Evaluation of the acoustic (stapedius) reflex test in children and adolescents with peripheral facial nerve palsy

The middle ear muscle reflex: Current and future role in assessing noise-induced cochlear damage

The middle ear muscle reflex (MEMR) in humans is a bilateral contraction of the middle ear stapedial muscle in response to moderate-to-high intensity acoustic stimuli. Clinically, MEMR thresholds have been used for differential diagnosis of otopathologies for decades. More recently, changes in MEMR amplitude or threshold have been proposed as an assessment for noise-induced synaptopathy, a subclinical form of cochlear damage characterized by suprathreshold hearing problems that occur as a function of inner hair cell (IHC) synaptic loss, including hearing-in-noise deficits, tinnitus, and hyperacusis. In animal models, changes in wideband MEMR immittance have been correlated with noise-induced synaptopathy; however, studies in humans have shown more varied results. The discrepancies observed across studies could reflect the heterogeneity of synaptopathy in humans more than the effects of parametric differences or relative sensitivity of the measurement. Whereas the etiology and degree of synaptopathy can be carefully controlled in animal models, synaptopathy in humans likely stems from multiple etiologies and thus can vary greatly across the population. Here, we explore the evolving research evidence of the MEMR response in relation to subclinical noise-induced cochlear damage and the MEMR as an early correlate of suprathreshold deficits.

Evaluation of Acoustic Reflex Thresholds in COVID-19 Patients With Taste Disorders

OBJECTIVE

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, can result in persistent loss of taste and smell. This study was performed to assess acoustic reflex threshold (ART) in patients with taste disorders caused by SARS-CoV-2.

MATERIAL AND METHODS

This retrospective study enrolled 11 patients (9 men, 2 women; average age = 22.3 years) with a history of COVID-19 and had complaints of taste disorder and sensitivity to loud sounds. The control group consisted of 13 healthy participants (10 men, 3 women; average age = 23.4 years). Anamnesis, neuro-otological, ear, nose and throat, and eye examinations, as well as a taste test, pure tone audiometry, speech discrimination test, and impedance audiometry were performed in all participants.

RESULTS

All participants in the study group had a negative taste test result. In addition, ART values were significantly higher in the study group than the control group at all frequencies.

CONCLUSIONS

SARS-CoV-2 could be a neurotropic virus that can cause facial nerve neuropathy.

Prognostic factors for the outcome of Bells' palsy: A cohort register-based study

OBJECTIVES

There is a lack of data on patients' and diagnostic factors for prognostication of complete recovery in patients with Bell's palsy.

DESIGN AND SETTING

Cohort register-based study of 368 patients with Bell's palsy and uniform diagnostics and standardised treatment in a university hospital from 2007 to 2017 (49% female, median age: 51 years).

MAIN OUTCOME MEASURES

Clinical data, facial grading, electrodiagnostics, motor function tests, non-motor function tests and onset of prednisolone therapy were assessed for their impact on the probability of complete recovery using univariable and multivariable statistics.

RESULTS

Median onset of treatment was 1.5 days. 46% of patients had a House-Brackmann scale at baseline of ≥ III. The median recovery time was 2.6 months (95% confidence interval [CI] = 2.1-3.0). 54.9% achieved a complete recovery. If prednisolone therapy started later than 96 hours after onset, the recovery rate decreased significantly. Beyond less severe palsy, no abnormal electroneurography side difference, no pathological spontaneous activity in electromyography and normal stapedius reflex testing were the most powerful tool for prognostication of recovery after Bell's palsy.

CONCLUSION

Beyond severity of the palsy, facial electrodiagnostics and stapedius reflex testing are the most powerful tool for prognostication of recovery time after Bell's palsy. Prednisolone therapy should have started at best within a time window of 96 hours after onset to reach the highest probability of complete recovery.