Auricular Research Articles

Mange in farmed rabbits

In this study we determined occurrence of mange in breeding rabbits on 1368 commercial farms in Portugal and Spain during 1996-2022. We obtained our information by carrying out 11 737 visits to 1334 doe farms, 11 farms only with growers, and 23 artificial insemination (AI) centres. The median size of the visited doe farms was 450 does (minimum to maximum: 100–2500 does) and 1175 does (ranging from100 to 6000 does) in 1996 and 2022, respectively. AI was used on 9% of the farms visited in 1996 and 95% in 2022. For our diagnoses we used (1) clinical observations on all visited farms to detect sarcoptic mange; (2) examination of the outer ear of breeding rabbits on a subset of farms to assess the prevalence of otodectic clinical mange (OCM); and (3) the examination of breeding rabbits and youngstock does (2.5 to 5.5 mo old) on a subset of 72 farms during 2018 to estimate prevalence of body mange compatible with cheyletiellosis. They were mainly clinical diagnoses, supported sometimes by a laboratorial confirmation. Over the course of the 27-yr clinical study, the cumulative incidence of sarcoptic mange was low; we recorded a total of 13 affected doe farms. The percentage of farms affected by OCM dropped from 55% in 1996 to 28% in 2022. OCM mean prevalence for the period 1996-2022 and 95% binomial confidence interval (CI) were 3.2% (95% CI [3.1-3.3%]), and 3.9% (95% CI [3.7-4.1%]) in does and bucks, respectively. We observed an improvement over time; the OCM yearly mean prevalence decreased from 7% in 1996 to 2.3% in 2022 in females and from 7.2% to 2.2% in males, respectively. This progress was compatible with the use of semen coming from AI centres; biosecurity measures and medical management also contributed. Genetic type was predisposing risk factor for OCM. Enabling risk factors were year and season (more affected in summer). Hair and skin disorders along the back, compatible with cheyletiellosis, were also assessed during 2018; we detected 50% of positive farms with various prevalence results in females, males or young does. In this study, we describe protocols observed in the control of benign and severe cases of mange in rabbitries, which included the use of ivermectin and synthetic acaricides. Ivermectin was used on 36% of doe farms visited during 2018-2022; we suggest that it should be used less often to lower its negative impact on the environment.

Prenatal post-implantation development of collared peccaries (Pecari tajacu Linnaeus, 1758).

Given the importance of information on intrauterine development in diagnosing anomalies in the gestational development of the species for the development of assisted reproduction technologies as well as understanding the autonomy and responsiveness of the newborn, the aim of the present study was to describe the external morphology of collared peccary conceptuses. For this study, two conceptuses were used per gestational age of 25-120 days post-copulation (dpc) and neonates with 145 dpc, totalling 22 animals. Females were euthanised, and embryos/foetuses were examined, measured, and photographed. During the first third of the gestational period (25-50 dpc, n = 8), a marked body curvature, brain vesicles, somites, internal organs, placid lens, auricular protrusion and limb buds are noted. In the second third of the gestational period (51-100 dpc, n = 10), foetuses lose their body curvature, displaying greater anatomical definition, including skeletal, external ears, nostrils, eyelids and tactile hair formation and cranial suture closure. In addition, dorsal scent gland and genital tubercle differentiation were visualized at 50 days post-copulation. In the third of the gestational period (101-145 dpc, n = 4), the organs become completely formed, alongside skin darkening, eyelid opening, dental eruption, dorsal odorous gland development, sexual organ externalization, and fanero attachment development. These data allowed for the construction of a prenatal growth curve, providing comparative anatomy information for ungulates and further contributing towards rational reproductive management and reproductive biotechnologies for this species.

Basal cell carcinoma at the pinna

Basal cell carcinoma (BCC) is the most common type of non melanoma cutaneous malignancy BCC usually present on sun exposed area such as nose, mandibular, periocular region. A review of the literature revealed only a few reports of BCC on the auricle or conchal bowl. Objectives were to report a case of BCC of right pinna. A 62 year old man presented to ENT OPD with a painless blackish lesion in the right pinna appreciated since 6 months and progressively increased to the present size. On local examination of the pinna a blackish plaque with irregular margins was appreciated in the cocha, helical crus and incisura. It was soft to firm in consistency and tenderness absent. Wide excision of the lesion with healthy margin done under local anesthesia. Histopathology of excised specimen confirmed the lesion as BCC. BCC of pinna is an uncommon external ear pathology which should be kept as a differential diagnosis of lesions of the pinna by the otorhinolaryngologist.

Distribution and anti-nociceptive function of endomorphin-1 in the rat cranial sensory ganglia.

Distribution of endomorphin-1 (EM-1) was immunohistochemically investigated in the rat cranial sensory ganglia. Small to medium-sized neurons in the trigeminal (TG), petrosal (PG), and jugular ganglia (JG) expressed EM-1-immunoreactivity. However, EM-1-immunoreactive (-ir) neurons were infrequent in the nodose ganglion. In the brainstem, EM-1-ir varicose fibers were detected in the superficial layer of the medullary dorsal horn and the caudal part of the nucleus tractus solitarius. By trichrome immunofluorescence analysis, approximately 70% of EM-1-ir neurons were also immunoreactive for transient receptor potential vanilloid 1 (TRPV1) in all the examined ganglia. Additionally, 56.8% of EM1-ir TG neurons and approximately 30% of EM-1-ir PG and JG neurons showed calcitonin gene-related peptide (CGRP)-immunoreactivity. By a retrograde tracing method, several TG, PG, and JG neurons innervating the facial and external ear canal skin expressed EM-1-immunoreactivity. However, EM-1-ir neurons innervating the tooth pulp, circumvallate papilla, and pharynx were relatively rare. Thus, EM-1 expression and its coexistence with TRPV1 and CGRP in the cranial sensory neurons may depend on their various peripheral targets. EM1-ir neurons probably project to the superficial layer of the medullary dorsal horn and caudal part of the nucleus tractus solitarius. EM-1 may be involved in nociceptive transmission from the skin.

Comparison of Tissue Factors in the Ontogenetic Aspects of Human Cholesteatoma.

An acquired cholesteatoma is a benign but locally aggressive lesion in the middle ear. It is characterized by chronic inflammation and the destruction of surrounding bone. Therefore, the aim of this study was to compare defensins HβD-2 and HβD-4; pro- and anti-inflammatory cytokines IL-1α and IL-10; proliferation marker Ki-67; transcription factor NF-κβ; angiogenetic factor VEGF; Sonic hedgehog gene protein SHH; and remodeling factors MMP-2, MMP-9, TIMP-2, and TIMP-4 in adult and pediatric cholesteatoma tissue, and to compare these groups with control skin tissue. The study included 25 cholesteatoma tissue material samples from children, 25 from adults, and 7 deep external ear canal skin samples from cadavers. The tissues were stained immunohistochemically and evaluated using semi-quantitative methods. Nonparametric tests, such as the Kruskal-Wallis test and Spearman rank correlation, were used. There were no statistically discernible differences between the adult and children groups when comparing the relative numbers of factor-positive cells. There are no histopathological differences between adult and children cholesteatoma tissues.

Classification, registration and segmentation of ear canal impressions using convolutional neural networks

Today, fitting bespoke hearing aids involves injecting silicone into patients’ ears to produce ear canal molds. These are subsequently 3D scanned to create digital ear canal impressions. However, before digital impressions can be used they require a substantial amount of effort in manual 3D editing. In this article, we present computational methods to pre-process ear canal impressions. The aim is to create automation tools to assist the hearing aid design, manufacturing and fitting processes as well as normalizing anatomical data to assist the study of the outer ear canal’s morphology. The methods include classifying the handedness of the impression into left and right ear types, orienting the geometries onto the same coordinate system sense, and removing extraneous artifacts introduced by the silicone mold. We investigate the use of convolutional neural networks for performing these semantic tasks and evaluate their accuracy using a dataset of 3000 ear canal impressions. The neural networks proved highly effective at performing these tasks with 95.8% adjusted accuracy in classification, 92.3% within 20° angular error in registration and 93.4% intersection over union in segmentation.

Otoacoustic emissions in African mole-rats

African mole-rats display highly derived hearing that is characterized by low sensitivity and a narrow auditory range restricted to low frequencies < 10 kHz. Recently, it has been suggested that two species of these rodents do not exhibit distortion product otoacoustic emissions (DPOAE), which was interpreted as evidence for a lack of cochlear amplification. If true, this would make them unique among mammals. However, both theoretical considerations on the generation of DPOAE as well as previously published experimental evidence challenge this assumption. We measured DPOAE and stimulus-frequency otoacoustic emissions (SFOAE) in three species of African mole-rats (Ansell's mole-rat - Fukomys anselli; Mashona mole-rat - Fukomys darlingi; naked mole-rat - Heterocephalus glaber) and found unexceptional otoacoustic emission values. Measurements were complicated by the remarkably long, narrow and curved external ear canals of these animals, for which we provide a morphological description. Both DPOAE and SFOAE displayed the highest amplitudes near 1 kHz, which corresponds to the region of best hearing in all tested species, as well as to the frequency region of the low-frequency acoustic fovea previously described in Ansell's mole-rat. Thus, the cochlea in African mole-rats shares the ability to generate evoked otoacoustic emission with other mammals.

Expert consensus on the application of bone-conducted hearing device in patients with congenital middle and external ear malformations

Expert consensus on the application of bone-conducted hearing device in patients with congenital middle and external ear malformations

Tracking cell layer contribution during repair of the tympanic membrane.

The tympanic membrane (i.e. eardrum) sits at the interface between the middle and external ear. The tympanic membrane is composed of three layers: an outer ectoderm-derived layer, a middle neural crest-derived fibroblast layer with contribution from the mesoderm-derived vasculature, and an inner endoderm-derived mucosal layer. These layers form a thin sandwich that is often perforated following trauma, pressure changes or middle ear inflammation. During healing, cells need to bridge the perforation in the absence of an initial scaffold. Here, we assessed the contribution, timing and interaction of the different layers during membrane repair by using markers and reporter mice. We showed that the ectodermal layer is retracted after perforation, before proliferating away from the wound edge, with keratin 5 basal cells migrating over the hole to bridge the gap. The mesenchymal and mucosal layers then used this scaffold to complete the repair, followed by advancement of the vasculature. Finally, differentiation of the epithelium led to formation of a scab. Our results reveal the dynamics and interconnections between the embryonic germ layers during repair and highlight how defects might occur.

Craniofacial phenotyping with fetal MRI: a feasibility study of 3D visualisation, segmentation, surface-rendered and physical models

This study explores the potential of 3D Slice-to-Volume Registration (SVR) motion-corrected fetal MRI for craniofacial assessment, traditionally used only for fetal brain analysis. In addition, we present the first description of an automated pipeline based on 3D Attention UNet trained for 3D fetal MRI craniofacial segmentation, followed by surface refinement. Results of 3D printing of selected models are also presented.Qualitative analysis of multiplanar volumes, based on the SVR output and surface segmentations outputs, were assessed with computer and printed models, using standardised protocols that we developed for evaluating image quality and visibility of diagnostic craniofacial features. A test set of 25, postnatally confirmed, Trisomy 21 fetal cases (24–36 weeks gestational age), revealed that 3D reconstructed T2 SVR images provided 66–100% visibility of relevant craniofacial and head structures in the SVR output, and 20–100% and 60–90% anatomical visibility was seen for the baseline and refined 3D computer surface model outputs respectively. Furthermore, 12 of 25 cases, 48%, of refined surface models demonstrated good or excellent overall quality with a further 9 cases, 36%, demonstrating moderate quality to include facial, scalp and external ears. Additional 3D printing of 12 physical real-size models (20–36 weeks gestational age) revealed good/excellent overall quality in all cases and distinguishable features between healthy control cases and cases with confirmed anomalies, with only minor manual adjustments required before 3D printing.Despite varying image quality and data heterogeneity, 3D T2w SVR reconstructions and models provided sufficient resolution for the subjective characterisation of subtle craniofacial features. We also contributed a publicly accessible online 3D T2w MRI atlas of the fetal head, validated for accurate representation of normal fetal anatomy.Future research will focus on quantitative analysis, optimizing the pipeline, and exploring diagnostic, counselling, and educational applications in fetal craniofacial assessment.

Designing an acoustical test fixture to evaluate the objective occlusion effect

Earplugs are commonly used to prevent noise-induced hearing loss. However, their effectiveness is often hindered by the discomfort they cause, impacting consistent and correct use. An important acoustical discomfort, known as the occlusion effect, arises from an increased perception of bone-conducted physiological sounds (such as one's own voice, breathing, and chewing) when the ear canal is occluded. To objectively assess this discomfort, the study proposes the use of an acoustical test fixture (ATF) that avoids direct measurements on human participants. The ATF employs an anatomically realistic truncated outer ear, incorporating soft tissues, cartilage, and bone components to replicate the outer ear's bone conduction path, crucial for occlusion effect assessments. The study demonstrates that the proposed ATF can replicate key effects observed in objective ccclusion effect (OE) measurements on human participants, including significant OE at low frequencies diminishing with increasing frequency, reduction of OE with greater insertion depths, and distinctions among various earplug types—especially noticeable at deeper insertions. Furthermore, a computationally efficient finite element method-based virtual tester for the ATF is developed and validated.

Post-auricular orientation of auditory attention in sound field versus virtual sound space

The post-auricular muscle in many species’ changes orientation of external ears to improve hearing for biologically relevant sounds. The muscle exists in humans but cannot similarly change direction of their ears. Objectives focused on measuring activity of muscle during speech-in-noise task where orientations of speaker and noise were controlled experimentally to determine how signal-to-noise varies as function of presentation mode and azimuth (target speech and noise co-localized, 45°, or spatially separated, 135° and 45°, respectively). It was hypothesized that activity would be elicited in same proportion of subjects when evoked via earphones compared to speakers; there would be no significant differences in magnitude between conditions; maximum engagement would be observed with speech 135°, noise 45°. Activity was recorded with electrodes affixed around ears, outer canthi and neck, while listeners completed a spatialized listening test (locations of speaker/noise controlled experimentally). There was significant main effect of channel; significant interaction between presentation mode and channel; no significant differences between presentation modes for other muscles; no significant effect of azimuth. Engagement in virtual sound-space suggests that muscle activation occurs consequently of spatially directed attention, even when changes in pinna orientation are unlikely to have effect on sound heard.

Making Recommendations for an Evaluation and Treatment Algorithm for Patients with Ear Fullness and No Objective Abnormalities.

To make recommendations for evaluation, approach to counseling and treatment for patients who present with ear fullness without abnormalities on otomicroscopic examination, standard audiometric studies, or imaging results. Retrospective chart review of adult patients in a tertiary referral center presenting with ear fullness and/or otalgia without external, middle, and/or inner ear pathologies. Data collected include demographics (age and gender), laterality and duration of symptoms, co-morbid conditions and final diagnoses of temporomandibular joint (TMJ) dysfunction, intermittent Eustachian tube dysfunction (iETD), migraine disorder, and anxiety. In the span of 8 years of a single neurotologist's practice, 964 patients presented with ear fullness. After excluding all instances where external, middle, and inner ear disorders were identified and where audiometric and radiologic findings were abnormal, 263 patients had ear fullness and no objective causes. Women were more likely than men to complain of ear fullness and/or otalgia and were also more likely to present with no objective abnormalities ( p < 0.05). Patients who reported isolated ear fullness were more likely to be diagnosed with iETD, whereas patients who reported pain were more likely to be diagnosed with TMJ dysfunction (TMJD). Fourteen patients (5.3%) had completely unexplained sensation of ear fullness. There were 94.7% of the patients presenting with unexplained ear fullness were diagnosed as having a possible contribution of TMJ dysfunction, IETD, migraine disorder, anxiety, or a combination of these conditions to their symptomatology. Directing treatments toward these diagnoses may alleviate symptoms of ear fullness or, if unsuccessful, provide an avenue for counseling in the framework of functional neurologic disorders.

Swimming nose clips: A versatile strategy for achieving efficient dressing and compression in instances of external ear wounds

Swimming nose clips: A versatile strategy for achieving efficient dressing and compression in instances of external ear wounds

Quantitative analysis of 3D-printed custom ossicular prostheses motion using laser Doppler vibrometry.

&lt;b&gt;&lt;br&gt;Introduction:&lt;/b&gt; In chronic otitis media, the reconstruction of the middle ear&apos;s sound conducting system involves repairing the tympanic membrane and filling the space between ossicular chain remnants. The final shape of the prosthesis is usually determined intraoperatively. However, the ossicular chain may be preoperatively measured using computed tomography (CT) scans, and an individualized prosthesis can be designed. Custom 3D printing seems to be an attractive solution for optimal adjustment.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Aim:&lt;/b&gt; Our study aimed to assess the 3D-printed custom prosthesis movability and compare it to the original ossicular chain.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Material and methods:&lt;/b&gt; Five fresh-frozen temporal bone specimens were used. Using Cone-Beam CT scans, the incus model was designed individually and 3D-printed. The ossicular chain was reconstructed inside the cadaveric temporal bone. Acoustic stimuli were applied to the external ear canal one frequency at a time. The laser Doppler vibrometer (LDV) measured the intact and 3D-printed prosthesis reconstructed ossicular chain vibrations.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Results:&lt;/b&gt; At all stimulation frequencies, there was no significant difference in velocity values between the intact and reconstructed ossicular chain at the intensity of 80 dB SPL. The obtained values of the velocity gain were: -7.9 (SD-19) dB, -6.8 (SD8.12) dB, -10,9 (SD-5.3) dB, -7.4 (SD-8.16) dB for 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, respectively. The vibration threshold shift values ranged between -0.57 dB at 500 Hz and 3.81 dB at 2000 Hz.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Conclusions:&lt;/b&gt; This study analyzed the movability of individualized 3D-printed custom ossicular prostheses using LDV. Compared to the intact ossicular chain, the reconstructed ossicular chain movability was characterized by statistically insignificant reduced movability at all tested frequencies. Because the prosthesis&apos;s new design conception as custom 3D individualized printing allows for patient-specific ossiculoplasty, it represents a promising new direction for ossicular chain reconstruction. It seems to be an attractive solution for prosthesis optimal adjustment and, hopefully, better hearing results.&lt;/br&gt.

Tympanic membrane perforations cannot be reliably detected using computed tomography based on 15 cadaver dogs.

The integrity of the tympanic membrane is an important factor when deciding treatment and therapeutic recommendations for dogs with ear disease; however, otoscopic examination may be difficult to perform due to features of external ear canal disease or patient compliance. CT is useful for the evaluation of middle ear disease, including cases in which middle ear disease is detected incidentally. The tympanic membrane is detectable using CT, but anecdotally, apparent focal defects or discontinuities of the tympanic membrane are often seen in patients with and without ear disease. The purpose of this prospective, observer agreement study was to determine if perforations of the tympanic membrane are reliably detectable on CT. Fifteen cadaver dogs underwent CT and video otoscopy to verify the integrity of each tympanic membrane. Cadavers were randomly assigned to have the tympanic membranes left intact or to undergo a myringotomy on either the left, the right, or both sides. CT was performed immediately following the myringotomies. Four blinded evaluators evaluated the pre- and post-myringotomy scans for a total of 30 scans (60 tympanic membranes). Average accuracy was low (44%), and interobserver agreement for all four evaluators was fair. Although the tympanic membrane is visible on CT, perforations of the tympanic membrane are unlikely to be accurately detected or excluded. The appearance of an intact tympanic membrane or defect in the membrane on CT should not be used as criteria to guide clinical treatment recommendations based on this cadaver model.

ZSCAN10 deficiency causes a neurodevelopmental disorder with characteristic oto-facial malformations.

Neurodevelopmental disorders are major indications for genetic referral and have been linked to more than 1500 loci including genes encoding transcriptional regulators. The dysfunction of transcription factors often results in characteristic syndromic presentations; however, at least half of these patients lack a genetic diagnosis. The implementation of machine learning approaches has the potential to aid in the identification of new disease genes and delineate associated phenotypes. Next generation sequencing was performed in seven affected individuals with neurodevelopmental delay and dysmorphic features. Clinical characterization included reanalysis of available neuroimaging datasets and 2D portrait image analysis with GestaltMatcher. The functional consequences of ZSCAN10 loss were modelled in mouse embryonic stem cells (mESCs), including a knockout and a representative ZSCAN10 protein truncating variant. These models were characterized by gene expression and western blot analyses, chromatin immunoprecipitation and quantitative PCR (ChIP-qPCR) and immunofluorescence staining. Zscan10 knockout mouse embryos were generated and phenotyped. We prioritized bi-allelic ZSCAN10 loss-of-function variants in seven affected individuals from five unrelated families as the underlying molecular cause. RNA-sequencing analyses in Zscan10-/- mESCs indicated dysregulation of genes related to stem cell pluripotency. In addition, we established in mESCs the loss-of-function mechanism for a representative human ZSCAN10 protein truncating variant by showing alteration of its expression levels and subcellular localization, interfering with its binding to DNA enhancer targets. Deep phenotyping revealed global developmental delay, facial asymmetry and malformations of the outer ear as consistent clinical features. Cerebral MRI showed dysplasia of the semicircular canals as an anatomical correlate of sensorineural hearing loss. Facial asymmetry was confirmed as a clinical feature by GestaltMatcher and was recapitulated in the Zscan10 mouse model along with inner and outer ear malformations. Our findings provide evidence of a novel syndromic neurodevelopmental disorder caused by bi-allelic loss-of-function variants in ZSCAN10.

A 76-base pair duplication within the enhancer region of the HMX1 gene causes sheep microtia

Sheep congenital microtia is characterized by underdeveloped ears and provides an ideal basis for studying human microtia. This study identified the causal mutation and regulatory mechanisms underlying this disorder. Whole-genome association analysis was conducted using 23 ear tissue samples from sheep with microtia and 28 samples from normal-eared sheep. A significant correlation was found between microtia and a 76-base pair duplication in the enhancer region of the HMX1 gene. Further analysis of offspring phenotypes confirmed an autosomal dominant inheritance pattern. Genotypic analysis showed that individuals that are homozygous for this duplication were earless, heterozygous individuals exhibited shortened ears, and wild-type individuals had normal ears. Moreover, luciferase assays confirmed that this duplication increased HMX1 gene expression, and duplication knock-in mice also exhibited shorter and narrower external ears compared to wild-type mice. Transcriptomic analysis further demonstrated that this duplication enhanced HMX1 gene expression in animal models. This study characterized the causal regulatory mutation underlying sheep microtia.

A Novel Ear Impression-Taking Method Using Structured Light Imaging and Machine Learning: A Pilot Proof of Concept Study with Patients' Feedback on Prototype.

Taking an ear impression is a minimally invasive procedure. A review of existing literature suggests that contactless methods of scanning the ear have not been developed. We proposed to establish a correlation between external ear features with the ear canal and with this proof of concept to develop a prototype and an algorithm for capturing and predicting ear canal information. We developed a novel prototype using structured light imaging to capture external images of the ear. Using a large database of existing ear impression images obtained by traditional methods, correlation analyses were carried out and established. A deep neural network was devised to build a predictive algorithm. Patients undergoing hearing aid evaluation undertook both methods of ear impression-taking. We evaluated their subjective feedback and determined if there was a close enough objective match between the images obtained from the impression techniques. A prototype was developed and deployed for trial, and most participants were comfortable with this novel method of ear impression-taking. Partial matching of the ear canal could be obtained from the images taken, and the predictive algorithm applied for a few sample images was within good standard of error with proof of concept established. Further studies are warranted to strengthen the predictive capabilities of the algorithm and determine optimal prototype imaging positions so that sufficient ear canal information can be obtained for three-dimensional printing. Ear impression-taking may then have the potential to be automated, with the possibility of same-day three-dimensional printing of the earmold to provide timely access.

Genetics and Epigenetics in the Genesis and Development of Microtia.

Microtia is a congenital malformation of the external and middle ear associated with varying degrees of severity that range from mild structural abnormalities to the absence of the external ear and auditory canal. Globally, it is the second most common congenital craniofacial malformation and is typically caused by inherited defects, external factors, or the interaction between genes and external factors. Epigenetics notably represents a bridge between genetics and the environment. This review has devoted attention to the current proceedings of the genetics and epigenetics of microtia and related syndromes.