Identification of novel MYH14 variants in families with autosomal dominant sensorineural hearing loss.

Autosomal dominant sensorineural hearing loss (ADSNHL) is a genetically heterogeneous disorder caused by pathogenic variants in various genes, including MYH14. However, the interpretation of pathogenicity for MYH14 variants remains a challenge due to incomplete penetrance and the lack of functional studies and large families. In this study, we performed exome sequencing in six unrelated families with ADSNHL and identified five MYH14 variants, including three novel variants. Two of the novel variants, c.571G > C (p.Asp191His) and c.571G > A (p.Asp191Asn), were classified as likely pathogenic using ACMG and Hearing Loss Expert panel guidelines. In silico modeling demonstrated that these variants, along with p.Gly1794Arg, can alter protein stability and interactions among neighboring molecules. Our findings suggest that MYH14 causative variants may be more contributory and emphasize the importance of considering this gene in patients with nonsyndromic mainly post-lingual severe form of hearing loss. However, further functional studies are needed to confirm the pathogenicity of these variants.

Genome sequencing identifies coding and non-coding variants for non-syndromic hearing loss.

Hearing loss (HL) is a common heterogeneous trait that involves variants in more than 200 genes. In this study, we utilized exome (ES) and genome sequencing (GS) to effectively identify the genetic cause of presumably non-syndromic HL in 322 families from South and West Asia and Latin America. Biallelic GJB2 variants were identified in 58 probands at the time of enrollment these probands were excluded. In addition, upon review of phenotypic findings, 38/322 probands were excluded based on syndromic findings at the time of ascertainment and no further evaluation was performed on those samples. We performed ES as a primary diagnostic tool on one or two affected individuals from 212/226 families. Via ES we detected a total of 78 variants in 30 genes and showed their co-segregation with HL in 71 affected families. Most of the variants were frameshift or missense and affected individuals were either homozygous or compound heterozygous in their respective families. We employed GS as a primary test on a subset of 14 families and a secondary tool on 22 families which were unsolved by ES. Although the cumulative detection rate of causal variants by ES and GS is 40% (89/226), GS alone has led to a molecular diagnosis in 7 of 14 families as the primary tool and 5 of 22 families as the secondary test. GS successfully identified variants present in deep intronic or complex regions not detectable by ES.

Assessment of in vitro fertilization outcomes after hysteroscopic isthmoplasty in recurrent implantation failure.

AIM: The aim of this study was to assess the in vitro fertilization (IVF) treatments outcomes of women with recurrent implantation failure (RIF) after hysteroscopic isthmoplasty for isthmocele. METHODS: This retrospective, observational study included 61 patients with RIF and isthmocele who presented to IVF Unit of Hüma Obstetrics and Gynecology Hospital between January, 2018 and December, 2020. Thirty-one patient who underwent hysteroscopic isthmoplasty-before IVF procedure-were included. Remaining 30 patients underwent IVF without hysteroscopic isthmoplasty were included as controls. The fertility outcome were compared between groups. RESULTS: After 3 months, spontaneous pregnancy was achieved in 18.4% (7/38) of patients with isthmocele who underwent hysteroscopic isthmoplasty. In the isthmoplasty group, implantation rate, clinical pregnancy rate, biochemical pregnancy rate, and the miscarriage rate were 41.9% (13/31), 35.5% (11/31), 6.5% (2/31), and 9.7% (3/31), respectively. The live birth rate after in vitro fertilization was 25.8% (8/31) in the isthmoplasty group and 3.3% (1/30) in the control group (p < 0.05). There were no significant differences in the IVF outcomes such as the biochemical pregnancy rate and miscarriage rate between the isthmoplasty and control groups. CONCLUSION: This study demonstrated that hysteroscopic isthmoplasty improves pregnancy and live birth rates for women with a history of RIF and isthmocele. Reproductive results of the IVF cycles after hysteroscopic correction of isthmocele were comparable to those of the patients without any uterine abnormalities and those with diagnosis of unexplained infertility.

The effect of different types of convergent strabismus on horizontal eye movements.

PURPOSE: To investigate the effect of different types of convergent strabismus on horizontal eye movements and compare data with healthy control subjects. MATERIALS AND METHODS: This prospective, cross-sectional study included 38 patients with convergent strabismus (16 fully accommodative, 13 partially accommodative and 9 non-accommodative esotropia) and 19 age-matched control subjects. All of the participants had a detailed ophthalmological examination including visual acuity assessment, cover-uncover prism test, slit lamp, and indirect ophthalmoscopy examination. Videonystagmography (VNG) was used for the evaluation of horizontal eye movements such as saccadic accuracy, velocity, latency, and smooth pursuit velocity gain. RESULTS: The saccadic accuracy in the rightward direction was lower in the fully accommodative esotropia group compared to the partially accommodative esotropia group in the right eye (p = 0.002). The saccadic latency in the rightward direction was longer in the fully accommodative esotropia group compared to the control group (p = 0.008) and smooth pursuit velocity gain in the leftward direction was lower in the partially and non-accommodative esotropia group compared to the control group in binocular recording (p = 0.004, p = 0.001, respectively). There was no difference in the saccadic velocity among the study groups (p > 0.05). Finally, asymmetry of saccadic velocity and latency was observed between right- and leftward directions in the partially accommodative esotropia group in the right eye (p = 0.003, p = 0.008, respectively). CONCLUSION: This study demonstrated that horizontal eye movements may vary in different types of convergent strabismus. VNG may be an auxiliary tool to the clinical examination in differentiating fully or non-accommodative esotropia.

Does the SARS-CoV-2 pandemic really increase the frequency of peripheral facial palsy?

PURPOSE: Publications about increased number of peripheral facial paralysis in the COVID-19 pandemic emerged in the literature. However, these studies comprised of an estimate rather than a broad analysis of exact numbers. In this study, we planned to investigate whether the pandemic really resulted in an increase in facial paralysis cases admitted to the hospital by evaluating the cases who applied to our hospital due to facial paralysis in the COVID-19 pandemic year and in the previous 4 years. MATERIALS AND METHODS: Patients who applied to our hospital due to facial paralysis between March 2016-February 2017 (Group 1), between March 2017-February 2018 (Group 2), between March 2018-February 2019 (Group 3), between March 2019-February 2020 (Group 4), and between March 2020-February 2021 (Group 5) were investigated and detailed data were noted. RESULTS: 156, 164, 149, 172 and 157 patients were admitted to the hospital due to peripheral facial paralysis in Group 1, 2, 3, 4, and 5, respectively. Of these patients, 155, 164, 145, 169, and 153 were Bell's palsy, respectively. SARS-CoV-2 RT-PCR test was positive in only 2 of the 153 patients who were diagnosed in the year of the pandemic. CONCLUSIONS: This study showed that the number of peripheral facial paralysis detected during the COVID-19 pandemic was similar to previous years. Very few number of positive SARS-CoV-2 RT-PCR test results may have been found incidentally in Bell's palsy patients. Theses stating that SARS-CoV-2 causes peripheral facial paralysis should be supported by laboratory studies and postmortem research.

Audiological and vestibular measurements in Behçet's disease.

INTRODUCTION: Behçet's disease (BD) is a vasculitis that involves all small vessels and influences the multiple systems of the human body. This study aimed to evaluate the audio-vestibular system involvement of patients with BD and healthy individuals. MATERIALS AND METHODS: This study was designed as a prospective case-control blinded study. Thirty-one patients with BD and 31 healthy individuals were included. All the subjects were evaluated via pure tone audiometry (PTA), video head impulse test (vHIT), post head shake nystagmus test (PHSNT) and dizziness handicap inventory (DHI) to check for audio-vestibular system involvement. RESULTS: Patients with BD showed higher PTA scores in both speech and high frequencies. The vHIT revealed pathological saccades, particularly in horizontal canals (right ear: p = 0.002, left ear: p = 0.039). The gain values of the patients were slightly lower than those of the control group; however, gain and gain asymmetry differed significantly in a few canals. In the spontaneous nystagmus test and PHSNT, pathological nystagmus was detected to be significantly higher in the patient group than control group (p = 0.001); but the saccade presence in vHIT and nystagmus in PHNT did not differ among the patients (p = 0.106). In addition, the DHI scores of the patients group were higher than those of the control group (p < 0.001). No correlation was found between disease duration and saccade presence. CONCLUSION: The vHIT was used preliminary for evaluating the vestibular system in BD. This study showed the influence of BD on the audio-vestibular system, in particular isolated horizontal canal involvement was discovered in patients with BD. LEVEL OF EVIDENCE: Level III b.

Proteomics analysis of pleomorphic adenoma of the human parotid gland.

The objective of this study is to perform proteomic analysis of pleomorphic adenoma (PA) in the human parotid gland (PG) with comparison of normal PG. This is an individual prospective randomized controlled trial. This study was performed in a tertiary referral center. Tissue samples of PG and PA were taken after surgical excision of PG from 13 patients. Protein extracts were prepared and protein pools created from the soluble extracts were subjected to 2D-DIGE analysis. Proteins displaying regulation in their abundance were determined and identified using MALDIT-OF/TOF analysis. The identified proteins were subjected to STRING analysis for classification of the proteins based on their biological roles in metabolic pathways. Fifteen proteins, carbonic anhydrase 1, carbonic anhydrase 2, fibrinogen beta chain, alpha-amylase 1, heats hock protein hsp 90-alpha, clusterin, 78 kDa glucose-regulated protein, endoplasmin, alpha-amylase 2b, ATP synthase subunit alpha (mitochondrial), elongation factor 1-gamma, malate dehydrogenase, cytoplasmic, triosephosphate isomerase, receptor of activated protein c kinase 1, and aconitate hydratase, mitochondrial were down-regulated, whereas 11 proteins including ig kappa chain c region, serotransferrin, vimentin, annexin a5, glial fibrillary acidic protein, calreticulin, cartilage oligomeric matrix protein, microfibril-associated glycoprotein 4, 14-3-3 protein epsilon, fibulin-5, and f-box only protein 2 were up-regulated in PA samples in comparison to healthy parotid tissue. This study described the differences observed in protein expression patterns of the PA and normal PG. The results may provide new insights into the pathogenesis and diagnosis of PA in human PG. LEVEL OF EVIDENCE: 1b.

Prophylactic etanercept treatment in cisplatin ototoxicity.

The aim of our study was to evaluate the audiological protective effects of etanercept using distortion product otoacoustic emission (DPOAE) in rats with hearing loss due to cisplatin ototoxicity. The study began with 36 healthy female albino rats; 31 rats had good measurements in DPOAE and were included in the study. On day 0, a single dose of etanercept was given by intraperitoneal administration to 15 rats (etanercept group). No medication was given to the control group. After 24 h, 16 mg/kg cisplatin was given to all rats. DPOAE measurements were performed on the 3rd, 7th, and 21st day. After the DPOAE test on the 21st day, the animals were killed by decapitation. Between-group and intra-group comparisons were made using the data of the two groups. A statistically significant difference was observed on the 3rd day at 4921 Hz and higher frequencies, on the 7th day at 6064 Hz and higher frequencies, and on the 21st day at 6494 Hz and higher frequencies (p < 0.05). We observed 10% ototoxicity in the etanercept group and 56% ototoxicity in the control group. A single dose of etanercept 1 day before cisplatin administration decreases cisplatin ototoxicity in the early period. This effect comes to the fore especially over 4500 Hz frequencies at 65 dB and higher.

A Simple Closure Technic for Tracheoesophageal Puncture Failures.

Tracheosephageal puncture is the one of the most favorable methods, and widely used by physicians for voice reconstruction after total laryngectomy. Intractable leakages from the tracheosephageal punctures are the most common complication, and management of these fistulas is still troublesome for the patients and physicians. Local surgical sutures, rotational flaps, injections are reported previously, but in this report the authors aimed to mention on a very simple method with silicone septal button. Insertion of a temporary silicone septal button may be well tolerated by patients and can help to manage this complication easily on exact indications. The authors discussed indications and long-term results of this method with different patients.

Vestibulo-Ocular Reflex in the Aging Population.

Objectives: The aim of this study was to evaluate vestibulo-ocular reflex (VOR) of individuals over 60 years of age who have not been diagnosed with a specific vestibular pathology. Methods: Bilateral six-semicircular canal video head impulse test (vHIT), Dizziness Handicap Inventory and European Evaluation of Vertigo scales were applied to participants. Results: In total, 103 participants were included in the study (75 male, 28 female), and the mean age was 69.35 ± 7.41 years. The mean age of 7th decade group was 64.32±3.12 (59 participants; 38 male, 21 female), and the mean age of 8th decade and older group was 76.11±5.93 (44 participants; 37 male, 7 female). No significant differences were found between the VOR gains of the lateral or vertical semicircular canals between the 7th decade and 8th decade and older groups (p>0.05). In the 8th decade and older group, the presence of right lateral semicircular canal corrective saccade and left posterior semicircular canal corrective saccade showed a positively moderate correlation with VOR gains of the same semicircular canals (r=0.455, p=0.002, and r=0.518, p=0.001, respectively). No significant correlation was found between age and VOR gain in the 7th decade group, however, there was a negatively weak correlation between age and left lateral semicircular canal VOR gain (r=-0.366, p=0.017) in the 8th decade and older group. Conclusion: While assessing the age-related changes in VOR using vHIT, it must be considered that the changes related to aging of the vestibular system begin to emerge in the population over 70 years of age, and corrective saccade findings may be more informative than VOR gains in revealing these changes.

Human Organoids for Rapid Validation of Gene Variants Linked to Cochlear Malformations.

Developmental anomalies of the hearing organ, the cochlea, are diagnosed in approximately one-fourth of individuals with congenital deafness. Most patients with cochlear malformations remain etiologically undiagnosed due to insufficient knowledge about underlying genes or the inability to make conclusive interpretations of identified genetic variants. We used exome sequencing for genetic evaluation of hearing loss associated with cochlear malformations in three probands from unrelated families. We subsequently generated monoclonal induced pluripotent stem cell (iPSC) lines, bearing patient-specific knockins and knockouts using CRISPR/Cas9 to assess pathogenicity of candidate variants. We detected FGF3 (p.Arg165Gly) and GREB1L (p.Cys186Arg), variants of uncertain significance in two recognized genes for deafness, and PBXIP1(p.Trp574*) in a candidate gene. Upon differentiation of iPSCs towards inner ear organoids, we observed significant developmental aberrations in knockout lines compared to their isogenic controls. Patient-specific single nucleotide variants (SNVs) showed similar abnormalities as the knockout lines, functionally supporting their causality in the observed phenotype. Therefore, we present human inner ear organoids as a tool to rapidly validate the pathogenicity of DNA variants associated with cochlear malformations.

Genetic heterogeneity in hereditary hearing loss: Potential role of kinociliary protein TOGARAM2.

Hearing loss (HL) is a heterogenous trait with pathogenic variants in more than 200 genes that have been discovered in studies involving small and large HL families. Over one-third of families with hereditary HL remain etiologically undiagnosed after screening for mutations in the recognized genes. Genetic heterogeneity complicates the analysis in multiplex families where variants in more than one gene can be causal in different individuals even in the same sibship. We employed exome or genome sequencing in at least two affected individuals with congenital or prelingual-onset, severe to profound, non-syndromic, bilateral sensorineural HL from four multiplex families. Bioinformatic analysis was performed to identify variants in known and candidate deafness genes. Our results show that in these four families, variants in a single HL gene do not explain HL in all affected family members, and variants in another known or candidate HL gene were detected to clarify HL in the entire family. We also present a variant in TOGARAM2 as a potential cause underlying autosomal recessive non-syndromic HL by showing its presence in a family with HL, its expression in the cochlea and the localization of the protein to cochlear hair cells. Conclusively, analyzing all affected family members separately can serve as a good source for the identification of variants in known and novel candidate genes for HL.

Effects of Personal Protective Equipment on Speech Acoustics.

Objectives: The transmission of severe acute respiratory syndrome coronavirus-2 occurs primarily through droplets, which highlights the importance of protecting the oral, nasal, and conjunctival mucosas using personal protective equipment (PPE). The use of PPE can lead to communication difficulties between healthcare workers and patients. This study aimed to investigate changes in the acoustic parameters of speech sounds when different types of PPE are used. Methods: A cross-sectional study was conducted, enrolling 18 healthy male and female participants. They were instructed to produce a sustained [ɑː] vowel for at least 3 s to estimate voice quality. In addition, all Turkish vowels were produced for a minimum of 200 ms. Finally, three Turkish fricative consonants ([f], [s], and [ʃ]) were produced in a consonant/vowel/consonant format with different vowel contexts within a carrier sentence. Recordings were repeated under the following conditions: no PPE, surgical mask, N99 mask, face shield, surgical mask + face shield, and N99 mask + face shield. All recordings were subjected to analysis. Results: Frequency perturbation parameters did not show significant differences. However, in males, all vowels except [u] in the first formant (F1), except [ɔ] and [u] in the second formant (F2), except [ɛ] and [ɔ] in the third formant (F3), and only [i] in the fourth formant (F4) were significant. In females, all vowels except [i] in F1, except [u] in F2, all vowels in F3, and except [u] and [ɯ] in F4 were significant. Spectral moment values exhibited significance in both groups. Conclusion: The use of different types of PPE resulted in variations in speech acoustic features. These findings may be attributed to the filtering effects of PPE on specific frequencies and the potential chamber effect in front of the face. Understanding the impact of PPE on speech acoustics contributes to addressing communication challenges in healthcare settings.

Does COVID-19 have an impact on hearing?

BACKGROUNDS: SARS-CoV-2 is known to be a neurotrophic virus. However, the effect of this virus on the hearing system is still uncertain. OBJECTIVES: We aimed to investigate the possible effect of COVID-19 on hearing. MATERIALS AND METHODS: Thirty healthcare workers who had COVID-19 after hearing evaluation with pure tone audiometry (PTA) for any reason in the last 1 year were included in the study. PTA and transient evoked otoacoustic emissions (TEOAE) tests were performed in 15 of 30 patients during the active infection period. For all 30 patients, otoscopic examination plus PTA and TEOAE tests were performed at the end of the first month after their treatment. RESULTS: When the PTA results of 30 patients (60 ears) before and after COVID-19 were compared, a significant decrease in hearing level was found only at 1000 Hz (p < .05). There were no significant differences at other frequencies. When the PTA and TEAOE test results of 15 patients (30 ears) that were performed during and after COVID-19 were compared, no significant differences were found. CONCLUSION AND SIGNIFICANCE: We conclude that COVID-19 may cause hearing loss. However, this result needs to be confirmed with comprehensive studies to be conducted in larger patient groups.

Long-Term Effects of COVID-19 and the Pandemic on Tinnitus Patients.

This study aimed to explore the effect of COVID-19 and the pandemic period on the tinnitus-related complaints of patients with chronic tinnitus. Ninety-six patients who were diagnosed with chronic tinnitus before the pandemic were enrolled in this study. Before the pandemic and in January 2022, all patients used the Visual Analog Scale (VAS) to assess tinnitus loudness, annoyance, and effect on everyday life, sleep, and concentration. Additionally, patients filled the Tinnitus Handicap Inventory (THI) and the Hyperacusis Questionnaire (HQ). In the entire cohort, tinnitus loudness, annoyance, and tinnitus-induced difficulties with concentration as well as THI and HQ scores increased significantly during the two pandemic years. Thirty-seven tinnitus patients contracted COVID-19 between March 2020 and January 2022. These patients were asked to list leading COVID-19 symptoms, changes in tinnitus complaints during and after the disease, and whether their hearing abilities were affected. Three patients in the COVID-19 group confirmed worsening their hearing abilities. There was no decrease in the tinnitus complaint during COVID-19, 24.3% of the infected patients reported exacerbation of tinnitus, and 75.7% said tinnitus remained the same. In the COVID-19-negative group, 13.5% reported tinnitus decrease during the pandemic, 57.6% said it remained the same, and 28.8% reported exacerbation of tinnitus. When split into infected and non-infected groups, a significant increase in tinnitus loudness, tinnitus effect on concentration, and THI scores were seen only in patients who contracted COVID-19, while hyperacusis worsened significantly (p < 0.05) only in COVID-19-negative tinnitus patients. Despite significant differences within the groups, there were no differences found between the groups. This study points to possible different effects of the infection with SARS-CoV-2 and the pandemic period on patients with chronic tinnitus. It also provides evidence for deterioration of preexisting tinnitus as a possible long-term effect of COVID-19.

Bone-Anchored Hearing Implants: Surgical and Audiological Comparison of Different Surgical Techniques.

Introduction The bone-anchored hearing implant system (BAHS) is an effective amplification system that transmits the sounds received by an external operating system to the inner ear by bypassing the middle ear placed in the temporal bone. Objective This study compares the results of patients who underwent bone-anchored hearing implant system (BAHS) surgery using two different surgical methods in terms of preoperative and postoperative complications, surgical time, audiological findings, and patient satisfaction. Methods The results of 22 patients who underwent BAHS were evaluated retrospectively from video records and audiological results, The Turkish Version of the Glasgow Benefit Inventory (GBI) questionnaire were evaluated. Two different surgical approaches were used for implantation: the linear incision technique ( n = 9) and the punch technique ( n = 13). Results Mean surgical durations were 9.67 ± 2.85 and 47.65 ± 6.13 minutes for Groups A and B, respectively, and these were significantly different ( p < 0.001). There were no significant differences between the groups' speech recognition scores for a signal-to-noise ratio (SNR) of +5 ( p = 0.173), SNR of 0 ( p = 0.315), or SNR of -5 ( p = 0.360) and results of the GBI scores. Conclusion The punch technique has a significant advantage due to a shorter surgery duration without increased surgical complications. Additionally, the punch technique showed no significant difference in hearing performance or satisfaction compared with linear incision.

Vestibulo-ocular reflex evaluation of the children with acquired esotropia.

OBJECTIVES: This study aims to evaluate the effects of acquired esotropia on vestibulo-ocular reflex (VOR) gain in children using video (vHIT) and functional head impulse (fHIT) tests. METHODS: A total of 62 children aged 6-18 years, with acquired esotropia and normal vision, were evaluated in the study. The patients were divided into two sub-groups: accommodative and non-accommodative. VOR gains were analyzed by performing lateral canal vHIT and fHIT with monocular and binocular recordings by a single examiner. RESULTS: Seventeen (10 male, 7 female) children with accommodative esotropia, 24 (14 male, 10 female) children with non-accommodative esotropia, and 21 (8 male and 12 female) healthy controls were included in this study. The vHIT findings did not differ between the groups (p˃.05). In the non-accommodative esotropia group, the location of the camera in both binocular and monocular vHIT recordings made a significant difference in the left VOR gain (p = .025, z = -2.243, p = .032, and z = -2.143, respectively), but no difference was observed in the right VOR gain. In the accommodative esotropia group, while the camera was on the left there was a significant difference in the right VOR gain between binocular and monocular recordings (p = .016, z = -2.413) but no difference was observed in the left VOR gain. No overt or covert saccade was detected in any group. CONCLUSIONS: The statistical differences found in vHIT and fHIT in acquired esotropia patients are thought to be sporadic and based on the results of this study no correction or change in recording technique is required for vHIT or fHIT in children with acquired esotropia.

Auricular anthropometric growth study in individuals with trisomy 21.

In this study, we aimed to measure the auricle dimensions of individuals with Down syndrome, which are known to have different anomalies, and to evaluate the auricle development from birth. A total of 18 groups were formed, consisting of individuals from the neonatal period to age 18 years. Additionally, individuals older than 18 years old were added as an adult group (19 groups in total). Each group has 20 individuals. Measurements were taken in six dimensions. These measurements included the distance from the suprahelix to infralobule (A), helix to tragus (B), antihelix to tragus (C), conchal attachment point to tragus (D), suprahelix to the mastoid, (E), and helix to mastoid at the tragus level (F). It was found that the A value reached adult size at the age of 13 in both boys and girls. For the B, D, and E values, it was found that sizes reach the adult size at the ages of 5, 8, and 7 for both genders, respectively. The C value reached adult size in boys by age 1, but there was no significant difference for girls between the adult and any age value. It was found that the F value reached the adult size at age of 4 for boys and 5 for girls. These results may be a guide for individuals with Down syndrome in terms of the surgical timing of the auricle if necessary.

Does Hypochlorous Acid Cause Ototoxicity? An Experimental Study.

AIM: Hypochlorous acid (HOCl) is a weak acid that ionizes in water. It is an effective antiseptic exhibiting low toxicity on living tissues. We aimed to investigate the ototoxic effects of HOCl on an animal model by using electrophysiological and histological methods. MATERIALS AND METHODS: The study comprised 32 Sprague-Dawley rats, which were separated into four groups: control group (A), saline solution group (B), 70% isopropyl alcohol + 2% chlorhexidine group (C), and HOCl group (D). After recording the auditory brainstem response (ABR) for basal hearing thresholds (8, 16, 24, and 32 kHz), 0.03 ml of the aforementioned materials was injected intratympanically three times every 2 days in groups B, C, and D. ABR measurements were repeated on the 7th and 21st days. All animals were sacrificed, and temporal bones were prepared for examinations of cochlear histology and vascular endothelial growth factor immunohistochemistry. RESULTS: Basal hearing levels were normal across all frequencies and groups, with no statistical differentiation. On the 7th and 21st days after the ABR test, all other groups demonstrated a significant deterioration in hearing levels compared with group A. When the results from 7th and 21st days were compared within group D, a partial recovery was observed. In histopathology, groups C and D demonstrated moderate and severe cochlear degeneration, along with decreased immunoreactivity in the organ of Corti, stria vascularis, and spiral ligament. CONCLUSION: This is the first study to evaluate the safety of using HOCl in otology. Although HOCI is less ototoxic than the disinfectant used, it may have a toxic effect on cochlea.Level of Evidence: Animal Research.