Hearing aid technology is developing at a fast pace and it is easy to get left behind. Below is a list of the most common terms associated with hearing aids.
Adaptive directional microphones: a microphone system which can adapt itself based on where the sound is located.
Adaptive feedback cancellation: the process of digitally filtering sounds within the amplifier to cancel feedback noise the moment it is detected. This is done without compromising, altering, reducing or diminishing the initial sound.
ASP (Bill Circuitry): Automatic Signal Processing Bass Increases at Low Levels. This circuit increases sound signals at low levels and also decreases bass at high levels. BILL circuitry is sometimes marketed under the name “Manhattan” circuitry. BILL circuitry is intended for users who are more frequently in noisy environments, particularly environments where low frequency noises are more prevalent. High frequency noises that could be harsh or shrill are reduced with this circuit.
ASP (Pill Circuitry): Automatic Signal Processing Programmable Increases at Lower Levels. This circuit is more versatile that other circuitry because it can be programmed to perform as a BILL or TILL circuit on each channel, enabling the user to switch between the two as their environment requires.
ASP (Till Circuitry): Automatic Signal Processing Treble Increases at Low Levels. This circuit decreases the volume of high frequencies making them more comfortable. TILL circuitry is sometimes marketed under the name “K-AMP”. TILL circuitry is intended for users who require more volume for quiet sounds. High frequency noises that could be harsh or shrill are unfiltered through this circuit.
Audiogram: a graph used to record and analyse the auditory threshold of a patient’s hearing.
Audiology: the science and study of hearing.
Audiometry: the measurement of hearing.
Aural: to do with the ears.
Auditory nerve: the nerve that connects the inner ear to the brain, serving the purpose for hearing and balance.
Automatic directional microphones: technology that automatically engages and disengages the microphones without user direction.
Automatic Signal Processing (ASP): a group of aid circuits that automatically change the volume and respond to the frequencies detected in the hearing aid microphone.
BiCROS: Bilateral Contralateral Routing of Signal. This type of aid has two microphones, one for each ear but one receiver. This kind of aid is used for someone who only has hearing on one side, but sounds from both sides can be detected and processed.
Bluetooth wireless hearing aid technology: the ability for hearing aids to communicate wirelessly.
BTE: Behind-the-Ear aid.
Canal hearing aid: a custom-made aid that is worn mostly in the ear canal with a small part that sits in the outer ear.
Cochlea: the part or the inner ear, filled with fluid that picks up vibrations from sound making the tiny hair cells to vibrate and generate nerve impulses that travel to the brain.
Completely-in-the-Canal (CIC): the smallest aids which fit completely in the opening of the ear canal, beyond the visual part of the ear. Often marketed as ‘invisible hearing aids’.
Compression amplification: a feature of aids that compresses (decreases) the volume of the hearing aid as the loudness in the environment increases. The goal of compression amplification is to provide a more natural sense of loudness without under-amplification or over-amplification.
CROS: Contralateral Routing of Signal, a hearing aid system designed for people with normal hearing in one ear and no hearing in the other.
dB: Decibel, the unit of measurement for describing the intensity or loudness of a sound.
Digital hearing aid: a hearing aid that converts the electric signal from the microphone to digital values that can be processed within the hearing aid, which are then converted back to electric signals for the ear.
Direct audio input: when an aid has the ability to receive sound directly from another electronic device such as a TV or smartphone.
Directional microphone: when the microphone is more sensitive to sound approaching from one direction.
Dynamic range: the difference in decibels between the levels of being able to hear and being in discomfort.
Earmold: the impression taken of the shape of the ear canal which is then used to model the shape of the hearing aid.
Expansion technology: the digital process allowing the hearing aid to provide less volume for sounds that are quieter than conversational speech, therefore improving the quality of sound from the hearing aid when worn in quiet environments.
External receiver: the design of a hearing aid which has a processor worn behind the ear and a speaker inserted in the canal.
Feedback: high-pitched squealing or whistling sounds made when a sound has been picked up by the microphone and re-amplified in a continuous loop.
Filter: a device allowing some frequencies to pass through the hearing aid system while others are attenuated.
Frequency (Hz): the number of complete oscillations per unit of time, measured in number of cycles per second.
Gain: the amount of decibels (dB) that has increased.
Gain control: being able to adjust the gain, such as a volume control or a potentiometer.
Gain reduction: used to automatically lower the gain on a specific channel to try and control feedback.
Hearing aid: a wearable device designed to aid, improve or correct defective human hearing.
High pass filter: a filter allowing high frequencies to pass through while attenuating low frequencies.
In-the-Ear hearing aids (ITE): a custom-made hearing aid.
In-the-Canal hearing aids (ITC): see ‘canal hearing aid’.
Invisible-in-the-Canal (IIC): a tiny hearing aid that fits deep within the ear canal, completely out of sight.
Kneepoint: also known as a compression threshold. This is the point at which a compression circuit begins to reduce the gain.
Limiting Compression Circuits: this kind of circuit automatically limits the volume as it enters the hearing aid’s microphone.
Linearity: where a change in input level causes a similar change in output.
Low pass filter: a filter that allows low frequencies to pass through while attenuating high frequencies.
Low profile: the size of hearing aid shell that is between a half shell and a full ITE.
Mixed hearing loss: a hearing loss which is a combination of conductive and sensorineural.
Multi-channel adaptive directional microphones: an adaptive microphone system that can manage multiple sources of noise simultaneously.
Multi-channel technology: the process of electronically separating sounds into bands. the intensity of the sound can be adjusted independently on each band providing a more finely-tuned frequency response, unique to each person’s needs.
Narrow band filter: a filter allowing a specific range of frequency to pass through while attenuating the frequencies not required.
Noise management: the process of automatically altering the response of the hearing aid to match the settings the user requires in noisy environments.
Non-programmable multi-channel: technology that automatically separates sounds into bands and adjusts the intensity of each sound independently. The provides a more fine-tuned frequency response that is unique to each person’s hearing needs.
Open-fit: a group of hearing aids that do not block the ear canal.
Potentiometer: a volume wheel or control that allows for fine-tuning and adjustments to be made to a hearing aid.
Presbycusis: a sensorineural age-related hearing loss.
Probe microphone: a microphone with a long tube used for Real-Ear testing.
Programmable circuitry: this feature allows the hearing aid to be digitally programmed, offering a preciseness of adjustments to be made.
Ratio (compression ratio): the degree to which loud sounds are reduced.
Real ear testing: the measurement of sound in the ear canal, using a probe tube and electronic equipment.
Rechargeable: when a hearing aid has a built-in rechargeable battery, eliminating the need for disposable ones.
Receiver-in-Canal (RIC): a BTE hearing aid, which has a separate receiver worn in the ear canal, connected by a thin wire.
Remote volume control: a wireless remote control device that allows the user to adjust the volume of the hearing aid.
Speech discrimination: a test that measures someone’s ability to distinguish words and speech.
Speech recognition threshold (SRT): the lowest level that a person can correctly repeat spondiac (two syllable) words.
Static feedback cancellation: a digital process that creates a filter in the amplifier. The filter helps to cancel feedback happening during the fitting. The filter will continue to cancel feedback occurring in the same, but cannot adapt to changing situations.
Threshold: the level at which someone can hear well.
Toggle: the switch on a hearing aid that a user can switch between listening modes for different situations.
Tympanogram: a graphical representation of the changes in acoustic immittance of the middle ear in response to changes in pressure.
Tympanometry: the measurement of sound flowing through the middle ear in response to changes in pressure.
Vent: a hold drilled into an ITE hearing aid shell to allow sound to escape.
Video otoscope: a miniature camera that enables an audiologist to view and photograph the ear and eardrum.
Wireless technology: the wireless ability for digital instruments to communicate information.