Objectives/hypothesis: Congenital cytomegalovirus (CMV) infection is estimated to account for 30% of sensorineural hearing loss (SNHL) cases. Differences in clinical characteristics between CMV-related and unrelated SNHL cases were scrutinized.
Methods: Using dried umbilical cord, we have recently developed a polymerase chain reaction (PCR)-based assay for the retrospective detection of congenital CMV infection. Medical records of 7 CMV-related patients identified from 31 SNHL patients by the assay were evaluated for the following: type and degree of hearing impairment, computed tomographic scan results, mental retardation, cerebral palsy, autism, and other multiple disorders.
Results: Clinical characteristics of the seven CMV-related SNHL cases were as follows: 1) six of the seven exhibited severe bilateral SNHL, whereas one had severe unilateral SNHL in the right ear. Although the hearing levels of CMV-related patients were more greatly impaired than those of CMV-negative patients, there was no hearing impairment pattern specific to the CMV-related patients; 2) five patients had mental retardation, which was more frequent than in CMV-negative patients; 3) birth weights of the CMV-positive cases were relatively lower.
Discussion: Although CMV-positive cases are clinically indistinguishable from CMV-negative cases, our PCR system allowed the retrospective diagnosis of CMV-related SNHL.
Conclusion: CMV-related SNHL tends to accompany mental retardation and low birth weight more frequently than does CMV-negative SNHL.