Unilateral Hearing Loss in Children Could Affect Later Development

Hearing loss in infants and toddlers can have a strong effect on speech development. In the most direct sense, not being able to hear adults and other children speaking can inhibit the process of learning to speak for oneself. Many studies have charted this relationship, particularly for children who have hearing loss in both ears, otherwise known as bilateral hearing loss. With the entire volume of the world turned down, you can understand why it might be difficult to learn to speak. 

A recent study has contributed to this finding with new information about children who have hearing loss in only one ear, otherwise known as unilateral hearing loss. This type of loss enables an infant or child to hear out of one ear, so it might seem as though speech development could continue unhindered. Puzzlingly, these children had similar limitations in speech development as the children who had bilateral hearing loss. What might account for this difference? 

Though at this phase the researchers have only discovered the statistical connection, they are now interested to find out why and how speech development is delayed in babies and children with unilateral hearing loss, as well. 

The Study

The Hearing Center at the West China Hospital of Sichuan University in China published their study under the title “Early Prelingual Auditory Development of Infants and Toddlers with Unilateral Hearing Loss” in the journal Otology & Neurotology. The study recruited 167 children of three different types. 65 of the children had unilateral hearing loss, and 32 children had bilateral mild hearing loss. The remaining 70 children did not have hearing loss in either ear. This profile led researchers toward a comparative analysis of the speech development process for children from birth to age 3. 

They found that the children with both types of hearing loss had problems with sound discrimination, sound identification, and preverbal vocalization. They also demonstrated problems with early prelingual auditory development. All of these preverbal patterns pointed toward speech pathology as they emerged into speaking age. These findings would have been expected among babies and children with hearing loss in both ears. Yet, what might account for the finding among young children with hearing loss in only one ear?

The Discussion

The process of language acquisition is not as simple as mimicking the sounds that adults and other children make. It seems that something about the balance in hearing between the ears had to do with language acquisition, as well. It is possible that the reduction in overall sound did have a relationship with speech development that was strong enough for the children with unilateral severe hearing loss to appear as their counterparts with bilateral mild hearing loss. 

And yet, what about the other matched pairs in the study? The binaural effect of sounds in combination might be a key to understanding this finding. We do not simply hear two distinct sounds, one in each ear. Instead, many sounds combine to form something unique in the mind. This binaural effect might be more important than we realized to the process of speech and language acquisition among preverbal children.

Childhood Hearing Loss

Some children are born with hearing loss, more properly termed hearing impairment. Yet, it can be difficult to identify this loss until later in childhood when signs are available to parents and healthcare workers. Babies at a young age can demonstrate signs of hearing loss, including the inability or slow response to loud sounds in a room. 

If you notice that your infant is not turning their head to look at the source of loud sounds within the first few months of life, it is worth making a visit to the doctor to discuss the possibility of hearing loss or impairment. The earlier you are able to begin with assistance, treatment, and speech pathology services, the more likely your child will be to continue on the path toward language acquisition. The options for childhood treatment for hearing loss are advancing every day, and many options are available to facilitate the best quality of communication possible. 

If you are interested in learning more about these possibilities, talk to your pediatrician or one of our hearing health professionals for the details.