Viral causes of hearing loss: a review for hearing health professionals

Inner Ear Drug Delivery for Sensorineural Hearing Loss: Current Challenges and Opportunities

Most therapies for treating sensorineural hearing loss are challenged by the delivery across multiple tissue barriers to the hard-to-access anatomical location of the inner ear. In this review, we will provide a recent update on various pharmacotherapy, gene therapy, and cell therapy approaches used in clinical and preclinical studies for the treatment of sensorineural hearing loss and approaches taken to overcome the drug delivery barriers in the ear. Small-molecule drugs for pharmacotherapy can be delivered via systemic or local delivery, where the blood-labyrinth barrier hinders the former and tissue barriers including the tympanic membrane, the round window membrane, and/or the oval window hinder the latter. Meanwhile, gene and cell therapies often require targeted delivery to the cochlea, which is currently achieved via intra-cochlear or intra-labyrinthine injection. To improve the stability of the biomacromolecules during treatment, e.g., RNAs, DNAs, proteins, additional packing vehicles are often required. To address the diverse range of biological barriers involved in inner ear drug delivery, each class of therapy and the intended therapeutic cargoes will be discussed in this review, in the context of delivery routes commonly used, delivery vehicles if required (e.g., viral and non-viral nanocarriers), and other strategies to improve drug permeation and sustained release (e.g., hydrogel, nanocarriers, permeation enhancers, and microfluidic systems). Overall, this review aims to capture the important advancements and key steps in the development of inner ear therapies and delivery strategies over the past two decades for the treatment and prophylaxis of sensorineural hearing loss.

Smartphone as a Disease Screening Tool: A Systematic Review

Disease screening identifies a disease in an individual/community early to effectively prevent or treat the condition. COVID-19 has restricted hospital visits for screening and other healthcare services resulting in the disruption of screening for cancer, diabetes, and cardiovascular diseases. Smartphone technologies, coupled with built-in sensors and wireless technologies, enable the smartphone to function as a disease-screening and monitoring device with negligible additional costs and potentially higher quality results. Thus, we sought to evaluate the use of smartphone applications for disease screening and the acceptability of this technology in the medical and healthcare sectors. We followed a systematic review process using four databases, including Medline Complete, Web of Science, Embase, and Proquest. We included articles published in English examining smartphone application utilisation in disease screening. Further, we presented and discussed the primary outcomes of the research articles and their statistically significant value. The initial search yielded 1046 studies for the initial title and abstract screening. Of the 105 articles eligible for full-text screening, we selected nine studies and discussed them in detail under four main categories: an overview of the literature reviewed, participant characteristics, disease screening, and technology acceptance. According to our objective, we further evaluated the disease-screening approaches and classified them as clinically administered screening (33%, n = 3), health-worker-administered screening (33%, n = 3), and home-based screening (33%, n = 3). Finally, we analysed the technology acceptance among the users and healthcare practitioners. We observed a significant statistical relationship between smartphone applications and standard clinical screening. We also reviewed user acceptance of these smartphone applications. Hence, we set out critical considerations to provide equitable healthcare solutions without barriers when designing, developing, and deploying smartphone solutions. The findings may increase research opportunities for the evaluation of smartphone solutions as valid and reliable screening solutions.

Self-reported Tinnitus and Vertigo or Dizziness in a Cohort of Adult Long COVID Patients

Tinnitus, vertigo and dizziness are symptoms commonly reported among Long and Post COVID patients, however the severity of these symptoms has not been assessed in large trials. Therefore, in this study a large cohort of Long COVID patients was surveyed about the presence and severity of tinnitus and vertigo or dizziness symptoms. The online survey was completed by a German cohort of 1,082 adult Long COVID patients after a mean period of 43.2 weeks ± 23.4 weeks after infection. Eighty percent were not fully vaccinated (at least two vaccinations) at the time of their first COVID symptoms and 9.8% were hospitalized in the course of their acute SARS-CoV-2 infection. At the time of the survey, 60% of patients reported the presence of vertigo or dizziness with a mean severity of 4.6 ± 2.7 on a scale of 1 (least severe) to 10 (most severe) and 30% complained of tinnitus with a mean severity of 4.8 ± 3.0. Approximately one fifth of the participants with tinnitus and vertigo or dizziness, rated their symptoms to be severe. The data shown in this study confirms that tinnitus and vertigo or dizziness are common symptoms in Long COVID patients and demonstrates, that a compelling number of patients rate their symptoms as severe. The self-reported severity highlights the need for Long COVID clinics to address these symptoms effectively. We suggest a multidisciplinary diagnostic and therapeutic approach to prevent further morbidity and socioeconomic burden for Long COVID patients suffering from severe vertigo, dizziness or tinnitus.

CD4 T-cell depletion prevents Lassa fever associated hearing loss in the mouse model

Lassa virus (LASV) is the causative agent of Lassa fever (LF), which presents as a lethal hemorrhagic disease in severe cases. LASV-induced hearing loss in survivors is a huge socioeconomic burden, however, the mechanism(s) leading to hearing loss is unknown. In this study, we evaluate in a mouse LF model the auditory function using auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) to determine the mechanisms underlying LASV-induced hearing loss. In the process, we pioneered measures of ABR and DPOAE tests in rodents in biosafety level 4 (BSL-4) facilities. Our T cell depletion studies demonstrated that CD4 T-cells play an important role in LASV-induced hearing loss, while CD8 T-cells are critical for the pathogenicity in the acute phase of LASV infection. Results presented in this study may help to develop future countermeasures against acute disease and LASV-induced hearing loss.

Incidence and duration of self-reported hearing loss and tinnitus in a cohort of COVID-19 patients with sudden chemosensory loss: A STROBE observational study

AIMS

To investigate the self-reported audiological symptoms in a cohort of coronavirus disease 2019 (COVID-19) patients and monitor improvement or recovery.

MATERIAL AND METHODS

Following the STROBE guidelines for observational studies, a retrospective questionnaire concerning audio-vestibular symptoms was conducted in a cohort of Danish COVID-19 patients with self reported chemosensory loss. Data regarding demographics, symptoms onset, duration and remission was registered in a REDCap database.

RESULTS

Of the 225 respondents with chemosensory loss, 59 (26.2%) reported concomitant hearing loss (10.7%) or tinnitus (16.4%). In a follow-up questionnaire focused on ear-symptoms, severity, and duration (n=31), 17 reported hearing loss and 21 reported tinnitus. Debut of hearing loss and tinnitus were on average 10 and 30 days respectively, after onset of initial symptoms. Among the hearing loss patients, only two patients experienced full recovery, whereas 15 had partial or no recovery after on average 266 days from COVID-19 symptom onset. Among the tinnitus patients, 7/21 had full recovery, while 14 had partial or no recovery after on average 259 days from COVID-19 symptom onset.

CONCLUSION

In a large Danish cohort of COVID-19 patients, a significant proportion experienced concomitant audiological symptoms which seem long lasting and with negative impact on quality of life. This study warrants further investigation of the association between COVID-19 and audio-vestibular symptoms, and the need for rehabilitation among convalescents.

Neuro-otological Symptoms: An Atypical Aspect of COVID-19 Disease

This study aimed to evaluate the various neuro-otological symptoms experienced by patients with COVID-19 disease. This is a retrospective study conducted from September 2020 to August 2021. Patients with positive RTPCR tests for COVID-19, aged between 18 and 60 years were included in the study. The patients were assessed for neuro-otological symptoms, the type, frequency, and character of these symptoms, their relation with age, gender and COVID-19 disease. Of the 286 patients, 64 (22.3%) had neuro-otological symptoms. The mean age of the patients was 36.3 ± 8.1 years. The frequency of neuro-otological symptoms was higher in females than males and was more frequent in the age group of 18–30 years as compared with other age groups. Of these 64 patients, 29 had vertigo (10.1%), 21 (7.3%) tinnitus, 16 (5.5%) experienced hearing loss. Like many viral diseases, apart from its typical prodromal symptoms, COVID-19 can also cause symptoms like tinnitus, hearing loss, and vertigo.

Prognostic determinants of hearing outcomes in children with congenital cytomegalovirus infection

Congenital cytomegalovirus (cCMV) infection is the most prevalent cause of non-genetic sensorineural hearing loss (SNHL) in children. However, the prognostic determinants of SNHL remain unclear. Children with cCMV infection in a tertiary hospital were enrolled. The presence of cCMV-related symptoms at birth, the newborn hearing screening (NHS) results, and the blood viral loads were ascertained. Audiologic outcomes and initial blood viral loads were compared between different groups. Of the 39 children enrolled, 16 developed SNHL. SNHL developed in 60% of children who were initially symptomatic, and in 34.5% of those who were initially asymptomatic with normal hearing or isolated hearing loss, respectively. Failuire in NHS was a reliable tool for early detection of SNHL. The initial viral loads were higher in children who were symptomatic at birth, those who failed NHS, and those who developed SNHL. We observed SNHL deterioration in a patient after CMV DNAemia clearance was achieved, and in another patient with the flare-up of viral load. The presence of cCMV-related symptoms at birth, failure in NHS, and blood viral load might be the prognostic factors for hearing outcomes. Regular audiologic examinations are necessary in all children with cCMV infection even after CMV DNAemia clearance.

Shedding Light on SARS-CoV-2, COVID-19, COVID-19 Vaccination, and Auditory Symptoms: Causality or Spurious Conjunction?

There are reports of associations between SARS-CoV2, COVID-19, COVID-19 vaccines, and auditory symptoms (hearing difficulty, tinnitus). However, most studies have relied on self-report and lack baseline and/or non-COVID control groups. This makes it problematic to differentiate if symptoms are associated with SARS-CoV2, COVID-19, the vaccine, psychosocial factors or recall bias. In this study, we differentiate these by comparing hearing and tinnitus survey data collected pre- and during the pandemic. The survey conducted during the pandemic asked about the onset and change in three types of symptom. Type One—known association (loss of smell, memory/concentration issues, persistent fatigue), Type Two—indeterminate association (auditory symptoms), and Type Three—no established association with COVID-19 (toothache). We hypothesized that if auditory symptoms are directly associated with COVID-19, their onset and change would be similar to Type One symptoms, but if indirectly associated (reflecting psychosocial factors and/or recall bias) would be more similar to Type Three symptoms. Of the 6,881 individuals who responded, 6% reported confirmed COVID-19 (positive test), 11% probably had COVID-19, and 83% reported no COVID-19. Those with confirmed or probable COVID-19 more commonly reported new and/or worsened auditory symptoms than those not reporting COVID-19. However, this does not imply causality because: (1) new auditory symptoms coincided with COVID-19 illness among just 1/3 of those with confirmed or probable COVID-19, and another 1/3 said their symptoms started before the pandemic—despite reporting no symptoms in the pre-pandemic survey. (2) >60% of individuals who had COVID-19 said it had affected their Type 3 symptoms, despite a lack of evidence linking the two. (3) Those with confirmed COVID-19 reported more Type 1 symptoms, but reporting of Type 2 and Type 3 symptoms did not differ between those with confirmed COVID-19 and those without COVID-19, while those who probably had COVID-19 most commonly reported these symptom types. Despite more reports of auditory symptoms in confirmed or probable COVID-19, there is inconsistent reporting, recall bias, and possible nocebo effects. Studies that include appropriate control groups and use audiometric measures in addition to self-report to investigate change in auditory symptoms relative to pre-COVID-19 are urgently needed.

Vestibular Cochlear Manifestations in COVID-19 Cases

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a high transmissible infectious disease that primarily impacts the respiratory system and leads to death as it worsens. Ever since the World Health Organization declared the disease as a global pandemic, the pathophysiology, clinical manifestations, and disease prognosis has been discussed in various literature. In addition to impaired respiratory health, the symptoms also indicated the involvement of the cardiovascular and neurological system after SARS-CoV-2 infection. Despite the pulmonary, cardiovascular, and neurological complications, many reports also revealed the prevalence of vestibulocochlear symptoms like dizziness, vertigo, vestibular neuritis, sudden sensorineural hearing loss, and tinnitus. Though many clinical reports and scientific reviews reported the vestibular and cochlear impairments associated with coronavirus disease 2019 (COVID-19) infection, the underlying pathological mechanisms are still unclear and unexplored. In this review, we discussed the published clinical reports, research articles, and literature reviews related to vestibulocochlear manifestations following SARS-CoV-2 infections. We also summarized the current knowledge about the prevalence, epidemiological and clinical features, and potential pathological mechanisms related to vestibular and cochlear manifestations resulting from COVID-19 infections.

Hearing Function, Degeneration, and Disease: Spotlight on the Stria Vascularis

The stria vascularis (SV) is a highly vascularized tissue lining the lateral wall of the cochlea. The SV maintains cochlear fluid homeostasis, generating the endocochlear potential that is required for sound transduction. In addition, the SV acts as an important blood-labyrinth barrier, tightly regulating the passage of molecules from the blood into the cochlea. A healthy SV is therefore vital for hearing function. Degeneration of the SV is a leading cause of age-related hearing loss, and has been associated with several hearing disorders, including Norrie disease, Meniere's disease, Alport syndrome, Waardenburg syndrome, and Cytomegalovirus-induced hearing loss. Despite the SV's important role in hearing, there is still much that remains to be discovered, including cell-specific function within the SV, mechanisms of SV degeneration, and potential protective or regenerative therapies. In this review, we discuss recent discoveries elucidating the molecular regulatory networks of SV function, mechanisms underlying degeneration of the SV, and otoprotective strategies for preventing drug-induced SV damage. We also highlight recent clinical developments for treating SV-related hearing loss and discuss future research trajectories in the field.

Short- and Long-Term Self-Reported Audiovestibular Symptoms of SARS-CoV-2 Infection in Hospitalized and Nonhospitalized Patients

BACKGROUND

Audiovestibular symptoms during the acute stage have been reported in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), while very few studies investigated the long-term audiovestibular manifestations of SARS-CoV-2.

OBJECTIVE

The objective of this study was to examine the occurrence of short- and long-term audiovestibular symptoms associated with SARS-CoV-2 infection.

METHOD

In this cross-sectional study, a questionnaire was distributed to severe hospitalized cases and nonhospitalized patients with mild disease, all with confirmed SARS-CoV-2 test results. Participants were inquired to report audiovestibular symptoms during the acute phase and at 6-month follow-up after contracting SARS-CoV-2.

RESULTS

A total of 301 participants completed the questionnaire. Auditory symptoms were reported by 21.9% and 1.99% of patients during the acute phase and 6 months post SARS-CoV-2 infection, respectively. During the acute phase of SARS-CoV-2 infection, aural fullness represents the most common symptoms (18.94%) followed by tinnitus (9.97%) and hearing loss (6.31%). Vestibular symptoms were reported by 34% during the acute phase; most commonly was dizziness (29.9%) followed by vertigo (24.25%) and unsteadiness (8.31%). Long-term and persistent vestibular problems were reported by 3.99% patients. There were no statistically significant differences in self-reported audiovestibular symptoms between patients with severe SARS-CoV-2 disease compared to those with mild disease.

CONCLUSION

The current study showed that audiovestibular symptoms are common among SARS-CoV-2 infected patients during the acute phase of the disease. However, these symptoms are mostly temporary and showed complete spontaneous recovery during the first 2 weeks postinfection.

Patients’ perspective about speech, swallowing and hearing status post-SARS-CoV-2 (COVID-19) recovery: E-survey

Objective

The present study investigates the COVID-19 survivors' perspective on speech, swallowing, and hearing-related issues post-COVID-19. We further investigate the recovery duration for speech, swallowing, and hearing-related symptoms post-COVID.

Design

Survey study; E-survey.

Methodology

A total of 78 subjects (35.78 years ± 11.93) participated in the survey. All the participants were diagnosed with the RTPCR method. To understand the recovery duration for the speech, swallowing and hearing issues post-COVID-19, we conducted a three-phase study.

Results

In the first phase of the survey, 68 subjects reported symptoms related to speech, swallowing, and hearing issues 15 days of post-COVID recovery. A total of 76.4% of subjects reported only swallowing-related issues, 4.41% only speech-related issues, whereas 1.47% reported the problem in speech and hearing functions. The 2nd phase of the study was conducted after the first phase of the study. Only 22 subjects reported the presence of swallowing, speech and hearing-related issues from the 68 subjects. During the last phase, only 12 subjects reported speech, swallowing, and hearing issues. All subjects recovered from the olfaction and gustation impairment, whereas 50% of subjects reported the presence of xerostomia.

Conclusion

From the present study, we conclude that the SARC-CoV-2 virus directly affects the respiratory system and affects the aero-digestive system and laryngeal system physiology. Individuals with comorbid conditions admitted in ICU during COVID-19 treatment and prolonged hospital stay were at higher risk of developing speech, swallowing, and hearing-related issues post-COVID-19. The present study indicated that all COVID-19 survivors should be screened for speech, swallowing, and hearing-related issues for early rehabilitation if needed.

Selective Inner Hair Cell Loss in a Neonate Harbor Seal (Phoca vitulina)

Simple Summary

Congenital hearing loss (i.e., hearing impairment present at birth) is recognized in humans and other terrestrial species, but there is a lack of information on congenital malformations and associated hearing loss in pinnipeds (seals, sea lions, and walruses). Baseline knowledge on marine mammal inner ear malformations is essential to differentiate between congenital and acquired abnormalities, which may be caused by infectious agents, age, or anthropogenic interactions, such as noise exposure. Analysis of the cochlea of a neonate harbor seal (Phoca vitulina) revealed bilateral loss of inner hair cells (sensory cells responsible for transducing the auditory signal) while the outer hair cells (sensory cells responsible for sound amplification and frequency selectivity and sensitivity) were intact. The selective inner hair cell loss (up to 84.6% of loss) was more severe in the basal turn, where the high frequencies are encoded. Potential causes and consequences are discussed. This is the first report of a case of selective inner hair cell loss in a marine mammal neonate, likely congenital.

Abstract

Congenital hearing loss is recognized in humans and other terrestrial species. However, there is a lack of information on its prevalence or pathophysiology in pinnipeds. It is important to have baseline knowledge on marine mammal malformations in the inner ear, to differentiate between congenital and acquired abnormalities, which may be caused by infectious pathogens, age, or anthropogenic interactions, such as noise exposure. Ultrastructural evaluation of the cochlea of a neonate harbor seal (Phoca vitulina) by scanning electron microscopy revealed bilateral loss of inner hair cells with intact outer hair cells. The selective inner hair cell loss was more severe in the basal turn, where high-frequency sounds are encoded. The loss of inner hair cells started around 40% away from the apex or tip of the spiral, reaching a maximum loss of 84.6% of hair cells at 80–85% of the length from the apex. Potential etiologies and consequences are discussed. This is believed to be the first case report of selective inner hair cell loss in a marine mammal neonate, likely congenital.

[Triggers and predictors of development and formation of sensorineural hearing loss]

The purpose of the study is to review the results of scientific researches in recent years in an expanded interdisciplinary view of the problem of etiopathogenesis of sensorineural hearing loss, as well as the role of comorbidities and triggers in the formation of persistent changes in the audio-receiving part of the auditory analyzer.

Effectiveness of oral corticosteroids (prednisolone) in sensorineural hearing loss post COVID-19

Background

Numerous infections can result in neurological symptoms, including anosmia, facial paralysis, and abrupt sensorineural hearing loss (SSNHL). During the earlier SARS pandemic, coronaviruses were linked to a loss of smell and taste due to brain damage.

Purpose

To clinically detect corticosteroid treatment effectiveness in SSNHL post-COVID-19 infection and to detect the factors that affect the prognosis for these patients for better diagnosis and earlier management.

Subjects and method

Subjects included 20 subjects diagnosed by PCR as COVID-19 virus positive, complaining of sudden onset hearing loss post viral infection in different durations. All subjects had basic audiological evaluation done pre-treatment and repeated after 1 week, 2 weeks, and 1 month after treatment with methylprednisolone 21-acetate tablets.

Results

Onset of hearing loss post-COVID infection ranged from 1 to 3 months. As regards the improvement recognized with treatment course, thirteen patients (65%) of all twenty patients showed complete improvement at 1 month after starting treatment, and seven patients (35%) showed no improvement even after 1 month.

Conclusion

SSNHL has been widely recognized in the context of COVID-19 to date. Early corticosteroid therapy could help in the recovery of hearing, especially if the beginning of therapy was early in the first 2 weeks.

Audiological follow-up of children with congenital Zika syndrome

How does the auditory function of children with congenital Zika syndrome present during the first three years of life? To determine the auditory function of children with congenital Zika syndrome during the first three years of life and estimate the frequency and long-term presentation of hearing loss in this syndrome, an auditory assessment with screening and diagnostic tests was conducted. The screening test consisted of measuring the short latency ABR using click stimuli. If the ABR click indicated hearing loss, confirmation was obtained with a frequency-specific ABR (FS-ABR), in which the stimuli were tone bursts at frequencies of 500 and 2000 Hz by bone and air conduction. This case series included 107 children with confirmed congenital Zika syndrome, and the cumulative incidence of sensorineural hearing loss in the first three years of life was 9.3% (10/107). There were no cases of delayed-onset or progressive deficits in hearing. Early presentation of sensorineural hearing loss seems to occur with a higher frequency in children with congenital Zika syndrome than in the general population. Sensorineural hearing loss resulting from congenital Zika virus infection does not appear to present with delayed onset or with progressive deficits.

Does COVID-19 have an impact on hearing?

BACKGROUNDS

SARS-CoV-2 is known to be a neurotrophic virus. However, the effect of this virus on the hearing system is still uncertain.

OBJECTIVES

We aimed to investigate the possible effect of COVID-19 on hearing.

MATERIALS AND METHODS

Thirty healthcare workers who had COVID-19 after hearing evaluation with pure tone audiometry (PTA) for any reason in the last 1 year were included in the study. PTA and transient evoked otoacoustic emissions (TEOAE) tests were performed in 15 of 30 patients during the active infection period. For all 30 patients, otoscopic examination plus PTA and TEOAE tests were performed at the end of the first month after their treatment.

RESULTS

When the PTA results of 30 patients (60 ears) before and after COVID-19 were compared, a significant decrease in hearing level was found only at 1000 Hz (p < .05). There were no significant differences at other frequencies. When the PTA and TEAOE test results of 15 patients (30 ears) that were performed during and after COVID-19 were compared, no significant differences were found.

CONCLUSION AND SIGNIFICANCE

We conclude that COVID-19 may cause hearing loss. However, this result needs to be confirmed with comprehensive studies to be conducted in larger patient groups.

Sudden sensorineural hearing loss after covid-19 vaccine; A possible adverse reaction?

Background

Sudden Sensorineural Hearing Loss (SSNHL) is a relatively rare symptom after immunisation from commonly used vaccines such as rabies, hepatitis B, measles and H1N1 and it could be an occasional symptom of COVID-19, even in mild manifestations of the disease.

Case report

We describe the case of a 57-year-old patient that reported SSNHL and tinnitus in his right ear 2 days after the inoculation of the Oxford-AstraZeneca (VAXZEVRIA) Covid-19 vaccine. The patient almost fully recovered after therapy and was referred to a long term follow-up program.

Conclusion

The current report underlines the importance to consider SSNHL as a possible rare adverse effect of the Covid-19 vaccine and take in account this possibility to promptly proceed with diagnosis and treatment of suspect cases.

COVID-19-related sudden sensorineural hearing loss

BACKGROUND

Sudden sensorineural hearing loss (SSNHL) can be a feature of COVID-19. It may present alone or with other symptoms of the disease. However, there is little written in the literature about its occurrence. We aimed to evaluate the socio-clinical characteristics and outcome of confirmed mild- to moderate COVID-19 cases with SSNHL in Tikrit city, Iraq.

MATERIALS AND METHODS

This descriptive study was conducted at the Otolaryngology Department, Tikrit General Hospital, Tikrit city, Iraq. The period of the study was from December 1, 2020 to June 30, 2021.Mild and moderate COVID-19 subjects confirmed by real-time polymerase reaction were included in the study. Detailed demographic (age, gender, and smoking habit) and clinical characteristics (onset and duration of deafness, side, severity, associated ear, nose, and throat symptoms, and comorbidity) were recorded for every patient. Outcomes following the steroid treatment protocol were also registered.

RESULTS

SSNHL was identified in 26 patients, of whom 20 (76.9%) were women, 20 (76.9%) were in the age group ≥ 30 years, and 21 (80.8%) were non-smokers. Around three-quarters of the subjects were identified within the first week of deafness occurrence. Bilateral (18/26) was more common than unilateral deafness (8/26); therefore, the total number of deaf ears was 44. Besides, bilateral symmetrical deafness (13/18) outnumbered the asymmetrical type (5/18). Around three-quarters were of moderate severity. The most common otological symptom was tinnitus (25/26). The most common nose and throat symptom was anosmia (6/26). The mean hearing threshold before and after treatment with oral steroids ± intratympanic steroids was 50.91 ± 11.777 dB and 40.24 ± 15.693, respectively. One patient with bilateral SSNHL was lost to follow-up; the remaining number of deaf ears was 42, and half of them were partially improved. The outcome of the treatment showed no statistically significant relation with the duration, side, and severity of SSNHL (p>0.05).

CONCLUSION

The majority of COVID-19-related SSNHL cases presented within one week of onset, with bilateral outnumbering unilateral cases. Tinnitus was the most common associated symptom. Treatment with steroids achieved partial improvement in half of the cases, and this outcome was not affected by the duration, side, and severity of deafness.

Evidence of Hearing Loss and Unrelated Toxoplasmosis in a Free-Ranging Harbour Porpoise (Phocoena phocoena)

Simple Summary

Evidence of hearing impairment was identified in a female harbour porpoise (Phocoena phocoena) on the basis of inner ear analysis. The animal live stranded on the Dutch coast at Domburg in 2016 and died a few hours later. Ultrastructural examination of the inner ear revealed evidence of sensory cell loss, which is compatible with noise exposure. In addition, histopathology also revealed multifocal necrotising protozoal encephalitis. A diagnosis of toxoplasmosis was confirmed by positive staining of tissue with anti-Toxoplasma gondii antibodies; however, T. gondii tachyzoites were not observed histologically in any of the examined tissues. This is the first case of presumptive noise-induced hearing loss and demonstration of T. gondii cysts in the brain of a free-ranging harbour porpoise from the North Sea.

Abstract

Evidence of hearing impairment was identified in a harbour porpoise (Phocoena phocoena) on the basis of scanning electron microscopy. In addition, based on histopathology and immunohistochemistry, there were signs of unrelated cerebral toxoplasmosis. The six-year old individual live stranded on the Dutch coast at Domburg in 2016 and died a few hours later. The most significant gross lesion was multifocal necrosis and haemorrhage of the cerebrum. Histopathology of the brain revealed extensive necrosis and haemorrhage in the cerebrum with multifocal accumulations of degenerated neutrophils, lymphocytes and macrophages, and perivascular lymphocytic cuffing. The diagnosis of cerebral toxoplasmosis was confirmed by positive staining of protozoa with anti-Toxoplasma gondii antibodies. Tachyzoites were not observed histologically in any of the examined tissues. Ultrastructural evaluation of the inner ear revealed evidence of scattered loss of outer hair cells in a 290 µm long segment of the apical turn of the cochlea, and in a focal region of ~ 1.5 mm from the apex of the cochlea, which was compatible with noise-induced hearing loss. This is the first case of concurrent presumptive noise-induced hearing loss and toxoplasmosis in a free-ranging harbour porpoise from the North Sea.

Hearing test results of newborns born from the coronavirus disease 2019 (COVID-19) infected mothers: A tertiary center experience in Turkey

Objective

Congenital infections can cause newborn hearing loss. Although vertical transmission of coronavirus disease 2019 (COVID‐19) infection is theoretically possible, this has not been proven yet. To our knowledge, there is no previous report on whether COVID‐19 infection during pregnancy can cause congenital hearing loss. This paper aimed to find an answer to this question.

Method

This retrospective, single‐center study was performed between April 2020 and May 2021 at a tertiary care referral center in Turkey. A total of 422 pregnant women who had coronavirus infection during pregnancy were followed and 203 of them gave birth in our institution. Results of hearing screening tests of 199 newborns were assessed retrospectively.

Results

Of patients included in the study, 23 (11.6%) had the disease in the first trimester, 62 (31.2%) in the second trimester, and 114 (57.3%) in the third trimester. In the first hearing test performed on newborns, unilateral hearing loss was observed in 21 babies (10.5%). Hearing tests of these newborns were found to be normal in the second test performed 15 days later.

Conclusion

Considering the incidence of congenital hearing loss, the absence of hearing loss in our newborn population does not confirm the argument that coronavirus infection does not cause congenital hearing loss. This issue should be evaluated with larger patient series. In addition, it should be kept in mind that hearing loss can occur at later ages as well.

Severe sudden sensorineural hearing loss related to risk of stroke and atherosclerosis

The cause of idiopathic sudden sensorineural hearing loss (idiopathic SSNHL)—diagnosed after excluding other causes of hearing loss, such as SSNHL associated with vestibular schwannoma (VS)—is unknown. The presumed pathogenesis of idiopathic SSNHL includes circulatory disorders (e.g., cochlear infarction). We tested the hypothesis that patients with SSNHL who are at high stroke risk will have a lower rate of VS compared to those with low stroke risk. The rationale is that the primary cause of SSNHL in patients with high stroke risk might be a circulatory disturbance. We conducted a retrospective study in six hospitals. Our sampling of SSNHL patients included those diagnosed with idiopathic SSNHL and VS-associated SSNHL. SSNHL patients who had a head MRI were stratified by severity of hearing loss and evaluated for differences in the detection rate of VS between the high-scoring CHADS₂ (CHADS₂-H-), an index of stroke risk, and low-scoring CHADS₂ (CHADS₂-L-) groups. We identified 916 patients who met the inclusion criteria. For severe hearing loss, the CHADS₂-H group had a significantly lower rate of VS than the CHADS₂-L group (OR 0 [95% CI 0.00–0.612]; P = 0.007). These results indirectly support the hypothesis that a primary cause of severe idiopathic SSNHL in those at high risk of stroke might be a circulatory disorder.

Sudden sensorineural hearing loss in a post-COVID-19 patient

A detailed history and diagnostic evaluation for recent or past COVID-19 infection is vital in patients presenting with Sudden Sensorineural Hearing Loss (SSNHL) since SSNHL could be a sequelae of COVID-19 and timely diagnosis and intervention could significantly improve hearing and quality of life.

The correlation between neonatal parameters and late-onset inner ear disorders in congenital cytomegalovirus infection: a 10-year population-based cohort study

OBJECTIVE

To evaluate the correlation of neonatal parameters with late-onset sensorineural hearing loss (SNHL) and vestibular dysfunction in individuals with congenital cytomegalovirus (cCMV) infection using the National Health Insurance Research Database (NHIRD) in Taiwan.

DESIGN

Retrospective cohort study.

SETTING

The whole Taiwanese population.

PARTICIPANTS

Patients with related diagnostic codes and examinations in their records were regarded as having cCMV infection. Each subject in that group was matched to 10 control individuals with noncongenital CMV infection on the basis of several neonatal parameters, including low gestational age, low birth weight, low Apgar score, maternal history of CMV infection and prolonged cCMV infection. A total of 5893 and 58 930 participants were enrolled in the study and control groups, respectively.

MAIN OUTCOME MEASURES

The main outcomes were the development of SNHL and the development of vestibular dysfunction within one year after birth as reflected by diagnostic codes and specific examinations. Cox proportional hazard regression was used to calculate the adjusted hazard ratio (HR) and 95% confidence interval (CI) of each primary outcome between the two groups.

RESULTS

Overall, 109 and 397 episodes of SNHL developed in the study group and the control group, respectively, and the study group demonstrated a significantly higher incidence of SNHL (adjusted HR: 2.56; 95% CI: 2.07-3.18). In addition, similar incidence rates of vestibular dysfunction were found in the study group and the control group, with 7 and 90 events, respectively (adjusted HR: 0.77; 95% CI: 0.36-1.67). In subgroup analyses, a higher incidence of SNHL was correlated with lower gestational age (GA) (adjusted HR: 2.09; 95% CI: 1.29-3.39), lower birth weight (BW) (adjusted HR: 2.05; 95% CI: 1.28-3.30) and prolonged cCMV infection (adjusted HR: 3.92; 95% CI: 1.95-7.88).

CONCLUSIONS

Low GA, low BW and a long disease course are significantly correlated with late-onset SNHL in cCMV infection.

Detecting Novel Ototoxins and Potentiation of Ototoxicity by Disease Settings

Over 100 drugs and chemicals are associated with permanent hearing loss, tinnitus, and vestibular deficits, collectively known as ototoxicity. The ototoxic potential of drugs is rarely assessed in pre-clinical drug development or during clinical trials, so this debilitating side-effect is often discovered as patients begin to report hearing loss. Furthermore, drug-induced ototoxicity in adults, and particularly in elderly patients, may go unrecognized due to hearing loss from a variety of etiologies because of a lack of baseline assessments immediately prior to novel therapeutic treatment. During the current pandemic, there is an intense effort to identify new drugs or repurpose FDA-approved drugs to treat COVID-19. Several potential COVID-19 therapeutics are known ototoxins, including chloroquine (CQ) and lopinavir-ritonavir, demonstrating the necessity to identify ototoxic potential in existing and novel medicines. Furthermore, several factors are emerging as potentiators of ototoxicity, such as inflammation (a hallmark of COVID-19), genetic polymorphisms, and ototoxic synergy with co-therapeutics, increasing the necessity to evaluate a drug's potential to induce ototoxicity under varying conditions. Here, we review the potential of COVID-19 therapies to induce ototoxicity and factors that may compound their ototoxic effects. We then discuss two models for rapidly detecting the potential for ototoxicity: mammalian auditory cell lines and the larval zebrafish lateral line. These models offer considerable value for pre-clinical drug development, including development of COVID-19 therapies. Finally, we show the validity of in silico screening for ototoxic potential using a computational model that compares structural similarity of compounds of interest with a database of known ototoxins and non-ototoxins. Preclinical screening at in silico, in vitro, and in vivo levels can provide an earlier indication of the potential for ototoxicity and identify the subset of candidate therapeutics for treating COVID-19 that need to be monitored for ototoxicity as for other widely-used clinical therapeutics, like aminoglycosides and cisplatin.

Is COVID-19 associated with self-reported audio-vestibular symptoms?

OBJECTIVE

To determine if a positive test for COVID-19 is associated with self-reported audio-vestibular symptoms.

DESIGN

Self-reported changes in hearing, tinnitus, hyperacusis, and dizziness/rotatory vertigo were assessed in hospitalised and non-hospitalised COVID-19 patients during and after the acute phase of the disease and compared to non-COVID controls.

STUDY SAMPLE

There were 150 severe cases of COVID-19 requiring hospital admission and 150 mild cases that were managed at home. Controls were 267 adults, 32 of whom had been hospitalised for a non-COVID-19 condition, and a further 85 who worked in hospital settings.

RESULTS

Deterioration in hearing and/or tinnitus was reported in 8% of the COVID-19 cases (tinnitus had resolved in 2% after the acute phase), with no significant difference between severe and mild cases. Deterioration in hearing or tinnitus was not significantly different from controls. However, rotatory vertigo was reported by 5% in the COVID-19 groups and 1.1% in the controls, and this difference was statistically significant.

CONCLUSIONS

There is no evidence that COVID-19 results in deterioration in hearing or tinnitus during the acute phase or after recovery in mild or severe cases. However, rotatory vertigo, which could be vestibular in origin, may be a clinical manifestation of COVID-19.

New insights into Perrault syndrome, a clinically and genetically heterogeneous disorder

Hearing loss and impaired fertility are common human disorders each with multiple genetic causes. Sometimes deafness and impaired fertility, which are the hallmarks of Perrault syndrome, co-occur in a person. Perrault syndrome is inherited as an autosomal recessive disorder characterized by bilateral mild to severe childhood sensorineural hearing loss with variable age of onset in both sexes and ovarian dysfunction in females who have a 46, XX karyotype. Since the initial clinical description of Perrault syndrome 70 years ago, the phenotype of some subjects may additionally involve developmental delay, intellectual deficit and other neurological disabilities, which can vary in severity in part dependent upon the genetic variants and the gene involved. Here, we review the molecular genetics and clinical phenotype of Perrault syndrome and focus on supporting evidence for the eight genes (CLPP, ERAL1, GGPS1, HARS2, HSD17B4, LARS2, RMND1, TWNK) associated with Perrault syndrome. Variants of these eight genes only account for approximately half of the individuals with clinical features of Perrault syndrome where the molecular genetic base remains under investigation. Additional environmental etiologies and novel Perrault disease-associated genes remain to be identified to account for unresolved cases. We also report a new genetic variant of CLPP, computational structural insight about CLPP and single cell RNAseq data for eight reported Perrault syndrome genes suggesting a common cellular pathophysiology for this disorder. Some unanswered questions are raised to kindle future research about Perrault syndrome.

Intrauterine exposure to Zika virus and hearing loss within the first few years of life: A systematic literature review

BACKGROUND

Identification of the factors that could potentially lead to congenital hearing loss is of paramount importance, as early detection of congenital hearing loss and intervention could prevent developmental delays in speech, language development as well as childhood cognitive impairment. Hitherto, intrauterine exposure to Zika virus has emerged as a cause of various fetal malformations, including cases of congenital hearing loss. The aim of this systematic review is to investigate the association between intrauterine exposure to Zika virus and hearing loss in children.

METHODS

A systematic literature search was conducted to the databases PubMed, Cochrane library, Scopus, ClinicalTrials.gov, SciELO and Lilacs in order to identify studies that examine the association between prenatally Zika exposure and hearing loss within the first few years of life. Studies were eligible for inclusion, if solely objective methods for hearing evaluation of patients such as otoacoustic emissions (OAEs) and/or auditory brainstem response (ABR) were used, in children who intrauterine exposed to the Zika virus.

RESULTS

Thirteen studies were included, which included 1275 children who are prenatally exposed to Zika virus. In 852 of the cases an objective hearing evaluation was performed using either OAEs or ABR. 709 children were tested with ABR and 79 had a failed outcome. 143 children were tested with OAEs whilst of these, 30 had a failed outcome. Altered OAEs ranged from 8.7% to 30.2%, while altered ABR ranged from 0% to 19.9%. The initial sample includes 428 children with microcephaly, while 5 of the studies comprise microcephaly to the inclusion criteria.

CONCLUSION

It seems to be a possible association between prenatal Zika virus exposure and hearing loss in children during the first years of their life. It is of great importance that in future studies possible confounding factors, like microcephaly, will be appropriately controlled. Additionally, the follow-up period of monitoring hearing loss in children should be prolonged in order to identify potential late onset hearing problems caused by intrauterine exposure to Zika virus.

Study of Hearing Status in COVID-19 Patients: A Multicentered Review

To evaluate the hearing status of COVID-19 patients and compare with control group. Prospective study carried out in 9 institutes. The pure tone audiogram and impedance audiometry of COVID-19 patients performed initially and at 3 months follow up. The control group consisted COVID-19 negative individuals with no history of ear related diseases. The average of air and bone conduction threshold (AC and BC) were compared between the COVID-19 patients and control group using independent t-test with a p value of less than 0.05 considered significant. Total of 331 patients, age 32 ± 4.3 years, 66.7% males and 33.3% females were included in the study. There were 80 individuals in the control group. Aural symptoms were, tinnitus in 1.8%, aural fullness in 1.4%, hearing loss in 3. 9%, and ear ache in 1.8% were present initially, resolved at 3 months follow up. The impedance audiometry demonstrated type B and type C curve in 5.1% and 1.15% ears, and out of these 64.7% and 40% improved at 3 months follow up respectively. No significant difference observed between the average AC and BC of the COVID-19 patients and control group. The COVID-19 infection may present with aural symptoms; however, it was concluded that there was no significant difference in the hearing status of the COVID-19 positive patients in comparison to the control group. The presence of some changes in the normal functioning of the eustachian tube and middle ear in the COVID-19 infection was also highlighted.

COVID-19 caused hearing loss

Purpose

The objective of this cross-sectional study was to determine if there is a potential link between COVID-19 infection and hearing loss.

Methods

The prospective study was conducted in the COVID Hospital Clinical Centre Niš, Serbia. We performed tonal audiometry and used a custom questionnaire and medical histories to determine the incidence of hearing loss in COVID-19 positive patients.

Results

There were 74 patients with COVID-19 that met the inclusion criteria of this study and they composed our experimental group. Fifty-four (73%) were men and 20 (27%) women. There were 30 (40.5%) patients with hearing loss. Seventeen patients had unilateral and 13 had bilateral hearing loss. Significant differences between hearing loss groups and control group were found across all age groups, but not at all frequencies. No important differences were found when unilateral hearing loss and bilateral hearing loss groups were compared. There were no significant differences in distributions of comorbidities between the patients with hearing loss and normal hearing patients.

Conclusions

We found that 30 (40.5%) of the COVID-19 positive patients had sensorineural type of hearing loss. Across all age groups, there were statistically significant differences in frequencies between the COVID-19 positive patients and the control group. There were no significant differences in distributions of comorbidities between the patients with hearing loss and normal hearing patients. Distribution of unilateral and bilateral hearing loss and audiogram types was also not significantly different between the age groups.

Sudden Sensorineural Hearing Loss in Mild COVID-19: Case Series and Analysis of the Literature

Background: There is growing evidence of otoneurological involvement of SARS-CoV-2, such as tinnitus and balance disorders and smell and taste disorders, but HL in COVID-19 patients has still been marginally studied. Investigating the role of SARS-CoV-2 as an aetiological factor of Sudden Sensorineural Hearing Loss (SSNHL) may offer the opportunity to address treatment strategies to maximize clinical recovery and avoid side effects. Methods and results: For this purpose, we will present case studies of five patients who experienced SSNHL during COVID-19. Patients were selected from COVID-19 positive adult subjects with mild clinical presentation, admitted to the outpatient Ear Nose and Throat Department of Cardarelli Hospital due to the onset of SSNHL during the infection. All underwent a complete audio-vestibular investigation before and after SSNHL treatment protocol. Each patient is described with a detailed analysis. Conclusions: SSNHL could be an occasional symptom of COVID-19, even in mild manifestations of the disease. Our experience leads us to underline the value of promptly recognizing and addressing this and other uncommon symptoms, giving patients the opportunity to receive early treatment.

Evaluation of cochlear functions in infants exposed to SARS-CoV-2 intrauterine

Purpose

The novel coronavirus (SARS-CoV-2) caused an acute respiratory illness named COVID-19 and the disease spread all over the World. Fever, cough, fatigue, gastrointestinal infection symptoms form the main clinical symptoms. Pregnants and newborns form a vulnerable population and urgent measures must be addressed. Studies about the effect of COVID-19 on pregnant women, developing fetuses, and infants are limited. Various viral diseases can cause congenital or acquired, unilateral or bilateral hearing loss.

Methods

37 infants whose mother was pregnant between March 2020 and December 2020 and were born after the diagnosis of COVID- 19 during pregnancy and 36 healthy infants were included in the study. Transient evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE) and contralateral suppression of OAE (CLS OAE) tests were performed on all infants.

Results

According to the TEOAE results of patients and controls in the silent a statistically significant difference was observed between the two groups at 3 kHz and 4 kHz (p < 0.05). Contralateral suppression of OAE test results of patients and controls a statistically significant difference was found in all frequencies (p< 0.05). Suppression was much more effective at all frequencies in the normal group than patient group. This difference was found to be more significant at higher frequencies (2,3 and 4 kHz) (p < 0.001).

Conclusions

Our results suggest an insufficiency in medial olivocochlear efferent system in infants exposed to SARS-CoV-2 intrauterine. Cochlear functions should be examined in infants whose mothers had COVID-19.

SARS-CoV-2 and hearing: An audiometric analysis of COVID-19 hospitalized patients

PURPOSE

COVID-19 associated hearing loss is still an ongoing matter of debate. No original studies exist on audiological effects of SARS-CoV-2 infection in hospitalized patients. The main objective was to determine whether SARS-CoV-2 may affect auditory function in clinically ill COVID-19 patients.

MATERIALS AND METHODS

COVID-19 patients with moderate-severe disease and without prior history of hearing abnormalities were enrolled from a tertiary referral center, and matched with controls. Participants performed an audiometric evaluation, and thresholds were compared.

RESULTS

120 ears from 60 patients were enrolled. Patients with COVID-19 showed worse mean auditory thresholds starting from 1000 Hz through higher frequencies, when compared to controls (1000 Hz: 18.52 ± 5.49 dB HL in controls vs 25.36 ± 6.79 dB HL in COVID-19, p < 0.001; 2000Hz: 17.50 ± 5.57 dB HL in controls vs 21.96 ± 7.05 dB HL in COVID-19, p = 0.010; 3000Hz: 17.97 ± 8.07 dB HL in controls vs 25 ± 9.38 dB HL in COVID-19, p = 0.003; 4000 Hz: 20.16 ± 10.12 dB HL in controls vs 29.55 ± 11.26 dB HL in COVID-19, p = 0.001; 8000 Hz: 31.09 ± 12.75 dB HL in controls vs 40.71 ± 19.40 dB HL in COVID-19, p = 0.030; Pure Tone Average: 20.42 ± 4.29 dB HL in controls vs 24.85 ± 5.62 dB HL in COVID-19, p = 0.001). Statistical significance persisted after adjusting for confounders such as age, gender and various comorbidities (p < 0.05).

CONCLUSIONS

SARS-CoV-2 may affect hearing in COVID-19 patients with moderate-severe disease. Results are in line with the previous suggested effects of COVID-19 on auditory system. This study is expected to encourage further research on this topic.

Congenital and Neonatally Acquired Sensorineural Hearing Loss

Hearing loss is one of the most common congenital diagnoses, recognized in large part by a robust newborn hearing screening program. Ensuring appropriate follow-up of failed newborn hearing screening is crucial to avoid delay in initiation of treatment for hearing loss. The most common etiology for congenital hearing loss is genetic, but some cases can be acquired. Understanding of the etiology aids in counseling for the family and in direction of treatment. Early diagnosis and treatment results in dramatically improved speech and developmental outcomes for affected children. Treatment including amplification, speech therapy, adaptations in the classroom, and family support leads to gains in academic performance, parental satisfaction, and quality of life. Early cochlear implantation has been shown to be beneficial in obtaining speech and language skills in patients with severe to profound sensorineural hearing loss and should be considered in the appropriate patient population. [Pediatr Ann. 2021;50(7):e292-e296.].

ReCOV: recovery and rehabilitation during and after COVID-19 - a study protocol of a longitudinal observational study on patients, next of kin and health care staff

BACKGROUND

The knowledge of the long-term consequences of covid-19 is limited. In patients, symptoms such as fatigue, decreased physical, psychological, and cognitive function, and nutritional problems have been reported. How the disease has affected next of kin, as well as staff involved in the care of patients with covid-19, is also largely unknown. The overall aim of this study is therefore three-fold: (1) to describe and evaluate predictors of patient recovery, the type of rehabilitation received and patients' experiences of specialized rehabilitation following COVID-19 infection; (2) to study how next of kin experienced the hospital care of their relative and their experiences of the psychosocial support they received as well as their psychological wellbeing; (3) to describe experiences of caring for patients with COVID-19 and evaluate psychological wellbeing, coping mechanisms and predictors for development of psychological distress over time in health care staff.

METHODS

This observational longitudinal study consists of three cohorts; patients, next of kin, and health care staff. The assessments for the patients consist of physical tests (lung function, muscle strength, physical capacity) and questionnaires (communication and swallowing, nutritional status, hearing, activities of daily living, physical activity, fatigue, cognition) longitudinally at 3, 6 and 12 months. Patient records auditing (care, rehabilitation) will be done retrospectively at 12 months. Patients (3, 6 and 12 months), next of kin (6 months) and health care staff (baseline, 3, 6, 9 and 12 months) will receive questionnaires regarding, health-related quality of life, depression, anxiety, sleeping disorders, and post-traumatic stress. Staff will also answer questionnaires about burnout and coping strategies. Interviews will be conducted in all three cohorts.

DISCUSSION

This study will be able to answer different research questions from a quantitative and qualitative perspective, by describing and evaluating long-term consequences and their associations with recovery, as well as exploring patients', next of kins' and staffs' views and experiences of the disease and its consequences. This will form a base for a deeper and better understanding of the consequences of the disease from different perspectives as well as helping the society to better prepare for a future pandemic.

The Impact of COVID-19 and the Pandemic on Tinnitus: A Systematic Review

This review aimed to systematically review what has been published regarding tinnitus during the coronavirus disease 2019 (COVID-19) pandemic up to March 2021 by performing both narrative and quantitative meta-analyses. Of the 181 records identified, 33 met the inclusion criteria, which generally had a fair risk of overall bias. In the included, 28 studies focused on the impact of the COVID-19 virus on tinnitus and 5 studies focused on the impact of the pandemic on tinnitus. From the studies identifying the impact of COVID-19 on tinnitus, there were 17 cross-sectional studies (n = 8913) and 11 case series or case report studies (n = 35). There were 2 cross-sectional studies (n = 3232) and 3 pre-post-test design studies (n = 326) focusing on the impact of the pandemic on tinnitus. No consistent patterns were found regarding the presentation of the tinnitus or additional factors that could have tinnitus developing in the disease impact studies. For the pandemic impact studies, the associated stress and anxiety of the pandemic were consistently suggested to contribute to tinnitus experiences. The pooled estimated prevalence of tinnitus post COVID-19 was 8% (CI: 5 to 13%). Medical professionals should be aware that tinnitus might be more problematic following the pandemic or after having COVID-19.

Auditory and Language Development Assessment of Newborns Aged One to Four Years Exposed to Gestational Zika Virus Infection: A Case Series

The known neurotropism of the Zika virus (ZikV) suggests that auditory organs and their neural pathways may be affected by prenatal Zika infections. Among the possible manifestations are audiological and language disorders, but so far, the data in the literature are inconclusive. Objective: To describe early and late hearing disorders in children with Congenital Zika Virus Infection (CZVI) and evaluate the language development of this population between 14 and 47 months of age and its possible correlation with the alterations found in auditory exams. Methods: Longitudinal, prospective, observational study of newborns born in Juiz de Fora and its macroregion with confirmed diagnosis of ZikV infection during pregnancy. Participants were examined from one to four years of age for hearing using the transient otoacoustic emissions (TOAE) test, immittance testing and brainstem auditory evoked potential (BAEP), and language using the Bayley Scales of Infant Development—Third Edition (Bayley III). Results: 15 participants were included; eight (53.33%) presented alterations in at least one of the hearing tests, one had an early loss (6%) of sensorineural origin, and seven (46.67%) had a poor language performance. In the three (20%) participants whose audiological exams were altered, there was language impairment, and two (13.33%) participants had extensive malformations in the central nervous system (CNS), presented language delay, and hearing exams were within normality. Conclusion: Infants and preschoolers with CZVI may present early neurosensory loss and late hearing loss with fluctuating character. Even if there were no significant association between the audiological exams results and the Bayley III performance, in the present sample, language development was below expectations for the age in the participants who had alterations in the three audiological exams, when there is early hearing loss or extensive lesions to the CNS. The results reinforce the importance of audiological examinations, especially the BAEP morphological and auditory threshold, in monitoring cases of CZVI until at least three years of age.

Congenital Deafness and Recent Advances Towards Restoring Hearing Loss

Congenital hearing loss is the most common birth defect, estimated to affect 2-3 in every 1000 births. Currently there is no cure for hearing loss. Treatment options are limited to hearing aids for mild and moderate cases, and cochlear implants for severe and profound hearing loss. Here we provide a literature overview of the environmental and genetic causes of congenital hearing loss, common animal models and methods used for hearing research, as well as recent advances towards developing therapies to treat congenital deafness. © 2021 The Authors.

Auditory Performance in Recovered SARS-COV-2 Patients

OBJECTIVE

While COVID-19 symptoms impact rhinology (anosmia) and laryngology (airways), two major disciplines of the otolaryngology armamentarium, the virus has seemed to spare the auditory system. A recent study, however, reported changes in otoacoustic emission (OAE) signals measured in SARS-COV-2 positive patients. We sought to assess the effect of COVID-19 infection on auditory performance in a cohort of recovered SARS-COV-2 patients and controls. To avoid a potential bias of previous audiological dysfunction not related to SARS-COV-2 infection, the study encompasses patients with normal auditory history. We hypothesized that if SARS-COV-2 infection predisposes to hearing loss, we would observe subtle and early audiometric deficits in our cohort in the form of subclinical auditory changes.

STUDY DESIGN

Cross-sectional study.

SETTING

Tertiary referral center.

PATIENTS

The Institutional Review Board approved the study and we recruited participants who had been positive for SARS-COV-2 infection, according to an Reverse Transcription Polymerase Chain Reaction (RT-PCR) test on two nasopharyngeal swabs. The patients included in this study were asymptomatic for the SARS-COV-2 infection and were evaluated following recovery, confirmed by repeated swab testing. The control group comprised healthy individuals matched for age and sex, and with a normal auditory and otologic history.

INTERVENTIONS

The eligibility to participate in this study included a normal audiogram, no previous auditory symptoms, normal otoscopy examination with an intact tympanic membrane, and bilateral tympanometry type A. None of our volunteers reported any new auditory symptoms following SARS-COV-2 infection. Ototacoustic emissions (OAE) and auditory brainstem response (ABR) measurements were used to evaluate the auditory function.

MAIN OUTCOME MEASURES

OAE and ABR measurements.

RESULTS

We have found no significant differences between recovered asymptomatic SARS-COV-2 patients and controls in any of transitory evoked otoacoustic emission (TEOAE), distortion product otoacoustic emissions (DPOAE), or ABR responses.

CONCLUSIONS

There is no cochlear dysfunction represented by ABR, TEOAE, and DPOAE responses in recovered COVID-19 asymptomatic patients. Retrocochlear function was also preserved as evident by the ABR responses. A long-term evaluation of a larger cohort of SARS-COV-2 patients will help to identify a possible contribution of SARS-COV-2 infection to recently published anecdotal auditory symptoms associated with COVID-19.

The prevalence and demographic features of congenital cytomegalovirus infection in an urban area of East Asia: A population-based study

Congenital cytomegalovirus (cCMV) infection is the leading environmental cause of childhood hearing impairment. However, its significance remains largely undocumented in many regions of the world. The purpose of this study was to investigate the prevalence and clinical features of cCMV infection in East Asia. Neonates born at a municipal hospital in Taipei were prospectively recruited and underwent concurrent hearing and CMV screenings. Those who failed the hearing screening or screened positive for CMV were subjected to a focused audiological and/or virological surveillance. The characteristics of the newborns and their mothers were compared between the CMV-positive and CMV-negative groups. Of the 1,532 newborns who underwent concurrent hearing and CMV screenings, seven (0.46%) were positive for cCMV infection. All seven CMV-positive newborns were asymptomatic at birth, and none of them developed hearing or other symptoms during a follow-up period of 14.4±6.3 months. The mothers of the CMV-positive newborns demonstrated higher gravidity (2.4 ± 1.4 vs. 2.1 ± 1.2) and parity (2.0 ± 1.2 vs. 1.6 ± 0.7) than those in the CMV-negative group; however, the difference did not reach statistical significance. The prevalence of cCMV infection in Taipei newborns was 0.46%, which is slightly lower than that of other populations and that of a previous report in the Taiwanese population. The relatively low prevalence in this study might be attributed to the improved public health system and decreased fertility rate in Taiwan.

One year on: an updated systematic review of SARS-CoV-2, COVID-19 and audio-vestibular symptoms

OBJECTIVE

The aim was to systematically review the literature to December 2020, in order to provide a timely summary of evidence on SARS-CoV-2, COVID-19 and audio-vestibular symptoms.

DESIGN

The protocol was registered in the International Prospective Register of Systematic Reviews. The methods were developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Risk of bias was assessed using the National Institutes of Heath quality assessment tools.

STUDY SAMPLE

After rejecting 850 records, 28 case reports/series and 28 cross-sectional studies met the inclusion criteria.

RESULTS

There are multiple reports of hearing loss (e.g. sudden sensorineural), tinnitus and rotatory vertigo in adults having a wide range of COVID-19 symptom severity. The pooled estimate of prevalence based primarily on retrospective recall of symptoms, was 7.6% (CI: 2.5-15.1), 14.8% (CI: 6.3-26.1) and 7.2% (CI: 0.01-26.4), for hearing loss, tinnitus and rotatory vertigo, respectively. However, these could be an over-estimate because it was not always clear that studies report a change in symptom.

CONCLUSION

There are multiple reports of audio-vestibular symptoms associated with COVID-19. However, there is a dearth of high-quality studies comparing COVID-19 cases and controls.

REVIEW REGISTRATION

Prospective Register of Systematic Reviews (PROSPERO); registration number CRD42020227038).

Paediatric Sudden Sensorineural Hearing Loss: Pooled Analysis and Systematic Review

Sudden sensorineural hearing loss (SSNHL) is defined as hearing loss of ≥30 dB in one or both ears, developing within 3 days, affecting ≥3 contiguous frequencies. It is rare in children, but if untreated can cause significant morbidity. During the critical developmental period, it may cause lifelong social, behavioral, and mental sequelae. Currently, little guidance exists on prognosis and management within a pediatric population. A systematic literature review of pediatric SSNHL on PubMed, EMBASE, and the Cochrane CENTRAL database was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. A total of 620 papers met the Medical Subject Headings criteria, of which 14 met analysis criteria-13 were level 4 and 1 was level 2b evidence. A population of 732 individuals was analyzed. Most reported cases of pediatric SSNHL were idiopathic. Other etiologies included viral infection, trauma, ototoxic drugs, and structural abnormalities. Recovery was defined as any improvement in hearing after the initial loss, from "slight" to "complete." Recovery ranged from 20% to 100%, with a pooled rate of 56%. Systemic steroids were the mainstay of treatment, although salvage intratympanic steroid therapy had a role after the failure of systemic steroids. Children with bilateral SSNHL had poorer outcomes than those with unilateral loss, with 29% showing improvement. Two studies reported outcomes with no treatment, for which recovery rate was 7%. This analysis of SSNHL shows that 61% of children with unilateral and 29% of children with bilateral SSNHL demonstrate some recovery, a worse prognosis than adults. Multiple treatment regimens exist, although comparison is challenging owing to inconsistently reported improvement parameters.

Almeida AR, Reis MG, Harris E, Ko AI, Costa F. Developmental outcomes in children exposed to Zika virus in utero from a Brazilian urban slum cohort study

Background

The prevalence of developmental alterations associated with in-utero Zika virus (ZIKV) exposure in children is not well understood. Furthermore, estimation of the Population Attributable Fraction (PAF) of developmental alterations attributed to ZIKV has not been performed due to lack of population-based cohorts with data on symptomatic and asymptomatic ZIKV exposures and an appropriate control group. The aim of this study was to characterize neurodevelopmental outcomes of children at 11 to 32 months of age with intrauterine ZIKV exposure and estimate the PAF of alterations secondary to ZIKV exposure.

Methodology/Principal findings

We performed a cohort of biannual community-based prospective serosurveys in a slum community in Salvador, Brazil. We recruited women participating in our cohort, with a documented pregnancy from January 2015 to December 2016 and children born to those mothers. Children were classified as ZIKV exposed in utero (born from women with ZIKV seroconversion during pregnancy) or unexposed (born from women without ZIKV seroconversion or that seroconverted before/after pregnancy) by using an IgG monoclonal antibody blockade-of-binding (BoB). We interviewed mothers and performed anthropometric, audiometric, ophthalmological, neurologic, and neurodevelopmental evaluations of their children at 11 to 32 months of age. Among the 655 women participating in the cohort, 66 (10%) were pregnant during the study period. 46 (70%) of them completed follow-up, of whom ZIKV seroconversion occurred before, during, and after pregnancy in 25 (54%), 13 (28%), and 1 (2%), respectively. The rest of women, 7 (21.2%), did not present ZIKV seroconversion. At 11 to 32 months of life, the 13 ZIKV-exposed children had increased risk of mild cognitive delay (RR 5.1; 95%CI 1.1–24.4) compared with the 33 children unexposed, with a PAF of 53.5%. Exposed children also had increased risk of altered auditory behavior (RR 6.0; 95%CI 1.3–26.9), with a PAF of 59.5%.

Conclusions

A significant proportion of children exposed in utero to ZIKV developed mild cognitive delay and auditory behavioral abnormalities even in the absence of gross birth defects such as microcephaly and other neurodevelopmental domains. Furthermore, our findings suggest that over half of these abnormalities could be attributed to intrauterine ZIKV exposure.

ZIKV is a neurotropic virus associated with congenital abnormalities that have been grouped under congenital Zika syndrome (CZS), the most prominent being microcephaly. Recent studies have uncovered a spectrum of other abnormalities. However, what remains unclear is the Population Attributable Fraction (PAF) of developmental alterations attributable to ZIKV intrauterine exposure in children (> one year of life). In this population-based cohort study, we found that children (without microcephaly) exposed in utero to ZIKV have an increased incidence of mild cognitive delay and auditory behavior abnormalities, with over half of these events attributable to intrauterine exposure. The results of this study suggest that more than half of alterations found in the population study can be attributed to intrauterine ZIKV exposure, thus demonstrating the importance of monitoring apparently healthy children born during the epidemic, even to asymptomatic mothers. Health services should implement early interventions to limit the morbidity of congenital ZIKV infection.

Embryonic Origins of Virus-Induced Hearing Loss: Overview of Molecular Etiology

Hearing loss, one of the most prevalent chronic health conditions, affects around half a billion people worldwide, including 34 million children. The World Health Organization estimates that the prevalence of disabling hearing loss will increase to over 900 million people by 2050. Many cases of congenital hearing loss are triggered by viral infections during different stages of pregnancy. However, the molecular mechanisms by which viruses induce hearing loss are not sufficiently explored, especially cases that are of embryonic origins. The present review first describes the cellular and molecular characteristics of the auditory system development at early stages of embryogenesis. These developmental hallmarks, which initiate upon axial specification of the otic placode as the primary root of the inner ear morphogenesis, involve the stage-specific regulation of several molecules and pathways, such as retinoic acid signaling, Sonic hedgehog, and Wnt. Different RNA and DNA viruses contributing to congenital and acquired hearing loss are then discussed in terms of their potential effects on the expression of molecules that control the formation of the auditory and vestibular compartments following otic vesicle differentiation. Among these viruses, cytomegalovirus and herpes simplex virus appear to have the most effect upon initial molecular determinants of inner ear development. Moreover, of the molecules governing the inner ear development at initial stages, SOX2, FGFR3, and CDKN1B are more affected by viruses causing either congenital or acquired hearing loss. Abnormalities in the function or expression of these molecules influence processes like cochlear development and production of inner ear hair and supporting cells. Nevertheless, because most of such virus-host interactions were studied in unrelated tissues, further validations are needed to confirm whether these viruses can mediate the same effects in physiologically relevant models simulating otic vesicle specification and growth.

Congenital Cytomegalovirus and Human Immunodeficiency Virus: Effects on Hearing, Speech and Language Development, and Clinical Outcomes in Children

Prenatal infections can have adverse effects on an infant's hearing, speech, and language development. Congenital cytomegalovirus (CMV) and human immunodeficiency virus (HIV) are two such infections that may lead to these complications, especially when left untreated. CMV is commonly associated with sensorineural hearing loss in children, and it can also be associated with anatomical abnormalities in the central nervous system responsible for speech, language, and intellectual acquisition. In terms of speech, language, and hearing, HIV is most associated with conductive and/or sensorineural hearing loss and expressive language deficits. Children born with these infections may benefit from cochlear implantation for severe to profound sensorineural hearing losses and/or speech therapy for speech/language deficits. CMV and HIV simultaneously present in infants has not been thoroughly studied, but one may hypothesize these speech, language, and hearing deficits to be present with potentially higher severity. Early identification of the infection in combination with early intervention strategies yields better results for these children than no identification or intervention. The purpose of this review was to investigate how congenital CMV and/or HIV may affect hearing, speech, and language development in children, and the importance of early identification for these populations.

Time to Evaluate the Clinical Repercussions of Zika Virus Vertical Transmission? A Systematic Review

Background: Vertical transmission of Zika Virus (ZIKV) can be associated with several clinical features in newborn infants. The goal of the present review was to analyze the current state of knowledge regarding clinical repercussions following perinatal exposure to ZIKV in children up to 3 years of age. Methods: A systematic review of published studies was carried out, without the restriction of language or date of publication, identified in the databases PubMed, Virtual Health Library (BVS), Scopus, and Web of Science and the catalog for CAPES theses and dissertations. According to the proposed flowchart, the bibliographic search resulted in 1,563 papers. Of these, according to the eligibility criteria, 70 were selected for systematic review; all were published between 2016 and 2021. Results: Regarding clinical findings, 19 papers evaluated clinical imaging alterations, 21 ophthalmic manifestations, and 39 evaluated the central nervous system; of these, 15 analyzed neuro-psychomotor development. The remainder evaluated audiological (n = 14), nutritional (n = 14), orthopedic (n = 7), cardiorespiratory (n = 5), genitourinary (n = 3) or endocrinological (n = 1) manifestations. Conclusion: It is critical for studies to continue monitoring children with antenatal ZIKV exposure as they grow, given the unknown long-term repercussions of ZIKV and the recognized postnatal complications of this infection during pregnancy. Broader descriptions of observed clinical findings are also important in order to characterize the entire spectrum of disease in children. Systematic Review Registration: PROSPERO REGISTER: CRD42020205947.

Slope of electrically evoked compound action potential amplitude growth function is site-dependent

OBJECTIVES

In human cochlear implant (CI) recipients, the slope of the electrically evoked compound action potential (ECAP) amplitude growth function (AGF) is not very well investigated, in comparison to the threshold derived from the AGF. This is despite the fact that it was shown in animal experiments that the slope correlates with the number of excitable neurons. The rationale of this study was to establish baseline data of the AGF slope for possible clinical applications, while investigating stability over time and dependence on cochlear site.

DESIGN

ECAP AGFs of 16 ears implanted with MED-EL CIs were recorded on all electrode contacts during the normal clinical routine at 4 different points in time.

RESULTS

Due to patient availability, not all 16 ears could be measured at all 4 points in time. A dependence of the slope on the electrode position was visible and statistically significant: At the three electrode contacts at the apical end of the array, the slope is greater compared to the medial and basal region of the cochlea.

CONCLUSION

The three most apical electrode contacts show greater slopes of ECAP AGF recordings. Our data of the cohort slopes show mild effects between the 4 different points in time.