Aims (1) To identify the yield of aetiological medical investigations in neonates confirmed to have permanent unilateral hearing loss (UHL) following detection by the newborn hearing screening, (2) To identify the association between aetiological medical investigations, risk factors for deafness, audiological profile and stability of hearing loss.
Method This was a 14-year retrospective case-note study of 59 newborns with permanent UHL confirmed by Auditory Brainstem Response test performed at a tertiary Paediatric Audiovestibular Medicine Department following referral by newborn hearing screening. The associations between the aetiological medical investigations, risk factors for deafness and audiological profile were analysed using χ2 statistics.
Results High yields were obtained with MRI of internal auditory meati and with CT of the petrous temporal bones (75% and 80%, respectively). Investigation of congenital Cytomegalovirus infection gave a yield of 22%. Significant associations were found between the presence of physical examination signs and a positive CT finding (p=0.005) and the type of UHL (p=0.004). Degree of UHL had a strong association with a positive MRI result (p<0.001). Both the degree and the type of UHL had strong associations (p<0.05) with a positive CT finding. Two children confirmed with congenital Cytomegalovirus infection had progression of deafness whereas others had stable UHL. Of these two, one child had progression of hearing thresholds in both ears and subsequently received a cochlear implant.
Conclusion We recommend prioritising imaging studies (MRI and/or CT) and investigation of congenital Cytomegalovirus infection in newborns confirmed with UHL. The results highlight the importance of a comprehensive physical examination as it will guide the medical investigation protocol, especially imaging studies. Those newborns confirmed with congenital Cytomegalovirus infection will benefit from longitudinal follow-up to detect progression of hearing loss. Future research with a larger sample is required for further recommendations.