Cause Of Sensorineural Hearing Loss Research Articles

From diagnosis to management: current perspectives on congenital cytomegalovirus infection.

Congenital CMV (cCMV) infection is the most common infection of newborns and a leading cause of hearing loss and other neurologic disabilities in children. This review focuses on the diagnosis, presentation and management of cCMV infection. Cytomegalovirus is one of the leading causes of sensorineural hearing loss in children. It also leads to neurodevelopmental disabilities and learning problems throughout childhood in both symptomatic and asymptomatic newborns. Urine and saliva PCR testing are the preferred methods of testing newborn infants for cCMV. In recent years, newborn-targeted and universal screening programs have been implemented in several states and major medical centers with the goal of identifying infected infants at risk for hearing loss. Treatment for infants diagnosed with cCMV infection should be limited to those who are moderately to severely symptomatic at birth with cCMV infection, though treatment may be beneficial for children who are asymptomatic with isolated sensorineural hearing loss. As more children with cCMV are being identified through newborn screening, understanding the clinical presentation and sequelae is important for appropriate management of children with cCMV.

From silence to sound – a case of autoimmune ear disease

Autoimmune inner ear disease (AIED) is a rare rheumatological cause of sensorineural hearing loss, accounting for less than 1% of worldwide hearing loss. It presents with rapidly progressive, unilateral or bilateral SNHL, often fluctuating. The progression is over weeks to months, along with vestibular symptoms. Diagnosing the condition is challenging because no adopted standardized tests are available. Hence, AIED is a challenging diagnosis based on exclusion. Clinical characteristics and how the patients respond to immunosuppressive agents are used for the diagnoses of AIED. Only a few cases have been reported in India till now. Here, we present a rare case of Autoimmune Ear Disease without any underlying systemic autoimmune disease.

Pcolce2 overexpression promotes supporting cell reprogramming in the neonatal mouse cochlea.

Hair cell (HC) damage is a leading cause of sensorineural hearing loss, and in mammals supporting cells (SCs) are unable to divide and regenerate HCs after birth spontaneously. Procollagen C-endopeptidase enhancer 2 (Pcolce2), which encodes a glycoprotein that acts as a functional procollagen C protease enhancer, was screened as a candidate regulator of SC plasticity in our previous study. In the current study, we used adeno-associated virus (AAV)-ie (a newly developed adeno-associated virus that targets SCs) to overexpress Pcolce2 in SCs. AAV-Pcolce2 facilitated SC re-entry into the cell cycle both in cultured cochlear organoids and in the postnatal cochlea. In the neomycin-damaged model, regenerated HCs were detected after overexpression of Pcolce2, and these were derived from SCs that had re-entered the cell cycle. These findings reveal that Pcolce2 may serve as a therapeutic target for the regeneration of HCs to treat hearing loss.

Bilateral, Sequential Sudden Hearing Loss in a Patient With Multiple COVID-19 Infections and Potential Implications on Subsequent Cochlear Implant Performance.

Viruses are often implicated as a cause of sensorineural hearing loss (SNHL), particularly sudden cases, including COVID-19. Determining the viral mechanism that leads to hearing loss is necessary for its future prevention and treatment. The 47-year-old woman who is the subject of this case study presented with sudden SNHL following multiple infections of COVID-19. Following a trial of a contralateral routing of sound device, she received a right cochlear implant (CI). Following a period of high performance, additional cases of COVID-19 infection and device failure issues resulted in the explant/reimplant of 1 ear and implantation of the contralateral ear. Despite extensive rehabilitation after these events, the patient continues to experience difficulties in speech understanding, not reaching her initial high levels of right ear performance. Further research is needed to determine the implications of COVID-19 as it relates to SNHL. This case study aimed to highlight the course of treatment and provide insight into the impact of COVID-19 on sudden hearing loss and its relationship to CI performance.

The effects of acute and chronic noise trauma on stimulus-evoked activity across primary auditory cortex layers.

Exposure to intense noise environments is a major cause of sensorineural hearing loss and auditory perception disorders, such as tinnitus and hyperacusis, which may have a central origin. The effects of noise-induced hearing loss on the auditory cortex have been documented in many studies. One limitation of these studies, however, is that the effects of noise trauma have been mostly studied at the granular layer (i.e, the main cortical recipient of thalamic input), while the cortex is a very complex structure, with six different layers each having its own pattern of connectivity and role in sensory processing. The present study aims to investigate the effects of acute and chronic noise trauma on the laminar pattern of stimulus-evoked activity in the primary auditory cortex of the anesthetized guinea pig. We show that acute and chronic noise trauma are both followed by an increase in stimulus-evoked cortical responses, mostly in the granular and supragranular layers. The cortical responses are more monotonic as a function of the intensity level after noise trauma. There was minimal change, if any, in local field potential (LFP) amplitude after acute noise trauma, while LFP amplitude was enhanced after chronic noise trauma. Finally, LFP and the current source density analysis suggest that acute but more specifically chronic noise trauma is associated with the emergence of a new sink in the supragranular layer. This result suggests that supragranular layers become a major input recipient. We discuss the possible mechanisms and functional implications of these changes.NEW & NOTEWORTHY Our study shows that cortical activity is enhanced after trauma and that the sequence of cortical column activation during stimulus-evoked response is altered, i.e. the supragranular layer becomes a major input recipient. We speculate that these large cortical changes may play a key role in the auditory hypersensitivity (hyperacusis) that can be triggered after noise trauma in human subjects.

Droplet Digital PCR (ddPCR) Does Not Enhance the Sensitivity of Detection of Cytomegalovirus (CMV) DNA in Newborn Dried Blood Spots Evaluated in the Context of Newborn Congenital CMV (cCMV) Screening.

Congenital cytomegalovirus (cCMV) infection is a leading cause of sensorineural hearing loss (SNHL) and neurodevelopmental disabilities in children worldwide. Some regions in the United States and Canada have implemented universal newborn screening for cCMV, which requires molecular diagnostic technologies for identifying cCMV, such as PCR testing of newborn dried blood spots (DBS). This study aimed to evaluate the sensitivity of droplet digital PCR (ddPCR) compared to quantitative real-time PCR to detect CMV DNA in newborn DBS. The limit of detection of various ddPCR primer/probe combinations (singleplex UL55-HEX, singleplex UL83-FAM, and multiplex UL55-HEX/UL83-FAM) was evaluated using the National Institute of Standards and Technology's (NIST) CMV quantitative standard. Singleplex UL55-HEX ddPCR exhibited the lowest limit of detection among the primer/probe combinations tested for ddPCR. UL55 ddPCR was then compared to real-time PCR in 49 infants with confirmed cCMV identified through newborn screening for CMV in saliva swabs and confirmed by a urine test. The results showed that ddPCR was only positive for 59% (29 out of 49) of the cCMV infants, while real-time PCR was positive for 80% (39 out of 49). Due to its lower sensitivity and throughput, ddPCR may not be suitable for cCMV newborn screening.

Risk factors and outcomes in patients with cochlear nerve deficiency

IntroductionCochlear nerve deficiency (CND) is a cause of sensorineural hearing loss made by radiologic criteria. There is sparse literature involving audiological outcomes and cochlear implantation (CI) success in patients with CND. MethodsA retrospective chart review of all patients with sensorineural hearing loss at a tertiary children's hospital from 2000 to 2020 was conducted. Patients with CND on radiographic imaging were included and categorized as hypoplastic, aplastic, or indeterminate. ResultsIn this study, 53 patients were identified with CND, totaling 70 ears. Of the 53 patients, 30 (56.6 %) were male, 8 (16.0 %) had a family history of childhood hearing loss, 6 (11.3 %) were born preterm, and 11 (23.4 %) required neonatal intensive care admission. The median maternal age was 29 years old [IQR: 27, 35], and 8 (15 %) patients were born to mothers with diabetes. Of the 70 ears, 49 (70 %) utilized conventional hearing aids, 12 (17.1 %) utilized a bone-anchored hearing aid, and 10 (14.3 %) underwent CI. Of the 10 ears implanted, 4 (40 %) ears had nerves classified as hypoplastic, 3 (30 %) as aplastic, and 3 (30 %) as indeterminate. Improvement in pure tone averages compared to preoperative testing was demonstrated in 8 (80 %), and 6 (60 %) displayed improved speech awareness thresholds. ConclusionThis study demonstrates that there may be an association between CND and maternal diabetes and NICU admission. There are variable results with hearing amplification options in patients with CND, and further research is needed to better describe the role of CI, bone-anchored hearing aids and conventional hearing aids in patients with CND.

Cortisol Sensitizes Cochlear Hair Cells to Gentamicin Ototoxicity Via Endogenous Apoptotic Pathway.

The widespread use of aminoglycosides is a prevalent cause of sensorineural hearing loss. Patients receiving aminoglycosides usually have elevated levels of circulating stress hormones due to disease or physiological stress; however, whether the stress hormone cortisol impacts aminoglycoside-mediated injury of cochlear hair cells has not been fully investigated. House Ear Institute-Organ of Corti 1 (HEI-OC1) cells with or without cortisol pretreatment were exposed to gentamicin, we investigated the effect of cortisol pretreatment on gentamicin ototoxicity by assessing cell viability. Molecular pathogenesis was explored by detecting apoptosis and oxidative stress. Meanwhile, by inhibiting glucocorticoid receptors (GR) and mineralocorticoid receptors (MR), the potential roles of receptor types in cortisol-mediated sensitization were evaluated. Cortisol concentrations below 75 μmol/l did not affect cell viability. However, pretreatment with 50 μmol/l cortisol for 24 hours sensitized hair cells to gentamicin-induced apoptosis. Further mechanistic studies revealed that cortisol significantly increased hair cell apoptosis and oxidative stress, and altered apoptosis-related protein expressions induced by gentamicin. In addition, blockade of either GR or MR attenuated cortisol-induced hair cell sensitization to gentamicin toxicity. Cortisol pretreatment increased mammalian hair cell susceptibility to gentamicin toxicity. Sensitization was related to the activation of the intrinsic apoptotic pathway and excessive generation of reactive oxygen species. Cortisol may exacerbate aminoglycoside ototoxicity.

Dispersed DNA variants underlie hearing loss in South Florida’s minority population

BackgroundWe analyzed the genetic causes of sensorineural hearing loss in racial and ethnic minorities of South Florida by reviewing demographic, phenotypic, and genetic data on 136 patients presenting to the Hereditary Hearing Loss Clinic at the University of Miami. In our retrospective chart review, of these patients, half self-identified as Hispanic, and the self-identified racial distribution was 115 (86%) White, 15 (11%) Black, and 6 (4%) Asian. Our analysis helps to reduce the gap in understanding the prevalence, impact, and genetic factors related to hearing loss among diverse populations.ResultsThe causative gene variant or variants were identified in 54 (40%) patients, with no significant difference in the molecular diagnostic rate between Hispanics and Non-Hispanics. However, the total solve rate based on race was 40%, 47%, and 17% in Whites, Blacks, and Asians, respectively. In Non-Hispanic Whites, 16 different variants were identified in 13 genes, with GJB2 (32%), MYO7A (11%), and SLC26A4 (11%) being the most frequently implicated genes. In White Hispanics, 34 variants were identified in 20 genes, with GJB2 (22%), MYO7A (7%), and STRC-CATSPER2 (7%) being the most common. In the Non-Hispanic Black cohort, the gene distribution was evenly dispersed, with 11 variants occurring in 7 genes, and no variant was identified in 3 Hispanic Black probands. For the Asian cohort, only one gene variant was found out of 6 patients.ConclusionThis study demonstrates that the diagnostic rate of genetic studies in hearing loss varies according to race in South Florida, with more heterogeneity in racial and ethnic minorities. Further studies to delineate deafness gene variants in underrepresented populations, such as African Americans/Blacks from Hispanic groups, are much needed to reduce racial and ethnic disparities in genetic diagnoses.

Sensorineural Hearing Loss in Patients With Chronic Kidney Disease: A Comprehensive Review.

This article aims to ascertain the prevalence of loss of hearing in patients with chronic kidney disease (CKD) and also to examine potential causes of sensorineural hearing loss (SNHL) in patients suffering from CKD. It has been discovered in recent years that there is a relationship between the occurrence of SNHL and CKD. Nowadays many people are suffering from CKD. These patients deal with several otorhinolaryngological issues, such as SNHL, candidiasis, epistaxis, halitosis, dysgeusia, xerostomia, and lip and thyroid malignancies. One of the most frequent otorhinolaryngological complications is audiovestibular system impairment. There are various proposed mechanisms for the appearance of loss of hearing in people suffering from CKD. The kidney and the inner ear have multiple functional and structural similarities, which may be the cause of these problems in CKD patients. In addition, changes in the homeostasis of water and electrolytes can affect the endolymphatic fluid and result in endolymphatic hydrops. Finally, some medications, like aminoglycosides and loop diuretics, are well known for their ototoxicity and are utilized to treat patients with CKD. Only a small number of population-based research have so far been able to show a connection between CKD and audiovestibular system impairment. Some investigationhasshown that CKD patients are more likely than healthy people to experience vestibular impairment. The quality of life of a patient can be reduced by hearing loss. People with hearing loss experience communication issues in daily life, which negatively affects their cognitive and psychosocial functioning. Social isolation and a poor quality of life in terms of health can all result from hearing loss. In addition, decreased renal function has also been linked to poor quality of life, hospitalization, and cognitive dysfunction.

Risk Factors for Natural Hearing Evolution in Newborns With Congenital Cytomegalovirus Infection

Congenital cytomegalovirus (cCMV) is the major cause of congenital nonhereditary sensorineural hearing loss in children. Currently, criteria to identify infants at increased risk for unfavorable hearing outcome are lacking. To identify risk factors associated with cCMV-related hearing improvement, hearing deterioration, and late-onset hearing loss. This multicenter cohort study included patients from 6 secondary and tertiary hospitals enrolled in the Flemish CMV registry (Belgium). Newborns with untreated cCMV infection with at least 4-year audiological follow-up were included. Patients who presented with other possible causes of sensorineural hearing loss were excluded. Data were collected for 15 years (January 1, 2007, to February 7, 2022) and analyzed from September 26, 2022, to January 16, 2023. Primary outcome was hearing evolution (per-ear analysis; described as stable hearing, improvement, or deterioration). The association of gestational characteristics, clinical findings, timing of seroconversion, viral load, and hearing status at birth with hearing evolution was investigated using effect sizes (Cramer V, odds ratio [OR], or Hedges g). Of the 387 children, 205 of 385 with nonmissing data were male (53.2%), 113 (29.2%) had a symptomatic infection, and 274 (70.8%) had an asymptomatic infection. Every child was 4 years or older at final hearing evaluation. A total of 701 of 774 ears (90%) showed stable hearing (normal hearing or stable hearing loss since birth) over time. Late-onset hearing loss (normal hearing at birth followed by hearing loss) was present in 43 of 683 ears (6.3%). Among children with hearing loss present at birth, 24 of 34 ears (70.6%) had hearing deterioration, and 6 of 91 ears (6.6%) had hearing improvement. Prematurity was associated with a higher chance of hearing improvement (OR, 12.80; 95% CI, 2.03-80.68). Late-onset hearing loss was more prevalent in a first trimester infection (OR, 10.10; 95% CI, 2.90-34.48). None of the 104 ears of children with a third trimester seroconversion developed late-onset hearing loss. Findings of this cohort study support that ongoing audiological follow-up for untreated children with congenital hearing loss is important, as the majority of patients had hearing deterioration. The timing of seroconversion was associated with the risk of developing late-onset hearing loss. These insights can aid in parental counseling, patient stratification, and follow-up. Future research should focus on the effect of treatment, the influence of determined risk factors, and the study of eventual new risk factors in patients at high risk to develop hearing loss.

Emerging biotechnologies and biomedical engineering technologies for hearing reconstruction

AbstractHearing impairment is a global health problem that affects social communications and the economy. The damage and loss of cochlear hair cells and spiral ganglion neurons (SGNs) as well as the degeneration of neurites of SGNs are the core causes of sensorineural hearing loss. Biotechnologies and biomedical engineering technologies provide new hope for the treatment of auditory diseases, which utilizes biological strategies or tissue engineering methods to achieve drug delivery and the regeneration of cells, tissues, and even organs. Here, the advancements in the applications of biotechnologies (including gene therapy and cochlear organoids) and biomedical engineering technologies (including drug delivery, electrode coating, electrical stimulation and bionic scaffolds) in the field of hearing reconstruction are presented. Moreover, we summarize the challenges and provide a perspective on this field.

Stem Cell-Based Hair Cell Regeneration and Therapy in the Inner Ear.

Hearing loss has become increasingly prevalent and causes considerable disability, thus gravely burdening the global economy. Irreversible loss of hair cells is a main cause of sensorineural hearing loss, and currently, the only relatively effective clinical treatments are limited to digital hearing equipment like cochlear implants and hearing aids, but these are of limited benefit in patients. It is therefore urgent to understand the mechanisms of damage repair in order to develop new neuroprotective strategies. At present, how to promote the regeneration of functional hair cells is a key scientific question in the field of hearing research. Multiple signaling pathways and transcriptional factors trigger the activation of hair cell progenitors and ensure the maturation of newborn hair cells, and in this article, we first review the principal mechanisms underlying hair cell reproduction. We then further discuss therapeutic strategies involving the co-regulation of multiple signaling pathways in order to induce effective functional hair cell regeneration after degeneration, and we summarize current achievements in hair cell regeneration. Lastly, we discuss potential future approaches, such as small molecule drugs and gene therapy, which might be applied for regenerating functional hair cells in the clinic.

Congruence and incongruence on the radiological and functional examination of inner ear hemorrhage

Background Inner ear hemorrhage (IEH) is an increasingly recognized cochlear lesion that can cause sensorineural hearing loss (SNHL). Magnetic resonance imaging (MRI) is known to be the best imaging modality for clarifying the causes of SNHL and providing images that point to those causes. Aims Evaluate the lesional patterns in patients with presumed Inner ear hemorrhage (IEH) from radiological and functional aspects. Material and Methods We retrospectively reviewed 10 patients performed in our institution from 2014 to 2020, with suspected labyrinthine hemorrhage based on radiological and functional examination. Results We included 8 patients with IEH and sensorineural hearing loss (SNHL). The median age was 55 years (range: 3 months − 78 years). The results from the MRI and functional tests were compared for each end-organ. Only three cases (37.5%) showed a correlation between signal abnormalities and dysfunction in the labyrinthine apparatus. Conclusions In patients with SNHL inner ear hemorrhage needs to be ruled out in the differential diagnosis, so specific MRI sequences should be requested. It represents a way to a better understanding of the disorder and the variety of findings claim for a complete auditory and vestibular testing.

Dexamethasone treatment of murine auditory hair cells and cochlear explants attenuates tumor necrosis factor-α-initiated apoptotic damage.

The most common cause of sensorineural hearing loss is damage of auditory hair cells. Tumor necrosis factor-alpha (TNF-α) is closely associated with sensorineural hearing loss. The present study examined the preconditioning effect of dexamethasone (DEX) on TNF-α-induced ototoxicity in mouse auditory hair cells (HEI-OC1) and cochlear explants. Treatment of HEI-OC1 with 10 ng/ml TNF-α for 24 h decreased cell viability, increased the accumulation of reactive oxygen species (ROS), and induced caspase-mediated apoptotic signaling pathways. Pretreatment with 10 nM DEX for 6 h before TNF-α exposure restored cell viability, decreased ROS accumulation, and attenuated apoptotic signaling activation induced by TNF-α. Incubation of cochlear explants with 20 ng/ml TNF-α for 24 h resulted in significant loss of both inner hair cells (IHCs) and outer hair cells (OHCs) and an increase in apoptotic activation accessed by annexin V staining. The cochlear explants pre-incubated with 10 nM DEX attenuated TNF-α ototoxicity in both IHCs and OHCs and apoptotic cell death. These results indicated that DEX plays a protective role in ototoxicity induced by TNF-α through attenuation of caspase-dependent apoptosis signaling pathway and ROS accumulation.

Loop-mediated isothermal amplification assay for screening congenital cytomegalovirus infection in newborns

Congenital cytomegalovirus (CMV) infection is a common cause of sensorineural hearing loss and neurodevelopmental impairment in newborns. However, congenital CMV infection cannot be diagnosed using samples collected more than 3 weeks after birth because testing after this time cannot distinguish between congenital infection and postnatal infection. Herein, we developed a robust loop-mediated isothermal amplification (LAMP) assay for the large-scale screening of newborns for congenital CMV infection. In contrast to conventional quantitative polymerase chain reaction (qPCR), which detects CMV within a dynamic range of 1.0 × 106 to 1.0 × 102 copies/μL, our quantitative LAMP assay (qLAMP) detects CMV within a dynamic range of 1.1 × 108 to 1.1 × 103 copies/μL. Moreover, the turnaround time for obtaining results following DNA extraction is 90 min in qPCR but only 15 min in qLamp. The colorimetric LAMP assay can also detect CMV down to 1.1 × 103 copies/μL within 30 min, irrespective of the type of heat source. Our LAMP assay can be utilized in central laboratories as an alternative to conventional qPCR for quantitative CMV detection, or for point-of-care testing in low-resource environments, such as developing countries, via colorimetric naked-eye detection.Key points• LAMP assay enables large-scale screening of newborns for congenital CMV infection.• LAMP allows colorimetric or quantitative detection of congenital CMV infection.• LAMP assay can be used as a point-of-care testing tool in low-resource environments.

Optimizing congenital cytomegalovirus detection by pool testing in saliva by a rapid molecular test

Universal congenital cytomegalovirus (cCMV) screening in saliva is increasingly recommended. The aim of our study was to correlate the performance of a point-of-care rapid molecular test with CMV real time PCR (CMV RT-PCR) detection, using saliva pool-testing in newborns under a universal screening strategy. Saliva swabs were prospectively collected from newborns < 21 days old and tested by Alethia-LAMP-CMV assay in pools of 5 samples. In positive pools, subjects were tested individually and by saliva and urine CMV RT-PCR. A subset of negative pools were studied with both techniques and viral loads in whole blood were determined in positive patients. From 1,642 newborns included in 328 pools, 8 were confirmed by urine CMV RT-PCR, (cCMV prevalence 0,49%). The PPA and NNA of the pooled saliva Alethia-LAMP-CMV testing were 87,5% and 99,8% with a negative and positive predictive value of 99,9% and 77,7%, respectively. Two false positives were detected (0,12%). A subset of 17 negative pools (85 samples), studied by saliva CMV RT-PCR, showed 100% concordance. Conclusion: CMV pool-testing using a rapid molecular test in saliva proved feasible when compared to PCR gold standards. This strategy could improve cost-effectiveness for cCMV universal neonatal screening, based on the low prevalence of the infection and could be a more affordable approach in less developed regions with reduced detection capacity.What is Known:• cCMV is the most frequent congenital infection and a leading nongenetic cause of sensorineural hearing loss and brain disease.• Universal screening could allow early detection of congenitally infected infants, improving clinical outcome.• Saliva PCR is the preferred and non-invasive test for newborn cCMV screening.What is New:• The feasibility of a universal cCMV screening by pool-testing in saliva using a rapid test in pools of 5 samples.• PPA and NPA were 87,5 and 99,8% compared to CMV PCR in urine.• This strategy could be relevant specially in LMIC where detection capacity is reduced and could improve cost-effectiveness.• cCMV prevalence in our center was 0,49%.

Differential outcomes of high-fat diet on age-related rescaling of cochlear frequency place coding.

Auditory frequency coding is place-specific, which depends on the mechanical coupling of the basilar membrane-outer hair cell (OHC)-tectorial membrane network. Prestin-based OHC electromotility improves cochlear frequency selectivity and sensitivity. Cochlear amplification determines the frequency coding wherein discrete sound frequencies find a 'best' place along the cochlear length. Loss of OHC is the leading cause of age-related hearing loss (ARHL) and is the most common cause of sensorineural hearing loss and compromised speech perception. Lipid interaction with Prestin impacts OHC function. It has been established that high-fat diet (HFD) is associated with ARHL. To determine whether genetic background and metabolism preserve cochlear frequency place coding, we examined the effect of HFD in C57BL/6J (B6) and CBA/CaJ (CBA) on ARHL.We found a significant rescuing effect on ARHL in aged B6 HFD cohort. Prestin levels and cell sizes were better maintained in the experimental B6-HFD group. We also found that distortion product otoacoustic emission (DPOAE) group delay measurement was preserved, which suggested stable frequency place coding. In contrast, the response to HFD in the CBA cohort was modest with no appreciable benefit to hearing threshold. Notably, group delay was shortened with age along with the control. In addition, the frequency dependent OHC nonlinear capacitance gradient was most pronounced at young age but decreased with age. Cochlear RNA-seq analysis revealed differential TRPV1 expression and lipid homeostasis. Activation of TRPV1 and downregulation of arachidonic acid led to downregulation of inflammatory response in B6 HFD, which protects the cochlea from ARHL. The genetic background and metabolic state-derived changes in OHC morphology and function collectively contribute to a redefined cochlear frequency place coding and improved age-related pitch perception.

Causes of hearing loss and implantation age in a cohort of Danish pediatric cochlear implant recipients.

Sensorineural hearing loss (SNHL) is the most common birth disorder. The cause of SNHL is heterogeneous and varies in different populations. Understanding the causes of a hearing loss (HL) predict the outcome of cochlear implantation and is of great importance in understanding the mechanism of the disease and in providing the best treatment. Undiagnosed and untreated HL has a profound effect on the acquisition of early communication skills, speech, language, academic, emotional, and psychosocial development in children. To determine the cause of HL and implantation age in pediatric cochlear implant (CI) users in a Danish population. Data of 100 children (54 females and 46 males), age 0-17 years, was analyzed. All of the children were implanted during 2020-2022. Hereditary HL was diagnosed in 44 cases (44%), with pathogenic variants in the SLC26A4 gene found in 14 cases (14%). Syndromic HL was diagnosed in 23 children (23%). Non-syndromic HL was diagnosed in 21 children (21%), where the most common genetic variation was found in the GJB2 gene. Acquired prenatal and postnatal sensory disorders TORCH risk factors were associated with HL in 25 cases (25%). Congenital CMV DNA was diagnosed in 23 samples (23%). The cause of the HL remained unknown for 31 (31%) children. In 70 (70%) of the participants the HL was diagnosed at time of newborn hearing screening (NHS). Twenty-three of the children were diagnosed with congenital severe to profound bilateral HL and were simultaneously implanted between 8 and 14 months (mean age 10.5 months). In the remaining 47 cases, the HL was progressive and the children were implanted when the HL reached the criteria for implantation. In the current study, the major causes of HL were alterations in the SLC26A4 gene: 13% with Pendred syndrome and 1% non-syndromic. Thirty-one (31%) had HL of unknown origin and almost half of these cases had inner ear malformations (n=16).

Congenital Cytomegalovirus and Hearing Loss: The State of the Art.

In developed countries, congenital cytomegalovirus (cCMV) infection is the most common congenital viral infection, representing the leading non-genetic cause of sensorineural hearing loss (HL). Diagnosis of cCMV infection can be performed by detection of CMV DNA in urine or saliva within 2-3 weeks after birth, or later in dried blood samples on the Guthrie card. Currently, there are many controversies regarding the preventive, diagnostic, and therapeutic approaches to cCMV infection. HL secondary to cCMV is highly variable in onset, side, degree, audiometric configuration, and threshold changes over time. Therefore, it is of paramount importance to perform a long and thorough audiological follow-up in children with cCMV infection to ensure early identification and prompt treatment of progressive and/or late-onset HL. Early cochlear implantation appears to be a valid solution not only for children with bilateral profound HL, but also for those with single-sided deafness, improving localization ability and understanding speech in noisy environments. Moreover, the decision to apply a unilateral cochlear implant in children with cCMV is strengthened by the non-negligible possibility of hearing deterioration of the contralateral ear over time.