Unilateral Sudden Sensorineural Hearing Loss Research Articles

Neurovascular conflict and sudden unilateral sensorineural hearing loss: coincidence or coexistence?

To study the association between neurovascular conflict (NVC) of the 8thcranial nerve (CN8) and unilateral sudden sensorineural hearing loss SSNHL (SSNHL). A systematic literature search of "MEDLINE" via "PubMed," "Embase," and "Google-Scholar" was conducted. Meta-analysis of pooled data was performed for NVC prevalence of SSNHL affected ears versus controls. The literature search identified 941 publications, of which, 9 included in qualitative synthesis (1030 ears) and 5 in quantitative synthesis (484 ears). NVC was as prevalent as 0.8-69% for affected ears and as 19-57% for controlled ears. No association between MRI protocol and NVC prevalence was proved. An odds ratio of 1.05 (95% confidence interval = 0.79-1.39) was calculated for association of NVC in unilateral SSNHL ears versus controls. The prevalence of NVC of CN8 in unilateral SSNHL affected ears is not significantly bigger than controls. Hence, NVC of CN8 is probably NOT associated with unilateral SSNHL.

Is Sudden Sensorineural Hearing Loss an Otologic Emergency? Evidence-Based Cutoff for Optimal Treatment Initiation for Sudden Unilateral Sensorineural Hearing Loss: A Case Series and Meta-Analyses.

To study the need for defining unilateral idiopathic sudden sensorineural hearing loss (ISSNHL) as an otologic emergency and establish an evidence-based cutoff for treatment initiation for optimal outcome. A systematic literature search of "MEDLINE" via "PubMed," "Embase," and "Web of Science" and original case series comparing the outcome of steroidal treatment for ISSNHL as a function of delays of patient presentation, of diagnosis, and of treatment initiation. Total delay was defined as days from ISSNHL onset to first steroidal dose and divided into up to 3 days, up to 7 days, up to 14 days, and >14 days. The literature search identified 1,469 ears and our original case series contributed 154 ears suitable for study inclusion, resulting in 1,623 ears for statistical analysis. An odds ratio (OR) of 0.42 (95% confidence interval [CI], 0.25-0.71) was calculated for recovery if treatment had been initiated within the third day since the sudden occurrence of a unilateral hearing loss compared with treatment initiation on or after the fourth day (I 2 = 40.1%). The calculated OR for recovery was 0.35 (95% CI, 0.26-0.47) when treatment was initiated during the first 7 days after the sudden hearing loss onset compared with a delay of 8 days or more (I 2 = 52.1%). The OR was 0.31 (95% CI, 0.21-0.46) when treatment was initiated during the first 14 days after the event compared with a longer delay (I 2 = 0.0%). Unilateral ISSNHL should be considered a medical emergency. Initiating treatment before 3 days have elapsed since the event portends the best outcome. Level I.

Sound localization in patients with idiopathic sudden hearing loss

Background Patients with unilateral hearing loss have difficulty localizing sound. Severe-to-profound unilateral hearing loss is most commonly caused by idiopathic sudden sensorineural hearing loss (SSNHL). Aims/Objectives To assess the sound localization ability of patients with idiopathic unilateral SSNHL and examine the factors affecting the results. Material and Methods We retrospectively enrolled 141 patients with idiopathic unilateral SSNHL. The assessment stimuli were speech-shaped noise from one of the nine loudspeakers in a 180° arc. Multiple regression analysis was used to examine the factors that affected sound localization ability. Results There was a strong correlation between the hearing level on the affected side post-treatment and the deviation score as the index of sound localization ability. The results of the multiple regression analysis suggested that sound localization may be partially affected by hearing level on the unaffected side and age. Conclusions and significance The results showed that sound localization ability decreased in idiopathic SSNHL patients with severe-to-profound hearing loss post-treatment. This study provides important data for future interventions for unilateral hearing loss, including cochlear implants.

Sudden unilateral hearing loss and vertigo following isolated cerebellar hypoperfusion without infarction due to vertebral artery dissection

BackgroundThe definition of sudden sensorineural hearing loss (SSNHL) is broadly accepted as acute sensorineural hearing loss of more than 30 dB over at least three consecutive frequencies in a pure-tone audiogram (PTA). Acute audiovestibular loss is common with ischaemic stroke in the territory of the anterior inferior cerebellar artery (AICA). However, cases in which SSNHL and vertigo occur with hypoperfusion alone are very rare. We describe a patient who developed unilateral SSNHL and vertigo as initial symptoms caused by cerebellar hypoperfusion by vertebral artery (VA) dissection without the occurrence of infarction.Case presentationA 51-year-old man suddenly developed acute hearing loss (AHL) in his left ear and vertigo. On neurological examination, he had vibration-induced right-beating nystagmus and left-beating nystagmus after a head-shaking test. Additionally, he had apogeotropic nystagmus during head turns to either side. The head impulse test (HIT) was normal. PTA showed mild unilateral SSNHL in the left ear. Diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) showed territorial perfusion deficits in the left posterior inferior cerebellar artery (PICA) and anterior inferior cerebellar artery (AICA) without infarction. Two months later, the patient had no vertigo but still had hearing impairment in his left ear. A follow-up PTA documented persistent unilateral SSNHL in the left ear. Additionally, perfusion computed tomography (CT) showed that perfusion deficits remained in the left cerebellum along the PICA and AICA territories.ConclusionsOur case highlights a case of AHL and vertigo presented by isolated cerebellar hypoperfusion without infarction. It is necessary to consider the possibility of a central cause in patients with AHL and vertigo, and it is important to confirm this possibility through brain magnetic resonance imaging (MRI), including PWI, and magnetic resonance angiography (MRA).

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.

Delivery of Dexamethasone to the Round Window Niche by Saturated Gelatin Sponge for Refractory Sudden Sensorineural Hearing Loss: A Preliminary Study.

The aim of this study was to evaluate the hearing outcome of dexamethasone sodium phosphate (DSP) delivery to the round window niche by saturated gelatin sponge for refractory sudden sensorineural hearing loss. Twenty patients with unilateral sudden sensorineural hearing loss with an improvement of pure-tone average (PTA) less than 10 dB after primary systemic treatment with steroids. Delivery of DSP to the round window niche via saturated sponge gelatin for 2 weeks. Pure-tone audiometry was taken at the beginning and 4 to 8 weeks after the end of the salvage treatment. PTA thresholds were improved at least 10 dB in 11 of 20 patients (55%) by a mean value of 11.9 dB. The hearing threshold at 500, 1000, and 2000 Hz were improved after salvage treatment, but there was no significant change at 4000 Hz. The PTAs also recovered after the salvage treatment. Delivery of DSP to the round window niche via saturated gelatin sponge is a simple and feasible way to treat refractory sudden sensorineural hearing loss with a risk of permanent tympanic membrane perforation.

Characteristics and prognosis analysis of bilateral sudden sensorineural hearing loss: A retrospective case-control study.

To evaluate the clinical characteristics and prognostic factors of simultaneous and sequential bilateral sudden sensorineural hearing loss (Si-BSSNHL and Se-BSSNHL, respectively). Retrospective case-control study. A single tertiary referral centre. Patients diagnosed with unilateral sudden sensorineural hearing loss (USSNHL), Si-BSSNHL, or Se-BSSNHL between September 2018 and November 2019. Demographic and clinical characteristics, audiological features, laboratory results and hearing recovery were analysed for intergroup comparisons. Prognostic factors for BSSNHL were analysed using univariate and multivariate logistic analyses between the overall and no-recovery groups. Compared to the USSNHL group, a larger final pure-tone average (PTA) (H=38.0 and 53.8, respectively, both adjusted p-value (p adj) <.05), lower hearing gain (H=-70.8 and - 74.6, respectively, both p adj <.001) and higher homocysteine levels (H=46.8, 58.8, respectively, both p adj <.05) were observed in the Si-BSSNHL and Se-BSSNHL groups, while the rate of positive vestibular tests and proportion of tinnitus were lower in the Se-BSSNHL group (χ2 =8.5 and 38.1, respectively, both p adj <0.05). The USSNHL group showed a significant difference in the degree of deafness and therapeutic outcome in the Se-BSSNHL and Si-BSSNHL groups, respectively (χ2 =12.4, p adj <.05; χ2 =13.6; p adj <.05). Hypertension (95% confidence interval, 1.014-28.623, p < .05) and onset days (95% confidence interval, 0.007-0.626, p < .05) were associated with the therapeutic effects of BSSNHL. Higher homocysteine levels in BSSNHL may implicate microvascular disorders as a causative factor of BSSNHL. Hypertension and onset days were associated with the prognosis of BSSNHL.

Diagnostic value and prognostic significance of MRI findings in sudden sensorineural hearing loss.

PurposeWe evaluated the clinical significance of magnetic resonance imaging (MRI) findings and their prognostic value for initial hearing loss and recovery in patients with sudden sensorineural hearing loss (SSNHL).Materials and MethodsThis retrospective study included consecutive adult patients with unilateral SSNHL, contrast‐enhanced MRI and audiometric testing evaluated in our institution between 2005 and 2017. MRI reports, patient data, treatment, and audiometric tests were reviewed, with the relationship between MRI findings and hearing loss/recovery analyzed.ResultsOverall, 266 patients were included. Additional symptoms comprised tinnitus (114/266; 43%), vertigo (45/266; 17%), ear pain (26/266; 10%), and ear pressure (6/266; 2%). At least one cardiovascular risk factor (hypertension, diabetes, hypercholesterolemia, cardiopathy, and active smoking) existed in 167/266 (63%) patients. Corticosteroid treatment was followed by 198/266 (74%) patients while contraindications/refusal/compliance precluded treatment in 68/266(26%). Complete, partial or slight hearing recovery occurred in 167/266 (63%) patients. Three MRI patient groups were identified: a group with normal MRI examinations or incidentalomas (128/266; 48%), a group with peripheral auditory system (PAS) lesions (95/266; 36%), and a group with central nervous system (CNS) lesions (43/266; 16%). PAS lesions included lesions from the cochlea to the brain stem (e.g., schwannoma, meningioma, labyrinthitis, intracochlear hemorrhage, vestibulocochlear neuritis), whereas CNS lesions corresponded in 42/43(98%) of cases to leukoaraiosis and other vascular lesions (e.g., stroke, hemorrhage, aneurysm, venous sinus thrombosis, and cavernoma). Belonging to one of the three MRI groups did not influence the degree of initial hearing loss, affected frequencies or treatment, p > .05. Gender and cardiovascular risk factors did neither affect initial hearing loss nor recovery. However, age > 70 years negatively affected initial hearing loss in all frequencies, as well as recovery in all frequencies except 1000 Hz. Also, poor recovery of initial high‐frequency hearing loss (>1000 Hz) was significantly associated with CNS lesions.ConclusionAge > 70 years and CNS lesions depicted by MRI independently predicted poor auditory recovery, albeit in different frequencies.Lay SummaryIn patients with sudden hearing loss, older age (above 70 years) predicts poorer hearing recovery than in younger patients in most hearing frequencies. In addition, abnormalities of brain tissue revealed by MRI predict poorer hearing recovery at high frequencies.Level of EvidenceLevel III.

Sudden Hearing Loss in Patients With COVID-19: Case Series and Analysis of the Literature

This study reports on patients with severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) presenting with sudden sensorineural hearing loss (SSNHL) during the coronavirus disease 2019 (COVID-19) pandemic. The study included four adult patients who presented with the complaint of unilateral SSNHL after testing positive for SARS-CoV-2 by RT-PCR from January to April 2022. Of the four patients, only one young adult recovered his hearing following a combination of oral and intratympanic steroid therapy. It is a challenge to confirm evidence of association between COVID-19 and SSNHL. Nevertheless, the early screening and diagnosis for SSNHL following COVID-19 enables prompt treatment with steroids, which offers the best chance of hearing recovery.

Association of sudden sensorineural hearing loss and its prognosis with the brain white matter hyperintensity

Objective:To explore the relationship between white matter hyperintensity（WMH） and sudden sensorineural hearing loss（SSHL） and evaluate the influence of WMH on the prognosis of SSHL. Methods:Fifty hospitalized unilateral SSHL patients and 50 age and gender matched routine physical examination individuals without SSHL history from June 2019 to June 2020 were included for a case-control study. All included subjects underwent 3.0 Tesla cranial magnetic resonance examination, and the Fazekas scale was applied to evaluate periventricular white matter hyperintense（PVWMH） and deep white matter hyperintense（DWMH）. Fazekas score and distribution proportions of Fazekas score was compared between SSHL and control. Ordered logistic regression was used to study the relationship between prognosis of SSHL and WMH. Results:The Fazekas score of WMH in SSHL group was significantly higher than that of control group（PVWMH: P=0.004, DWMH: P=0.010）; There was a significant difference in the distribution proportions of Fazekas scores between SSHL and control（PVWMH: P=0.036, DWMH: P=0.047）; The results of ordered logistic regression showed that patients without WMH（Fazekas=0） is an independent predictor of good prognosis in SSHL（P=0.025, OR=12.779）. Conclusion:The prevalence of WMH in SSHL patients was higher than that of control. SSHL patients without WMH has a better prognosis than those with WMH.

Relationship between sudden sensorineural hearing loss and facial auditory nerve and anterior inferior cerebellar artery vascular loop in the internal auditory tract MRI

Objective:To investigate the correlation between the facial auditory nerve and anterior inferior cerebellar artery vascular loop in MRI of the internal auditory meatus and idiopathic sudden sensorineural hearing loss. Methods:This retrospective study enrolled 144 patients with idiopathic sudden sensorineural hearing loss（SSNHL）（experimental group） and 36 healthy subjects with 72 ears（control group）, who attended the Department of Otolaryngology Head and Neck Surgery, the 940th Hospital of the Joint Logistics Support Unit of the Chinese PLA from January, 2019 to January, 2021. The magnetic resonance imaging（MRI） data of the internal auditory meatus and clinical data were collected and compared between the two groups. Results:The distance between the auditory nerve and the peripheral vessels in the unilateral SSNHL-affected ear was significantly different from that in the contralateral ears and that in the healthy ears of the control group （P<0.05）. The distance between the auditory nerve and the peripheral vessels in both ear affected by bilateral SSNHL was significantly different from that in the healthy ears of the control group （P<0.05）. There was no significant difference in radiological grading of vascular loops between the ears affected by unilateral SSNHL and the contralateral ears and the healthy ear of the control group （P>0.05）. No statistically significant differences in radiological grading of vascular loops were found between both ears with bilateral SSNHL and the healthy ears in the control group（P>0.05）. The severity of hearing loss, audiometric configuration, radiological grading of vascular loops and the distance between the facial auditory nerve and peripheral vessels were not significantly different between the affected ears in unilateral SSNHL and both ears in bilateral SSNHL （P>0.05）. Conclusion:SSNHL is associated with the distance between the auditory nerve and the nearest peripheral vessel. SSNHL may occur when the vessel compresses the auditory nerve.

Analysis of cerebral blood perfusion changes in patients with unilateral sudden sensorineural hearing loss based on three-dimensional pseudo-continuous arterial spin labeling

Objective: To explore the changes of cerebral blood perfusion in patients with unilateral sudden sensorineural hearing loss (SSNHL) by using the three-dimensional pseudo-continuous arterial spin labeling (3D pCASL) technique. Methods: The clinical characteristics and ASL data of the 32 patients with unilateral SSNHL were retrospectively collected from November 2020 to June 2021 in Beijing Fuxing Hospital of Capital Medical University, among them, there were 7 males and 25 females, aged from 17 to 73 (44.9±14.4) years. According to the location of SSNHL, they were divided into the left SSNHL (L-SSNHL) group (18 cases) and the right SSNHL (R-SSNHL) group (14 cases). A total of 34 healthy volunteers, which including 14 males and 20 females, aged from 24 to 68 (46.2±14.4) years were enrolled from the local community. The parameter of cerebral blood flow (CBF) of each brain area was obtained using the CereFlow software. The Brainnetome Atlas software package based on MATLAB was used for visualization. The independent-samples t test was conducted to compare the difference of cerebral blood perfusion between the unilateral SSNHL group and healthy control (HC) group. Pearson correlation analysis was used to evaluate the correlation between changes in cerebral blood perfusion and clinical scale scores. Results: The CBF of left orbital gyrus part 5, left inferior temporal gyrus part 7, right orbital gyrus part 5, right inferior temporal gyrus part 1, right inferior temporal gyrus part 7, and right parahippocampal gyrus part 3 of the L-SSNHL group were higher than that in the HC group[(49.1±8.8) vs (31.6±10.9)ml·100g-1·min-1;(42.8±14.3) vs (27.1±13.6)ml·100g-1·min-1;(51.8±9.4) vs (27.2±11.2)ml·100g-1·min-1;(38.8±5.7) vs (28.0±9.2)ml·100g-1·min-1;(38.4±13.8) vs (23.6±10.3)ml·100g-1·min-1;(42.4±9.4) vs (30.1±12.6)ml·100g-1·min-1; all P<0.05]. The CBF of left superior frontal gyrus part 7 and left middle frontal gyrus part 3 of the L-SSNHL group were lower than that in the HC group[(48.2±7.9) vs (59.3±13.7)ml·100g-1·min-1;(46.4±10.3) vs (59.3±16.9)ml·100g-1·min-1;all P<0.05]. The CBF of left orbital gyrus part 5, right orbital gyrus part 5, right inferior temporal gyrus part 1, and right inferior temporal gyrus part 7 of the R-SSNHL group were higher than that in the HC group[(50.6±7.0) vs (31.6±10.9)ml·100g-1·min-1;(50.9±8.8) vs (27.2±11.2)ml·100 g-1·min-1;(38.0±7.2) vs (28.0±9.2)ml·100g-1·min-1;(35.7±8.5) vs (23.6±10.3)ml·100g-1·min-1;all P<0.05]; the CBF of right insular part 4 was lower than that in the HC group [(44.2±6.1) vs (54.4±11.3) ml·100 g-1·min-1, P=0.018]. In the L-SSNHL group, the CBF of left superior frontal gyrus part 7 and right orbital gyrus part 5 were negatively correlated with the VAS score(r=-0.83, -0.81, all P<0.05), and the CBF of right orbital gyrus part 5 was negatively correlated with the THI score(r=-0.75, P=0.013). There was no statistically significant correlation between the remaining differences in brain regions and clinical scale scores(all P>0.05). Conclusion: Changes in cerebral blood perfusion in multiple brain regions were found in patients with unilateral SSNHL by using the 3D pCASL technique.

Speech perception in noise in patients with idiopathic sudden hearing loss

Background Patients with unilateral hearing loss have difficulties perceiving speech in a noisy environment. Unilateral severe to profound hearing loss is most commonly caused by idiopathic sudden sensorineural hearing loss (SSNHL). Objectives To assess speech perception in noise among patients with idiopathic unilateral SSNHL, and examine the factors affecting the results. Material and methods We retrospectively enrolled 93 patients with idiopathic unilateral SSNHL. The speech signal was presented at a constant sound pressure level, while the noise signal varied from +5 dB to −5 dB signal-to-noise ratio (SNR) in units of 5 dB (S0/Nhe). Results As the SNR decreased, the percentage of correct answers also decreased. The correct answer rate decreased with increased hearing level at post-treatment. There was a correlation between age and speech perception, especially when dividing the patients into two groups: <65 years old and ≥65 years old. Conclusions and significance The results showed that speech perception clearly decreased in a noisy environment rather than in a quiet environment, and the correct answer rate of the speech perception test in noise was significantly correlated with hearing level at post-treatment. This study provides important data for future interventions for unilateral hearing loss, including cochlear implants.

Prediction of hearing recovery in unilateral sudden sensorineural hearing loss using artificial intelligence

Despite the significance of predicting the prognosis of idiopathic sudden sensorineural hearing loss (ISSNHL), no predictive models have been established. This study used artificial intelligence to develop prognosis models to predict recovery from ISSNHL. We retrospectively reviewed the medical data of 453 patients with ISSNHL (men, 220; women, 233; mean age, 50.3 years) who underwent treatment at a tertiary hospital between January 2021 and December 2019 and were followed up after 1 month. According to Siegel’s criteria, 203 patients recovered in 1 month. Demographic characteristics, clinical and laboratory data, and pure-tone audiometry were analyzed. Logistic regression (baseline), a support vector machine, extreme gradient boosting, a light gradient boosting machine, and multilayer perceptron were used. The outcomes were the area under the receiver operating characteristic curve (AUROC) primarily, area under the precision-recall curve, Brier score, balanced accuracy, and F1 score. The light gradient boosting machine model had the best AUROC and balanced accuracy. Together with multilayer perceptron, it was also significantly superior to logistic regression in terms of AUROC. Using the SHapley Additive exPlanation method, we found that the initial audiogram shape is the most important prognostic factor. Machine/deep learning methods were successfully established to predict the prognosis of ISSNHL.

Cerebral Blood Flow Pattern Changes in Unilateral Sudden Sensorineural Hearing Loss.

ObjectiveThis study analyzed the differences in the cerebral blood flow (CBF) between unilateral Sudden Sensorineural Hearing Loss (SSNHL) patients and healthy controls (HCs). We also investigated CBF differences in auditory-related areas in patients with left- and right-sided SSNHL (lSSNHL and rSSNHL) and HCs. We further explore the correlation between unilateral SSNHL characteristics and changes in the CBF.Methods36 patients with unilateral SSNHL (15 males and 21 females, 40.39 ± 13.42 years) and 36 HCs (15 males and 21 females, 40.39 ± 14.11 years) were recruited. CBF images were collected and analyzed using arterial spin labeling (ASL). CereFlow software was used for the post-processing of the ASL data to obtain the CBF value of 246 subregions within brainnetome atlas (BNA). The Two-sample t-test was used to compare CBF differences between SSNHL patients and HCs. One-way ANOVA or Kruskal-Wallis test was used to compare the CBF difference of auditory-related areas among the three groups (lSSNHL, rSSNHL, and HCs). Then, the correlation between CBF changes and specific clinical characteristics were calculated.ResultsThe SSNHL patients exhibited decreased CBF in the bilateral middle frontal gyrus (MFG, MFG_7_1 and MFG_7_3), the contralateral precentral gyrus (PrG, PrG_6_3) and the bilateral superior parietal lobule (SPL, bilateral SPL_5_1, SPL_5_2, and ipsilateral SPL_5_4), p < 0.0002. Compared with HCs, unilateral SSNHL patients exhibited increased rCBF in the bilateral orbital gyrus (OrG, OrG_6_5), the bilateral inferior temporal gyrus (ITG, contralateral ITG_7_1 and bilateral ITG_7_7), p < 0.0002. lSSNHL showed abnormal CBF in left BA21 caudal (p = 0.02) and left BA37 dorsolateral (p = 0.047). We found that the CBF in ipsilateral MFG_7_1 of SSNHL patients was positively correlated with tinnitus Visual Analog Scale (VAS) score (r = 0.485, p = 0.008).ConclusionOur preliminary study explored CBF pattern changes in unilateral SSNHL patients in auditory-related areas and non-auditory areas, suggesting that there may exist reduced attention and some sensory compensation in patients with SSNHL. These findings could advance our understanding of the potential pathophysiology of unilateral SSNHL.

Bilateral Sudden Sensorineural Hearing Loss: A Distinct Phenotype Entity.

To investigate the clinical phenotype and hearing prognosis of patients with unilateral and bilateral (simultaneous and nonsimultaneous) sudden sensorineural hearing loss (SSNHL). Retrospective cohort. Otology outpatient clinic of a tertiary university hospital. Three hundred eighty-five medical records from patients with SSNHL. Comparison of demographic, clinical, and audiometric (pretreatment and posttreatment) data of patients with unilateral and bilateral SSNHL. Our final analysis comprised of 239 medical records of patients with SSNHL. Most patients had unilateral SSNHL (186, 77.82%). We identified a potential underlying cause for the SSNHL in 105 (43.9%) of the cases, being more frequent in cases of bilateral simultaneous SSNHL (100%) as compared with unilateral (45.6%) and nonsimultaneous bilateral SSNHL (22.7%). Cases of simultaneous bilateral SSNHL presented more frequently with severe or profound hearing loss (89%; unilateral SSNHL 50.5%; nonsimultaneous bilateral SSNL, 59.1%) and had a significantly worse hearing recovery prognosis as compared with unilateral or nonsimultaneous bilateral SSNHL (p = 0.002). We observed a high heterogeneity of clinical presentations of SSNHL, the most common being unilateral SSNHL. Our results demonstrate that the clinical and audiological prognosis of simultaneous bilateral SSNHL differed significantly from unilateral and nonsimultaneous bilateral SSNHL, suggesting that simultaneous cases of bilateral SSNHL may be a part of a different disease process. The presence of a simultaneous, bilateral SSNHL indicates the need to investigate the presence of an underlying systemic disease.

Possible Existence of Cochlear Synaptopathy in Patients Completely Recovered from Idiopathic Sudden Sensorineural Hearing Loss.

Cochlear synaptopathy refers to a subclinical hearing pathology which could potentially explain hearing difficulties within the normal hearing threshold; it is also called “hidden hearing loss”. We hypothesized that a temporary threshold shift in sudden sensorineural hearing loss (ISSNHL) also affects the function in the synapse. The aim of the study was to evaluate the presence of cochlear synaptopathy in patients who had completely recovered from unilateral SSNHL Nineteen patients who had completely recovered from ISSNHL from January 2018 to June 2021 were assessed. Complete recovery was established by pure tone audiometry (PTA) 3 months after treatment, according to the American Academy of Otolaryngology–Head and Neck Surgery criteria. Subjects completed the pure tone audiometry, speech audiometry and auditory brain stem response (ABR) test, and completed a questionnaire regarding hearing loss after hearing recovery. The ABR amplitudes of wave I and wave V, and the ratio of wave I/V of both ears (recovered side and healthy side) were assessed. A visual analog scale (VAS) and a hidden hearing loss questionnaire were used to evaluate subjective hearing difficulty. The ABR waves I of the recovered ears had a significantly lower amplitude (p = 0.002) than those of the healthy side, whereas there was no difference in wave V (p = 0.985) or in the ratio of wave I/V (p = 0.107). Some patients still felt mild hearing difficulty although their PTA results were normal, but there was no clear relationship between the VAS score, wave I amplitude and speech recognition scores. The present findings point to the possible existence of cochlear synaptopathy in ears that have completely recovered from unilateral sudden sensorineural hearing loss. We suggest that the causes of cochlear synaptopathy and of idiopathic sudden hearing loss may have something in common.

Dynamic alterations of functional connectivity and amplitude of low-frequency fluctuations in patients with unilateral sudden sensorineural hearing loss

Unilateral sudden sensorineural hearing loss (SSNHL) adversely affects the quality of life, leading to increased risk of depression and cognitive decline. Our previous studies have mainly focused on the static brain function abnormalities in SSNHL patients. However, the dynamic features of brain activity in SSNHL patients are not elucidated. To explore the dynamic brain functional alterations in SSNHL patients, age- and sex- matched SSNHL patients (n = 38) and healthy controls (HC, n = 44) were enrolled. The dynamic functional connectivity (dFC) and dynamic amplitude of low-frequency fluctuation (dALFF) methods were used to compare the temporal features and dynamic neural activity between the two groups. In dFC analyses, the multiple functional connectivities (FCs) were clustered into 2 different states; a greater proportion of FCs in SSNHL patients showed sparse state compared with HC. In dALFF analyses, SSNHL individuals exhibited decreased dALFF variability in bilateral inferior occipital gyrus, middle occipital gyrus, calcarine, right lingual gyrus, and right fusiform gyrus. dALFF variability showed a negative correlation with activated partial thromboplatin time. The dynamic characteristics of SSNHL patients were different from static functional connectivity and static amplitude of low-frequency fluctuation, especially within the visual cortices. These findings suggest that SSNHL patients experience cross-modal plasticity and visual compensation, which may be closely related to the pathophysiology of SSNHL.

The impairment of speech perception in noise following pure tone hearing recovery in patients with sudden sensorineural hearing loss

To explore whether patients with unilateral idiopathic sudden sensorineural hearing loss (uISSNHL) have normal speech in noise (SIN) perception under different masking conditions after complete recovery of pure tone audiometry. Eight completely recovered uISSNHL patients were enrolled in ISSNHL group, while 8 normal-hearing adults matched with age, gender, and education experience were selected as the control group. Each group was tested SIN under four masking conditions, including noise and speech maskings with and without spatial separation cues. For both ISSNHL and control groups a two-way ANOVA showed a statistically significant effect of masking type (p = 0.007 vs p = 0.012). A significant effect of perceived spatial separation (p < 0.001 vs p < 0.001). A significant interaction between masking type and perceived spatial separation was found (p < 0.001 vs p < 0.001). A paired sample T-test showed that the SIN perception of the control group was statistically significant lower than that of ISSNHL patients only under speech masking without spatial separation cues (p = 0.011). There were still abnormalities in the auditory center shortly after complete recovery in the ISSNHL group (within 2 weeks). However, the auditory periphery and higher-level ability to use spatial cues was normal.

Vestibular function of pediatric patients with sudden sensorineural hearing loss: based on vertigo symptom and vestibular function testing.

This study aimed to evaluate the relationship between vestibular and auditory functions in pediatric patients with sudden sensorineural hearing loss (SSHL). A total of 30 pediatric patients experiencing unilateral SSHL between 5.9 and 13.0years of age were enrolled in this study. Pure tone audiometry was evaluated prior to treatment initiation and again after one month of treatment. Prior to treatment initiation, vertigo symptoms were noted; then several vestibular function tests were conducted including caloric testing, ocular vestibular evoked myogenic potentials (o-VEMPs) and cervical vestibular evoked myogenic potentials (c-VEMPs). Associations between pre and post-treatment vestibular function and hearing threshold levels were analyzed. Initial hearing thresholds of children with vertigo were higher than thresholds of children without vertigo (92dB vs 79dB, P = 0.033), while initial hearing thresholds of children with abnormal caloric test findings were higher than thresholds of children with normal caloric test findings (93dB vs 67dB, P = 0.014). Cutoff values of hearing thresholds for those with vertigo symptoms and abnormal vestibular test results were 86.000- and 89.583-dB HL, respectively. Regarding prognosis, children with vertigo exhibited lower recovery rates than children without vertigo (33% vs 75%, P = 0.025); recovery rates of children with abnormal caloric test results were lower than the overall recovery rate (25% vs 73%, respectively, P = 0.039). Assessments of vertigo symptoms and vestibular function are useful tools in predicting pediatric SSHL patient disease severity and prognosis.