A single dose of AC102 restores hearing in a guinea pig model of noise-induced hearing loss to almost prenoise levels.

Although sudden sensorineural hearing loss (SSNHL) is a serious condition, there are currently no approved drugs for its treatment. Nevertheless, there is a growing understanding that the cochlear pathologies that underlie SSNHL include apoptotic death of sensory outer hair cells (OHCs) as well as loss of ribbon synapses connecting sensory inner hair cells (IHCs) and neurites of the auditory nerve, designated synaptopathy. Noise-induced hearing loss (NIHL) is a common subtype of SSNHL and is widely used to model hearing loss preclinically. Here, we demonstrate that a single interventive application of a small pyridoindole molecule (AC102) into the middle ear restored auditory function almost to prenoise levels in a guinea pig model of NIHL. AC102 prevented noise-triggered loss of OHCs and reduced IHC synaptopathy suggesting a role of AC102 in reconnecting auditory neurons to their sensory target cells. Notably, AC102 exerted its therapeutic properties over a wide frequency range. Such strong improvements in hearing have not previously been demonstrated for other therapeutic agents. In vitro experiments of a neuronal damage model revealed that AC102 protected cells from apoptosis and promoted neurite growth. These effects may be explained by increased production of adenosine triphosphate, indicating improved mitochondrial function, and reduced levels of reactive-oxygen species which prevents the apoptotic processes responsible for OHC death. This action profile of AC102 might be causal for the observed hearing recovery in in vivo models.

Vertebrobasilar System Laterality and Idiopathic Sudden Sensorineural Hearing Loss.

INTRODUCTION: The etiology of idiopathic sudden sensorineural hearing loss (ISSNHL) remains elusive, with vascular compromise as a proposed cause. This study aimed to explore the correlation between the vertebrobasilar vascular system laterality (VBVSL) and ISSNHL laterality. METHODS: We conducted a retrospective analysis of consecutive patients diagnosed with ISSNHL from 2015 to 2020. The VBVSL pattern was established via magnetic resonance imaging scans by a neuroradiologist. ISSNHL occurring contralaterally to the basilar artery (BA) curvature or ipsilaterally to the dominant vertebral artery (VA) was designated as a "positive match," with all other scenarios classified as a "negative match." RESULTS: Our study included 191 ISSNHL patients (median age 57 years, 89 males, 93 right ears). The majority of patients did not exhibit a positive match between ISSNHL laterality and the sides of BA curvature or dominant VA (28.8% and 36.6% for BA and VA, respectively). Notably, VA-positive match patients were significantly older than VA-negative match patients (59 vs. 53 years, p = 0.043), with a similar trend observed in BA-positive match compared to BA-negative match (59 vs. 54.5 years, p = 0.057). However, there was no significant difference in any other clinical, audiometric, or outcome factors between the positive and negative match groups. CONCLUSION: The findings suggest no association between VBVSL and ISSNHL laterality. Furthermore, patients in the positive match group did not exhibit distinct clinical or audiometric features compared to those without a match.

Serum lipid metabolism characteristics and potential biomarkers in patients with unilateral sudden sensorineural hearing loss.

BACKGROUND: Glycerophospholipids (GPLs) are essential for cell membrane structure and function. Sphingomyelin and its metabolites regulate cell growth, apoptosis, and stress responses. This study aimed to investigate lipid metabolism in patients experiencing sudden sensorineural hearing loss across all frequencies (AF-SSNHL). METHODS: The study included 60 patients diagnosed with unilateral AF-SSNHL, among whom 30 patients had a level of hearing improvement ≥ 15 dB after 6 months of follow-up. A propensity score-matched (2:1) control group was used. Liquid chromatography‒mass spectrometry based untargeted lipidomics analysis combined with multivariate statistics was performed to investigate the lipids change. The "lipidome" R package and weighted gene co-expression network analysis (WGCNA) were utilised to assess the lipids' structural features and the association between lipids and hearing. RESULTS: Lipidomics successfully differentiated the AF-SSNHL group from the control group, identifying 17 risk factors, mainly including phosphatidylcholine (PC), phosphatidylethanolamine (PE), and related metabolites. The ratios of lysophosphatidylcholine/PC, lysophosphatidylethanolamine/PE, and lysodimethylphosphatidylethanolamine/PE were upregulated, while some glycerophospholipid (GPL)-plasmalogens were downregulated in the AF-SSNHL group, indicating abnormal metabolism of GPLs. Trihexosylceramide (d34:1), PE (18:1e_22:5), and sphingomyelin (d40:3) were significantly different between responders and nonresponders, and positively correlated with hearing improvement. Additionally, the results of the WGCNA also suggested that partial GPL-plasmalogens were positively associated with hearing improvement. CONCLUSION: AF-SSNHL patients exhibited abnormally high blood lipids and pronounced GPLs metabolic abnormalities. Sphingolipids and GPL-plasmalogens had an association with the level of hearing improvement. By understanding the lipid changes, clinicians may be able to predict the prognosis of hearing recovery and personalize treatment approaches.

Efficacy of intratympanic steroid therapy for severe and profound sudden sensorineural hearing loss.

BACKGROUND: Intratympanic steroids (ITS) in treating sudden sensorineural hearing loss (SSNHL) have become more widespread. AIM: This study investigates whether ITS treatment provides additional benefits when combined with systemic steroids (SS) in patients with severe and profound SSNHL. MATERIALS AND METHODS: Patients diagnosed with severe and profound SSNHL were divided into two groups: SS group and SS combined with ITS group. Pure-tone audiometry was performed before and three months after treatment completion. The pure-tone average (PTA), frequency-specific hearing gains, and average values were compared between the groups. RESULTS: The study included 57 patients (27 SS, 30 ITS), with a mean age of 50.09 ± 15.56. Before treatment: SS PTA 84.40 ± 15 dB HL, ITS 87.50 ± 9.38 dB HL (p = 0.36). After treatment: SS 62.2 ± 23.13 dB HL, ITS 65.17 ± 12.19 dB HL (p = 0.55). Average hearing gain: SS 22.19 ± 13.81 dB HL, ITS 22.33 ± 12.24 dB HL (p = 0.96). Frequency-specific gains were similar (p > 0.05). SS group: 12 slight improvement, 10 no improvement, 3 partial, 2 complete recovery. ITS group: 23 slight improvement, 6 no improvement, 1 partial. CONCLUSION: In our study, combining ITS with SS treatment did not provide additional benefits in treating severe and profound SSNHL.

Importance of early objective auditory testing in the presentation of sudden sensorineural hearing loss in children.

BACKGROUND: Functional hearing loss can be due to an auditory manifestation of functional neurological disorder, previously known as conversion disorder. METHODS: This is a case series of 3 pediatric patients with a diagnosis of idiopathic SSNHL who ultimately were found to have functional neurological disorder. RESULTS: Average age was 12.7 years at presentation (range 10-14 years). All three patients underwent invasive interventions prior to their initial clinic visit. All patients demonstrated profound SNHL on behavioural audiogram, but normal otoacoustic emissions (OAE) and auditory brainstem response testing. With counselling, both patients demonstrated significant hearing improvement. CONCLUSIONS: Early use of OAE's in the workup of SSNHL can avoid unnecessary and potentially harmful therapies and expedite access to counselling services which may help lead to symptom resolution.

N-Acetylcysteine combined with prednisolone treatment shows better hearing outcome than treatment with prednisolone alone for patients with idiopathic sudden sensorineural hearing loss: a retrospective observational study.

OBJECTIVES: Internationally, corticosteroids are still the mainstay treatment for patients with idiopathic sudden sensorineural hearing loss (ISSHL). This is a retrospective monocentric study investing the impact of adding N-acetylcysteine (NAC) to prednisolone treatment on patients with ISSHL at a tertiary university otorhinolaryngology department. METHODS: 793 patients (median age 60 years; 50.9% women) with a new diagnosis of ISSHL from 2009 to 2015 were included in the study. 663 patients received NAC administration in addition to standard tapered prednisolone treatment. Univariate and multivariable analysis were performed to identify independent factors regarding negative prognosis of hearing recovery. RESULTS: Mean initial ISSHL and hearing gain after treatment in 10-tone pure tone audiometry (PTA) were 54.8 ± 34.5 dB and 15.2 ± 21.2 dB, respectively. In univariate analysis, treatment with prednisolone and NAC was associated with a positive prognosis of hearing recovery in the Japan classification in 10-tone PTA. In multivariable analysis on Japan classification in 10-tone PTA including all significant factors from univariate analysis, negative prognosis of hearing recovery were age > median (odds ratio [OR] 1.648; 95% confidence interval [CI] 1.139-2.385; p = 0.008), diseased opposite ear (OR 3.049; CI 2.157-4.310; p < 0.001), pantonal ISSHL (OR 1.891; CI 1.309-2.732; p = 0.001) and prednisolone alone without NAC treatment (OR 1.862; CI 1.200-2.887; p = 0.005). CONCLUSIONS: Prednisolone treatment combined with NAC resulted in better hearing outcomes in patients with ISSHL than treatment without NAC.

A prognostic value of estimated pulse wave velocity in idiopathic sudden sensorineural hearing loss.

PURPOSE: Arterial stiffness, represented by estimated pulse wave velocity (ePWV), is the independent surrogate marker for cardiovascular event. The aim of the study was to investigate the significance of ePWV in the treatment outcome of idiopathic sudden sensorineural hearing loss (SSNHL). METHODS: One hundred and ten patients with idiopathic SSNHL who hospitalized between April 2019 and March 2022 were evaluated. Arterial stiffness was calculated with formula for ePWV and other cardiovascular parameters of body mass index (BMI), and serum lipid level was determined. All patients received systemic high-dose steroid therapy and intratympanic steroid injections as a salvage management. Treatment outcome was assessed at 6 months after treatment, and classified as recovery and nonrecovery groups according to hearing recovery. RESULTS: The initial pure-tone hearing threshold was 72.6 ± 23.8 dB and final hearing threshold was 52.63 ± 31.10 dB. After treatment, 60 (54.5%) patients included in recovery group and other 50 (45.5%) were classified as nonrecovery group. Age, days of onset to treatment, BMI, waist circumference, and ePWV were higher in the nonrecovery group compared to recovery group in univariate analysis (p = 0.039, p = 0.049, p = 0.003, p = 0.004, p = 0.007, respectively). In multivariate analysis, days of onset to treatment, BMI, and ePWV were associated with recovery (p = 0.030, p = 0.007, p = 0.022). CONCLUSION: Higher ePWV, a measure of arterial stiffness, was associated with a poor hearing recovery of SSNHL.

Idiopathic sudden sensorineural hearing loss after COVID-19 vaccination: a systematic review and meta-analysis.

OBJECTIVE: To provide pooled analyses on the association between COVID-19 vaccine and the incidence of idiopathic sudden sensorineural hearing loss (ISSNHL). DATA SOURCES: "Medline" via "PubMed", "EMBASE", and "Google scholar". REVIEW METHODS: Data sources were inspected from January 2020 to January 2024 using search terms relevant to vaccines for COVID-19. Included were papers with reported numbers of vaccinated populations and incidence if ISSNHL in those populations. Quality assessment was performed with the Newcastle-Ottawa Quality Assessment Scale Criteria. RESULTS: Three publications encompassing more than 191.8 million patients and at least 283 million vaccine doses were included in the quantitative data synthesis. The pooled reported incidence (95%confidence interval) of ISSNHL among COVID-19 vaccine recipients was 1.2588 per 100,000 (0.1385-3.4836). This incidence is significantly lower than the incidence of 5-27 and 60 per 100,000/year reported in the United States and in the European Union, respectively (P < 0.0001). CONCLUSION: There is no evidence to indicate that the COVID-19 vaccine is associated with the incidence of ISSNHL.

Impact of audiovestibular factors on prognosis in patients with sudden sensorineural hearing loss without vertigo.

PURPOSE: This study aimed to investigate the hearing outcomes in patients with sudden sensorineural hearing loss without vertigo (SSNHLwoV). METHODS: Patients with SSNHLwoV managed from December 2016 to March 2020 were prospectively enrolled in an academic tertiary referral center. Fifty-one patients with SSNHLwoV who completed high-dose steroid treatment. The hearing prognosis was analyzed using a multivariate Cox regression model. RESULTS: The rates of complete, partial, and no hearing recovery were 52.9%, 17.6%, and 29.4% in patients with SSNHLwoV, respectively. The video head impulse test (vHIT) of the posterior semicircular canal (PSC), high-tone hearing loss (4-8 kHz) ≥ 30 dB, and average hearing threshold (0.5-1-2-4 kHz) were significantly associated with incomplete recovery of hearing after treatment. In multivariate analysis, the vHIT of the PSC (hazard ratio [HR], 14.502; 95% confidence interval [CI], 1.371-153.355) and high-tone hearing loss ≥ 30 dB (HR, 9.170; 95% CI, 2.283-36.830) remained robust. CONCLUSIONS: Abnormal vestibular function tests were performed in 80.4% of the patients with SSNHLwoV. Abnormal vHIT of the PSC and high-tone hearing loss ≥ 30 dB were independent factors resulting in incomplete recovery of hearing in patients with SSNHLwoV. In the SSNHLwoV cohort, the caloric test was not significantly associated with hearing prognosis, and vHIT was a feasible predictor of treatment outcome.

MRI-confirmed cochlear artery infarct clinically diagnosed in a patient with sickle cell disease: a case report.

PURPOSE: To corroborate the vascular etiology of sudden sensorineural hearing loss (SNHL) utilizing magnetic resonance imaging (MRI). PATIENT: A 24-year-old male with a history of sickle cell disease experienced sudden SNHL and right horizontal nystagmus, without accompanying vertigo. INTERVENTION: Audiometric evaluation revealed left-sided SNHL, predominantly affecting high frequencies. Video head impulse testing demonstrated isolated dysfunction of the left posterior semicircular canal. An urgent brain MRI identified a recent punctiform ischemic stroke in the frontal region. A subsequent MRI, conducted with a 4-hour delay and post-contrast enhancement, highlighted a hyperintense signal within the left cochlear region and the left posterior semicircular canal. CONCLUSION: The investigative results substantiate an infarction in the territory of the cochlear artery, precipitated by a vaso-occlusive event, thereby reinforcing the vascular hypothesis of cochleovestibular artery syndrome. This case underscores the congruence between clinical observations and delayed post-contrast MRI findings.

One mechanism of sudden sensorineural hearing loss after sildenafil and sexual activity.

OBJECTIVES: A case of sudden sensorineural hearing loss following use of sildenafil was examined in detail over a period of three days from first report to recovery. DESIGN: Case study. The subject presented with sudden sensorineural hearing loss and diplacusis a day after onset. Testing involved detailed interview, standard audiometry, detailed inter-octave audiometry, and measurement of detailed psychophysical frequency tuning curves during a two day recovery period. STUDY SAMPLE: One male aged in his thirties with otherwise normal hearing. RESULTS: Although standard audiometry was within normal limits, detailed inter-octave audiometry and psychophysical frequency tuning curves were consistent with a punctate unilateral intra-cochlear lesion that resolved over a period of three days. CONCLUSIONS: This is the first report of such a frequency-specific audiometric shift and diplacusis after sildenafil, and is not consistent with previous reports of direct ototoxic pharmacological effects. We propose that the lesion was most likely caused by a cochlear bleed, and may have been due to physical exertion rather than a direct pharmaceutical effect. The study highlights the important role of additional diagnostic testing that can be easily achieved in a clinical setting with minimal equipment.

Salvage therapy for refractory sudden sensorineural hearing loss (RSSNHL): a systematic review and network meta-analysis.

OBJECTIVE: Approximately 30-50% of sudden sensorineural hearing loss (SSNHL) patients show poor response to systemic steroid therapy. Additionally, the most appropriate treatment for patients with refractory sudden sensorineural hearing loss (RSSNHL) is unknown. This study aimed to explore the best treatment for RSSNHL. DESIGN: Using a frequentist contrast-based model and PRISMA guidelines, this study compared five salvage regimes: intratympanic injection of steroids (ITS), hyperbaric oxygen (HBO) therapy, post auricle steroid injection (PSI), ITS combined with HBO therapy, and continued systemic steroids. STUDY SAMPLE: We searched the PubMed, EMBASE, Web of Science, and Cochrane Library databases for randomised controlled trials and cohort studies comparing treatment regimens for RSSNHL. RESULTS: Compared with the control group (no additional treatment), PSI and ITS demonstrated significant improvements. The mean hearing gain was greater after PSI (11.1 dB [95% CI, 4.4-17.9]) than after ITS (7.7 dB [95% CI, 4.8-10.7]). When a restricted definition of RSSNHL was used, the ITS + HBO therapy showed the largest difference in improvement for pure tone average compared with the control group (14.5 dB [95% CI, 4.2-25.0]). CONCLUSIONS: The administration of either PSI or ITS leads to the greatest therapeutic effect in patients with RSSNHL. However, a consensus on the definition of RSSNHL is needed.

The value of gadolinium-enhanced MRI in predicting the development of sudden hearing loss into Ménière's disease.

OBJECTIVE: To compare the clinical features of sudden hearing loss (SHL) in patients with and without endolymphatic hydrops (EH), and to investigate the association between SHL with EH and Ménière's disease (MD). METHODS: The clinical data of 63 SHL patients with first symptoms were evaluated retrospectively. Patients were separated into two groups based on the results of gadolinium-enhanced magnetic resonance imaging: EH and non-EH groups. Independent sample t-test and U-test were used to compare groups for continuous variables, and the chi-squared test, corrected chi-squared test and Bonferroni correction test were used to compare groups for binary and ordinal variables. The binary logistic regression model was utilised for univariate and multivariate analysis of follow-up patient prognosis. RESULTS: The EH and non-EH groups contained 32 and 31 patients, respectively. The EH group had a higher prevalence of low-tone descending hearing loss. Fifty-one patients were followed for more than 2 years. In the EH group, 11 and 15 patients were diagnosed with sudden sensorineural hearing loss (SSNHL) and MD, respectively, while in the non-EH group, 24 patients were diagnosed with SSNHL and only one with MD. EH, low-tone descending hearing loss and vertigo were risk factors for the diagnosis of MD in a subgroup univariate regression analysis of patients experiencing SHL. EH was found to be a risk factor for the progression of SHL into MD in a multifactor regression analysis. CONCLUSIONS: Patients with SHL who have EH are more likely to present with low-tone descending hearing loss. EH is a risk factor for the subsequent development of MD.

[Increase in the natural hearing threshold after treatment with cochlear implants]. / Anstieg der natürlichen Hörschwelle nach Cochleaimplantatversorgung.

More than 5% of the world's population suffers from disabling hearing loss. If the cause of hearing loss is unclear, it is referred to as idiopathic sudden sensorineural hearing loss (ISSNHL). After failure of standard treatment, the use of hearing aids or a cochlear implant is generally recommended. In this case, a 55-year-old patient was treated with cochlear implantation (CI) after ISSNHL and unsuccessful conservative therapy. Approximately 1 year after implantation and 7 years after the sudden hearing loss, subjective measurements revealed restoration of the hearing threshold.

Deafness gene screening based on a multilevel cascaded BPNN model.

Sudden sensorineural hearing loss is a common and frequently occurring condition in otolaryngology. Existing studies have shown that sudden sensorineural hearing loss is closely associated with mutations in genes for inherited deafness. To identify these genes associated with deafness, researchers have mostly used biological experiments, which are accurate but time-consuming and laborious. In this paper, we proposed a computational method based on machine learning to predict deafness-associated genes. The model is based on several basic backpropagation neural networks (BPNNs), which were cascaded as multiple-level BPNN models. The cascaded BPNN model showed a stronger ability for screening deafness-associated genes than the conventional BPNN. A total of 211 of 214 deafness-associated genes from the deafness variant database (DVD v9.0) were used as positive data, and 2110 genes extracted from chromosomes were used as negative data to train our model. The test achieved a mean AUC higher than 0.98. Furthermore, to illustrate the predictive performance of the model for suspected deafness-associated genes, we analyzed the remaining 17,711 genes in the human genome and screened the 20 genes with the highest scores as highly suspected deafness-associated genes. Among these 20 predicted genes, three genes were mentioned as deafness-associated genes in the literature. The analysis showed that our approach has the potential to screen out highly suspected deafness-associated genes from a large number of genes, and our predictions could be valuable for future research and discovery of deafness-associated genes.

Functional to structural plasticity in unilateral sudden sensorineural hearing loss: neuroimaging evidence.

A cortical plasticity after long-duration single side deafness (SSD) is advocated with neuroimaging evidence while little is known about the short-duration SSDs. In this case-cohort study, we recruited unilateral sudden sensorineural hearing loss (SSNHL) patients and age-, gender-matched health controls (HC), followed by comprehensive neuroimaging analyses. The primary outcome measures were temporal alterations of varied dynamic functional network connectivity (dFNC) states, neurovascular coupling (NVC) and brain region volume at different stages of SSNHL. The secondary outcome measures were pure-tone audiograms of SSNHL patients before and after treatment. A total of 38 SSNHL patients (21 [55%] male; mean [standard deviation] age, 45.05 [15.83] years) and 44 HC (28 [64%] male; mean [standard deviation] age, 43.55 [12.80] years) were enrolled. SSNHL patients were categorized into subgroups based on the time from disease onset to the initial magnetic resonance imaging scan: early- (n = 16; 1-6 days), intermediate- (n = 9; 7-13 days), and late- stage (n = 13; 14-30 days) groups. We first identified slow state transitions between varied dFNC states at early-stage SSNHL, then revealed the decreased NVC restricted to the auditory cortex at the intermediate- and late-stage SSNHL. Finally, a significantly decreased volume of the left medial superior frontal gyrus (SFGmed) was observed only in the late-stage SSNHL cohort. Furthermore, the volume of the left SFGmed is robustly correlated with both disease duration and patient prognosis. Our study offered neuroimaging evidence for the evolvement from functional to structural brain alterations of SSNHL patients with disease duration less than 1 month, which may explain, from a neuroimaging perspective, why early-stage SSNHL patients have better therapeutic responses and hearing recovery.

Clinical Value of a Novel Magnetic Resonance Imaging Protocol and Prognostic Model Establishment for Sudden Sensorineural Hearing Loss: A Prospective Study.

INTRODUCTION: Sudden sensorineural hearing loss (SSNHL) is one of the most common acute symptoms in the otolaryngology department. Etiological diagnosis is the premise of effective treatment of SSNHL, and prognostic evaluation is the key. However, most of the patients are diagnosed as idiopathic due to a lack of overall assessment, while prognostic factors of SSNHL are numerous and controversial. Our purpose was to validate the potential value of a novel three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) MR protocol in SSNHL and to establish a clinical-image prognostic model for unilateral SSNHL. METHODS: This prospective study included consecutive patients from May 2019 to November 2021. Pathogenic diagnosis relied on expertise-based estimation and the associations of MR findings with clinical features of unilateral SSNHL were assessed. The prognostic evaluation of unilateral SSNHL was adopted for recovery and no recovery groups and complete and incomplete recovery groups. Significant clinical and MR features were compared and screened out by single-factor analyses. The primary clinical-image prognosis assessment model was built by multifactor logistic regression analyses. RESULTS: A total of 101 patients were enrolled in our study who acquired the correct etiological diagnosis based on the novel 3D-FLAIR MR combined with clinical examination. Among the 93 patients with unilateral SSNHL, 30.1% (28/93) showed labyrinthine abnormalities on 3D-FLAIR images. The severity of initial hearing loss in the MR+ group was worse than that in the MR- group (p < 0.05), and patients with positive MR findings tended to have poor recovery. An excellent prognostic model was built for hearing complete recovery and no recovery. The combination of three independent risk factors, including abnormal distortion products otoacoustic emission and transient evoked otoacoustic emission, the period from onset to treatment, and PTA at the onset, was adopted for hearing recovery/no recovery (accuracy = 90.2%, AUC = 0.820). Furthermore, adding the factor of positive MRI findings could improve the confidence for the judgment of hearing no recovery. The only independent risk factor, PTA at the onset, was adopted for complete/incomplete hearing recovery (accuracy = 86.1%, AUC = 0.874). CONCLUSION: The novel MR protocol had a good advantage in pathogenic diagnosis. Labyrinthine MR 3D-FLAIR signal abnormalities were related to the severity of an initial hearing loss and had a greater tendency to be found in patients with no recovery. A prognostic model with two main steps of unilateral SSNHL, mainly for SSNHL with no recovery and complete recovery, was built successfully and needed further verification by larger series of patients.

Association between air pollution and sudden sensorineural hearing loss (SSHL): A systematic review and meta-analysis.

Recent studies have indicated that air pollution (AP) has harmful effects on hearing and ear diseases such as Sudden Sensorineural Hearing Loss (SSHL). The purpose of this study was to evaluate the impact of exposure to AP on SSHL incidence. Valid electronic databases were searched to retrieve studies published until December 1, 2022, using appropriate keywords. The result of the search was 1146 studies, and after screening according to the defined criteria, in total 8 studies were obtained. The risk of bias (ROB) in the studies and their quality were assessed. Finally, the meta-analysis with a significance level of 5% was performed. The findings revealed that the mean level of SO2, CO, NO2, and PM10 in the patient group was more than that of the control group, and p-values were 0.879, 0.144, 0.077, and 0.138, respectively. There was an indirect relation between air pollutants and SSHL, and PM2.5 showed a significant effect (p < 0.05). Given the limited research and the use of different statistical methods, more research is suggested to confirm this association and to determine the mechanisms by which AP exposure may cause SSHL.

The association of genetic polymorphisms in protocadherin 15 with sudden sensorineural hearing loss in a Chinese population.

BACKGROUND: Sudden sensorineural hearing loss (SSNHL) is a multifactorial disease, and its etiology is still unknown. SSNHL may be caused by environmental factors and genetic changes. PCDH15 is associated with susceptibility to hearing loss. The relationship between PCDH15 and SSNHL remains unknown. METHODS: In this study, the potential association between PCDH15 polymorphism and SSNHL in Chinese population was evaluated. Two single nucleotide polymorphisms PCDH15-rs7095441 and rs11004085 in 195 SSNHL patients and 182 healthy controls were determined by TaqMan technology. RESULTS: In Chinese population, the TT genotype and T allele of rs7095441 are associated with increased susceptibility to SSNHL. The relationships between rs7095441 and the degree of hearing loss were analyzed, and TT genotype increased the risk of hearing loss. Among SSNHL patients, patients with TT genotype of rs7095441 have an increased risk of vertigo. CONCLUSION: This study found that the TT genotype of SNP rs7095441 can increase the risk of SSNHL in Chinese population.

Nomogram for predicting the prognostic role in idiopathic sudden sensorineural hearing loss.

PURPOSE: A nomogram model was constructed to assist in early prediction of idiopathic sudden sensorineural hearing loss (ISSHL) prognosis. Additionally, this study contributed to evaluating and analyzing the usefulness of the nomogram model in ISSHL clinical intervention. METHODS: A retrospective analysis was performed concerning 355 ISSHL patients who were hospitalized between June 2021 and August 2022. Single-factor analysis was used to filter variables, which were subsequently used for multivariate analysis to construct a nomogram. The discriminative capability and clinical usefulness of the predictive model were estimated by calculating the area under the curve (AUC), calibration curve, and decision curve analysis (DCA). RESULTS: Hearing loss type, duration from onset to treatment, vertigo, periauricular paresthesia, and batroxobin use were included in the nomogram for ISSHL. The predictive model showed fair discrimination values (AUC =0.764; 95%CI: 0.715-0.813) and was well-calibrated, the C-index was 0.746 (95%CI: 0.715-0.793) in the internal validation. DCA indicated that the model was also clinically beneficial when the threshold range was between 0.246 and 0.840. CONCLUSIONS: The nomogram prediction model may have potential clinical practicability in effectively assisting clinicians in predicting ISSHL prognosis and optimizing treatment protocols.