Etiological profile of severe-to-profound sensorineural hearing loss in children undergoing cochlear implantation: the role of brain MRI in the etiological diagnosis of congenital cytomegalovirus

Abstract Background: Congenital cytomegalovirus (cCMV) is the leading non-genetic cause of pediatric sensorineural hearing loss (SNHL), but the contribution of brain magnetic resonance imaging (MRI) to its etiological diagnosis remains insufficiently explored. This study aimed to characterize the etiological profile of children with severe-to-profound SNHL undergoing cochlear implant evaluation and to investigate the clinical and neuroimaging spectrum of cCMV infection. Methods: This retrospective study included 126 children with severe-to-profound SNHL evaluated at a tertiary cochlear implant center. Clinical, etiological, genetic, and neuroimaging data were reviewed. Brain MRI examinations were systematically reassessed by a neuroradiology team, with particular emphasis on white-matter abnormalities. Results: An etiological diagnosis was established in 76% of cases. Acquired and congenital non-genetic causes accounted for 56 cases (44%), followed by genetic etiologies in 29 (24%). Congenital cytomegalovirus infection was identified in 25 patients (20%), representing the most frequent non-genetic etiology. Brain white-matter abnormalities, a hallmark of cCMV, were diffuse in 17/25 patients (68%), temporal in 4 (16%), periventricular in 2 (8%), and focal in 2 (8%). Three descriptive clinical-radiological groups were outlined: apparently isolated SNHL (n=7), SNHL with neurological involvement (n=14), and classical multisystem cCMV (n=4). Diffuse white-matter abnormalities predominated among patients with neurological manifestations but were also observed in children with apparently isolated hearing loss. Additional structural abnormalities, including ventriculomegaly, intracranial calcifications, parenchymal cysts, and cortical malformations, were more common in the classical multisystem group. Conclusion: Congenital cytomegalovirus was the leading non-genetic cause of severe-to-profound SNHL in this cohort. White-matter abnormalities frequently represented the primary clue to diagnosis, including in children with apparently isolated hearing loss. These findings support the concept of cCMV as a clinicoradiological spectrum and reinforce preoperative brain MRI, which may represent the final opportunity for reliable brain assessment before cochlear implantation.