Hearing Aid Choices
How is a hearing aid tested on a baby or a young child?
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A child's early years are important for speech and language learning. Finding the best hearing aids for your child will help. But testing hearing aids on children is not the same as testing adults. Adults can tell the audiologist if the hearing aid is too soft or too loud, or if it is working correctly. Babies and young children cannot do this. It is important to work with a pediatric audiologist who has experience fitting and testing hearing aids on young children.
Hearing aids must be set carefully for each child. When choosing what hearing aids are needed for a child, the audiologist will consider some important information:
- The degree and type of the child's hearing loss
- The durability of the hearing aid
- The service from the manufacturer
- The hearing aid's ability to connect to other devices that are used in school
Adults who wear hearing aids sometimes choose to wear only one hearing aid. Pediatric audiologists almost always recommend that babies and young children wear hearing aids in both ears. Listening with both ears is needed to help speech and language learning. It is also important for a child's safety because it helps them know from what direction sounds are coming. Even if a child has different amounts of hearing loss in each ear, two hearing aids usually will be recommended.
The best way to test hearing aid benefit is to see how the hearing aid is working in a person's ear. Audiologists measure hearing aid gain in the ear by using a probe microphone system. A small, soft tube is placed in the child's ear next to the earmold. The tube is attached to a microphone. The probe microphone measures the amount of sound coming out of the hearing aid while it is on the ear. Children have much smaller ears than adults, so it important to take measures on each child's ear to make sure hearing aids are set correctly.
It can be difficult to test babies and young children using regular probe microphone tests. Babies may not keep the probe tube in their ear for more than a few minutes. They may not be able to sit quietly enough to test the hearing aid when it is on their ear. A special test called the Real-Ear-to-Coupler Difference (RECD) can be used instead. The audiologist makes a quick probe-microphone measure with just the child's earmold in his or her ear. The hearing aid can be tested in a separate testing box. The hearing aid can be adjusted for the child and the child does not have to keep the probe microphone in their ear for more than a few minutes.
The RECD is one of the most recent tests designed for babies and young children. It is considered regular practice for pediatric audiologists when working with babies. Research studies have shown that the RECD test is safe for babies younger than 6 months of age.
The most important goal of hearing aid testing is to make sure speech is loud enough for the child to hear. Probe-microphone testing helps the audiologist judge how much speech will be heard through the hearing aid. This is called aided audibility. Using measures of aided audibility, the audiologist can compare different hearing aid settings and different listening situations. The differences between audibility with and without the hearing aid also can be compared.
The graphs above show how much speech a child with a mild to severe sloping hearing loss can hear. The circles are the child's hearing levels. The hatched areas tell how much of speech is loud enough to hear within a distance of 1 meter. The stars on the lower graph show the loudest levels of sound that can come from the hearing aid. The top graph shows what a child with this type of hearing loss can hear without a hearing aid. The bottom graph shows what the same child can hear with a hearing aid, With the hearing aid, this child can hear more of the sounds that make up conversation, especially in the high pitches. Click the icons to the left of the graphs to hear the differences.