For many years now, it has been well known in the audiology community that deafness in children leads to changes in brain development. Because hearing is an essential part of communication, learning, and language development, deaf children typically experience developmental delays. Hearing loss in children can contribute to a delay in the development of speech and language, a language deficit that creates learning problems, communication difficulties, and social isolation.
Due to these issues, deaf children often do not perform as well academically as their hearing peers. In addition, they may suffer from low self-esteem and social problems. Hearing loss can even impact the child’s future vocational choices.
Research has also shown that in profoundly deaf children, the development of the brain changes to accommodate their needs. It appears that the auditory system undergoes a functional reorganization in which it is repurposed to respond more to visual stimuli.
Until recently, however, little was known about brain and developmental changes in children with mild-to-moderate hearing loss. To investigate the development of children with mild-to-moderate hearing loss, rather than profound hearing loss, researchers evaluated the brain responses of 46 children who had been diagnosed with permanent mild-to-moderate hearing loss.
Dr. Lorna Halliday, now at the MRC Cognition and Brain Sciences Unit, University of Cambridge, led the research team for this study. The team used an electroencephalogram (EEG) technique, which measured the brain responses of the children while they were listening to sounds. The children were divided into two groups based on age. The older group consisted of children aged 12-16 years, while the younger group was made up of children aged 8-12 years.
Dr. Halliday and her team discovered that the younger group of children showed a greater brain response to the sounds than the older children did. The younger children demonstrated relatively typical brain responses; their responses were similar to those of children their age with normal hearing. The older children, in contrast, showed smaller brain responses to sound.
To verify their findings, the research team retested some of the younger children from the original study, six years later. They found that as the children grew older, their brain responses changed. Whereas their brain responses were fairly typical when they were younger, the children’s brain responses had now disappeared or grown smaller with age.
Since there was no evidence to suggest that the children’s hearing loss had worsened during that time period, the findings indicate that a functional reorganization was occurring. This seems to be similar to the functional reorganization found in children with profound hearing loss. Dr. Axelle Calcus, lead author of the paper on this study from PSL, Paris, says, “We know that children’s brains develop in response to exposure to sounds, so it should not be too surprising that even mild-to-moderate levels of hearing loss can lead to changes in the brain.”
Dr. Calcus also notes that these findings demonstrate the importance of screening for hearing loss, even mild hearing loss, in children so they can receive hearing aids or another treatment for hearing loss. This can ensure that children are able to develop speech and language, perform well in school, and find success in communication.
If you would like to learn more about this topic, or if you believe that your child may have hearing loss, we encourage you to contact our hearing professionals today.
