The Inheritance of Hearing Loss and Deafness: A Historical Perspective.

If the term "genetics" is a relatively recent proposition, introduced in 1905 by English biologist William Bateson, who rediscovered and spread in the scientific community Mendel's principles of inheritance, since the dawn of human civilization the influence of heredity has been recognized, especially in agricultural crops and animal breeding. And, later, in familial dynasties. In this concise review, we outline the evolution of the idea of hereditary hearing loss, up to the current knowledge of molecular genetics and epigenetics.

Age-related changes in auditory perception. Hearing loss in the elderly: aging ear or aging brain?

Hearing loss in the elderly is a very common disease: it is estimated to affect up to a third of the population aged 65 years or more, and 50% of people over 75 years old. There is a growing amount of data concerning the association between hearing loss and cognitive decline. Various possible mechanisms at the basis of this association have been proposed, such as the "common cause hypothesis," the "cascade hypothesis," and the "cognitive load hypothesis."Critically reviewing the data is essential to highlight the features of the relationship between hearing loss and cognitive decline. Most of the hearing tests available should take into account that dementia or even just mild cognitive impairment (MCI) may lead to poor performance during examination. On the other hand, clinicians should also remember that tests used to assess cognitive function require an adequate hearing capacity.In this article we propose to analyze current diagnostic tests, treatment options, auditory processing, and rehabilitation strategies for hearing loss in the elderly in order to facilitate the management of this handicap in this fragile population.

miR-218 Promotes Dopaminergic Differentiation and Controls Neuron Excitability and Neurotransmitter Release through the Regulation of a Synaptic-Related Genes Network.

In the brain, microRNAs (miRNAs) are believed to play a role in orchestrating synaptic plasticity at a higher level by acting as an additional mechanism of translational regulation, alongside the mRNA/polysome system. Despite extensive research, our understanding of the specific contribution of individual miRNA to the function of dopaminergic neurons (DAn) remains limited. By performing a dopaminergic-specific miRNA screening, we have identified miR-218 as a critical regulator of DAn activity in male and female mice. We have found that miR-218 is specifically expressed in mesencephalic DAn and is able to promote dopaminergic differentiation of embryonic stem cells and functional maturation of transdifferentiated induced DA neurons. Midbrain-specific deletion of both genes encoding for miR-218 (referred to as miR-218-1 and mir218-2) affects the expression of a cluster of synaptic-related mRNAs and alters the intrinsic excitability of DAn, as it increases instantaneous frequencies of evoked action potentials, reduces rheobase current, affects the ionic current underlying the action potential after hyperpolarization phase, and reduces dopamine efflux in response to a single electrical stimulus. Our findings provide a comprehensive understanding of the involvement of miR-218 in the dopaminergic system and highlight its role as a modulator of dopaminergic transmission.SIGNIFICANCE STATEMENT In the past decade, several miRNAs have emerged as potential regulators of synapse activity through the modulation of specific gene expression. Among these, we have identified a dopaminergic-specific miRNA, miR-218, which is able to promote dopaminergic differentiation and regulates the translation of an entire cluster of synapse related mRNAs. Deletion of miR-218 has notable effects on dopamine release and alters the intrinsic excitability of dopaminergic neurons, indicating a direct control of dopaminergic activity by miR-218.

Benefits of bone conduction hearing aid in children with unilateral aural atresia.

Objective: To assess the hearing benefit with a unilateral bone conduction hearing aid in a cohort of children with unilateral aural atresia. Methods: Cross-sectional case series pilot study involving 7 children (median age: 10 years, range 6-11). All patients underwent pure-tone, speech, aided sound field and aided speech audiometry and Simplified Italian Matrix Test (SIMT) with and without bone conduction hearing aid (Baha 5® CochlearTM). Cognitive abilities were assessed in 5 patients. Results: The mean air conduction pure-tone average (PTA) of the atretic ear was 63.2 ± 6.9 dB, while the bone conduction PTA was 12.6 ± 4.7 dB. Speech discrimination score of the atretic ear was 88.6 ± 3.8 dB, while with the hearing aid it was 52.8 ± 1.9 dB. In the contralateral ear, there was no significant air-bone gap, and PTAs for air and bone conduction thresholds were within normal range (PTA ≤ 25 dB). The mean aided air conduction hearing threshold was 26.2 ± 7.97. Mean speech recognition threshold without the hearing aid was -5.1 ± 1.9 dB, and -6.0 ± 1.7 dB with the hearing aid tested with the SIMT. The mean score of the cognitive test was 46.8 ± 42.8. Conclusions: These preliminary findings should encourage clinicians in proposing a unilateral bone conduction hearing aid in children with unilateral atresia.

Genetic Evaluation of Prelingual Hearing Impairment: Recommendations of an European Network for Genetic Hearing Impairment.

The cause of childhood hearing impairment (excluding infectious pathology of the middle ear) can be extrinsic (embryofoetopathy, meningitis, trauma, drug ototoxicity, noise trauma, etc [...].

Congenital Deafness and Deaf-Mutism: A Historical Perspective.

Hearing loss is the most common sensory deficit and one of the most common congenital abnormalities. The estimated prevalence of moderate and severe hearing loss in a normal newborn is 0.1-0.3%, while the prevalence is 2-4% in newborns admitted to the newborn intensive care unit. Therefore, early detection and prompt treatment are of utmost importance in preventing the unwanted sequel of hearing loss on normal language development. The problem of congenital deafness is today addressed on the one hand with hearing screening at birth, on the other with the early (at around 3 months of age) application of hearing aids or, in case of lack of benefit, by the cochlear implant. Molecular genetics, antibody tests for some viruses, and diagnostic imaging have largely contributed to an effective etiological classification. A correct diagnosis and timely fitting of hearing aids or cochlear implants is useful for deaf children. The association between congenital deafness and "mutism", with all the consequences on/the consideration that deaf mutes have had since ancient times, not only from a social point of view but also from a legislative point of view, continued until the end of the nineteenth century, with the development on one side of new methods for the rehabilitation of language and on the other of sign language. But we need to get to the last decades of the last century to have, on the one hand, the diffusion of "universal newborn hearing screening", the discovery of the genetic causes of over half of congenital deafness, and on the other hand the cochlear implants that have allowed thousands of children born deaf the development of normal speech. Below, we will analyze the evolution of the problem between deafness and deaf-mutism over the centuries, with particular attention to the nineteenth century.

Liquid Crystalline Nanoparticles Conjugated with Dexamethasone Prevent Cisplatin Ototoxicity In Vitro.

The conjugation of drugs with nanoparticles represents an innovative approach for controlled and targeted administration of therapeutic agents. Nanoparticle-based systems have been tested for the inner ear therapy, increasing the drug diffusion and being detected in all parts of the cochlea when locally applied near the round window. In this study, glycerol monooleate liquid crystalline NanoParticles were conjugated with Dexamethasone (NPD), a hydrophobic drug already used for inner ear treatments but defective in solubility and bioavailability. NPD has been tested in vitro in the cell line OC-k3, a model of sensory cells of the inner ear, and the therapeutic efficacy has been evaluated against cisplatin, a chemotherapeutic compound known to induce ototoxicity. After comparing the physical chemical characteristics of NPD to the equivalent naïve nanoparticles, an initial investigation was carried out into the nanoparticle's uptake in OC-k3 cells, which takes place within a few hours of treatment without causing toxic damage up to a concentration of 50 µg/mL. The NPD delivered the dexamethasone inside the cells at a significantly increased rate compared to the equivalent free drug administration, increasing the half-life of the therapeutic compound within the cell. Concerning the co-treatment with cisplatin, the NPD significantly lowered the cisplatin cytotoxicity after 48 h of administration, preventing cell apoptosis. To confirm this result, also cell morphology, cell cycle and glucocorticoids receptor expression were investigated. In conclusion, the NPD system has thus preliminarily shown the potential to improve the therapeutic efficacy of treatments delivered in the inner ear and prevent drug-induced ototoxicity.

Early-life social stress induces permanent alterations in plasticity and perineuronal nets in the mouse anterior cingulate cortex.

Child maltreatment disrupts trajectories of brain development, but the underlying pathways are unclear. Stressful stimuli in early life interfere with maturation of local inhibitory circuitry and deposition of perineuronal nets (PNNs), specialized extracellular matrix structures involved in the closure of critical periods of development. Alterations in cortical PNN and parvalbumin (PV) following early-life stress (ELS) have been detected in human and animal studies. Aberrations in the anterior cingulate cortex (ACC) are the most consistent neuroimaging findings in maltreated people, but the molecular mechanisms linking ELS with ACC dysfunctions are unknown. Here, we employed a mouse model of early social threat to test whether ELS experienced in a sensitive period for ACC maturation could induce long-term aberrations of PNN and PV development in the ACC, with consequences on plasticity and ACC-dependent behavior. We found that ELS increased PNN but not PV expression in the ACC of young adult mice. This was associated with reduced frequency of inhibitory postsynaptic currents and long-term potentiation impairments and expression of intense object phobia. Our findings provide information on the long-term effects of ELS on ACC functionality and PNN formation and present evidence for a novel neurobiological pathway underlying the impact of early adversity on the brain.

Multicentre study on resection margins in carcinoma of the oral cavity, oro-hypopharynx and larynx.

Objective: The prognostic significance of the resection margins is still subject of conflicting opinions. The purpose of this paper is to report the results of a study on the margins in carcinoma of the oral cavity, oro-hypopharynx and larynx. Methods: A multicentre prospective study was carried out between 2015 and 2018 with the participation of 10 Italian reference hospitals. The primary objective was to evaluate local control in patients with well-defined clinical characteristics and comprehensive histopathological information. Results: During the study period, 455 patients were enrolled; the minimum follow-up was 2 years. Previous treatment, grading and fresh specimen examination were identified as risk factors for local control in multivariate analysis. On the basis of these results, it seems possible to delineate "risk profiles" for different oncological outcomes. Discussion: The prognostic significance of the margins is reduced, and other risk factors emerge, which require diversified treatment and follow-up. Conclusions: Multidisciplinary treatment with adjuvant therapy, if indicated, reduces the prognostic importance of margins. Collaboration with a pathologist is an additional favourable prognostic factor and quality indicator.An appendix with literature review is present in the online version.

Long-Term Impedance Trend in Cochlear Implant Users with Genetically Determined Congenital Profound Hearing Loss.

BACKGROUND: Impedance is a basic parameter registered at any cochlear implant (CI) fitting section. It is useful in monitoring electrode functioning and the status of the surrounding anatomical structures. PURPOSE: The main aim of this study is to evaluate the 5-year impedance-value trend in patients affected by congenital genetically determined profound hearing loss implanted with Cochlear Nucleus devices. RESEARCH DESIGN: Observational, retrospective, monocentric study. STUDY SAMPLE: Twenty-seven consecutive patients (9 females: 12.0 ± 7.6 years old; range: 4.2-40.4) with genetic diagnosis of GJB2 mutation causing congenital profound hearing loss who underwent cochlear implantation from 2010 to 2020 with good auditory benefit. INTERVENTION: Impedance values of the CIs were obtained from the CIs' programming software that registers those parameters for each follow-up section of each patient. DATA COLLECTION AND ANALYSIS: Impedance values were measured over time (activation, 6, 12, 24, and 60 months after cochlear implantation), for each of the 22 electrodes, in common ground, monopolar 1, monopolar 2, and monopolar 1 + 2 stimulation modes. RESULTS: A significant variation was found between CI activation and 6-month follow-up. This difference was found for each of the 22 electrodes. Electrodes 1 to 4 showed higher impedance values compared with all other electrodes in each time interval. Repeated-measures analysis of variance ruled out significant variations in impedance values from 6-month to 5-year follow-up. CONCLUSIONS: Impedance values were extremely stable after activation, at least for the first 5 years. In these cases, even minimal impedance variations should be carefully evaluated for their possible implications on hearing performance.

Early Life Social Stress Causes Sex- and Region-Dependent Dopaminergic Changes that Are Prevented by Minocycline.

Early life stress (ELS) is known to modify trajectories of brain dopaminergic development, but the mechanisms underlying have not been determined. ELS perturbs immune system and microglia reactivity, and inflammation and microglia influence dopaminergic transmission and development. Whether microglia mediate the effects of ELS on dopamine (DA) system development is still unknown. We explored the effects of repeated early social stress on development of the dopaminergic system in male and female mice through histological, electrophysiological, and transcriptomic analyses. Furthermore, we tested whether these effects could be mediated by ELS-induced altered microglia/immune activity through a pharmacological approach. We found that social stress in early life altered DA neurons morphology, reduced dopamine transporter (DAT) and tyrosine hydroxylase expression, and lowered DAT-mediated currents in the ventral tegmental area but not substantia nigra of male mice only. Notably, stress-induced DA alterations were prevented by minocycline, an inhibitor of microglia activation. Transcriptome analysis in the developing male ventral tegmental area revealed that ELS caused downregulation of dopaminergic transmission and alteration in hormonal and peptide signaling pathways. Results from this study offer new insight into the mechanisms of stress response and altered brain dopaminergic maturation after ELS, providing evidence of neuroimmune interaction, sex differences, and regional specificity.

Neuron Compatibility and Antioxidant Activity of Barium Titanate and Lithium Niobate Nanoparticles.

The biocompatibility and the antioxidant activity of barium titanate (BaTiO3) and lithium niobate (LiNbO3) were investigated on a neuronal cell line, the PC12, to explore the possibility of using piezoelectric nanoparticles in the treatment of inner ear diseases, avoiding damage to neurons, the most delicate and sensitive human cells. The cytocompatibility of the compounds was verified by analysing cell viability, cell morphology, apoptotic markers, oxidative stress and neurite outgrowth. The results showed that BaTiO3 and LiNbO3 nanoparticles do not affect the viability, morphological features, cytochrome c distribution and production of reactive oxygen species (ROS) by PC12 cells, and stimulate neurite branching. These data suggest the biocompatibility of BaTiO3 and LiNbO3 nanoparticles, and that they could be suitable candidates to improve the efficiency of new implantable hearing devices without damaging the neuronal cells.

Correction: Martini, A.; Cassina, M. Victor A. McKusick, the "Father of Medical Genetics". Audiol. Res. 2021, 11, 636-638.

In the original article [...].

Cochlear implant in vestibular schwannomas: long-term outcomes and critical analysis of indications.

PURPOSE: To describe our institutional experience in cochlear implantation after vestibular schwannoma (VS) resection, and compare the audiological outcomes between sporadic and neurofibromatosis type 2 (NF2) VS sub-cohorts of patients, and in relation to preoperative contralateral hearing. METHODS: Seventeen patients (8 sporadic and 9 NF2-associated VSs) who had undergone VS resection and cochlear implant (CI) were analyzed retrospectively. Audiological outcomes at 24 months were correlated with preoperative clinical variables. The results according to VS type (sporadic vs. NF2-associated) and contralateral hearing (impaired vs. normal) were compared. RESULTS: Fourteen CIs were actively used by the patients (77.8%). Twenty-four months after CI activation, the median postoperative PTA (pure tone average) was 45.6 dB nHL and a measurable WRS (Word Recognition Score) was achieved by 44.4% of patients (median WRS = 40%). The median postoperative PTA in the implanted ear resulted better in the group with an impaired contralateral hearing (36.3 dB nHL vs. 78.8 dB nHL, p = 0.019). Good preoperative contralateral hearing status (A-B classes of AAO-HNS) was a negative prognostic factor for CI performance on open-set discrimination (OR = 28.0, 95% CI 2.07-379.25, p = 0.012). CONCLUSIONS: CI is a viable rehabilitative option for patients with sporadic or NF2-associated VS. A good contralateral hearing adversely affects CI outcome and should be taken into consideration for patients' selection and rehabilitation programs.

Position of Retrosigmoid Craniotomy in Hearing Preservation Surgery for Vestibular Schwannoma.

BACKGROUND: Surgical access to the internal auditory canal (IAC) fundus is a crucial aspect of the retrosigmoid approach for hearing preservation surgery in vestibular schwannoma. An appropriate positioning of the retrosigmoid craniotomy is necessary to obtain an adequate surgical corridor for full fundus exposure and labyrinth preservation. OBJECTIVE: To describe how the position of the posterior edge of the access related to the probability of exposing the fundus and to propose novel criteria for positioning the retrosigmoid craniotomy. METHODS: Data on fundus exposure were retrospectively collected in 33 consecutive cases of sporadic vestibular schwannoma, submitted to the retrosigmoid craniotomy in a park-bench position. Patients' computed tomography images were analyzed to calculate the position of the posterior edge of the craniotomy with reference to the fundus-labyrinth line (FLL), which starts at the fundus and, running just posterior to the labyrinth, reaches the occipital squama. A logistic regression model was used to correlate the craniotomy position with the probability of exposing the fundus. RESULTS: The fundus exposure rate was significantly higher (P = .005) for craniotomies located posteromedially to the FLL. In a logistic regression model, the probability of exposing the fundus reached 95% for craniotomies located 11.3 mm posteromedially to the FLL. CONCLUSION: This study showed a strong association between craniotomy position and fundus exposure rate. Our findings suggest that the posteromedial edge of the retrosigmoid craniotomy should lie approximately 11 mm posteromedially to FLL to maximize the chances of exposing the fundus.

Pediatric Hearing Loss Management in the COVID-19 Era: Possible Consequences and Resources for the Next Future.

Pediatric hearing loss early diagnosis and treatment have been limited by the current restrictions due to the coronavirus disease 2019 pandemic. The difficulty in accessing the multiple facilities required for the rehabilitative process is influencing the timing of each step of the process. Auditory hearing screening programs, etiological characterization, surgical timing, and speech therapies have all been limited in the past year. The current conditions have forced us to adopt different strategies to overcome the necessary social distancing prescriptions. Although their efficacy should be proved over time, some of these resources will be probably useful even in a nonpandemic future.

The prevalence of frailty and its associated factors in an Italian institutionalized older population: findings from the cross-sectional Alvise Cornaro Center Study.

BACKGROUND: While it is well established that frail older people have a higher risk of negative health outcomes, the prevalence of frailty and its associated factors in Italian older institutionalized population has never been investigated. AIMS: The aims of this study were to assess the prevalence of frailty and to identify its associated factors in an Italian residential care home population. METHODS: An observational cross-sectional study was designed to evaluate older people aged 70 or over of an Italian residential care home. A multidimensional assessment examining functional, geriatric, ophthalmic, and audiological domains was carried out to identify factors associated with frailty. Physical frailty was evaluated using Fried's criteria. RESULTS: Data analysis uncovered a 51.1% prevalence of pre-frailty and a 40.4% prevalence of frailty in the 94 eligible participants (64 females) whose data were complete. The multivariable analysis showed that a low education level (OR = 5.12, 95% CI 1.22-21.49), a low physical quality of life score (OR = 13.25, 95% CI 3.51-50.08), a low mental quality of life score (OR = 9.22, 95% CI 2.38-35.69), visual impairment (OR = 7.65, 95% CI 1.77-33.14), and hearing impairment (OR = 4.62, 95% CI 1.03-20.66) were independently associated with frailty. CONCLUSIONS: Frailty was found to be highly prevalent in the residential care home studied. Since frailty is a reversible condition, identifying the modifiable factors associated to it should be viewed as an important step in planning and implementing targeted, early prevention strategies.

Bulging of the Oval Window in Common Cavity Deformity: A Possible Predictor of Meningitis.

OBJECTIVE: To investigate the prevalence-rate of oval window bulging in the common cavity and its association with bacterial meningitis. PATIENTS: CT and clinical files of 29 children with preliminary diagnosis of common cavity deformity were collected from 13 Italian centers. INTERVENTION: A retrospective case review study was conducted with a centralized evaluation of the temporal bone CT imaging was performed at Azienda Ospedale - Università Padova, Padova, Italy. MAIN OUTCOME MEASURE: Diagnosis of common cavity was reviewed; in addition, a fluid protrusion into the middle-ear cavity through the oval window at CT imaging was considered as oval window bulging. Its association with the history of bacterial meningitis was investigated. RESULTS: Common cavity deformity was confirmed in 14/29 children (mean-age 11.4 ±â€Š3.8; age-range 5-20; nine females) referred with this diagnosis. In 7/14 patients, the common cavity deformity was bilateral (i.e., 21 common cavities). Oval window bulging was found in 3/19 common cavities (concomitant middle-ear effusive otitis hampered the evaluation in two cases), while the internal acoustic meatus fundus was defective in 10/21 cases. History of bacterial meningitis was found in three children (21%) and two of them had oval window bulging at CT. In the case unrelated to oval window bulging, meningitis occurred late at the age of 12 during acute otitis contralateral to common cavity deformity (ipsilaterally to incomplete partition type 1). CONCLUSION: Patients harboring common cavity deformity have a high risk of meningitis in their first years of life. Oval window bulging seems to be associated with a higher risk of meningitis. This information might be important for appropriate surgical planning.