Normal Ear Research Articles

A novel radiological software prototype for automatically detecting the inner ear and classifying normal from malformed anatomy

BackgroundTo develop an effective radiological software prototype that could read Digital Imaging and Communications in Medicine (DICOM) files, crop the inner ear automatically based on head computed tomography (CT), and classify normal and inner ear malformation (IEM). MethodsA retrospective analysis was conducted on 2053 patients from 3 hospitals. We extracted 1200 inner ear CTs for importing, cropping, and training, testing, and validating an artificial intelligence (AI) model. Automated cropping algorithms based on CTs were developed to precisely isolate the inner ear volume. Additionally, a simple graphical user interface (GUI) was implemented for user interaction. Using cropped CTs as input, a deep learning convolutional neural network (DL CNN) with 5-fold cross-validation was used to classify inner ear anatomy as normal or abnormal. Five specific IEM types (cochlear hypoplasia, ossification, incomplete partition types I and III, and common cavity) were included, with data equally distributed between classes. Both the cropping tool and the AI model were extensively validated. ResultsThe newly developed DICOM viewer/software successfully achieved its objectives: reading CT files, automatically cropping inner ear volumes, and classifying them as normal or malformed. The cropping tool demonstrated an average accuracy of 92.25%. The DL CNN model achieved an area under the curve (AUC) of 0.86 (95% confidence interval: 0.81-0.91). Performance metrics for the AI model were: accuracy (0.812), precision (0.791), recall (0.8), and F1-score (0.766). ConclusionThis study successfully developed and validated a fully automated workflow for classifying normal versus abnormal inner ear anatomy using a combination of advanced image processing and deep learning techniques. The tool exhibited good diagnostic accuracy, suggesting its potential application in risk stratification. However, it is crucial to emphasize the need for supervision by qualified medical professionals when utilizing this tool for clinical decision-making.

Gaze Patterns of Normal and Microtia Ears Pre- and Post-Reconstruction.

To understand attentional preferences for normal and microtia ears. Eye-tracking technology was used to characterize gaze preferences. A total of 71 participants viewed images of 5 patients with unilateral microtia. Profile images of patient faces and isolated ears including normal, microtia, and post-reconstruction microtia ears were shown. Total time of fixation in predefined areas of interest (AOI) was measured. Inferential statistics were used to assess significance of fixation differences between AOIs within and between facial or auricular features. The ear received most visual attention in lateral view of the face (1.91 s, 1.66-2.16 s) [mean, 95% CI], followed by features of the "central triangle"-the eyes (1.26 s, 1.06-1.46), nose (0.48 s, 0.38-0.58), and mouth (0.15 s, 0.15-0.20). In frontal view, microtia ears received less attention following surgical reconstruction (0.74 s vs. 0.4 s, p < 0.001). The concha was the most attended feature for both normal (2.97 s, 2.7-3.23) and reconstructed microtia ears (1.87 s, 1.61-2.13). Scars on reconstructed ears altered the typical visual scanpath. The ear is an attentional gaze landmark of the face. Attention to microtia ears, both pre- and post-reconstruction, differs from gaze patterns of normal ears. The concha was the most attended to subunit of the ear. Attentional gaze may provide an unbiased method to determine what is important in reconstructive surgery. NA Laryngoscope, 134:3136-3142, 2024.

CT features of abnormally whole-course wide eustachian tubes with microtia and atresia

Objective: To study the clinical and CT features of the abnormal whole-course wide of eustachian tube (AWWET) with microtia and atresia(MA). Methods: The clinical and CT data of 19 patients (20 ears) from January 2017 to December 2021 with AWWET with MA were retrospectively analyzed, including 15 males and 4 females. The age ranged from 5 to 16 years, with an average of 9.5 years. 50 patients with common MA without wide eustachian tube(ET) as a case control group, including 32 males and 18 females.The age ranged from 5 to 16 years, with an average of 9.2 years. 20 patients (40 ears) who had normal ear CT for tinnitus, otalgia as a normal control group, including 12 males and 8 females. The age ranged from 5 to 16 years, with an average of 12.5 years. We measured the dimension and length of the bony portion of the ET, the total length, the angle between the bony portion and the cartilage portion, and the horizontal angle of ET on CT imagings, and compared with 40 normal ears by SPSS 27.0 software. Results: According to the relationship between AWWET and tympanum, patients were divided into the communicated group and the blocked group. A male predominance, left ear predominance, with high incidence of hemifacial microsomia exhibited in both groups. AWWET was presented as a widened lumen on CT. In 11 ears (4 ears in the communicated group, 7 ears in the blocked group), ETs bifurcated, the upper bony tube extended to the sphenoid body, the lower part continued down to cartilaginous ET and opened onto the nasopharynx, with"mastoid-like"pneumatization of the sphenoid body in 6 ears. The middle ear deformity in case group was more serious than MA control group, especially the blocked group. The incidence of otitis media in the communicated group was lower than that in the MA control group, and 4 cases in the blocked group had effusion in the ET. Compaired with normal ear, the bony ET elongated significantly in the AWWET groups, and the whole course of ET was significantly shortened, specially in the blocked group. The angle between the bony ET and the cartilaginous ET was decreased and the horizontal angle of the ET increased in the AWWET groups, the difference was considered to indicate statistical significance(P<0.05). Conclusions: AWWET with MA is rare, a male predominance, left ear predominance, and with high incidence of hemifacial microsomia. The middle ear deformity is more serious than common MA, especially in the blocked group. The incidence of otitis media in the communicated group is significantly lower than that in the common MA, and the blocked group may be accompanied by ET inflammation.

Frequency response analysis and in vitro verification of 3D-printed ossicular replacement materials

As a bridge that transmits airborne sound signals to the auditory receptors of the inner ear, the eardrum and ossicular chain of the middle ear convert sound through two types of conversions: gas&amp;ndash;solid (airborne sound signal&amp;ndash;eardrum and ossicular chain) and solid&amp;ndash;liquid (eardrum and ossicular chain&amp;ndash;internal and external lymphatic fluid in the cochlea). This process concentrates and amplifies the sound to the inner ear through the lever principle structure formed by the three ossicles. However, diseases, hereditary factors, or trauma can reduce the sound transmission function of the middle ear. The effectiveness of middle ear replacement prostheses depends on their vibration response to the human auditory perception frequency, from the eardrum to the stapes plate. This response is influenced by the materials, geometry, and design of the replacement prosthesis and eardrum. This study explores the effects of different materials on hearing after artificial ossicular replacement. Usually, human temporal bone models are used for testing and validating numerical results. However, obtaining specimens from living humans is not always feasible. Therefore, we used three-dimensional printing technology to build a model of the middle ear to test the ossicular bone. Titanium alloy TC4, stainless steel 316L, and composite HA/PCL are chosen as materials for ossicular replacement. Using f&amp;zwj;inite element analysis and an in vitro verification experiment, individual replacements of the ossicles and three bone material replacements were conducted for frequency response analysis. The combination of the malleus made of TC4, the incus made of TC4, and the stapes made of HA/PCL were found to bear higher resemblance to a real normal ear ossicular model.

Risk of hearing loss in non-operated ear due to mastoid drilling

Background: The study purpose is to evaluate the effect of drill-generated high intensity noise on hearing sensitivity in contralateral ear. Methods: Sixty patients who underwent mastoidectomy were studied to see the effect of mastoid drilling on hearing sensitivity in normal ear using pure tone audiometry (PTA) and distortion product otoacoustic emission (OAE) values recorded preoperatively and postoperatively. Results: For PTA, there is no significant hearing loss for 0.25 kHz and 0.50 kHz for all PODs. For 1 kHz, 2 kHz and average PTA there is significant temporary hearing loss from POD 1 to POD 7 which normalizes around POD 30. However, there is significant temporary threshold shift for 4 kHz and 8 kHz from POD 1 to POD 5 and the hearing sensitivity improves to preoperative levels at POD 7. For OAE, 1 kHz, 4 kHz and average OAE there is significant temporary hearing loss from POD 1 to POD 7 which normalizes around POD 30. However, there is significant temporary threshold shift for 2 kHz and 6 kHz from POD 1 to POD 5 and hearing sensitivity improves to preoperative levels at POD 7. There is a significant correlation between drilling duration and PTA averages and OAE averages. Conclusions: Sensorineural hearing loss is more prevalent following modified radical and radical mastoidectomy as compared to canal wall up mastoidectomy. The factors influencing postoperative contralateral ear sensorineural hearing loss are type and size of burr and the duration of burr use.

Auditory Cortical Plasticity in Patients with Single-Sided Deafness Before and After Cochlear Implantation

PurposeThis study investigated neuroplastic changes induced by postlingual single-sided deafness (SSD) and the effects of a cochlear implantation for the deaf ear. Neural processing of acoustic signals from the normal hearing ear to the brain was studied before and after implantation using a positron emission tomography (PET)/CT scanner.MethodsEight patients with postlingual SSD received a cochlear implant (CI) in a prospective clinical trial. Dynamic imaging was performed in a PET/CT scanner using radioactively labeled water ([15O]H2O) to localize changes in the regional cerebral blood flow (rCBF) with and without an auditory task of logatomes containing speech-like elements without meaningful context. The normal hearing ear was stimulated before implantation and after the use of the cochlear implant for at least 8 months (mean 13.5, range 8.1–26.6). Eight age- and gender-matched subjects with normal hearing on both sides served as healthy control subjects (HCS).ResultsWhen the normal hearing ear of SSD patients was stimulated before CI implantation, the [15O]H2O-PET showed a more symmetrical rCBF in the auditory regions of both hemispheres in comparison to the HCS. The use of CI increased the asymmetry index (AI) in six of eight patients indicating an increase of activity of the contralateral hemisphere. Non-parametric statistics revealed a significant difference in the AI between patients before CI implantation and HCS (p < .01), which disappeared after CI implantation (p = .195).ConclusionThe functional neuroimaging data showed a tendency towards normalization of neuronal activity after CI implantation, which supports the effectiveness of CI in SSD patients.Trial RegistrationClinicalTrials.gov Identifier: NCT01749592, December 13, 2012.

Electrocochleography in the diagnosis of third window conditions.

Superior semicircular canal dehiscence (SSCD) is the best-known and most common presentation of so-called "third window conditions." There are a variety of diagnostic measures and tests for this condition in the current literature, including air-bone gap, vestibular-evoked myogenic potentials, and electrocochleography (EcochG). The purpose of this study was to investigate the diagnostic utility of EcochG and its relationship to air-bone gap in a cohort of patients with confirmed SSCD. We reviewed data from 20 patients (11 female and 9 male subjects, age ranging 21-78 years), with confirmed unilateral or bilateral superior canal dehiscence. In total, 11 patients had unilateral SSCD and 9 patients had bilateral SSCD as determined by high-resolution CT scan. This resulted in the inclusion of twenty-nine ears with superior canal dehiscence and 11 normal ears. Our results indicated that all confirmed SSCD ears presented with an abnormal EcochG SP/AP value and that there was a statistically significant difference between normal and dehiscent ears. There was no statistically significant relationship between air-bone gap and SP/AP ratio in the ears diagnosed with SSCD nor was there a significant difference between dehiscent and normal ears in terms of air-bone gap at three frequencies. These results are consistent with previous studies showing the diagnostic utility of EcochG for this condition and the variability of air-bone gap. While an unexpected air-bone gap continues to be a red flag for SSCD, its absence along with the presence of subjective symptoms is a reasonable indicator for further clinical investigation to include EcochG.

Association of iron deficiency with chronic suppurative otitis media in adults

Background Chronic suppurative otitis media (CSOM) is a prevalent chronic inflammatory disease globally. Current research suggests a possible association between anaemia and the development of CSOM. Objectives The objective of this trial was to investigate the relationship between iron metabolism and chronic suppurative otitis media (CSOM) in adults aged 20–60 years. Materials and methods A consecutive sampling case-control study was used. The study participants were divided into a case group (42 children diagnosed with CSOM) and a control group (42 children with normal ears). Haemoglobin (Hb), Hematocrit (Hct), mean corpuscular volume of erythrocytes (MCV), serum iron level (SI), unsaturated iron-binding capacity (UIBC), total iron-binding capacity (TIBC), transferrin (TF), ferritin (Fer) were tested in all the participants, and the results were compared with the normal ranges of the World Health Organization (WHO). The comparative analysis of cases and controls was performed using the Fisher extract test, independence t-test, or Mann–Whitney U test. p-value <.05 was considered statistically significant for correlation. Results There were 61 patients with CSOM and 61 controls included in the study. In the case group, 16 out of 61 patients (26.2%) had low ferritin levels and in the control group, 1 out of 61 patients (1.6%) had low ferritin levels (p < .001). In the case group, 6 (9.8%) of 61 patients had IDA, and in the control group, there were no patients with IDA among 61 patients (p = .027). There were significant differences in SI, UIBC, and Fer parameters between the groups. Conclusions In adult patients, the incidence of iron deficiency was higher in CSOM patients than in controls. Iron deficiency may be considered a potential risk factor for chronic suppurative otitis media, and serum iron parameters should be evaluated in these CSOM patients and further studies should be conducted to better understand the potential link between iron deficiency and CSOM.

Destructive foreign body granuloma: A case report

External auditory canal polyps are predominantly inflammatory processes but occasionally indicate more severe pathology. Prolonged conservative management may postpone accurate diagnosis and appropriate therapeutic intervention. This case report presents a 37-year-old woman, previously healthy with a normal ear, who underwent a right myringotomy with the insertion of a pressure-equalizing tube in one hospital after an upper respiratory tract infection. However, due to the pandemic era, she lost follow-up for 2 years and subsequently presented to another hospital with worsening hearing and persistent otorrhea. The attending physician found a large polypoid lesion occupying her right external ear canal. A computerized tomography scan revealed an irregular enhancement mass involving the right ear canal, the middle ear cavity, and mastoid air cells with multiple destruction of the skull base and intracranial involvement in the right middle cranial fossa. The possibility of malignancy was raised, prompting the patient to seek evaluation in a third hospital. A right tympanomastoidectomy was performed, and during a posterior tympanotomy, a pressure-equalizing tube was discovered in her middle ear. The pathological results confirmed the presence of foreign body granuloma. Following surgery, the patient’s otorrhea improved.

The spatial orientation of crista ampullaris: implications for BPPV diagnosis and treatment.

This study aimed to provide a comprehensive understanding of the spatial orientation of the crista ampullaris within the inner ear and its implications for the diagnosis and management of benign paroxysmal positional vertigo (BPPV). Using high-resolution MRI scans of 55 normal inner ears, 3D models of the semicircular canals were segmented. These were complemented by detailed membrane labyrinth models from micro-CT scans of human temporal bones, accessed via the Comparative Ear Bank (www.earbank.org). A statistical shape model of inner ears and eyeballs was established, and a standardized 3D spatial coordinate system was created. The horizontal plane was defined using the top of the common crus and the bottom of the eyeballs. This calibrated reference system allowed for precise quantification of crista ampullaris orientations by calculating angles between the defined crista planes and coordinate planes. The plane of the ampulla and the corresponding semicircular canal plane are nearly perpendicular to each other. In the upright position, the posterior semicircular canal crista ampullaris formed an angle of 48.9° with the horizontal plane. The relative orientations of the crista ampullaris of the lateral and superior canals were also defined. Furthermore, we identified "zero-point planes" representing crista orientations perpendicular to gravity, which resulted in minimal ampullary stimulation. A 6.2° tilt to the left in the supine position resulted in the plane of the left lateral semicircular canal crista ampullaris being parallel to the direction of gravity. This study elucidates the precise spatial orientation of the crista ampullaris, thereby providing an anatomical basis for understanding BPPV pathophysiology and improving the accuracy of diagnostic and therapeutic maneuvers. The findings have the potential to significantly enhance the management of BPPV and other inner ear disorders.

New Strategies for Remnant Ear Treatment in Microtia Reconstruction Based on Morphometric Studies.

Given the lack of specific evaluation indices, it is difficult to determine whether to transpose or abandon remnant ears in lobule-type microtia reconstruction. The authors illuminate referable parameters beneficial for proper treatment of remnant ear in an efficient manner. A series of 359 lobule-type microtia patients underwent autogenous costal cartilage auricular reconstruction between 2016 and 2021. Fourteen measuring points and defined distances as well as six ratios of specific distances based on position, plumpness, similarity and the width-to-length ratio of the remnant ear have been described, and relevant tactics for appropriate treatments are introduced. Definite morphometric results contribute to attaining satisfactory contours of reconstructed auricles with harmonious earlobes, which exhibit highly similar dimensions and appearances compared to the contralateral normal ears. With the help of the proposed locating points and measuring approaches, the procedure of remnant ear treatment is systematically clarified. This technique ensures operation safety and contributes to the aesthetic contour of the auricle. IV Laryngoscope, 134:2741-2747, 2024.

From research to clinical practice: An analysis of 226 Hz-probe tone tympanometry to identify otitis media with effusion in children

Objectives(1) To calculate the sensitivity and specificity of tympanometry with a 226 Hz probe to identify middle ear condition in children; (2) To propose the intersection range of static compliance and tympanometric peak pressure values obtained in ears with and without middle ear effusion. Methods224 children's ears without middle ear alteration, with a mean age of 1 year and 4 months (GI), and 56 children's ears with middle ear effusion (GII), with a mean age of two years, were analyzed. For analysis, the static compliance and tympanometric peak pressure values obtained in the tympanometry with a 226 Hz probe were considered. ResultsIn the group with no alteration, the Mann Whitney Test showed no significant difference between the sexes for the static compliance (p = 0.085) and tympanometric peak pressure (p = 0.782). No difference was seen, either, for compliance (p = 0.079) and pressure (p = 0.678) values, according to age. When applying the optimal criterion of the ROC curve, the cutoff value obtained was ≤0.26 ml for static compliance (sensitivity= 83.9 %; specificity= 86.6 %) and ≤−56 daPa for peak pressure (sensitivity= 82.1 %; specificity= 84.8 %). When comparing the values obtained for the two groups, it is noted that the data overlap, that is, they create an inconclusive intersection range between the normal middle ear and the altered one. ConclusionThe tympanometry cut-off with greater sensitivity and specificity was, respectively, 83.9 and 86.6 % for static compliance and 82.1 and 84.8 % for tympanometric peak pressure. The ranges from 0.16 to 0.43 ml for static compliance and from −109 to 25 daPa for tympanometric peak pressure do not allow defining the presence or absence of alteration in the middle ear, in children aged 6 to 36 months.

Bony Congenital Nasolacrimal Duct Obstruction: A Novel Phenotype of Aplasia of Lacrimal and Major Salivary Glands

PurposeAplasia of lacrimal and salivary gland (ALSG) is a syndromic disorder characterized by aplasia of lacrimal and salivary systems. Reported ophthalmic manifestations of ALSG include aplasia of lacrimal glands, punctal agenesis, lacrimal sac mucocele and membranous congenital nasolacrimal duct obstruction (CNLDO). Bony CNLDO, a rare cause of congenital epiphora, has not been associated with any syndromic disorder. This study investigated the relationship between genetic mutations and bony CNLDO in three Chinese families with ALSG. DesignSingle-center observational case study. ParticipantsThree Chinese families with bony CNLDO including 7 affected and 9 healthy family members. MethodsSlit-lamp ophthalmic examination, comprehensive physical examination, orbital Computed Tomography (CT), cervicofacial Magnetic Resonance Imaging (MRI), audiometry and whole exome sequencing on periphery blood were performed. Variants were cross-referenced with 1000 control genomes and various population databases. Pathologic variants were identified using bioinformatic tools. Main Outcome MeasuresClinical examination, diagnostic imaging, whole exome sequencing and bioinformatic analysis findings. ResultsAffected patients had decreased tear production on Schimer I Test and reduced tear break-up time. Bony CNLDO was observed on computed tomography, showing unilateral or bilateral bony termination at the middle or terminal segment of the nasolacrimal canal. Cervicofacial MRI showed aplasia or absence of lacrimal, parotid and submandibular glands. Physical examination revealed normal ears, digits and facial morphology. Audiometry and dental assessment were conducted on the pediatric patients and yielded normal results. The clinical characteristic of patients aligned with diagnosis of ALSG. Genomic analysis revealed three novel heterozygous missense mutations of Fgf10 gene: c.316T>C, c.327C>G, c.332T>G. The inheritance pattern was autosomal dominant with variable penetrance. These variants were not observed in 1000 control chromosomes and population databases. These variant positions were also shown to be highly conversed across various animal species. Mutated genes and proteins were predicted as “deleterious” with most computational models with a few suggesting they may be “benign”. ConclusionsBony CNLDO was identified as a novel phenotype of ALSG implicated by missense mutations of highly conserved residues in the Fgf10 gene. These cases broadened our knowledge of Fgf10-related phenotypes and prompt clinicians to consider syndromic associations in patients with bony CNLDO.

Enhancing cochlear duct length estimation by incorporating second-turn parameters

Estimating insertion depth, cochlear duct length (CDL), and other inner ear parameters is vital to optimizing cochlear implantation outcomes. Most current formulas use only the basal turn dimensions for CDL prediction. In this study, we investigated the importance of the second turn parameters in estimating CDL. Two experienced neuro-otologists blindly used segmentation software to measure (in mm) cochlear parameters, including basal turn diameter (A), basal turn width (B), second-turn diameter (A2), second-turn width (B2), CDL, first-turn length, and second-turn length (STL). These readings were taken from 33 computed tomography (CT) images of temporal bones from anatomically normal ears. We constructed regression models using A, B, A2, and B2 values fitted to CDL, two-turn length, and five-fold cross-validation to ensure model validity. CDL, A value, and STL were longer in males than in females. The mean B2/A2 ratio was 0.91 ± 0.06. Adding A2 and B2 values improved CDL prediction accuracy to 86.11%. Therefore, we propose a new formula for more accurate CDL estimation using A, B, A2, and B2 values. In conclusion, the findings of this study revealed a notable improvement in the prediction of two-turn length (2TL), and CDL by clinically appreciable margins upon adding A2 and B2 values to the prediction formulas.

Investigation of Age and Gender Effects on the Middle Ear With Wideband Tympanometry in Adults.

Several studies have reported the effects of age and gender on the middle ear of adults using wideband acoustic immittance (WAI) that measures middle ear function over a range of frequencies rather than the traditional measures with a single probe tone. Although these results are often based on WAI measurements under ambient pressure, using WAI under varying ear-canal pressures (wideband tympanometry [WBT]) may be able to provide more information about age and gender effects on the middle ear. The aim of this study is to examine the effects of age and gender on the middle ear with WBT in three different age groups consisting of young, middle-aged, and older adults. A total of 95 adults with normal middle ear function were assessed, including 32 young adults (16 men, 16 women, aged 20 to 39 years), 31 middle-aged adults (15 men, 16 women, aged 41 to 60 years), and 32 older adults (16 men, 16 women, aged 65 to 82 years). WBT measurements were performed from 226 to 8000 Hz using Interacoustics Titan. Energy absorbance data at tympanometric peak pressure (EA TPP ) and ambient pressure (EA AP ) at 1/3 octave frequencies, and resonance frequency (RF) data were analyzed according to age and gender variables. Analysis results showed that the mean EA TPP was significantly higher from 500 to 794 Hz and at 5040 and 6350 Hz, and significantly lower from 1587 to 3175 Hz in older adults compared with young adults. The mean EA AP was significantly lower from 1587 to 3175 Hz, and significantly higher at 5040 and 6350 Hz in older adults compared with young adults. There was no significant difference in the mean EA TPP and mean EA AP at any frequency between young and middle-aged adults, and middle-aged and older adults. RF was significantly lower in older adults compared with young adults. In all age groups, men had higher mean EA TPP and mean EA AP at lower frequencies and lower mean EA TPP and mean EA AP at higher frequencies than women. Men had slightly lower RF than women in young and older adults, while men had significantly lower RF than women in middle-aged adults. This study demonstrated that there are possible age and gender effects on the middle ear that may affect the mechanical transmission of sound. It may be useful to consider this finding in clinical evaluation in adults of different ages and genders, and to establish age- and gender-specific WBT norms in the adult population.

Combinatorial Atoh1, Gfi1, Pou4f3, and Six1 gene transfer induces hair cell regeneration in the flat epithelium of mature guinea pigs

Flat epithelium (FE) is a condition characterized by the loss of both hair cells (HCs) and supporting cells and the transformation of the organ of Corti into a simple flat or cuboidal epithelium, which can occur after severe cochlear insults. The transcription factors Gfi1, Atoh1, Pou4f3, and Six1 (GAPS) play key roles in HC differentiation and survival in normal ears. Previous work using a single transcription factor, Atoh1, to induce HC regeneration in mature ears in vivo usually produced very few cells and failed to produce HCs in severely damaged organs of Corti, especially those with FE. Studies in vitro suggested combinations of transcription factors may be more effective than any single factor, thus the current study aims to examine the effect of co-overexpressing GAPS genes in deafened mature guinea pig cochleae with FE. Deafening was achieved through the infusion of neomycin into the perilymph, leading to the formation of FE and substantial degeneration of nerve fibers. Seven days post neomycin treatment, adenovirus vectors carrying GAPS were injected into the scala media and successfully expressed in the FE. One or two months following GAPS inoculation, cells expressing Myosin VIIa were observed in regions under the FE (located at the scala tympani side of the basilar membrane), rather than within the FE. The number of cells, which we define as induced HCs (iHCs), was not significantly different between one and two months, but the larger N at two months made it more apparent that there were significantly more iHCs in GAPS treated animals than in controls. Additionally, qualitative observations indicated that ears with GAPS gene expression in the FE had more nerve fibers than FE without the treatment. In summary, our results showed that co-overexpression of GAPS enhances the potential for HC regeneration in a severe lesion model of FE.

An Absorbance Peak Template for Clinical Assessment of Sound Conduction in Newborn Ears.

Power absorbance measures recorded over a wide range of frequencies allow for clinical inferences about the outer/middle ears' acoustic mechanics. A frequency-dependent feature in the newborn wideband absorbance response, the prominent mid-frequency absorbance peak, has been linked to middle-ear resonance. However, current normative methods were not designed to assess subtle changes in such features. This work aims to develop and validate an absorbance peak template (APT) for assessment of absorbance peaks in newborns. Additional objectives are to compare test performance of absorbance peaks and APTs to existing normative methods, to demonstrate APT-based methods for categorization of abnormal absorbance peaks, and to describe absorbance peak test-retest variability. Peak absorbance and peak frequency were analyzed in a training data set (490 measurements in 84 newborn ears who passed transient evoked otoacoustic emissions [TEOAEs] screenings), and an APT was developed by computing normal limits on these two absorbance peak variables. Split-set analysis evaluated the reproducibility of APT, and test-retest analysis was performed. Test performance analysis, conveyed by area under the receiver operating characteristic curve (AROC) and 95% confidence intervals (CIs), compared absorbance peak variables to absorbance area indices (AAIs) in a validation data set (359 ears that passed distortion-product OAE [DPOAE] screening and 64 ears that failed). APT-based assessment paradigms for normal and abnormal ears were compared to the common absorbance normative range paradigm. Split-set analysis demonstrated a good reproducibility of APT, and test-retest of absorbance peak variables showed that they were stable measures for clinical assessment. Test performance of peak absorbance (AROC = 0.83; 95% CI [0.77, 0.88]) was comparable to the top-performing AAI variables (AROC = 0.85; 95% CI [0.80, 0.90]). APT-based assessment categorized measurements based on their peak absorbance and peak frequency and enhanced the detection of subtle frequency changes that were missed by the normative range method. Analysis of absorbance peaks guided by APT has the potential to simplify and improve assessments of sound conduction pathways in newborn ears and can be used together with or in-place of current methods for analysis of wideband absorbance data.

Use of simulated data to explore the application of optical coherence tomography for classifying middle-ear pathologies.

Optical coherence tomography (OCT) vibrometry is a non-invasive tool for functional imaging of the middle ear. It provides spatially resolved vibrational responses and also anatomical images of the same ear. Our objective here was to explore the potential of OCT vibration measurements at the incus, as well as at the umbo, to distinguish among middle-ear disorders. Our approach was to build finite-element models of normal and pathological ears, generate large amounts of synthetic data, and then classify the simulated data into normal and pathological groups using a decision tree based on features extracted from simulated vibration magnitudes. We could distinguish between normal ears and ears with incudomallear joint (IMJ) disarticulation or stapes fixation, with the sensitivity and specificity both being 1.0; distinguish between stapes fixation and IMJ disarticulation with a sensitivity of 0.900 and a specificity of 0.889; and distinguish ears with ISJ disarticulation from normal ears with a sensitivity of 0.784 and a specificity of 0.872. Less extreme pathologies were also simulated. The results suggest that the vibration measurements within the middle ear that can be provided by OCT (e.g., at the incus) may be very valuable for diagnosis.

Finite element analysis of repairing tympanic membrane perforation using autologous graft material and biodegradable bionic cobweb scaffold

Background and objectiveAs for repairing the perforated tympanic membranes (TM), temporalis fascia and tragal cartilage are popular in clinics as autologous graft materials. However, there is a significant hearing loss after repairing the TM with autologous graft materials, which needs to be addressed in biomechanical engineering. MethodsThe finite element model of normal middle ear is improved from two aspects: the repair method of tympanic fibrous layer and the bionic spider web tympanic scaffold. By creating the solid-shell coupling condition and strong coupling boundary condition to simulate the repair, TM umbo and stapes footplate displacement-frequency response are explored in 200–8000 Hz. ResultsThe tympanic membrane perforation (TMP) causes a significant conductive hearing loss in high frequency region, which is positively correlated with perforation area. Both temporalis fascia and tragal cartilage still perform a certain degree of high-frequency hearing loss after repairing TMP. The TM attachment the magnesium alloy scaffold (MAS) prevents appropriately the high frequency hearing loss after autologous graft repair and makes the sound transmission closer to the normal condition. Significantly, the density of graft material has a negative effect on high-frequency sound transmission without the MAS. The modal-motion of TM repaired with temporalis fascia and tragal cartilage is improved significantly after attaching the MAS. In addition, the MAS restores effectively the configuration and vibration frequency of the repaired TM, which is similar to that of the native TM. ConclusionThe area size of TMP is studied through the finite element method, which includes autologous graft materials, the MAS, parameter sensitivity analysis, modal analysis of graft material and the MAS in biological form on the effect of middle ear sound transmission. Relevant conclusions provide some references for clinical trial protocol and the follow-up repair ideas of TM of tympanoplasty.

Cochlear implantation in unilateral hearing loss: impact of short- to medium-term auditory deprivation.

Single sided deafness (SSD) results in profound cortical reorganization that presents clinically with a significant impact on sound localization and speech comprehension. Cochlear implantation (CI) has been approved for two manufacturers' devices in the United States to restore bilateral function in SSD patients with up to 10 years of auditory deprivation. However, there is great variability in auditory performance and it remains unclear how auditory deprivation affects CI benefits within this 10-year window. This prospective study explores how measured auditory performance relates to real-world experience and device use in a cohort of SSD-CI subjects who have between 0 and 10 years of auditory deprivation. Subjects were assessed before implantation and 3-, 6-, and 12-months post-CI activation via Consonant-Nucleus-Consonant (CNC) word recognition and Arizona Biomedical Institute (AzBio) sentence recognition in varying spatial speech and noise presentations that simulate head shadow, squelch, and summation effects (S0N0, SSSDNNH, SNHNSSD; 0 = front, SSD = impacted ear, NH = normal hearing ear). Patient-centered assessments were performed using Tinnitus Handicap Inventory (THI), Spatial Hearing Questionnaire (SHQ), and Health Utility Index Mark 3 (HUI3). Device use data was acquired from manufacturer software. Further subgroup analysis was performed on data stratified by <5 years and 5-10 years duration of deafness. In the SSD ear, median (IQR) CNC word scores pre-implant and at 3-, 6-, and 12-months post-implant were 0% (0-0%), 24% (8-44%), 28% (4-44%), and 18% (7-33%), respectively. At 6 months post-activation, AzBio scores in S0N0 and SSSDNNH configurations (n = 25) demonstrated statistically significant increases in performance by 5% (p = 0.03) and 20% (p = 0.005), respectively. The median HUI3 score was 0.56 pre-implant, lower than scores for common conditions such as anxiety (0.68) and diabetes (0.77), and comparable to stroke (0.58). Scores improved to 0.83 (0.71-0.91) by 3 months post-activation. These audiologic and subjective benefits were observed even in patients with longer durations of deafness. By merging CI-associated changes in objective and patient-centered measures of auditory function, our findings implicate central mechanisms of auditory compensation and adaptation critical in auditory performance after SSD-CI and quantify the extent to which they affect the real-world experience reported by individuals.