Ambient noise levels and infant hearing screening programs in developing countries: An observational report

Abstract

Considering that current newborn/infant hearing screening (NHS) instruments were designed primarily for use in developed countries, this study set out to ascertain the potential effects of higher ambient noise levels on transient-evoked otoacoustic emissions (TEOAE) in sub-Saharan Africa. Data was drawn from two hospital-based and community-based NHS programs in Lagos, Nigeria, with a total screened population of 11 893 infants. Two automated TEOAE screening devices-Echo-Screen and ECHOCHECK-were available for this study. Ambient noise levels ranged from 61.0-90.5 dBA in the hospital wards and 55.6-82.5 dBA in the community health centers. One TEOAE model could not be activated at the prevailing noise levels. No significant pattern was observed in average noise levels and overall TEOAE referrals across all screening sites. However, the false-positive rates ranged from 1.4-13.8%. This study suggests that valid TEOAE screening is attainable in the Negroid race in settings with ambient noise levels up to 68 dBA but the associated high false-positive rates may necessitate additional screening with auditory brainstem response to achieve acceptable overall referral rates for timely diagnostic evaluation.

Is discordance in TEOAE and AABR outcomes predictable in newborns?

“…Efforts were made to minimize the potential impact of well-established contributors to false-positives such as excessive ambient noise in the test environment, testing skills of the screening staff and the infant's age at screening [15,16]. However, the substantial risk of high follow-up default rates as previously demonstrated in this study population makes it difficult to overlook AABR even in resource-constrained environments [10,17].…”

Screening for neonatal deafness in resource-poor countries: challenges and solutions

“…90 In particular, some studies have highlighted the difficulties encountered in conducting NHS due to excessive ambient noise, especially in poorly located or very busy hospitals. 43,47,65 The quest for affordable technologies is therefore commonly associated with some trade-off in screening performance.…”

Contralateral Ear Occlusion for Improving the Reliability of Otoacoustic Emission Screening Tests

“…The main concerns however have related to the test ear rather than the contralateral ear. Thus there is concern about the signal-to-noise ratio in the test ear that has to be high for getting a valid OAE response [37, 38]. The authors are unaware of studies that have considered the effects of ambient noise on the contralateral ear.…”