Newborn hearing loss: From prevention to intervention
About 11,000 babies are born in the United States every day and most expectant mothers have myriad worries and fears before their baby is born. Studies show that, unfortunately, hearing loss is not one of them. As a matter of fact, in a survey by the Alexander Graham Bell Association for the Deaf in Washington, D.C., only 1 percent of expectant mothers considered hearing loss a top concern regarding their baby’s health. And 55 percent of moms-to-be reported they were not concerned about the possibility of their child having hearing loss.
But there is cause for concern. According to the American Speech-Language-Hearing Association (ASHA), hearing loss is the most common birth defect among newborns. And according to 2011 Centers for Disease Control (CDC) statistics, 1.6 percent of babies screened for hearing loss did not pass. Of those who did not pass, 8.6 percent were diagnosed with hearing loss in one or both ears. The good news is that, in many instances, newborn hearing loss is preventable,or treatable if addressed early.
Causes of hearing loss at or shortly after birth vary. Genetics can certainly be a factor and are thought to be responsible for between 50 and 60 percent of newborn hearing loss. In 90 percent of cases a child with profound hearing loss is born to hearing parents, indicating that a recessive gene in one or both parents is responsible.
While genetics plays a significant role in some cases, it is certainly not the only factor when it comes to newborn hearing loss. It is now known that certain viruses are associated with up to 20 percent of hearing loss in infants. One example is cytomegalovirus (CMV), the most common non-inherited cause of hearing loss in children, according to a recent study. If a woman has CMV while pregnant, the virus is then passed from mother to infant. Because a woman who has CMV while pregnant will have an infant who is at high risk of hearing loss, it is a good idea for an expectant mother to request a blood test if she is showing symptoms of a mononucleosis or flu-like illness. Infants identified as high risk can then be referred for early assessment, diagnosis and treatment.
As of now, there is no vaccine for CMV, only prevention. "Until a vaccine becomes available, behavioral and educational interventions are the most effective strategy to prevent mothers from being infected with CMV,” said researcher Dr. Julie Goderis, of University Hospital Ghent in Belgium in the study.
But CMV isn’t the only viral infection that puts infants at risk of hearing loss. Toxoplasmosis, syphilis, German measles (rubella) and herpes all carry a high risk of newborn hearing loss if the mother has had an infection while pregnant. Good prenatal care, in addition to being current on all vaccinations, can make a tremendous difference in reducing some of these risk factors. Proper prenatal care also reduces the possibility of low birth weight and premature birth, two other risk factors for newborn hearing loss.
To protect an unborn baby’s health, certain medications should be avoided during pregnancy, or only used under a doctor’s close supervision. Ototoxic medications, when given to an expectant mother or to a newborn, increase the possibility of profound hearing loss. One example is a certain family of antibiotics known as aminoglycosides, often given to babies for birth complications or infections such as pneumonia. While lifesaving for many sick or premature infants, it is estimated that anywhere from 20 to 60 percent of infants who receive these antibiotics suffer partial or complete hearing loss. However, researchers at the Stanford University School of Medicine have developed a modified version of an aminoglycoside that works effectively in mice without the risk of causing deafness. “If we can eventually prevent people from going deaf from taking these antibiotics, in my mind, we will have been successful,” said Anthony Ricci, PhD, co-senior author of the study. “Our goal is to replace the existing aminoglycosides with ones that aren’t toxic.”
But, after all of this, what if an infant’s hearing loss is neither preventable nor treatable? Along with stress, families are likely to experience a roller coaster of emotions, from sadness to fear and ultimately acceptance. After all, hearing loss affects every member of the family, as families are inherently communication-based. Thus experts recommend a family-centered intervention for the highest level of success and emphasize creating an environment of learning and socialization as early as possible, preferably by about six months of age. Mandatory screening, diagnosis and intervention are the key to language development for infants with hearing loss, allowing them to develop language skills comparable with other children their age by about 1st grade.
The good news is that 47 states and the District of Columbia now mandate newborn hearing screening. The possibility of earlier diagnosis, better technology, greater medical advances,and more resources than ever before promise to make life easier for babies with hearing loss, as well as their families.