Styles of Hearing Aids
When selecting hearing aids types, consider not only appearance, but also your manual dexterity and lifestyle needs.
Different sizes of hearing aids accommodate different features, exterior control options and battery sizes. Larger hearing aids accommodate more buttons, features, more gain and larger batteries that may be needed for to meet power consumption requirements.
Given the high complexity of the selection process and the variety of options available, our clinicians will provide you with the peace of mind that the right hearing aid matching your needs and expectations is selected in a collaborative process with you.
There are three categories of hearing aid types:
- Behind the Ear devices (BTE)
- Receiver in the Canal devices (RIC)
- Custom Devices (ITE, IIC, ITC, CIC, Instant Fit)
Behind the Ear Devices (BTE)
Behind the ear (BTE) hearing aids sit behind or on top of the outer ear with tubing that routes the sound down into the ear canal via a custom-fit ear mould or an ear tip that doesn’t block the entire ear canal opening. BTE styles are available in different colours to match hair or skin tone, as well as flashier designs to highlight personal flair.
BTE devices can come with thin tubes and domes or custom moulds depending on your hearing loss and needs.
Given the design of BTE’s they generally have more features, controls and power than any other style of hearing aid. Because the sensitive electrical components rest behind the ear, they are usually less susceptible to moisture or wax damage, requiring less frequent repairs.
Receiver in the Canal Device (RIC)
The receiver (speaker) is sitting inside the ear canal giving a greater sound quality. The microphone and the processor are encased behind the ear with a thin tube connecting to the speaker in the ear. Due to its design with the receiver in the ear canal, the actual device behind the ear is relatively small.
Custom Devices (ITE, ITC, CIC, IIC, Instant Fit)
Custom Devices – These hearing aids are worn in the ear and are usually custom-fit, based on an impression that is taken by the hearing care professional at the time of the hearing aid consultation. These styles are typically available in different skin tones to blend with the outer ear.
Custom devices fit deeply in the ear canal, allowing the wearer to benefit from the pinna’s natural resonance and localization characteristics. They are typically fit for mild or moderate hearing losses and offer high cosmetic appeal as they’re nearly invisible when worn. Because of their small size, they often come with fewer manual controls, like volume controls or program buttons. Given the design of custom devices the ability of clients to manage the device needs to be considered.
The bigger a custom device the more features, controls and battery life are available.
Recently, beside custom devices custom instant fit devices have become available.
Custom Instant fit devices are based on the same design principals as custom fit but do not require an impression to be taken. Fitting range is limited to mild hearing losses only.
A cochlear implant is a hearing aid type that is a surgically embedded device with an external sound processor worn behind the ear for severe hearing loss to profoundly deaf. While not a cure for deafness, the device gives the sensation of sound by stimulating the cochlear by using the impaired nerve in the ear to transmit sound to the brain.
The cochlear implant is made up of:
- a microphone – worn outside of the ear that receives sounds from the environment
- a sound processor – also worn outside the ear, converts the sound into electrical pulses
- a coil – carries the electrical impulses from the processor to the implant
- an implant – an array of electrodes placed in the cochlear, converts the electrical impulses and stimulates the auditory nerve
- the hearing nerve then sends the impulses to the brain which interprets the as sound
You can see more information on Cochlear Implants here.
Hearing Aid Features
The term binaural processing means that sound analysis is conducted in the brain after combining the sound input from each ear. Binaural Directionality in hearing aids works how fully functioning ears would. The latest hearing aid technology continually evaluates the signal-to-noise ratio and adds directional processing from the environment for the listener and automatically changing the response for each ear. This gives the listener more environmental awareness and the choice to focus in on the sound of interest.
There are three types of rechargeable batteries for hearing aids available:
- Nickle Metal Hydride (NI-MH) – older technology
- Lithium-Ion (Li-ion)
- Silver Zinc (Ag-Nz)
Lithium-ion batteries are the lightest, fastest charging and longest lasting; and are commonly used devices such as mobile phones, cameras, laptops and even cars.
Lithium-ion hearing aids are sealed in integrated power pack systems which means that they need to be replaced around every four/five years.
Like the Lithium-Ion, Silver-Zinc batteries provide a day’s worth of charge. The difference is Silver-Zinc rechargeable hearing aids are not integrated or sealed into the hearing aid, so if you forget to recharge your hearing aid, you can simply slip in a disposable battery. In addition, Silver-Zinc is more stable than Lithium-Ion so it won’t explode when damaged.
Noise reduction hearing aid systems
Some hearing aids types use noise reduction systems that reduce sounds for comfort, but this can interfere with clarity. Speech Priority Noise Reduction is different in that it helps listeners hear sounds that are important more clearly.
Speech Priority Noise Reduction works to separate speech from environmental noise by continuously monitoring incoming sounds. The system audits sounds that are highly modulated, with a variety of high and low tones, which are most likely speech and preserves those for the listener. Sounds that do not show modulation, like a constant humming noise, are most likely noise that needs to be reduced. By independently monitoring noise and keeping speech signals intact, Speech Priority Noise Reduction contributing to comfort and preserving the intelligibility of speech.
The design of traditional hearing aid types have not replicated the natural directivity of the human ear and have provided sound processing that differs from that produced by the unaided ear. Acuity Immersion Directionality reproduces this natural directivity, allowing the hearing aid wearer to feel more connected and immersed in their environment.
Acuity Immersion Directionality recreates natural directivity in a BTE/RIC hearing aid by using a directional microphone method in the higher frequency channels and an omnidirectional microphone pattern in the lower frequency channels. This technique effectively restores some of the localisation providing a more natural and immersive experience.