The Role of Anti-Endothelial Cell Autoantibodies and Immune Response in Acute Low-Tone Hearing Loss

Findings of Intravenous Gadolinium Inner Ear Magnetic Resonance Imaging in Patients With Acute Low-Tone Sensorineural Hearing Loss

OBJECTIVES

Acute low-tone sensorineural hearing loss (ALHL) is thought to have a different etiology from that of idiopathic sudden sensorineural hearing loss. We hypothesized that endolymphatic hydrops (EH) in the inner ear organ contributes to ALHL, even in patients without vertigo. This study investigated the presence of EH in ALHL and compared the clinical characteristics of patients with or without EH.

METHODS

We retrospectively reviewed 38 patients diagnosed with ALHL without vertigo from January 2017 to March 2022. EH was measured in all patients using inner ear magnetic resonance imaging (MRI). In addition, we selected patients who showed only mid- or high-frequency hearing loss and had available MRI data as a control group and compared the ALHL and control groups.

RESULTS

After treatment, the pure-tone average at low frequencies significantly improved compared to the initial hearing (P<0.001). Hearing recovery was observed in 63.1% of patients; however, the recovery rate did not differ based on the treatment method. During the follow-up period, six patients (15.8%) progressed to Meniere's disease, and 18 (47.4%) experienced recurrence. In the ALHL group, the cochlear hydrops ratio on the affected side (0.34±0.09) was significantly higher than on the contralateral side (0.29±0.12) (P=0.005), and most patients showed hydrops in the apex area of the cochlea. Compared with the control group (0.25±0.15), the ALHL group showed a significantly higher cochlear hydrops ratio (P=0.043). The correlation analysis showed a tendency for hearing thresholds at low frequencies to increase as the hydrops ratio increased, albeit without statistical significance.

CONCLUSION

The cochlear hydrops ratio, especially in the apex area on the affected side, was significantly higher in patients with ALHL, suggesting that EH in the cochlea contributes to the pathogenesis of ALHL.

Prognosis of Acute Low-Tone Hearing Loss Without Vertigo: A Scoping Review

OBJECTIVE

Despite its relatively high prevalence, our understanding of the natural clinical course of acute low-tone hearing loss (ALHL) without vertigo remains incomplete. The purpose of this study is to summarize the findings of studies that evaluated recovery from hearing loss (HL), recurrence and/or fluctuation of HL, and progression to Meniere's Disease (MD) of patients presenting with ALHL without vertigo.

METHODS

A scoping review of the English literature was performed. On May 14, 2020 and July 6, 2022, MEDLINE, Embase, and Scopus were searched to identify articles related to the prognosis of ALHL. To be included, articles had to present outcomes that were clearly distinguishable for patients with ALHL without vertigo. Two reviewers evaluated articles for inclusion and extracted data. Disagreements were adjudicated by a third reviewer.

RESULTS

Forty-one studies were included. There was extensive heterogeneity between studies in regard to defining ALHL, treatment methods, and time of follow-up. Most of the cohorts (39 out of 40) reported partial or complete recovery of hearing in the majority (>50%) of patients, although reports of recurrence were relatively common. Progression to MD was infrequently reported. Shorter time from onset of symptoms to treatment predicted better hearing outcomes in 6 of 8 studies.

CONCLUSION

The literature suggests that although the majority of patients with ALHL experience hearing improvement, recurrence and/or fluctuation are common, and progression to MD occurs in a minority of patients. Additional trials utilizing standardized inclusion and outcome criteria are needed to determine the ideal treatment for ALHL.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:2457-2469, 2023.

Clinical Findings That Differentiate Co-Occurrence of Hyperacusis and Tinnitus from Tinnitus Alone

PURPOSE

We aimed to assess the characteristics of patients with concurrent tinnitus and hyperacusis, determine the best audiological criteria for predicting hyperacusis, and confirm whether objective evidence of changes in the brain exists.

MATERIALS AND METHODS

The medical records of patients with tinnitus who visited the hospital between March 2020 and December 2021 were reviewed. Data on accompanying hyperacusis, audiological profiles, and questionnaires including the Tinnitus Handicap Inventory (THI), Beck Depression Inventory, and numerical rating scale were analyzed. Resting-state quantitative electroencephalography (qEEG) using power spectral density (PSD) and event-related spectral perturbation (ERSP) were performed to objectively quantify changes in the brain.

RESULTS

A total of 194 patients were analyzed. Among them, 51 (26.3%) reported combined subjective hyperacusis with tinnitus. However, the proportions widely varied from 7.4% to 68.4% based on three audiological criteria for assessment. A higher score on the THI questionnaire was independently associated with the co-occurrence of tinnitus and hyperacusis. Fair agreement was observed between subjective hyperacusis and the audiological criterion based on a loudness discomfort level (LDL) of ≤90 dB at two or more frequencies for the diagnosis of hyperacusis. An increased beta-PSD and decreased levels of gamma-PSD, all-ERSP, and delta-ERSP were observed in patients with hyperacusis (p<0.05).

CONCLUSION

Patients with co-occurring tinnitus and hyperacusis had more severe tinnitus distress. An LDL of ≤90 dB at two or more frequencies may be applicable to predict accompanying hyperacusis in subjects with tinnitus, and qEEG also provides more objective information.

The Relationship between Meniere's Disease and Acute Low-Tone Sensorineural Hearing Loss

Objective

To analyse the vestibular function characteristics of patients with Meniere's disease and acute hypophonic sensorineural hearing loss in order to find more reliable and objective ancillary tests that will reduce misdiagnosis and missed diagnoses.

Methods

From January 2021 to December 2021, 60 healthy adults who underwent physical examination in our hospital were included in the control group, 60 patients with Meniere's disease were included in Study Group A, and 60 patients with acute low-tone sensorineural hearing loss were recruited in Study Group B. All participants underwent the caloric test (CT), video-head impulse test (vHIT), headshaking test (HST), and vestibular-evoked myogenic potential (VEMP) testing, which includes ocular vestibular-evoked myogenic potential (oVEMP) and cervical vestibular-evoked myogenic potential (cVEMP).

Results

Statistical analyses of unilateral weakness and directional preponderance (DP) in the two groups of patients found no significant differences between the two groups (P > 0.05). There was no statistically significant difference in the abnormal rate of vHIT and HST results between the two study groups (P > 0.05). There was no significant difference in the wave latencies, interwave intervals, and amplitudes of cVEMP and oVEMP, among the three groups (P > 0.05).

Conclusion

This study found that factors affecting CT, vHIT, HST, and VEMP results included age, head posture and position during testing, stimulus type, manipulation method, and control of muscle tone, and also those that are related to the testing instrument, statistical software, and manipulation procedures, resulting in different excitation rates and testing parameters. The small sample size prevented a comprehensive assessment of the differences in vestibular function between patients with Meniere's disease and acute hypotonic sensorineural hearing loss, and a larger sample size will be investigated in the future to provide useful insight into the diagnosis, treatment and differentiation of Meniere's disease, and acute hypotonic sensorineural hearing loss.