However, it’s difficult to determine exactly how many, primarily because CMV-associated hearing loss often is not apparent until a child is 2 years of age or older, and at that point, it’s next to impossible to determine whether CMV infection was present at birth. Because CMV is so endemic in the population, CMV testing must occur before three weeks of age to accurately determine if the infection was congenital.
Explore This IssueJuly 2014
A 2007 review of more than 11 studies determined that 15% to 20% of cases of profound bilateral hearing loss are associated with congenital CMV infection (J Clin Virol. 2008;41:57-62). A 10-year prospective study of more than 14,000 infants found a 0.53% prevalence of congenital CMV infection; of those, 22% developed SNHL (J Pediatr. 2008;153:84-88). Albert Park, MD, section chief for pediatric otolaryngology at the University of Utah in Salt Lake City, recently conducted a soon-to-be-published five-year retrospective study that concluded that “approximately 30% of the children we saw for pediatric hearing loss showed either confirmed or probable diagnosis for CMV.”
CMV-associated hearing loss is progressive and can fluctuate. In a 1997 study of children with congenital CMV, 50% of infants with demonstrated hearing loss at birth experienced further deterioration of hearing, with the median age of first progression 18 months (J Pediatr. 1997;130:624-630). Delayed-onset SNHL occurred in 18.2% of the children, and the median age of detection was 27 months.
CMV Testing Can Direct Monitoring and Treatment
Currently, practitioners in Utah, Ohio, parts of Massachusetts, and elsewhere are using CMV testing to evaluate and direct the treatment of newborns who fail to pass their newborn hearing screening. “In Utah, the testing requirement is based on the failure of two hearing screenings,” said Stephanie Browning McVicar, AuD, CCC-A, director of Utah’s Early Hearing Detection and Intervention program in Salt Lake City. An infant who fails his in-hospital newborn hearing screen will be re-screened at 10 to 14 days of age, often at the hospital of birth. Children who fail that second screening are scheduled for diagnostic auditory brainstem response testing and the child’s pediatrician is notified. By law, CMV testing must be done before the child reaches 21 days of age.
Infants who test positive for congenital CMV are referred to the University of Utah, where medical providers educate the family about CMV, including possible sequelae, monitoring, and treatment options, as well as ways to prevent the spread of the infection.