HEARING SCREENING IN HIGH RISK NEONATES USING AUDITORY BRAIN STEM RESPONSE IN IBADAN

Abstract

Early detection of hearing loss and appropriate intervention are the key to speech and
language acquisition and cognitive development among the hearing impaired. Routine
newborn hearing screening has been recommended for early detection of hearing impairment.
This has not been available in Nigeria, neither has selective screening of high risk neonates;
hence the exact magnitude of hearing impairment among high risk newborns as well as the
general population remains largely unknown. This study was carried out to assess the
prevalence of hearing impairment among high risk newborns in University College Hospital
(UCH) Ibadan and the associated risk factors with the aim of identifying those that should be
recommended for selective/targeted hearing screening in view of unavailability of universal
newborn hearing screening.
It was a longitudinal study of 201 high risk newborns admitted into the neonatal unit of UCH
who were screened using the automated auditory brainstem response on admission and
discharge, while those that failed screening at discharge had repeat testing at 6 weeks post–
ddischarge. Pregnancy, birth and history of risk factors for hearing loss, as recommended by
the American Joint Committee on Infant Hearing, were documented. Descriptive statistics
and Chi Square were used in data analysis with the level of significance set at p < 0.05, while
student t-test was used to compare the mean TSB of newborns with hearing impairment and
those with normal hearing.
In this study, 83 (41.3%) and 32 (15.9%) newborns failed at admission and discharge
screening respectively, 5 (2.5%) defaulted from follow up, 1 (0.5%) died and 19 (9.5%)
failed at follow up screening. A majority of hearing loss during follow up screening are
bilateral 18 (94.7%) and severe 10 (52.6%). The risk factors associated with hearing loss (in
order of magnitude for predisposition for hearing loss) include: intraventricular haemorrhage,
acute bilirubin encephalopathy, meningitis, vancomycin administration, recurrent apnoea and
severe perinatal asphyxia. In conclusion, hearing impairment is common among high risk
newborns in UCH most of which were severe and bilateral and a majority of the hearing
impairment identified during admission resolved after treatment in the special care baby unit

HEARING SCREENING IN HIGH RISK NEONATES USING AUDITORY BRAIN STEM RESPONSE IN IBADAN