OBJECTIVE: Acute sensorineural hearing loss represents a spectrum of conditions characterized by sudden onset hearing loss. The \"Clinical Practice Guidelines for the Diagnosis and Management of Acute Sensorineural Hearing Loss\" were issued as the first clinical practice guidelines in Japan outlining the standard diagnosis and treatment. The purpose of this article is to strengthen the guidelines by adding the scientific evidence including a systematic review of the latest publications, and to widely introduce the current treatment options based on the scientific evidence.
METHODS: The clinical practice guidelines were completed by 1) retrospective data analysis (using nationwide survey data), 2) systematic literature review, and 3) selected clinical questions (CQs). Additional systematic review of each disease was performed to strengthen the scientific evidence of the diagnosis and treatment in the guidelines.
RESULTS: Based on the nationwide survey results and the systematic literature review summary, the standard diagnosis flowchart and treatment options, including the CQs and recommendations, were determined.
CONCLUSIONS: The guidelines present a summary of the standard approaches for the diagnosis and treatment of acute sensorineural hearing loss. We hope that these guidelines will be used in medical practice and that they will initiate further research.

Inner ear disorders have a variety of causes, and many factors can contribute to the exacerbation of cochlear and vestibular pathology. This systematic review aimed to analyze clinical data on the coexistence and potential causal interaction between allergic diseases and inner ear conditions. A search of PubMed and Web of Science identified 724 articles, of which 21 were selected for full-text analysis based on inclusion and exclusion criteria. The epidemiologic evidence found overwhelmingly supports an association between allergic disease and particular inner ear disorders represented by a high prevalence of allergic reactions in some patients with Ménière\'s disease (MD), idiopathic sudden sensorineural hearing loss (ISSHL), and acute low-tone hearing loss (ALHL). In addition, patients with MD, ISSHL, and ALHL had higher levels of total serum IgE than healthy subjects. Finally, in some cases, changes in cochlear potential may have been induced by antigen exposure, while desensitization alleviated allergy and inner ear-related symptoms. The exact mechanism of interaction between the auditory/vestibular and immune systems is not fully understood, and further clinical and basic research is needed to understand the relationship between the two systems fully.

OBJECTIVE: This study aimed to investigate the endolymphatic hydrops (EH)-positivity rates among patients with recurrent audiovestibular symptoms using intravenous injection of gadolinium-enhanced inner ear magnetic resonance imaging (ieMRI).
METHODS: We reviewed 710 successive patients with recurrent audiovestibular symptoms at the Vertigo/Dizziness Center of Nara Medical University and other related hospitals, between May 2014 and April 2020. We performed ieMRI on 153 patients with unilateral recurrent cochleovestibular symptoms (rCV), 51 with recurrent vertigo symptoms (rVO), and 84 with unilateral recurrent cochlear symptoms (rCO).
RESULTS: EH was observed in 69.4% of the participants: 81.7% in the rCV group, 19.6% in the rVO group, and 77.4% in the rCO group. The participants were divided into two groups according to the disease duration: short-duration and long-duration groups. In the short-duration group (less than 4 years), EH was observed in 82.3%, 42.9%, and 71.4% of the patients in rCV, rVO, and rCO groups, respectively; in the long-duration group (more than 5 years), EH was observed in 81.1%, 10.8%, and 81.6% of the patients in rCV, rVO, and rCO groups, respectively.
CONCLUSIONS: The longer the duration of the disease, the larger the EH-positivity rates in patients with rCO, smaller in those with rVO, and unchanged in those with rCV. Although ieMRI could not detect EH with 100% accuracy in Ménière\'s disease, the present pathological statistics of patients with recurrent audiovestibular symptoms might be helpful in considering the pathology-based treatment strategy.

BACKGROUND: Autoimmunity may play an important role in sudden onset sensorineural hearing loss. However, little is known about the relationship between immunoglobulin E (IgE) and acute low-tone sensorinerual hearing loss (ALHL).
OBJECTIVE: To investigate the relationship between IgE level and endolymphatic hydrops and outcomes of ALHL.
METHODS: A total of 242 subjects with sudden onset hearing loss, including 115 with ALHL and 127 with idiopathic sudden sensorineural hearing loss (ISSHL), were included in this study. Peripheral venous blood samples of 242 subjects were collected for detection. Clinical data, IgE level, and distribution of allergens were compared between the ALHL and ISSHL groups. The ALHL group received an electrocochleogram (ECochG) test and a follow-up in the outpatient unit or by telephone to evaluate outcomes.
RESULTS: Compared to the values in the ISSHL group, a significantly younger onset age (42.30±14.33 years old), higher female onset proportion (72/115, 62.61%), increased total IgE level (median: 66.47, interquartile range: 24.56, 180.96, IU/mL) and specific IgE level (median: 9.42, interquartile range: 1.42, 22.23 IU/mL) were noted in the ALHL group. A clear difference in allergen distribution was noted between the ALHL and ISSHL groups (p=.001). Total IgE and specific IgE levels were factors that contributed to the SP/AP ratio in the electrocochleogram (ECochG) (R2=0.413) in ALHL group. Finally, during the follow-up (17.61±3.46 months) for the ALHL group, 37 subjects recurred, and 17 subjects developed Meniere Disease. In the ROC curve for ALHL recurrence, the area under the curve (AUC) of total IgE was 0.709 and that of specific IgE was 0.679. For MD transformation, the AUC of total IgE was 0.736 and that of specific IgE was 0.716.
CONCLUSIONS: High IgE levels correlated with an enhanced SP/AP ratio in ALHL. High IgE levels could be used as a predictor of ALHL recurrence and MD transformation.

UNASSIGNED: Our objective was to perform a meta-analysis to compare the effectiveness of steroids and diuretics in the treatment of acute low-tone sensorineural hearing loss (ALHL).
UNASSIGNED: PubMed, Google Scholar, and Sci databases were searched for randomized controlled trials (RCTs) examining the treatment of ALHL with steroids and diuretics. The Cochrane Reviewer\'s Handbook 5.0 evaluation criteria were used to evaluate the quality of the included RCTs. Meta-analysis was performed using Revman 5.3 software to compare the recovery rate of low-tone hearing levels between patients treated with steroids and diuretics.
UNASSIGNED: A total of 3 RCTs were included. There was no heterogeneity between the 3 studies (χ2 = 2.61, P = .27, I2 = 23%); thus, a fixed-effects model of analysis was used. Meta-analysis showed there was no significant difference in the recovery rate of patients treated with steroids and those treated with diuretics (odds ratio = 1.48, 95% confidence interval: 0.64-3.40, P = .36).
UNASSIGNED: Steroids and diuretics are equally effective for the treatment of ALHL.

OBJECTIVE: The aim of this study was to measure the volume of the endolymphatic space (ELS) and to investigate prognosis in patients with acute low-tone sensorineural hearing loss (ALHL).
METHODS: A total of 61 ALHL patients participated; 47 were definite while 14 were probable ALHL cases. The definite ALHL patients were classified into three groups: A, \"Cure\"; B, \"No cure\"; and C, \"Recurrence.\" Also, nine patients for whom diagnosis changed from ALHL to cochlear Meniere\'s disease (cMD) without vertigo (ALHL-cMD group). Images of the inner ear fluid space, positive perilymph, and positive endolymph were acquired using a 3T magnetic resonance scanner. Three-dimensional (3D) images were semi-automatically reconstructed using anatomical and tissue information to fuse the 3D images of the inner ear fluid space with the 3D ELS images.
RESULTS: Patients in the no cure group showed a significantly higher ELS/total fluid space (TFS) volume ratio in the affected cochlear region than the patients of the other groups. Additionally, the affected vestibular ELS/TFS volume ratio in the cure group was significantly lower than that in the recurrence group. There were significantly higher cochlear and vestibular ELS/TFS ratios in ALHL-cMD patients than in control subjects.
CONCLUSIONS: These results indicate that the cochlear ELS/TFS volume ratio should be considered when investigating the extent of recovery, while the extended ELS in the vestibule should be considered when investigating cases of recurrence. Thus, our study suggests that the severe extended ELS appeared likely to change to cMD and that the prognostic determination of ALHL is possible.

OBJECTIVE: To employ magnetic resonance imaging (MRI) to measure the volume of the inner ear endolymphatic space (ELS) in patients with acute low-tone sensorineural hearing loss (ALHL), sudden deafness (SD), cochlear Meniere\'s disease (cMD), and unilateral MD (uMD) compared with control subjects (CS) with chronic rhinosinusitis.
METHODS: Forty-one patients with ALHL, 82 with SD, 48 with cMD, 72 with uMD, and 47 CS participated in the study. With the exception of all uMD patients, none of the subjects had vertigo. Images of the inner ear fluid space, positive perilymph signal, and positive endolymph signal were acquired using a 3-T MRI scanner. Three-dimensional images were reconstructed semi-automatically by using anatomical and tissue information to fuse the inner ear fluid space images and the ELS images.
RESULTS: The cochlear ELS/total fluid space (TFS) volume ratio was 10.2±6.7% (mean±standard deviation) in the CS group, 12.1±5.7% in ALHL patients, 15.2±8.7% in SD patients, 18.1±8.2% in cMD patients, and 21.9±16.4% in uMD patients. The vestibular ELS/TFS volume ratio was 17.7±10.2% in the CS group, 18.9±8.3% in ALHL patients, 19.9±11.3% in SD patients, 22.5±13.7% in cMD patients, and 35.7±24.1% in uMD patients. The cochlear ELS/TFS volume ratio in patients with uMD was similar to that in the cMD group and significantly higher than that in the CS, ALHL, and SD groups (CS=ALHLCONCLUSIONS: The cochlear ELS volume of patients with MD and other endolymphatic hydrops-related diseases differed from that of CS. Our results suggest that ALHL may not be caused by endolymphatic hydrops. We confirmed the presence of extended ELS in patients with SD.

Objective:We aimed to investigate the prognosis and clinical characteristics of patients with acute low-tone sensorineural hearing loss(ALHL) and the patients with sudden low-tone loss who were not classified in the audiometric definition ALHL of(non-ALHL).Method:Two hundred and seven patients diagnosed at the university hospital with idiopathic sudden low-tone loss of sensorineural hearing loss including 48 ALHL and 159 non- ALHL from Jan 2010 to Dec 2015.The patients were followed up in the long term with three months to 5 years.The rates of recurrence and/or progression to Ménière\'s disease for patients with ALHL were compared with those for non-ALHL patients.Result:The recurrence rate was 26.4% for non-ALHL and 16.7% for ALHL.There was statistically significant difference between the two patient groups.In ALHL patients,8.8% patients progressed to Ménière\'s disease,1.9% was diagnosised with acoustic neuroma and 5.7% with vestibular migraine.In non-ALHL patients,4.2% patients progressed to Ménière\'s disease.Conclusion:In clinical practice,sudden low-tone loss other than ALHL shows a potential for recurrence and progressed to Ménière\'s disease.

Objective:To predict the prognosis of acute lowtone sensorineural hearing loss（ALHL）by using the videonystagmography(VNG) and electrocochleography(ECochG).Method:A retrospective study was done in 70 patients with ALHL after long-term follow-up. The recurrence rate and rate of progression to definite Meniere \'s disease were determined according to the results of VNG and ECochG tests at the onset of the first episode of hearing loss.Result:Twentynine patients（41.4%）experienced recurrent hearing loss and 5 patients（7.1%）developed to Meniere\'s disease. In patients with an elevated SP/AP ratio and spontaneous nystagmus, the recurrence rate was 81.8%. However, in those with a normal SP/AP ratio and without spontaneous nystagmus, the recurrence rate was 23.3%.There was a statistically significant difference in the progression rate of Meniere\'s disease between the groups with(15.2%) and without spontaneous nystagmus.Conclusion:It has a certain reference value to predict prognosiswhen spontaneous nystagmus and an elevated SP/AP ratio are detected on initial examination in patients with ALHL.

Patulous Eustachian Tube (PET) is of increasing importance in otology. However, despite the abundance of diseases requiring a differential diagnosis from PET, such as superior semicircular canal dehiscence syndrome, perilymphatic fistula, acute low-tone sensorineural hearing loss, etc., there are currently no established diagnostic criteria for PET. In view of these circumstances, the Japan Otological Society (JOS) Eustachian Tube Committee proposed the diagnostic criteria for Patulous Eustachian Tube in 2012, in order to promote clinical research on PET. A revision was made in 2016, maintaining the original concept that the criteria should be very simple, avoid any contamination of \"Definite PET\" with uncertain cases. Moreover, it was also intended to minimize the number of cases that could be accidentally excluded even in the presence of some suspected findings (\"Possible PET\"). The criteria can be used by all otolaryngologists even without using the Eustachian tube function test apparatus. However, the use of such an apparatus may increase the chances of detecting \"Definite PET\". The algorithm for the diagnosis of PET using the criteria has also been described. The JOS diagnostic criteria for Patulous Eustachian Tube will further promote international scientific communication on PET.