New research from the National Institutes of Health (NIH) shows that children exposed to HIV in the womb may be more likely to experience hearing loss by age 16 than are their unexposed peers.

Compared to national averages for other children their age, children with HIV infection were about 200% to 300% more likely to have a hearing loss, according to the study. Children whose mothers had HIV during pregnancy but who themselves were born without HIV were 20% more likely to have hearing loss. The study was published online in The Pediatric Infectious Disease Journal.

“Children exposed to HIV before birth are at higher risk for hearing difficulty, and it’s important for them, and the health providers who care for them, to be aware of this,” said George K. Siberry, MD, of the Pediatric, Adolescent, and Maternal AIDS Branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the NIH institute that leads the research network.

The researchers estimated that hearing loss affects 9% to 15% of HIV-infected children and 5% to 8% of children who did not have HIV at birth, but whose mothers had HIV infection during pregnancy. Study participants ranged from 7 to 16 years old.

Even a mild hearing loss in children can delay the acquisition of language skills. More severe hearing loss may require the use of assistive devices, such as a hearing aid.

“If parents and teachers know the child has a hearing problem, then they may take measures to compensate in various communication settings, such as placement in the front of the classroom or avoiding noisy settings,” explained Howard Hoffman, MA, director of the Epidemiology and Statistics Program at the National Institute on Deafness and Other Communication Disorders (NIDCD), which provides funding to the network for studies related to hearing and language.

The research was conducted as part of the Pediatric HIV/AIDS Cohort Study network, led by NICHD in cooperation with and with co-funding from NIDCD and several other NIH institutes.

More than 200 children and teenagers participated. All had been exposed to HIV before birth, and about 60% were HIV-positive at the time of the study. Researchers conducted hearing tests on the children if their parents or caregivers had reported hearing problems, they had low scores on a standard test of language, or their health care providers detected hearing problems during standard hearing screenings.

The researchers classified participants who could not hear tones below a certain volume as having hearing loss with difficulties in quiet and noisy settings. The researchers documented a greater proportion of hearing loss cases among HIV-positive children and found that those who had developed AIDS at any point were even more likely to have hearing loss—even if the disease was under control at the time of the study.

Earlier studies have found that children with HIV are susceptible to middle ear infections. Repeated middle ear infections can cause hearing loss. However, in 60% of cases in the study, hearing loss was the result of problems with the transmission of sound from the nerves of the ear to the brain, rather than damage in the middle ear resulting from ear infections.

Consequently, although ear infections are more common among children with HIV, infections do not appear to be the reason their hearing is more likely to be compromised, the researchers concluded.

SOURCE: The National Institutes of Health (NIH)