ABSTRACT
Congenital cytomegalovirus infection is the most frequent nongenetic cause of pediatric hearing loss in the United States, affecting approximately 8,000 children each year. Due in part to variable cytomegalic involvement of the auditory cortex, cochlear implantation outcomes have varied widely. Functional magnetic resonance imaging (fMRI) has the potential to assist in determining candidacy for cochlear implantation through the detection of intact auditory pathways including the cortex. We report a case of a 21-month-old girl with cytomegalovirus-related deafness and diffuse white matter involvement in which fMRI was a determining factor for cochlear implantation and side selection.
Subject(s)
Auditory Cortex/pathology , Cochlear Implantation/methods , Cytomegalovirus Infections/diagnosis , Hearing Loss, Sensorineural/surgery , Hearing Loss, Sensorineural/virology , Magnetic Resonance Imaging/methods , Auditory Cortex/virology , Cochlear Implantation/adverse effects , Cochlear Implants , Cytomegalovirus/pathogenicity , Cytomegalovirus Infections/congenital , Cytomegalovirus Infections/surgery , Female , Follow-Up Studies , Hearing Loss, Sensorineural/etiology , Humans , Infant , Patient Selection , Preoperative Care/methods , Risk Assessment , Severity of Illness Index , Treatment Outcome , Viremia/complications , Viremia/diagnosis , Viremia/surgeryABSTRACT
Pseudorabies virus was used to label transneuronally descending auditory projections following intracochlear injections. At different time points after injection, virus-infected cells were detected immunohistochemically in the central nervous system. Initially (25 h), virus was transported retrogradely to olivocochlear cells in the pons. At 32-72 h after injection, labelling occurred in higher order auditory brainstem nuclei as well as in the locus coeruleus and pontine dorsal raphe. At 90-108 h, virus-infected neurons were found bilaterally in the medial geniculate body and in layer V of the auditory cortex. Viral transneuronal labelling in the auditory cortex after intracochlear application confirms the existence of a continuous descending chain of neurons from the auditory cortex to the cochlea, via the medial and lateral olivocochlear systems. The transneuronal labelling of the locus coeruleus and pontine dorsal raphe suggests that noradrenergic and serotonergic inputs may substantially influence the activity of olivocochlear cells, and thus the cochlea.
