Retrocochlear mass lesion in mid-frequency sudden deafness

Sudden Sensorineural Hearing Loss after COVID-19 Vaccination: A Review of the Available Evidence through the Prism of Causality Assessment

Sudden sensorineural hearing loss (SSNHL), a rare audiological condition that accounts for 1% of all cases of sensorineural hearing loss, can cause permanent hearing damage. Soon after the launch of global COVID-19 vaccination campaigns, the World Health Organization released a signal detection about SSNHL cases following administration of various COVID-19 vaccines. Post-marketing studies have been conducted in different countries using either pharmacovigilance or medico-administrative databases to investigate SSNHL as a potential adverse effect of COVID-19 vaccines. Here, we examine the advantages and limitations of each type of post-marketing study available. While pharmacoepidemiological studies highlight the potential association between drug exposure and the event, pharmacovigilance approaches enable causality assessment. The latter objective can only be achieved if an expert evaluation is provided using internationally validated diagnostic criteria. For a rare adverse event such as SSNHL, case information and quantification of hearing loss are mandatory for assessing seriousness, severity, delay onset, differential diagnoses, corrective treatment, recovery, as well as functional sequelae. Appropriate methodology should be adopted depending on whether the target objective is to assess a global or individual risk.

Red flags alerting a posterior cranial fossa tumor from audiovestibular perspectives - a review

BACKGROUND

There is no comprehensive and up-to-date overview of audiovestibular approach to the posterior fossa tumors in the literature.

OBJECTIVE

This paper reviewed the literature relating to tumors at the posterior cranial fossa to find red flags alerting a posterior fossa lesion from audiovestibular perspectives.

METHODS

This review was developed from articles published in those journals listed on the journal citation reports. Through the PubMed database, Embase, Google Scholar, and Cochrane library, 60 articles were finally obtained based on the PRISMA guidelines for reporting reviews.

RESULTS

The presence of one red flag indicates a positive predictive value of 33% for detecting a posterior fossa lesion. Clinical features, namely, 1) mid-frequency sudden sensorineural hearing loss (SNHL), 2) bilateral sudden SNHL, and 3) rebound nystagmus may indicate a posterior fossa lesion, representing one, two, and three red flags, respectively.

CONCLUSION

Those with 1) mid-frequency sudden SNHL, 2) bilateral sudden SNHL, and 3) rebound nystagmus trigger one, two, and three red flags, respectively, alerting clinicians the possibility of a posterior fossa lesion, which warrant MR imaging to exclude life-threatening or treatable conditions.

SIGNIFICANCE

Patients with posterior fossa tumors may have potential life-threatening outcome.

Declining prevalence of pediatric sudden deafness during the past two decades

OBJECTIVE

This study compared the prevalence of sudden deafness (SD) in children to investigate the evolution of pediatric SD during the past two decades.

METHODS

From 1996 to 2005, totaling 358 SD patients were experienced. Of them, 25 patients (7%) aged <15 years were assigned to Group A. In contrast, 5 patients (2%) aged <15 years of 242 SD patients encountered during the period 2006-2015 were assigned to Group B. All patients underwent audiovestibular function testing.

RESULTS

The measles-mumps-rubella (MMR) vaccination reached to 95% vaccination rate in Taiwan after 1994. As 1994 (MMR vaccination years) + 11 (mean age of pediatric SD) equals 2005, this study found that declining prevalence of pediatric SD was from 7% (1996-2005) to 2% (2006-2015) at our hospital, consistent with declining annual cases of SD in Taiwan during the past decades. A significantly higher abnormality rate of mean hearing level (93%) than abnormal caloric responses (20%) was identified indicating that pediatric SD predominately affected the cochlear partition.

CONCLUSION

The prevalence of pediatric SD cases has significantly declined during the past 20 years, probably due to global vaccination policy. Other causal factors such as growing numbers of hospital and advancement in radiological diagnostic technique may also contribute to the declining prevalence.

[Sudden onset hearing loss: imaging work-up]

Sudden onset hearing loss is idiopathic. It occurs in less than 24 h and spontaneously resolves within 15 days in two thirds of cases. Imaging is performed to exclude other causes of sudden onset hearing loss (vestibular schwannoma, vertebral artery dissection, stroke) and evaluate the inner ear structures. A few anatomical anomalies have been associated with an increased risk of hearing loss. Morphological anomalies involved the following structures in decreasing order of frequency: lateral semicircular canal (hypoplasia and dilatation), superior semicircular canal, posterior semicircular canal, vestibule and cochlea. Enlargement of the vestibular aqueduct also is frequently observed.

[Consensus on diagnosis and treatment of sudden hearing loss. Asociación Madrileña de ORL]

Idiopathic sudden sensorineural hearing loss is an unexplained unilateral hearing loss with onset over a period of less than 72 hours, without other known otological diseases. We present a consensus on the diagnosis, treatment and follow-up of this disease, designed by AMORL, after a systematic review of the literature from 1966 to June 2010. Diagnosis of sudden sensorineural hearing loss is based on mandatory otoscopy, acoumetry, tonal audiometry, speech audiometry, and tympanometry. After clinical diagnosis is settled, and before treatment is started, a full analysis should be done and an MRI should be requested later. Treatment is based on systemic corticosteroids (orally in most cases), helped by intratympanic doses as rescue after treatment failures. Follow-up should be done at day 7, with tonal and speech audiometries, and regularly at 15, 30, and 90 days after start of therapy, and after 12 months. By consensus, results after treatment should be reported as absolute dBs recovered in pure tonal audiometry, as improvement in the recovery rate in unilateral cases, and as improvement in speech audiometry.