Thulaseedharan Sreedharan1 , Nandakumar C.R.2 , Sinumol Sukumaran3 , Sheela Vasu4
BACKGROUND Hearing is one of the most important senses which constitutes the basis for acquiring language, communication, cognitive and psychosocial development. Hearing impairment in infants should be recognized as soon as possible after birth for early interventions. Hearing status of a newborn in this study is being assessed by two subsequent tests with Oto-Acoustic Emissions (OAE) followed by Brain stem Evoked Response Audiometry (BERA). We wanted to study the efficacy and role of two stage Otoacoustic Emission (OAE) test for screening high risk new-borns to detect hearing impairment. METHODS A prospective observational study was conducted from July 2014 to July 2017 at Govt. Medical College, Thrissur, Kerala. OAE screening was done in two stages for 500 high risk infants admitted in newborn intensive care unit (NBICU) during the study period. First OAE test was done on the day of admission and 2nd test was done after one month. All the infants underwent Brainstem Evoked Response Audiometry (BERA) test, a month after the second OAE test. Data was analysed for efficacy of the tests. RESULTS First OAE was passed by 290 babies i.e. 58 % whereas 210 babies (42 %) showed a result of ‘refer’ in both the ears. Second OAE tests were done after 1 month which showed a result of ‘pass’ by 460 babies (92 %) and a ’refer’ by 40 babies (8 %). All babies which underwent BERA 1 month after second OAE were included in the study; out of those babies, 10 babies showed impaired hearing and they were referred for further evaluation and intervention. In our study, OAE was 100 % sensitive in the first and second tests. Specificity of OAE was 59.1 % and 93.87 % in the first and second tests respectively. The study showed 2 % permanent congenital hearing impairment (PCHI). CONCLUSIONS OAE is an effective tool providing a quick, harmless and less expensive method for screening of hearing loss in infants, irrespective of comorbidities. No single test can detect all defects in the auditory pathway. As a primary option, a two-stage evaluation with OAE can easily detect infants who need further evaluation and early intervention. A two-stage screening with OAE will give a highly sensitive and reasonably specific test which can be easily implemented in all levels of the healthcare system.
