How Hearing Aids Work

The vast majority of hearing losses can be treated effectively with the use of amplification, or hearing aids. Hearing aids are designed to amplify sounds within specific frequency ranges based on your hearing loss. An audiologist or other hearing care professional will recommend a style of device that is most appropriate for your hearing loss, but no matter what the hearing aid looks like, they all have the same basic components: a battery, microphone, microchip, amplifier, and a receiver, which is the speaker. 

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Like all electronics, these devices need a power source. Lithium ion rechargeable batteries have taken the hearing aid world by storm as the technology continues to improve. However, Zinc-Air disposable batteries have been around for decades and are still offered by most manufacturers. If you’re on the fence between choosing rechargeable batteries or disposable batteries, I highly recommend watching this video from Dr. Cliff, AuD, where he discusses the pros and the cons of each. 

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The microphones are the first place sound is processed. Most hearing aids today have one or two microphones, depending on the model. Most hearing aids have two microphones: an omnidirectional and a directional microphone. An omnidirectional microphone is designed to pick up sound from all around you. A directional microphone is designed to pick up sound from in front of you. Directional microphones can be particularly helpful in the presence of background noise. However, not all hearing aid styles require a directional microphone. A completely-in-the-canal (CIC) hearing aid, for example, typically only uses one omnidirectional microphone. A CIC will sit deep in the ear canal, and the hearing aid can utilize the sound that is funneled into the canal naturally from the outer ear (pinna). As your pinna directs sound into the ear canal, the way sound travels gives localization cues naturally, making the directional microphone unnecessary. In contrast, a hearing aid that sits behind the ear cannot benefit from this natural pinna effect, making a directional microphone very helpful.

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No matter if the hearing aid has one or two, the microphones will collect the sound from your environment, which is then converted into a digital signal. That digital signal is then able to be processed by the microchip, based on your exact hearing loss. After processing, the amplifier  takes that digital signal and adds the prescribed amplification. These amplified digital signals are then relayed to the receiver or speaker of the hearing aid and converted into an acoustic signal, which can be delivered to the ear canal. 

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The delivery method of the amplified acoustic signal depends on the style of the hearing aid. An in-the-ear hearing aid is a device in which all components of the hearing aid are housed in a single, custom-molded casing which is inserted into the ear daily. A receiver-in-canal hearing aid houses a majority of its components in the device which sits just on top of the ear. From the device extends a thin wire with an earpiece on the end that houses the speaker. The earpiece can be a non-custom rubber dome or even a custom earmold, depending on the type, degree, and severity of your hearing loss. For more information about acoustic coupling of a hearing aid, I highly recommend watching this video from Dr. Cliff, AuD (Dr Cliff video about domes vs earmolds when it comes out). In a traditional behind-the-ear (BTE) hearing aid, which is typically used for severe to profound losses, all components of the hearing aid live in the housing that sits behind the ear, and a tube connects the hearing aid to a custom earmold that is inserted into the ear canal. 

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Though there are several styles of hearing aids, it is important to understand the fundamentals of these devices, particularly when it comes to cleaning, maintaining, and troubleshooting the devices. As a more informed consumer, you can work closely with your hearing care provider to make educated decisions about your care. If you’d like to learn more about the pros and cons of different device styles, please watch this video from Dr. Cliff.
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As always, if you have questions regarding your specific hearing loss and which treatment options are most appropriate, please see your hearing care provider. If you have not established care with a provider, you may use the Find a Provider tool on HearingUp.com to ensure your new audiologist follows comprehensive Best Practices. 

Our Hearing Aid Buyer's Guide

This information and more is included in Dr. Cliff's Guide to Buying Hearing Aids. This free resource includes information on different features, styles and the latest models.