BERA as a screerning tool for evaluating cases of SNHL due to suspected retrocochlear pathology
Author(s): Abhilash AM and Saritha HM
Abstract:Background: BERA is an objective study for assessing hearing loss on patients with inconsistent responses on pure tone audiogram. BERA is a non-invasive and the most cost-effective method for diagnosing retrocochlear lesion, not affected by sedation, anesthesia or age. Which helps to identify retrocochlear hearing loss. BERA is most accurate and sensitive for diagnosis of lesions in VIII nerve and auditory pathway in brainstem, especially in adults.
Objectives: Screening tool for evaluating cases of sensorineural hearing loss due to suspected retrocochlear pathology. Objective test in cases of inconsistent response for pure tone audiometry. Role in evaluating brainstem lesions.
Method and Aim: This is a cross sectional prospective cohortHospital based study, review of 50 patient subjected to BERA for SNHL in any age group referred to department of ENT Vijayanagara institute of medical sciences, Bellary. We aim to find Brainstem evoked response audiometry (BERA) andits applications in ENT.
Result: In this study threshold and latency measures were obtained from 50 cases (100 ears) by brainstem evoked response audiometry. No restrictions were imposed on age, sex, degree of hearing loss, or audiometric configuration. The data was analyzed separately for pediatric age group (36 cases) and adults(16 cases). out of 36 pediatric cases screened 15 cases (41.7%) had normal hearing in 13 cases had profound hearing loss without any risk factors. 6 cases ( 16.7 %) hearing loss due meningitis. 2 cases (5.6%) hearing loss due to neonatal jaundice. In adult age group (14 cases) BERA was done to identify cases of retocochlear pathology and in cases of threshold estimation of hearing.
Conclusion: BERA can be used to screen retrocochlear pathologies as seen in our study. Patients with hearing loss with tinnitus and giddiness screened and BERA performed had grossly degraded wave with identification of only wave I and absence of other waves and increased latencies and interaural difference in wave latencies suggests lesion in the auditory pathway. Depending on the absence of specific wave site of the lesion can also be made out. In our study 3 cases of retrocochlear pathology previously confirmed by MRI was taken and BERA was performed showing presence of only wave I and absence of remaining waves. BERA is screening test and should be confirmed by MRI.