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Background: Congenital hearing loss is one of the abnormalities reported at birth. Of 4 000 infants born deaf each year, more than half have a hereditary disorder. Even though it may be hereditary, some children develop hearing loss later in life. Genetic sensorineural deafness (SNHL) includes a range of disorders that affect infants, children and adults with affected individuals presenting with varying degrees of deafness, which may be unilateral or bilateral. About 50% of cases of congenital deafness are genetic with 70% being non-syndromic and the remaining 30% syndromic. Genetic/Congenital hearing loss is differentiated from acquired hearing loss with identification of perinatal conditions such as TORCH infections, Hyperbilirubinemia or trauma. Children who are identified with hearing loss at early stages of life have ended up with improved quality of life. There is paucity of data on congenital hearing loss in Tanzania and thus the aim of this study was to address this gap.
Methods: Eight months Hospital based, descriptive cross sectional study from May to December 2016 conducted in three hospitals and one health Centre where neonatal hearing screening was done in Zanzibar. Data was collected using a three staged protocol neonatal hearing screening with OAE and AABR, and other information was collected clinically using specialized forms and check list. A total of 600 neonates were recruited and data was analyzed using SPSS program version 21.
Results: This study enrolled 600 neonates. Among these, 323 (53.8%) were females and 277 (46.2%) were males. Among neonates who underwent 1st OAE, 36.2% failed the test and went for second test. For those who underwent 2nd OAE, 13.8% failed the test and went for AABR. 41.4% of those who went for AABR failed and went for Diagnostic ABR and among these only 3 (25%) failed. Three neonates were diagnosed with hearing loss and they were all males, with bilateral SNHL, making a prevalence of 0.5%. Among those with hearing loss 33.3% had severe SNHL and 66.7% profound SNHL. The most frequent risk factors were ototoxic medications use (11.8%), low APGAR score (11%), family history of childhood hearing loss (7%) and hyperbilirubinemia (2.5%). Hyperbilirubinemia was the only risk factor significantly associated with hearing loss (p=0.001).
Conclusion: The prevalence of hearing loss in neonates was found to be 0.5% and was more common in males. Hearing loss was bilateral, of sensorineural type and associated with some risk factors like ototoxicity, low APGAR score and hyperbilirubinemia.
Keywords: Prevalence, Hearing loss, Neonates, Zanzibar