January 16, 2018

By J.L. McCall

The ears are the doorway to the brain: In order for the brain to develop auditory connections, we have to feed the brain auditory information. The brain can only grow connections based on the data it receives. What comes out of the child is what went into the brain. 

 

Auditory Learning Impacts Brain Development

Auditory brain development is the foundation of listening, language, and literacy for all children. Language is learned by listening. Literacy depends on language. In order for the brain to develop auditory connections, children’s brains need access to clear auditory information. Children need to be able to hear well enough to pick up incidental conversation around them. About 90% of what is learned is through incidental learning. If a child wears hearing aids four hours a day, for example, it will take him or her six years to hear what a typical hearing child hears in one year.   

If the child has a hearing loss, he or she has a damaged auditory system. A hearing aid or cochlear implant improves the child’s hearing, but he or she is still listening through a damaged auditory system. The child may hear well face-to-face, but may still have problems hearing at a distance and hearing if his or her back is turned. If the hearing aid is turned up too loud, the sound will be distorted, making understanding difficult. Competing background noise will also be amplified through the hearing device, again making understanding difficult.

 

Auditory Differences Between Children and Adults

Children spend up to 70% of their school day listening to teachers, peers, instructional media, and their own speech. Children cannot listen like adults. Children under the age of 13 have the most difficulty hearing in noise, and the auditory brain is not fully developed until a child is about 15 years old. Adults have a skill called “automatic auditory cognitive closure” that allows them to fill in the gaps if they don’t hear some of the information a speaker is trying to convey. Children haven’t yet learned the information in order to make the inferences and perform automatic auditory cognitive closure. You can only fill in the gaps of missed information if you already know what the information is.

All children need a quieter environment and a louder signal than adults require. Children are the biggest source of noise in a classroom. The larger the room, the more children, the more simultaneous activities, the noisier the room and the more obscure the desired signal is. There are three main negative effects of poor classroom acoustics: misunderstanding verbal instruction, missing verbal information, and cognitive fatigue.

 

Louder Isn’t Always Better

We can improve children’s hearing/listening by managing the environment. One way to do this is to make the speech signal louder than background noise. Teachers raise their voice in the classroom to overcome background noise. When the voice is raised, vowels get louder but consonants stay weak. Even though the teacher is talking louder, the students are missing a significant amount of information. A better speech-to-noise ratio will make speech more intelligible, meaning listeners can hear the low-frequency sounds (vowels) and high-frequency sounds (consonants), as well as hearing the unstressed parts of speech like pronouns and word endings.

Adults can function with a speech-to-noise ratio of +6dB, meaning that speech is about twice as loud as background noise. Because children’s neurological connections are not developed, they need a much louder speech-to-noise ratio to develop those connections in their brains. A better speech-to-noise ratio for children can be achieved by using a classroom amplification system or a personal system. (Teacher wears a microphone connected to a speaker, which gives a consistent speech signal throughout the classroom, or the microphone delivers the teacher’s voice directly to the hearing aid.)

 

Slowing Down Speech to Speed up Learning

Another way to enhance children’s listening ability is to slow down our speech. Adults can speak up to 200 words a minute, but children can only process about 124 words a minute. Slowing down a bit, pausing, and using stress, pitch or melody to enhance meaning can improve the listener’s speech discrimination by up to 40%. Adults who want to connect with kids should mindful of clear speech. Slow down, pause, give that child’s brain time to process and grow those connections.

Improving children’s hearing and listening environment promotes auditory brain development. An improved listening environment reduces misunderstanding verbal instruction and missing verbal instruction and reduces cognitive fatigue. The clearer the input signal, the less cognitive energy will be draining from the child, leaving more capacity for thinking, processing, and learning. 

 

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[RESEARCH] MARRS Study 

[VIDEO]  Auditory Brain Development from Carol Flexer


JL McCall

JL McCall

J.L. McCall is an audiologist at the West Central Illinois Special Education Cooperative in Macomb, IL. Contact McCall via email at jmccall@wcisec.org.

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