Topic Card 3: How a Hearing Aid Works


Related Terms:

Amplify; In-the-Ear / Behind-the-Ear; Bilateral; Binaural; Programmable Technology / Adaptive Hearing Aids; Probe microphone (real ear) measurement; Real Ear to Coupler Difference


What does a hearing aid do?

What kind of hearing aid does my child need?

Why does my child need hearing aids?

What is the difference between the different technologies?

How will the audiologist decide what hearing aids are best for my child?

My child is so young…how do we know the hearing aids are providing what is needed?

Will my child understand everything with hearing aids?

  • What does a hearing aid do?

Hearing aids amplify (make louder) sounds so that a child who is hard of hearing or deaf is more likely to hear the sounds. Hearing aids will not make your child’s hearing normal; they are an “aid” or “tool” to help your child hear better. All hearing aids consist of several parts including a microphone, amplifier and receiver or loudspeaker. They are powered by a small battery. Hearing aids can be easily removed for sleeping, bathing and swimming.

  • What kind of hearing aid does my child need?

There  are many  different styles  of  hearing  aids.  They  can  be  classified  into  two  main  categories: (1) in-the-ear (ITE), and (2) behind-the-ear (BTE). Your audiologist may discuss these types with you. Infants and children are generally fit with BTE hearing aids. A BTE hearing aid fits over and behind the ear and is attached to a custom earmold.  The earmold delivers amplified sound to the ear through tubing, and the earmold, because of its snug fit, secures the aid in place behind the ear. The BTE, with its separate, exchangeable ear mold accommodates your child’s growth; earmolds can be made as often as necessary to ensure a good fit. 

  • Why does my child need hearing aids?

The goal of a hearing aid fitting is to make speech audible (i.e., loud enough to hear). When a majority of the speech frequencies can be heard, your child will have a better chance to learn to communicate and to understand speech through listening. In most cases of bilateral (in both ears) hearing loss, two hearing aids will be recommended. This is called a binaural fitting. By wearing two hearing aids as much as possible, your child may be able to use his or her residual hearing to develop spoken language. Visual communication (sign language, cued speech) may be used along with hearing aids depending on family preference, the degree of hearing loss, and the presence of other developmental concerns that may affect spoken language. 

  • What is the difference between the different hearing aid technologies?

Hearing aids have improved significantly over the years. Most children, even those with profound loss, can be helped to some degree with hearing aids. Because of advances in technology, almost all hearing aids currently available are digital hearing aids. A digital hearing aid contains a chip, programmed on a computer, which provides amplification that is an improvement over previous analog hearing aids.

Programmable Technology – Virtually all digital hearing aids are programmable. Programmability allows the audiologist to manipulate the amplification characteristics of the hearing aid very precisely for the child’s benefit. Programmable hearing aids can be set quickly and efficiently for a variety of hearing loss degrees. Multiple “memories” can be placed in hearing aids so that experienced older children can select “programs” that improve their functional abilities in various situations.

Adaptive Hearing Aids – Hearing aids that change the way they work based upon the sound environment are called adaptive hearing aids. Adaptive noise reduction technology attempts to distinguish between noise and speech, and reduce noise levels improving your child’s ability to hear in background noise. Adaptive directional microphones identify the location of noise sources and reduce amplification from those directions, improving your child’s ability to hear in noise. Adaptive feedback cancellation applies digital technology to reduce bothersome feedback sound as it occurs while only minimally affecting the amplification characteristics of the hearing aids.

  • How will the audiologist decide what hearing aids are best for my child?

The audiologist can make the best hearing aid recommendation when complete audiological evaluation data is available. Even with on-going and frequent assessment, young children are difficult to test and detailed results may not be available when a decision about hearing aids must be made. For this reason first hearing aids are selected to be as flexible as possible so that they may be modified through programming as more is learned about the type, degree and configuration of the hearing loss. Continued evaluation after the fitting is extremely important so that modifications to the hearing aids can be made as quickly as new information about the hearing loss is obtained.

  • My child is so young…how do we know the hearing aids are providing what is needed?

Validation that a fitting is providing speech audibility for your child is based upon probe microphone (real ear) measurement, and takes into account your child’s actual ear canal volume (measured using a procedure called “Real Ear to Coupler Difference [RECD]”). Once the RECD is measured, the hearing aid can be programmed in real time if your child will allow the probe microphone to be placed, or in a simulated mode if your child is not fully cooperative with the procedure. This programming involves a comparison of the hearing aid output of a speech signal to your child’s audiogram values across the speech frequencies. This comparison will tell us how much of the speech signal is made audible by the hearing aids.

  • Will my child understand everything with hearing aids?

How much your child hears with the hearing aids may be related to the severity of the hearing loss, and how fully the hearing aids can provide speech audibility. The hearing aids must be worn during all waking hours to give the auditory system a chance to use the amplified signal. Hearing aids do not change the underlying cause of the hearing loss so your child may always have difficulty in some situations. Your parent advisor can discuss and demonstrate strategies to help your child learn to use the hearing aids. Some strategies that you can use when communicating with your child include

  • minimize background noise
  • get close to your child
  • gain your child’s attention before speaking •look at your child when speaking
  • speak clearly and precisely

Simply talking to your child about things happening during daily routines and pointing out interesting, meaningful sounds in your home and community are some of the best things you can do to help your child learn to listen with his/her new hearing aids. Topic Card #7 provides ideas for encouraging early communication development.