Newborn Hearing Loss and Newborn Hearing Screening / 한양의대학술지

The incidence of bilateral profound hearing loss of newborns is 1 to 2 per 1,000 newborns. It is higher in infants with risk factors for hearing loss. Congenital hearing loss can cause many problems in language, learning, speech development and educational and occupational performance. Most developed countries have conducted the Universal Newborn Hearing Screening (UNHS) with automated otoacoustic emissions (AOAE) or automated auditory brainstem response (AABR). UNHS reduced the average age of identification of permanent hearing loss in infants 6 months or less after birth. This early identification and intervention of hearing loss with amplification and speech therapy optimizes communication during the early critical period of language acquisition and can improve language outcomes in children between 2 and 5 years of age. The aims of this paper are to explain the incidence of newborn hearing loss, the importance of early detection of hearing loss and intervention and newborn hearing screening methods.

Feasibility of two staged newborn hearing screening and identification of risk factors for hearing loss other than those included in high risk registry (HRR) given by joint committee on infant hearing (JCIH).

Background: Hearing impairment in neonates is a hidden disability, which is usually detected around 2 years of age. Crucial speech and language development begins during first six months of life. Undetected hearing loss present from an early age can impede acquisition of speech language, communication, cognitive and social-emotional development of a child. Across the globe, there is an evolving consensus that all infants should be screened for hearing impairment and appropriate interventions should be instituted in those found to have the problem by six months of age. Most developed countries have introduced mandatory screening and interventional programme with strategies appropriate for their public health concerns. Unfortunately, in developing countries, due to the paucity of resources, infant hearing screening programme has not been introduced as national programme. There have been very few large scale hearing screening studies done in India, to know the feasibility of universal hearing screening or high risk neonate hearing screening. The present study is taken to fill in the lacune in this aspect. Aims & Objective: To study the feasibility of using two staged Transient Evoked Otoacoustic Emissions (TEOAE) followed by confirmation with Auditory Brainstem Response (ABR) in hearing screening of newborns along with an attempt to identify additional risk factors, other than those included in “High Risk Registry (HRR)” given by Joint Committee on Infant Hearing (JCIH) in 2007. Material and Methods: A prospective observational study of hearing impairment screening was conducted on 800 newborns, who were screened with two staged Transient Evoked Otoacoustic Emissions TEOAE, using handheld TEOAE device, followed by confirmation with Auditory Brainstem Response (ABR). The study was done in Command Hospital Air Force, Bangalore, during Jan 2010 to May 2011, where in all new born, born during the study period were screened, which included 757 healthy neonates and remaining 43 high risk neonates as per HRR of JCIH 2007. Additional risk factors that could affect the hearing in the normal neonates was also studied. Results: At the end of the two TEOAE tests, 15 (1.8%) neonates of the 800 cohort screened were suspected of hearing impairment and referred for ABR test. Sensorineural hearing loss was confirmed by ABR in 5 (0.6%) of those 15 referred, with a 1.2% false positive rate at the end of 2nd TEOAE. 2 of the hearing impaired infants belonged to “at risk group” neonates with remaining 3 not having any risk factor as per “High Risk Registry (HRR)” of Joint Committee on Infant Hearing (JCIH). This study showed the presence of medical conditions like maternal Urinary Tract Infection (UTI), Gestational Diabetes Mellitus (GDM) or maternal Diabetes Mellitus (DM) and Pregnancy Induced Hypertension (PIH) along with the well-known risk factors of HRR in the infants with hearing loss. But a strong association between these maternal conditions and hearing impairment could not be established due to small sample size, warranting a detailed study of these other possible risk factor. Conclusion: This study has shown that two–stage hearing screening with TEOAE & ABR is a feasible method that can be successfully implemented for newborn hearing screening, for early detection of hearing impaired, on a large scale, in hospital, to achieve the high quality standard of screening programs. 3 of the 5 hearing impaired detected in the study had no known risk factor for hearing loss, advocating universal hearing screening and an extensive efforts are required to find additional risk factors that can be included in the HRR of JCIH so as to make high risk screening more effective.

Diagnostic Value of Main Frequency of Transient Evoked Otoacoustic Emissions in Meniere's Disease / 听力学及言语疾病杂志

The purpose of this study was to assess the diagnostic value of main frequency of transient evoked otoacoustic emissions for Meniere's disease. The click- evoked transient otoacoustic emissions(TEOAE) in normal subjects and in patients with Meniere' s disease were examined using ILO 88 otodynamic analyzer system to observe the main frequency distrbution. The main frequeencies ranged from 1.2 to 1.6 kHz in normal ears, and from 0.8 to 1. 1 kHz in Meniere' s ears. The main frequency range of normal ears was obviously higher than that in Meniere's ears. After application of glycerol, the main frequencies in some Meniere's ears were shifted from relative low frequency range to relative high frequency range. TEOAE appeared in some Meniere's ears in which TEOAEs could not be evoked before application of glycerol. The results suggest that the TEOAE can be used in the diagnosis of Meniere's disease.