In a little over three months, my husband and I will meet our baby girl for the first time. She is due to arrive in December. There are so many things to think about and wonder about our baby’s development. It is incredible that the intricacies of human development are occurring inside of me every day.
As an audiologist, I cannot help but think about my baby’s developing ears and hearing. She can now hear the sounds of my body, including my heartbeat, which lulls her to sleep and the sounds of my voice as I talk to patients throughout the day. When my little girl is born in December, she will already be familiar with the sounds of my voice.
A baby hears its mother’s voice better than all other sounds because her voice is transmitted through vibrations in her body. Studies have shown that infants prefer their mothers’ voices to other voices, and further prefer their mothers’ voice when filtered to sound as it did in the womb.
A study referred to as the “The-Cat-in-the-Hat Study” asked mothers to read the children’s book The Cat in the Hat aloud during pregnancy for 3½ hours. Two to three days after birth, the babies showed a preference for hearing The Cat in the Hat over other stories read aloud. These babies were not only able to hear in the womb, they were also able to remember and recognize a specific story.
The tiny structures of a baby’s outer, middle and inner ears develop during the first 20 weeks of pregnancy. Although a baby is able to hear after these tiny structures have developed, hearing becomes more sophisticated as the auditory parts of the brain develop in the last 20 weeks of pregnancy. This critical auditory brain development continues into the first 5 to 6 months of life. During this time, the auditory system uses outside stimulation such as music, speech and environmental sounds to finely tune how the baby hears and understands pitch and loudness.
Hearing and auditory function at birth are so important that almost all 50 states have programs in place to either administer newborn hearing screenings on all babies or at least to educate parents on the importance of having a newborn hearing screening. In 2010, the state of Georgia screened the hearing of 96% of its newborns.
Why are newborn hearing screenings so important? The most critical time for auditory development and for development in general, occurs in the first three years of life. Before the use of newborn hearing screenings at birth, most children with hearing loss were often not identified until two years of age. By the time a child was identified as having a hearing loss, auditory development was already significantly delayed. Plain and simple, newborn hearing screenings enable early identification of hearing loss in babies which result in earlier intervention and treatment. This treatment takes the form of hearing aids and cochlear implants, as well as hearing and language training.
Though I have an extensive education and training on my baby’s auditory development, I am always questioning how my baby is reacting to sound and what she may be hearing. No doubt witnessing my daughter’s auditory development firsthand will continue to amaze and excite me as our journey together continues.