[How much digitization do ENT curricula need? : Opportunities and limits from the perspective of students and teachers]. / Wieviel Digitalisierung braucht die HNO-Lehre? : Chancen und Grenzen aus Sicht von Studierenden und Lehrenden.

BACKGROUND: Digitalization has long been an integral part of students' everyday lives and increasingly also of their medical training. It seems to be an unwritten law that "digital natives" want as much digitalization as possible. This study aims to shed more light on how students in the clinical phase of medical studies perceive the increasing digitalization of teaching and what they need for good education. MATERIALS AND METHODS: This study analyzed two surveys that were conducted using an online questionnaire. On the one hand, students in the 5th-9th semesters of the medical faculty at the University of Hamburg (n = 282) were surveyed (survey 1). Another survey addressed all employees of ENT clinics in Germany (n = 175; survey 2). RESULTS: A total of 76 students took part in survey 1 and 123 lecturers in survey 2. The results show that both students and lecturers do not want face-to-face teaching to be completely replaced by digital formats. A total of 72.7% of students reject the possibility of teaching practical skills through digital formats. The majority of students surveyed stated that offline formats improve their concentration (61.1%), participation probability (63.9%), and motivation to learn (76.6%). In contrast, 40.2% of lecturers see digitalization as a way to reduce the workload without any relevant loss in teaching quality. CONCLUSION: Digital teaching formats have a negative impact on the medical education of the students surveyed. Interaction and physical presence are needed to increase the motivation to learn. This leads to the first conclusion that students are critical of the increasing digitalization of medical studies.

Cholesteatoma Severely Impacts the Integrity and Bone Material Quality of the Incus.

Cholesteatoma can lead to progressive destruction of the auditory ossicles along with conductive hearing loss but precise data on the microstructural, cellular, and compositional aspects of affected ossicles are not available. Here, we obtained incus specimens from patients who had cholesteatoma with conductive hearing loss. Incudes were evaluated by micro-computed tomography, histomorphometry on undecalcified sections, quantitative backscattered electron imaging, and nanoindentation. Results were compared with two control groups taken from patients with chronic otitis media as well as from skeletally intact donors at autopsy. The porosity of incus specimens was higher in cholesteatoma than in chronic otitis media, along with a higher osteoclast surface per bone surface. Histomorphometric assessment revealed higher osteoid levels and osteocyte numbers in cholesteatoma incudes. Incudes affected by cholesteatoma also showed lower matrix mineralization compared with specimens from healthy controls and chronic otitis media. Furthermore, the modulus-to-hardness ratio was higher in cholesteatoma specimens compared with controls. Taken together, we demonstrated increased porosity along with increased osteoclast indices, impaired matrix mineralization, and altered biomechanical properties as distinct features of the incus in cholesteatoma. Based on our findings, a possible impact of impaired bone quality on conductive hearing loss should be further explored.

[Validity of the German Menière's Disease Patient-Oriented Symptom Severity Index]. / Validierung des deutschsprachigen Menière's Disease Patient-Oriented Symptom Severity Index.

BACKGROUND: The MD POSI is a disease-specific questionnaire to determine the health-related quality of life (HRQoL) of patients with Menière's disease (MD). OBJECTIVES: Validity and reliability of the German translation of the MD POSI. MATERIAL AND METHODS: Prospective data analysis of a patient group with vertigo (n = 162), which was treated in the otorhinolaryngology of a University Hospital from 2005-2019. A clinical selection was made according to the new Bárány classification in a "definite" and "probable" Menière's disease. HRQoL was assessed using the German translation of the MD POSI, the Vertigo Symptom Score (VSS) and the Short Form (SF-36). Reliability was measured by Cronbach's α and test-retesting after 12 months and again 2 weeks later. Content and agreement validity were examined. RESULTS: Cronbach α values greater than 0.9 indicated good internal consistency. There was no statistically significant difference from baseline to 12 months, except for the subscore "during the attack". There were significant positive correlations between the VSS overall/VER/AA and the overall index of the MD POSI and negative significant correlations with the SF-36 domains physical functioning, physical role functioning, social functioning, emotional role functioning, mental well-being. There were low SRM (standardized response mean) values below 0.5. CONCLUSIONS: The German translation of the MD POSI is a valid and reliable instrument to evaluate the impact of MD on patients' disease-specific quality of life.

A direct comparison of voice pitch processing in acoustic and electric hearing.

In single-sided deafness patients fitted with a cochlear implant (CI) in the affected ear and preserved normal hearing in the other ear, acoustic and electric hearing can be directly compared without the need for an external control group. Although poor pitch perception is a crucial limitation when listening through CIs, it remains unclear how exactly the cortical processing of pitch information differs between acoustic and electric hearing. Hence, we separately presented both ears of 20 of these patients with vowel sequences in which the pitch contours were either repetitive or variable, while simultaneously recording functional near-infrared spectroscopy (fNIRS) and EEG data. Overall, the results showed smaller and delayed auditory cortex activity in electric hearing, particularly for the P2 event-related potential component, which appears to reflect the processing of voice pitch information. Both the fNIRS data and EEG source reconstructions furthermore showed that vowel sequences with variable pitch contours evoked additional activity in posterior right auditory cortex in electric but not acoustic hearing. This surprising discrepancy demonstrates, firstly, that the acoustic detail transmitted by CIs is sufficient to distinguish between speech sounds that only vary regarding their pitch information. Secondly, the absence of a condition difference when stimulating the normal-hearing ears suggests a saturation of cortical activity levels following unilateral deafness. Taken together, these results provide strong evidence in favour of using CIs in this patient group.

Prospective study on health-related quality of life in patients before and after cochlear implantation.

PURPOSE: Assessing cochlear implant (CI)-associated patient outcomes is a focus of implant research. Most studies have analyzed outcomes retrospectively with low patient numbers and few measurement time points. In addition, standardized CI-specific health-related quality of life (HRQoL) instruments have not been used. To address this, we prospectively assessed HRQoL in patients before and after implantation. METHODS: We assessed HRQoL using the Nijmegen Cochlear Implant Questionnaire (NCIQ), Abbreviated Profile of Hearing Aid Benefit (APHAB), Hearing Participation Scale (HPS), and the Visual Analogue Scale (VAS) in 100 deaf or severely hearing-impaired patients (57 unilaterally deaf and 43 bilaterally deaf) before and 3, 6, and 12 months after cochlear implantation. We compared the results of unilaterally and bilaterally hearing-impaired patients and patients with or without a hearing aid. Principal component (PCA) and exploratory factor analyses (EFA) were also conducted. RESULTS: The NCIQ measured improvements in all 6 domains after CI and correlated well with other QoL instruments. The PCA revealed that the NCIQ can be better explained by physical, physical advanced, and socio-psychological components. The APHAB score ameliorated over time, except for the background noise domain. The overall HPS score improved over time, but the hearing handicap subscore significantly decreased. Sociodemographic influences on the questionnaire scores were relatively weak. CONCLUSION: Assessing HRQoL is essential for quantifying the patient outcome after CI. NCIQ scores in our patient cohort showed improved HRQoL in all domains and we recommend that the NCIQ be used as a first-line questionnaire for assessing QoL in hearing-impaired patients after CI.

Face, Content, and Construct Validity of a Virtual Reality Otoscopy Simulator and Applicability to Medical Training.

OBJECTIVE: Otologic diseases are common in all age groups and can significantly impair the function of this important sensory organ. To make a correct diagnosis, the correct handling of the otoscope and a correctly performed examination are essential. A virtual reality simulator could make it easier to teach this difficult-to-teach skill. The aim of this study was to assess the face, content, and construct validity of the novel virtual reality otoscopy simulator and the applicability to otologic training. STUDY DESIGN: Face and content validity was assessed with a questionnaire. Construct validity was assessed in a prospectively designed controlled trial. SETTING: Training for medical students at a tertiary referral center. METHOD: The questionnaire used a 6-point Likert scale. The otoscopy was rated with a modified Objective Structured Assessment of Technical Skills. Time to complete the task and the percentage of the assessed eardrum surface were recorded. RESULTS: The realism of the simulator and the applicability to medical training were assessed across several items. The ratings suggested good face and content validity as well as usefulness and functionality of the simulator. The otolaryngologists significantly outperformed the student group in all categories measured (P < .0001), suggesting construct validity of the simulator. CONCLUSION: In this study, we could demonstrate face, content, and construct validity for a novel high-fidelity virtual reality otoscopy simulator. The results encourage the use of the otoscopy simulator as a complementary tool to traditional teaching methods in a curriculum for medical students.

Cross-cultural adaptation and validation of the 22-item sinonasal outcome test (SNOT-22) in German-speaking patients: a prospective, multicenter cohort study.

PURPOSE: Chronic rhinosinusitis (CRS) is a common condition associated with a significant reduction of the health-related quality of life. One of the most widely used assessment tools in CRS is the disease-specific, health-related questionnaire SNOT-22. The aim of this study was to translate and validate the SNOT-22 into the German language. METHODS: The questionnaire was translated using the forward-backward translation technique. After the translation its reliability, validity, and sensitivity were evaluated. For this purpose, the questionnaire was completed by patients diagnosed with CRS before, 3 months and 1 year after endoscopic sinus surgery and by healthy individuals as controls at three university hospitals in Germany. The individual scores of the questionnaire before surgery was correlated with the Lund-Mackay score as well as a global disease-specific question. RESULTS: A total of 139 CRS patients and 31 healthy individuals participated in the study. Internal consistency at all timepoints was very good, with Cronbach's alpha scores of 0.897, 0.941, and 0.945. The questionnaire was able to discriminate between CRS patients and control subjects (p < 0.0001) and scores improved significantly 3 month and 1 year after sinus surgery (p < 0.0001), indicating a good test-retest reliability, validity, and responsiveness. A significant correlation to the single global disease-specific question could be found (p < 0.0001), but no correlation with the Lund-Mackay score. CONCLUSION: The German Version of the SNOT-22 is a reliable, valid, and sensitive instrument for measuring health-related quality of life in patients with CRS. It can be recommended for clinical practice and outcome research for German-speaking patients.

[Validity and reliability of the Nijmegen Cochlear Implant Questionnaire in German]. / Validierung und Reliabilitätsprüfung des Nijmegen Cochlear Implant Questionnaire in deutscher Sprache.

BACKGROUND: The Nijmegen Cochlear Implant Questionnaire (NCIQ) is a disease-specific questionnaire to determine the health-related quality of life (HRQoL) of patients before and after cochlear implantation. OBJECTIVE: This study aimed to assess the validity and reliability of the German translation of the NCIQ. MATERIALS AND METHODS: A prospective study was performed in 100 postlingually deaf or severely hearing-impaired patients. HRQoL was assessed using the NCIQ, the Abbreviated Profile of Hearing Aid Benefit (APHAB), and the Hearing Participation Scale (HPS) before as well as 3 and 6 months after cochlear implantation. An untreated group of postlingually deaf or severely hearing-impaired patients (n = 54) served as a control. Cronbach's α and test-retest reliability were measured. The content, discrimination, and agreement validity were tested. The evaluation of construct validity was based on recently published data. Sensitivity and receiver operating curve (ROC) analysis, including consideration of the area under the curve (AUC), were used as quality criteria. RESULTS: The test-retest analysis showed stable NCIQ values 3 and 6 months postoperatively. The Cronbach's α values indicated good internal consistency. The NCIQ validly discriminated between treated and untreated patient groups. There were statistically significant albeit weak correlations between the NCIQ and the APHAB (r = -0.22; p = 0.04) and the HPS (r = 0.30; p = 0.01). Sensitivity and ROC analyses showed good measurement quality of the German-speaking NCIQ. CONCLUSION: The German translation of the NCIQ reliably and validly measures HRQoL before and after cochlear implantation and can be used for clinical monitoring after treatment with cochlear implants.

Decalcification method for nondestructive exposure of human inner ear specimens using ultrasonic EDTA scrubbing.

Owing to the density of the surrounding bone, preparation for histological preparation of the delicate inner ear is difficult and time-consuming; long preparation time increases the risk of deterioration. We present an EDTA decalcification method using an ultrasonic bath and microscopic removal of tissue along defined anatomical landmarks. Our method is rapid and enables preservation of delicate inner ear structures while minimizing the bony capsule. The reduction in volume made possible by our method creates ideal conditions for further processing with digital imaging techniques, in which the resolution is increased with reduced volume.

Conductive Hearing Loss in the Hyp Mouse Model of X-Linked Hypophosphatemia Is Accompanied by Hypomineralization of the Auditory Ossicles.

X-linked hypophosphatemia (XLH) is a hereditary musculoskeletal disorder caused by loss-of-function mutations in the PHEX gene. In XLH, increased circulating fibroblast growth factor 23 (FGF23) levels cause renal phosphate wasting and low concentrations of 1,25-dihydroxyvitamin D, leading to an early clinical manifestation of rickets. Importantly, hearing loss is commonly observed in XLH patients. We present here data from two XLH patients with marked conductive hearing loss. To decipher the underlying pathophysiology of hearing loss in XLH, we utilized the Hyp mouse model of XLH and measured auditory brain stem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs) to functionally assess hearing. As evidenced by the increased ABR/DPOAE threshold shifts in the mid-frequency range, these measurements indicated a predominantly conductive hearing loss in Hyp mice compared to wild-type (WT) mice. Therefore, we carried out an in-depth histomorphometric and scanning electron microscopic analysis of the auditory ossicles. Quantitative backscattered electron imaging (qBEI) indicated a severe hypomineralization of the ossicles in Hyp mice, evidenced by lower calcium content (CaMean) and higher void volume (ie, porosity) compared to WT mice. Histologically, voids correlated with unmineralized bone (ie, osteoid), and the osteoid volume per bone volume (OV/BV) was markedly higher in Hyp mice than WT mice. The density of osteocyte lacunae was lower in Hyp mice than in WT mice, whereas osteocyte lacunae were enlarged. Taken together, our findings highlight the importance of ossicular mineralization for hearing conduction and point toward the potential benefit of improving mineralization to prevent hearing loss in XLH. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Hearing Preservation Following Repeated Adenovector Delivery.

Factors influencing the damage to the inner ear can include the surgical approach used for vector delivery, the volume of vector used, the buffer that the vector is suspended in as well as the host response to the vector capsid and vector genes that are transferred. We evaluated the effect of Ad5 capsid adenovectors on hearing function after delivery to the perilymph of adult C57Bl/6 mice. Hearing was evaluated before surgery and 3 days post-surgery by auditory brain stem response (ABR) and distortion product otoacoustic emissions (DPOAE). A second group of mice underwent repeated delivery of adenovector two times to determine if a preliminary exposure to an Ad vector could induce an inflammatory response leading to further loss. The first adenovector (Ad.11D.LacZ) was delivered to the posterior semicircular canal or via round window. In the second surgery, a second adenovector (Ad.11D.gfp) was delivered to the horizontal semicircular canal. The functional outcome was tested prior, 7 days post first vector delivery, and 3 days post second vector delivery via ABR and DPOAE. Dual delivery via the semicircular canals resulted in preservation of hearing suggesting that pre-exposure to Ad5 capsid does not predispose to hearing loss. Delivery to the round window resulted in hearing loss that was worsened after the second vector delivery, suggesting that delivery route and prior injury to the inner ear rather than the repetition of delivery predisposes to further hearing loss. Anat Rec, 303:600-607, 2020. © 2019 American Association for Anatomy.

Are human ATP-binding cassette transporter C11 and earwax associated with the incidence of cholesteatoma?

Cholesteatoma is an ear disease based on a locally destructive noncancerous conglomerate of epidermis and keratin debris. Abnormal growth of stratified keratinized squamous epithelium in the temporal bone causes destruction of the outer and middle ear, potentially leading to hearing impairment, facial palsy, vertigo, lateral sinus thrombosis, and intracranial complications. Although cholesteatoma is effectively treated by surgical resection (mastoidectomy), the lack of effective and nonsurgical therapies potentially results in fatal consequences, establishing the need for a comprehensive investigation of cholesteatoma pathogenesis. Although its etiology is still being debated, interestingly, we found that the trend associated with the 538G allele frequency of the adenosine triphosphate-binding cassette transporter C11 (ABCC11) gene, the determinant of wet-type earwax, and ethnic groups was similar to that between the incidence of cholesteatoma and ethnic groups (countries). The incidences of cholesteatoma in Europe (Denmark, Finland, and Scotland) are higher than in East Asia (Japan), and the frequencies of the ABCC11 538G allele in African, American, and European (Finland and Scotland) populations are higher than those in East Asian populations (Japan). Additionally, a single-nucleotide polymorphism in the ABCC11 gene (rs17822931, 538G > A; Gly180Arg) is closely related to earwax morphotypes. While earwax is often beneficial to ear health, it is sometimes harmful in cases where it causes hearing impairment. Based on independent findings of associations between ABCC11 and the physiological environment of the auditory canal, we hypothesize a possible link between ABCC11, earwax, and the incidence of cholesteatoma.

Living with otosclerosis: disease-specific health-related quality-of-life measurement in patients undergoing stapes surgery.

INTRODUCTION: Otosclerosis is associated with hearing disability, leading to communication deficits and social and psychological restrictions. The objective of our study was to analyze disease-specific health-related quality of life (HRQOL) after stapes surgery and compare the outcome of HRQOL with audiometric parameters. SUBJECTS AND METHODS: Our clinical case study was conducted at two tertiary referral centers. All the 37 patients who had undergone stapes surgery were analyzed clinically and by audiometric testing (pure tone and speech audiometry) in the pre- and postoperative settings. Disease-specific HRQOL was assessed by the validated Stapesplasty Outcome Test 25 (SPOT-25) pre- and postoperatively. The subjective hearing disability was evaluated by the hearing handicap inventory for adults (HHIA). The postinterventional benefit was measured by the Glasgow Benefit Inventory (GBI). RESULTS: Disease-specific HRQOL improved significantly after stapes surgery in all scales of the SPOT-25. Postoperatively, the total score and the subscore "hearing function" correlated well with the audiometric data. The subscores "tinnitus", "social restrictions", and "mental condition" did not show significant association with audiometric parameters. The comparison of pre- and postoperative HHIA offered a significant improvement in the hearing disability. The scores of the HHIA correlated very well with the audiometric data. The GBI showed a postoperative benefit for each individual patient. CONCLUSION: Stapes surgery leads to a significant improvement in the hearing handicap and of disease-specific HRQOL. The audiometric parameters were shown as not being a sufficient indicator of social and mental well-being. HRQOL outcome measuring instruments should be used routinely in clinical practice to provide an individualized postoperative assessment.

A new approach for the determination of ECAP thresholds.

BACKGROUND: Electrically evoked compound action potentials (ECAPs) of the auditory nerve are routinely recorded for testing the cochlear implant integrity and its functional connection to the auditory system. The response thresholds derived from ECAP recordings are widely used as a helpful guide in the fitting of the dynamic range of electric stimulation, although they may not always predict the behavioral thresholds of individuals well. Conventionally, this threshold is based on the identification of a minimum N peak and maximum P peak and linear extrapolation of the resulting amplitude growth function (AGF). As an alternative, a new procedure involving numeric signal processing and requiring less user intervention is presented here. Data acquisition: In 12 adults implanted with MED-EL FLEX28 electrodes, two series of ECAPs were recorded immediately after implantation: (i) a full profile involving all 12 channels across the whole stimulus range in steps of 200 current units and (ii) a high resolution section (20 records in the immediate neighborhood of the threshold) of the AGF in one selected channel. Data treatment: It was observed that N and P wave latencies do not depend on stimulus intensity. Fixed time windows were hence defined for stimulus plus noise and noise alone regions. In these windows, the variance of the compound signal representing response and noise is extracted, whereas the noise variance is extracted from the tail of the curve following this time window. The base line is corrected by fitting an exponential function to reduce stimulus or amplifier artifacts. The response threshold is then derived from the response to noise ratio which should exceed the limit of 6 dB. RESULTS: The ECAP thresholds obtained from the new procedure coincide well with those determined by the conventional linear extrapolation of the AGF and they correlate to a greater degree with psychometric thresholds than the existing approach. CONCLUSIONS: The new ECAP algorithm looks promising and may reduce the need for user intervention in determining thresholds.

In vivo genetic manipulation of inner ear connexin expression by bovine adeno-associated viral vectors.

We have previously shown that in vitro transduction with bovine adeno-associated viral (BAAV) vectors restores connexin expression and rescues gap junction coupling in cochlear organotypic cultures from connexin-deficient mice that are models DFNB1 nonsyndromic hearing loss and deafness. The aims of this study were to manipulate inner ear connexin expression in vivo using BAAV vectors, and to identify the optimal route of vector delivery. Injection of a BAAV vector encoding a bacterial Cre recombinase via canalostomy in adult mice with floxed connexin 26 (Cx26) alleles promoted Cre/LoxP recombination, resulting in decreased Cx26 expression, decreased endocochlear potential, increased hearing thresholds, and extensive loss of outer hair cells. Injection of a BAAV vector encoding GFP-tagged Cx30 via canalostomy in P4 mice lacking connexin 30 (Cx30) promoted formation of Cx30 gap junctions at points of contacts between adjacent non-sensory cells of the cochlear sensory epithelium. Levels of exogenous Cx30 decayed over time, but were still detectable four weeks after canalostomy. Our results suggest that persistence of BAAV-mediated gene replacement in the cochlea is limited by the extensive remodeling of the organ of Corti throughout postnatal development and associated loss of non-sensory cells.

Cochlear Implant in Severe Impaired Psychiatric Patients: A Case Series.

OBJECTIVE: Psychotic disorders and intelligence deficiencies are no longer contraindications for cochlear implantation regarding the revised German guidelines from May 2012. This article aims to evaluate the outcome of patients with severe psychiatric comorbidities. Therefore the database of the Cochlear Implant Center of the University Hospital of Heidelberg was investigated. STUDY DESIGN: Retrospective case review. METHODS: We present three patients who received a cochlear implant (CI) despite a serious psychiatric disorder. Two were sent from psychiatrists asking if a CI was possible for their profound hearing loss. One patient had acoustic hallucinations and a recurrent depressive disorder, the other had a schizophrenic psychosis and a minor impairment of intelligence. The third patient had a recurrent depressive disorder, a posttraumatic stress disorder, a chronic pain disorder, and paranoid personality traits. We discuss the preoperative diagnosis, course of diseases, and psychosocial situation. RESULTS: All three patients received a CI and rehabilitation in the Cochlear Implant Center of the University Hospital of Heidelberg. All three of them opted for a second implant and developed a good hearing outcome. Free field understanding of words in quite is for all three of them over 60% in the Freiburger monosyllable test with two implants, similar to nonpsychiatric patients' results. No patient has acceptance problems. In the long run, no aggravation of the psychiatric diseases occurred. CONCLUSION: With interdisciplinary evaluation, a cochlear implantation is possible in severely impaired psychiatric patients. For a good result the indication is to be discussed interdisciplinary.

Cochlear implantation in recipients with single-sided deafness: Audiological performance.

OBJECTIVE: To examine the auditory benefit of cochlear implants (CI) in patients with single-sided deafness (SSD). MATERIAL AND METHODS: Twenty patients with a normal pure tone audiogram (n = 8) or moderate hearing loss (n = 12) in one ear and a CI system MED-EL SONATA/CONCERTO + OPUS2 (n = 12), COCHLEAR CI24RE(ST) + CP810 (n = 7) and Advanced Bionics HiRes90 K + Harmony (n = 1) in the contralateral ear and with at least 6 months of CI experience were tested with respect to directional hearing, speech perception in noise, binaural loudness matching, and binaural pitch matching. Twenty-six normal hearing controls were included for normative reference. RESULTS: Addition of the CI significantly improves directional hearing (percentage of correct source identifications improved from 14.9 to 15.6%, root mean square error decreased from 125 to 93°) and improves speech perception in noise (speech perception threshold median improved from -2.3 to -6.0 dB signal to noise ratio, equivalent to a binaural intelligibility level difference = 3.7 dB). Alternate binaural loudness balancing showed that matching takes place at levels between 48 and 55 dB HL (group averages). In the pitch matching experiment, the standard deviation of the relative interaural frequency difference at 500, 1000, and 2000 Hz was 24.5, 22.8, and 24.0%, respectively (compared to 11.7, 14.4, and 12.3% in the control group). CONCLUSIONS: In SSD, cochlear implantation considerably improves audiological performance in terms of directional hearing, binaural signal equivalence, and speech perception.

Cochlear NMDA receptors as a therapeutic target of noise-induced tinnitus.

BACKGROUND: Accumulating evidence suggests that tinnitus may occur despite normal auditory sensitivity, probably linked to partial degeneration of the cochlear nerve and damage of the inner hair cell (IHC) synapse. Damage to the IHC synapses and deafferentation may occur even after moderate noise exposure. For both salicylate- and noise-induced tinnitus, aberrant N-methyl-d-aspartate (NMDA) receptor activation and related auditory nerve excitation have been suggested as origin of cochlear tinnitus. Accordingly, NMDA receptor inhibition has been proposed as a pharmacologic approach for treatment of synaptopathic tinnitus. METHODS: Round-window application of the NMDA receptor antagonist AM-101 (Esketamine hydrochloride gel; Auris Medical AG, Basel, Switzerland) was tested in an animal model of tinnitus induced by acute traumatic noise. The study included the quantification of IHC ribbon synapses as a correlate for deafferentation as well as the measurement of the auditory brainstem response (ABR) to close-threshold sensation level stimuli as an indication of sound-induced auditory nerve activity. RESULTS: We have shown that AM-101 reduced the trauma-induced loss of IHC ribbons and counteracted the decline of ABR wave I amplitude generated in the cochlea/auditory nerve. CONCLUSION: Local round-window application of AM-101 may be a promising therapeutic intervention for the treatment of synaptopathic tinnitus.

Variability of an ideal insertion vector for cochlear implantation.

HYPOTHESIS: Based on a three-dimensional analysis, the orientation of the basal turn of the cochlea, the disposition of the basilar membrane, and the characteristics of the hook region--all of which determine the ideal electrode insertion vector during cochlear implantation--might vary among individuals to a greater degree than previously considered. The aim of this study is to assess the variability of an ideal insertion vector among a sample of surgical candidates from a purely anatomical perspective as well as from a more intraoperative-surgical perspective. BACKGROUND: During cochlear implantation through a cochleostomy or round window approach, the angle or vector of insertion after the first entry point seems to be related to intracochlear damage, which might correlate with anatomical and functional features. METHODS: Three-dimensional reconstructions of the temporal bones of 50 cochlear implant candidates (a total of 100 ears) were assessed. The spatial orientation of an ideal insertion vector for a cochleostomy and a round window approach were estimated. RESULTS: A difference as great as 60 degrees was observed for an ideal insertion vector among the subjects. From an intraoperative perspective, this variability involves pushing the electrodes "as near to the buttress" or "as near to the emergence of the corda tympani" as possible, depending on the case. CONCLUSION: The orientation of the basal turn and the corresponding ideal electrode insertion vector vary widely among subjects. A proper preoperative estimation on a case-to-case scenario for this feature might lead to technique adaptation during insertion, possibly contributing to minimizing electrode insertion trauma and thus optimizing the anatomical and functional results.