What are the top causes of hearing loss in children? For the answers, I turned to the Regional and National Summary Report of Data from the Annual Surveys of Deaf and Hard of Hearing Children and Youth done by the Gallaudet University's Gallaudet Research Institute. This survey looks at the characteristics of thousands of deaf and hard of hearing students nationally.
Unless otherwise indicated, data is from the 2004-2005 report, which has a detailed breakdown of pregnancy-related, post-natal and genetic/syndromic causes. The 2006-2007 report did not have such a breakdown.
Pregnancy-Related: PrematurityThe most common prenatal/pregnancy-related cause was "consequence of prematurity," at 4% of the cases of pregnancy-related causes nationally. According to the American Academy of Family Physicians, about 5% of children born before 32 weeks (8 months of pregnancy) have hearing loss by the time they are five years old.
Why does prematurity put babies at increased risk for hearing loss? A premature baby's auditory system is not yet mature when the baby is born before seven months of gestation. In addition, a premature baby's ears are vulnerable to damage.
Cytomegalovirus, another pregnancy-related cause, was cited as being responsible for 1.8% of the pregnancy-related cases nationally. CMV is very similar to rubella in how it can affect a fetus. Like rubella, it is a dangerous virus that can result in a baby being born with a progressive hearing loss, mental retardation, blindness, or cerebral palsy. Information on CMV is available from the National Congenital CMV Registry.
Pregnancy-Related: Other Pregnancy Complications"Other pregnancy complications" was the next most cited specific pregnancy-related cause in the survey, at 3.8% of pregnancy-related cases nationally. A pregnancy complication is anything that can harm the baby, mother, or both of them, and it can be mild or serious. According to the American Speech-Language-Hearing Association, this is a category that includes things such as prenatal infection, Rh factor, and lack of oxygen.
My own deafness is the result of a pregnancy complication called rubella. Rubella used to be a common pregnancy complication until a vaccine was developed in the 1960s. It can still occur today if a mother has not been vaccinated.
Post-Natal: Otitis MediaOtitis media was the most common post-natal cause cited, at 4.8% of post-natal cases nationally. Ear infections associated with otitis media are frustrating for both parents and doctors, who must decide whether or not to prescribe antibiotics. An occasional bout of otitis media may cause temporary hearing loss due to the fluid build-up in the middle ear, but repeated bouts of otitis media can cause permanent hearing loss.
Post-Natal: MeningitisMeningitis, at 3.6 percent of post-natal cases nationally, was the next most common post-natal cause of deafness cited. The antibiotics needed to treat bacterial meningitis can cause hearing loss, but this risk can be reduced with the use of steroids.
Genetic or Syndromic: Down SyndromeGenetic or syndromic factors were cited in the 2004-2005 report as being responsible for 22.7% of the genetic or syndromic cases. The 2006-2007 report actually showed a slight increase in genetic causes to 23%. Down syndrome was the most common syndromic cause, at 8.7% of the cases of genetic or syndromic hearing loss.
Genetic or Syndromic: CHARGE SyndromeCHARGE syndrome, at 5.6% of the genetic or syndromic cases, was the next most common genetic or syndromic cause after Down syndrome. CHARGE is a craniofacial disorder.
Genetic or Syndromic: Waardenburg SyndromeWaardenburg syndrome can create unique physical features as well as cause hearing loss; it was responsible for 4.8% of the cases of genetic or syndromic causes nationally.
Genetic or Syndromic: Treacher Collins SyndromeTreacher Collins syndrome was the next most frequently cited genetic or syndromic cause. Like CHARGE, Treacher Collins is a craniofacial disorder that can cause deafness.
Unknown CausesFinally, in the 2004-2005 report, the remainder of the cases were due to unknown causes (approximately 54% of cases). The 2006-2007 report saw an increase in unknown causes, to 57% of the cases of deafness.
American Academy of Family Physicians, http://www.aafp.org/
The Hospital for Sick Children in Canada, http://www.aboutkidshealth.ca
American Speech-Language-Hearing Association, http://www.asha.org/public/hearing/disorders/causes.htm#otitis