Frequency and natural course of congenital cytomegalovirus-associated hearing loss in children

Background Congenital cytomegalovirus-associated hearing loss (cCMV-associated HL) is a common cause of congenital or early-onset deafness. Although cCMV infection has been reported to lead to various types of HL, the natural course of cCMV-associated HL over a long period is not yet known. Objectives To investigate the clinical phenotype of cCMV-associated HL in the largest study to date. Methods Thirty-one CMV-positive children, diagnosed by examining CMV DNA extracted from their dried umbilical cords retrospectively, were divided into unilateral and bilateral HL groups, and their hearing ability was evaluated using pure-tone audiometry and auditory steady-state response over time. Results Thirteen patients (41.9%) had unilateral HL and 18 (58.1%) had bilateral HL. In most cases of unilateral cCMV-associated HL, the ear with better hearing maintained a normal hearing threshold. Notably, in most cases of both unilateral and bilateral HL, the ear with worse hearing ultimately showed severe to profound HL. Conclusion Our findings revealed that the natural course of cCMV-associated HL was different between the cases of unilateral and bilateral HL, as well as between the ears with better or worse hearing in all cases. These findings indicate that accurate diagnosis could enable proper follow-up and management of cCMV-associated HL in children.