 2018. We selected randomized controlled clinical trials, case-controlled studies, and cohort studies that dealt with outcomes of device therapy for the treatment of MD. RESULTS: Sixteen trials met our inclusion criteria. The use of device therapy resulted in improved vertigo control, which was described as a reduction in the number of vertigo days by month (weighted mean difference [WMD]: 3.15, 95% confidence interval [CI]: 2.00-4.31), in the number of vertigo episodes by month (WMD: 7.37, 95% CI: 2.40-12.35), and in the vertigo visual analog score (WMD: 41.51, 95% CI: 34.68-48.34). In addition, the overall complete vertigo control (class A) rate was 50% (95% CI: 37%-64%). The device therapy also reduced the number of sick days by month (WMD: 4.56, 95% CI: 2.15-6.97), and the functional level improved (WMD: 2.66, 95% CI: 2.15-3.17). The electrocochleographic parameters decreased. The device therapy proved beneficial for hearing changes (WMD: 3.19, 95% CI: 0.66-5.71). No publication bias was found in the funnel plot and the results of Egger's test. CONCLUSION: This study showed that the device therapy might reduce vertigo attacks and sick days in patients with MD. Additionally, the function level and hearing level may improve after the device therapy. In addition, the decrease in electrocochleographic parameters showed that inner ear electrophysiology improved after device therapy.

Different prognoses in patients with profound sudden sensorineural hearing loss.

Background: Inner ear hemorrhage is increasingly recognized as a cochlear lesion that can cause profound sudden sensorineural hearing loss (SSNHL). Objectives: To investigate changes of cochlear and vestibular function and to compare therapeutic recovery from profound SSNHL induced by different etiologies. Material and methods: Eighty patients with profound SSNHL (≥90 dB) were divided into an inner ear hemorrhage group and a non-inner ear hemorrhage group by MRI. Statistical analysis was performed to compare the therapeutic effects from vertigo and hearing loss and the outcomes of follow-up in the two groups. Results: There were significant differences between the two groups in terms of the overall 14-day therapeutic response rate (20 vs. 48%), the incidence of imbalance (26.7 vs. 6%), the incidence of semicircular canal dysfunction on the affected side (60 vs. 20%), the incidence of abnormal C-VEMP and O-VEMP on the affected side (63.3 vs. 38%; and 60 vs. 30%, respectively), the average hearing threshold (74.2 ± 10.7 vs. 53.6 ± 11.4 dB), and the word recognition score (65.5 ± 21.7 vs. 83.5 ± 24.5%) at a 12-month follow-up. Conclusions and significance: A higher percentage of patients with profound SSNHL induced by inner ear hemorrhage were associated with vertigo and had a poor prognosis.

Isolated Dizziness with Subjective Visual Vertical Tilt in Acute Infarction of Temporo-Parieto-Occipital Junction

Pathological tilts of the subjective visual vertical (SVV) in the roll plane are most sensitive and frequent clinical vestibular signs of unilateral lesions extending from the labyrinths via the brainstem and thalamus to the cortex. SVV deviations in cortical lesion are usually related with the parietoinsular vestibular cortex or superior temporal gyrus. We report isolated dizziness with contralesional SVV tilt with a focal infarction restricted to the right temporo-parieto-occipital junction.

Impedance measures for a better understanding of the electrical stimulation of the inner ear.

The performance of cochlear implant (CI) listeners is limited by several factors among which the lack of spatial selectivity of the electrical stimulation. Recently, many studies have explored the use of multipolar strategies where several electrodes are stimulated simultaneously to focus the electrical field in a restricted region of the cochlea. OBJECTIVE: These strategies are based on several assumptions concerning the electrical properties of the inner ear that need validation. The first, often implicit, assumption is that the medium is purely resistive and that the current waveforms produced by several electrodes sum linearly. The second assumption relates to the estimation of the contribution of each electrode to the overall electrical field. These individual contributions are usually obtained by stimulating each electrode and measuring the resulting voltage with the other inactive electrodes (i.e. the impedance matrix). However, measuring the voltage on active electrodes (i.e. the diagonal of the matrix) is not straightforward because of the polarization of the electrode-fluid interface. In existing multipolar strategies, the diagonal terms of the matrix are therefore inferred using linear extrapolation from measurements made at neighboring electrodes. APPROACH: In experiment 1, several impedance measurements were carried out in vitro and in eight CI users using sinusoidal and pulsatile waveforms to test the resistivity and linearity hypotheses. In experiment 2, we used an equivalent electrical model including a constant phase element in order to isolate the polarization component of the contact impedance. MAIN RESULTS: In experiment 1, high-resolution voltage recordings (1.1 MHz sampling) showed the resistivity assumption to be valid at 46.4 kHz, the highest frequency tested. However, these measures also revealed the presence of parasitic capacitive effects at high frequency that could be deleterious to multipolar strategies. Experiment 2 showed that the electrical model provides a better account of the high-resolution impedance measurements than previous approaches in the CI field that used resistor-capacitance circuit models. SIGNIFICANCE: These results validate the main hypotheses underlying the use of multipolar stimulation but also suggest possible modifications to their implementation, including the use of an impedance model and the modification of the electrical pulse waveform.

Modeling human early otic sensory cell development with induced pluripotent stem cells.

The inner ear represents a promising system to develop cell-based therapies from human induced pluripotent stem cells (hiPSCs). In the developing ear, Notch signaling plays multiple roles in otic region specification and for cell fate determination. Optimizing hiPSC induction for the generation of appropriate numbers of otic progenitors and derivatives, such as hair cells, may provide an unlimited supply of cells for research and cell-based therapy. In this study, we used monolayer cultures, otic-inducing agents, Notch modulation, and marker expression to track early and otic sensory lineages during hiPSC differentiation. Otic/placodal progenitors were derived from hiPSC cultures in medium supplemented with FGF3/FGF10 for 13 days. These progenitor cells were then treated for 7 days with retinoic acid (RA) and epidermal growth factor (EGF) or a Notch inhibitor. The differentiated cultures were analyzed in parallel by qPCR and immunocytochemistry. After the 13 day induction, hiPSC-derived cells displayed an upregulated expression of a panel of otic/placodal markers. Strikingly, a subset of these induced progenitor cells displayed key-otic sensory markers, the percentage of which was increased in cultures under Notch inhibition as compared to RA/EGF-treated cultures. Our results show that modulating Notch pathway during in vitro differentiation of hiPSC-derived otic/placodal progenitors is a valuable strategy to promote the expression of human otic sensory lineage genes.

Neurocranial anatomy of an enigmatic Early Devonian fish sheds light on early osteichthyan evolution.

The skull of 'Ligulalepis' from the Early Devonian of Australia (AM-F101607) has significantly expanded our knowledge of early osteichthyan anatomy, but its phylogenetic position has remained uncertain. We herein describe a second skull of 'Ligulalepis' and present micro-CT data on both specimens to reveal novel anatomical features, including cranial endocasts. Several features previously considered to link 'Ligulalepis' with actinopterygians are now considered generalized osteichthyan characters or of uncertain polarity. The presence of a lateral cranial canal is shown to be variable in its development between specimens. Other notable new features include the presence of a pineal foramen, the some detail of skull roof sutures, the shape of the nasal capsules, a placoderm-like hypophysial vein, and a chondrichthyan-like labyrinth system. New phylogenetic analyses place 'Ligulalepis' as a stem osteichthyan, specifically as the sister taxon to 'psarolepids' plus crown osteichthyans. The precise position of 'psarolepids' differs between parsimony and Bayesian analyses.