Self-Reported Tinnitus Severity Prior to and During the COVID-19 Lockdown in the United Kingdom

A Scoping Review of Corticosterone-Induced Changes in Ionotropic Glutamate Receptor Levels and Localization in the Rodent Brain: Implications for the Auditory System

BACKGROUND

The ionotropic glutamate receptor AMPA (AMPAR) mediates fast excitatory synaptic transmission and regulates synaptic strength in various parts of the CNS. Emotional challenges can affect these processes by influencing AMPAR levels and localization via stress hormones, resulting, e.g., in behavioral changes. AMPARs are essential for auditory processing, but their response to stress hormones in the central or peripheral auditory system remains poorly understood. Therefore, this scoping review examines the effects of corticosterone (CORT), a primary stress hormone in rodents, on AMPA receptor levels and localization in the rodent nervous system and considers potential implications for the auditory system.

METHODS

We systematically searched PubMed, Web of Science, and OVID EMBASE using MeSH terms related to AMPA receptors and corticosterone. Studies were screened based on predefined inclusion criteria, including original research published in English that focused on AMPA receptor subunits (e.g., GluR1-4, GluA1-4, Gria1-4). Of 288 articles screened, 17 met the criteria for final analysis.

RESULTS

No reports were found regarding CORT action in the auditory system. Three main experimental models used in the included research were identified: neuronal cultures, isolated tissue cultures, and animal models. Generally, short-term CORT exposure increases AMPAR surface localization and mobility in neuronal cultures, especially in the hippocampus and prefrontal cortex. However, results from animal models were inconsistent due to variations in experimental design and other factors. The isolated tissue study did not provide sufficient data for clear conclusions.

CONCLUSIONS

Variability in experimental models limits our ability to draw definitive conclusions about the effects of CORT on AMPARs across different regions of the nervous system. The differences in live animal studies highlight the need for standardized methods and reporting. Since AMPARs play a crucial role in auditory processing, CORT-induced changes in neuronal cultures may occur in the auditory system. Further research is needed to explore the specific responses of AMPAR subunits and how stress hormones may influence auditory disorders, which could help identify potential treatment strategies.

Tinnitus and COVID-19: effect of infection, vaccination, and the pandemic

Introduction

The COVID-19 pandemic, which began worldwide around March 2020, has had an impact on hearing health, specifically tinnitus and hearing loss. Physiologically, COVID-19 infection, or medication used to treat the infection, has been reported to be a potential risk factor for tinnitus onset. In addition, tinnitus was reported to be a long COVID symptom or to occur after a COVID-19 vaccination in some cases. With most reports focused on the clinical population, this study aimed to investigate how the onset of tinnitus is associated with COVID-19 infection, long COVID, and COVID-19 vaccination in the general population based on self-report, while accounting for otologic and psychological symptoms.

Methods

In this study, a cross-sectional online survey that included general demographic questions, questions about tinnitus, hearing loss, hyperacusis, emotional status, and the Tinnitus Functional Index (TFI) was conducted.

Results

Completed survey data of 1,511 respondents who reported having tinnitus or believed to have COVID-associated tinnitus were included in the analysis. Participants were categorized into four groups based on their judgment regarding the etiology of their tinnitus: (1) COVID infection group, (2) long COVID group, (3) COVID vaccination group, and (4) pre-existing tinnitus group. The results suggest that tinnitus severity (estimated using TFI scores) was significantly lower in the pre-existing tinnitus group than in any of the COVID-associated tinnitus groups. While varying factors were found to contribute to tinnitus severity among the COVID-associated groups, overall, depression and/or anxiety accounted for the most variance in predicting tinnitus severity.

Discussion

The findings highlight the need to evaluate the impact of varying otologic and psychological symptoms in individuals with COVID-associated tinnitus for better patient-centered care.

COVID-19 and tinnitus: an initiative to improve tinnitus care

OBJECTIVE

To investigate the effects of COVID-19 on individuals with tinnitus and their views to guide future tinnitus care.

DESIGN

A mixed-methods cross-sectional research design.

STUDY SAMPLE

An online survey was completed by 365 individuals with tinnitus from Australia and other countries.

RESULTS

Tinnitus was reported to be more bothersome during the pandemic by 36% of respondents, whereas 59% reported no change and 5% reported less bothersome tinnitus. Nearly half of the respondents had received COVID-19 vaccination(s) and 12% of them reported more bothersome tinnitus while 2% developed tinnitus post-vaccination. Australian respondents spent less time in self-isolation or quarantine and saw fewer change in in-person social contact than respondents from other countries. More than 70% of respondents thought that tinnitus care services were insufficient both before and during the pandemic. Regarding their opinions on how to improve tinnitus care in the future, five themes including alleviation of condition, government policies, reduced barriers, self- and public-awareness, and hearing devices were identified.

CONCLUSIONS

A majority of respondents did not perceive any change in tinnitus perception and one-third of respondents had worsened tinnitus during the pandemic. To improve tinnitus care, better awareness and more accessible resources and management are crucial.