For the study, researchers examined data on language abilities at age 5 for children born with permanent hearing loss who received similar interventions at different points in childhood.
Kids who received hearing aids at age 2 had worse language outcomes than kids who got the devices fitted when they were just 3 months old, the study found. Children who got cochlear implants at age 2 also had worse language outcomes than kids who got these devices when they were 6 months old.
“The shorter the period of deprived access to sounds, which would be non-existent in the case with normal hearing, the higher likelihood for the child with hearing loss to develop language that is on par with his/her normal-hearing peers,” Ching said by email.
Universal newborn hearing screenings have become standard in Australia and much of the developed world, with the goal of catching and treating hearing loss earlier when there’s the greatest potential benefit, the researchers write in Pediatrics.
But in practice, there’s still wide variation in how soon children with permanent hearing loss may receive hearing aids to amplify sounds or cochlear implants to transmit sound signals to the brain in kids with damage in the inner ear.
For the current study, researchers examined language outcomes at age 5 for 350 children with permanent hearing loss as well as for a control group of 120 kids with normal hearing.
The kids with hearing loss were compared to children with similar types of impairment who got the same intervention – hearing aids or cochlear implants – at a different time. Children were also similar in the degree of hearing loss, birth weight, IQ, additional disabilities and mode of communication.
The impact of earlier intervention was more pronounced for children with more severe hearing impairment than for kids with milder hearing loss, the study found.
Universal newborn hearing tests, however, didn’t appear to influence language outcomes. This might be because not all kids who got tested as newborns received hearing interventions as infants, and some children who missed out on newborn tests still received hearing aids or implants as babies, the authors note.