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Glossary of Audiology Terms
The following briefly defines some of the technical terms used in the texts.
Electronic automatic gain control for a hearing instrument. It sets the gain depending on the input level. AGCi is used for input signal compression (see Compression).
Electronic automatic gain control for a hearing instrument. It sets the gain depending on the output level. The AGCo is used to limit the output level.
Analog instruments can only process sound signals in analog format. Subsequent changes in functions are not possible. Digital programming of analog hearing instruments represents major progress in computer-supported, optimizing individual hearing instrument adjustment. It includes a series of controls (elements), while maintaining the instrument's small size. (see digitally programmable hearing instruments).
The frequency range that can be perceived by the human ear. It is between 16 Hz and 20 000 Hz (depending on age).
Contact at the hearing instrument that enables a connection cable or radio receiver to be connected. Used for interference-free reception of radio and TV, but also used for conferences, seminars, and training.
A small device attached to a BTE hearing instrument used to connect FM receiver or other similar devices.
A directional microphone that is controlled by the digital circuit to recognize moving noise signal in the listening environment and change/adapt the polar to reduce their effects on the primary signal. The moving signals generally are coming from behind the wearer in the quandant from 90 degrees to 270 degrees.
Digital technology makes it possible to continually analyze and process incoming sound to best amplify speech while reducing unwanted noise. Soft sounds are given more amplification, while very loud sounds are given little or no amplification. Automatomatic sound processing makes hearing instruments simple to use and comfortable to wear and create hands-free operation with no need for external controls such as volume control wheels.
A process in which the input signals from each hearing instrument of a binaural fitting are communicated via e2e wireless. They are combined to make a common decision on the optimal signal processing for that listening environment.
The process that allows the operation of both hearing instruments from one control. The control (VC or push button) may reside on either instrument.
The use of both ears (right and left).
A hearing instrument is used in each ear. Used because sound perception in both ears is required in order to differentiate between useful sounds and noise, concentrate on one person in a confusion of voices, or determine the direction of sounds in traffic.
An amplification system in which two hearing instruments are coupled to operate as one integrated unit. Functions such as volume control and memory (program) selection are synchronized between the two instruments for optimal performance of the system.
A cochlea implant is an electronic instrument that restores partial hearing to the deaf. It is surgically implanted in the inner ear, and is activated by a device worn outside the ear. In contrast to a hearing aid, it does not make sound clearer or louder. Instead, the instrument bypasses damaged parts of the auditory system and directly stimulates the nerve of hearing, allowing individuals who are profoundly hearing impaired to receive sound.
The cochlea is part of the inner ear. It is lined with thousands of microscopic hair cells. The vibrations of the stirrup set the colchlea fluid in motion, causing the hairs to bend from the waves of the moving fluid. The bending of these hairs sets off nerve impulses that are then passed through the right and left auditory nerves to the brain.
Automatic gain mechanism (see AGC) that reduces gain upon reaching a certain level. The compression ratio is set in the hearing instrument. For example, a compression ratio of 3:1 means that a 3-level increase in input signal only increases the output signal by one level.
A hearing test where an audiologist teaches a child to respond when a sound is heard by playing some sort of game. For example, the child puts a block in a box every time a sound is heard.
This type of hearing loss is characterized by impaired sound conduction in the auditory canal, middle ear, or oval window. It represents approx. 5 - 10% of hearing impairments usually can be treated surgically.
Instrument whose electroacoustic characteristics are set externally via computer. The primary advantage of programmable hearing instruments is that a range of electroacoustic parameters can be set, resulting in more accurate compensation for hearing loss. These hearing instruments are sometimes confused with or marketed as digital hearing instruments; actually, these instruments use analog signal processing (see fully digital hearing instruments).
If one turns a microphone 360° in front of a sound source and draws a diagram of the voltage produced by the microphone, the result is a diagram indicating the directional characteristic of the microphone. An important feature of the directional microphone is that the diagram shows greater sensitivity (higher voltage) in one direction.
Depending on the design, type, and placement of the directional microphone (anywhere in the sound field or positioned on the head), various curve shapes or characteristics are produced for the different areas of use.
Also called discomfort limit, indicates the sound pressure level at which sound becomes uncomfortably loud; for persons with normal hearing, this is 110 dB spl. Loudness recruitment refers to hearing-impaired persons whose discomfort threshold is around the same range (+/ - 10 dB).
Adaptive formula developed especially for children by a research group at the University of Western Ontario, under the direction of Dr. Richard C. Seewald. It considers the perception of loudness as follows: quiet signals are quiet, but are still perceived to be quiet. Medium-volume signals are perceived as comfortable, and loud signals are considered loud, but not uncomfortable.
Technology for coupling and synchronization of two hearing instruments into one holistic, binaural hearing system.
Remote control unit for CENTRA, ACURIS, ACURIS Life, and ARTIS e2e hearing instruments with read out function for, volume control setting, program and battery status.
A whistling or tone created by sound escaping the ear canal and thenre-amplified by the hearing instrument.
A circuit or algorithm that detects and eliminates feedback in a hearing instrument.
An listening device that improves listening in noise. Signals are transmitted from a talker to the listener by FM (frequency modulation) radio waves. The system uses a transmitter and a receiver. To connect the FM system with the hearing instrument, an audio shoe is necessary.
Frequency is defined as the number of oscillations per second and is identified by the unit Hertz. The most important frequencies for speech intelligibility are between 100 and 3000 Hz. In hearing instrument technology, frequencies above 3000 Hz are considered to be high frequency.
The gain of a hearing instrument based on frequency is displayed graphically. The resulting curve is called the frequency response curve.
Hearing instruments that convert the analog signal received at the microphone into a digital signal. The digital signal is processed corresponding to the commands of the programmed software (algorithm) and the integrated circuits on the chip. When processing is complete, the digital signal is converted back into analog signals, amplified, and sent to the hearer. Digitization allows for analysis and filtering of signals with respect to speech and noise. The incoming signal is measured at specific time intervals (signal sampling). The more frequent the signal sampling, the better the reproduction of the input signal. The key advantage to this complex signal processing is the more precise compensation for hearing loss, in particular when providing optimum speech intelligibility in a noisy environment.
A hearing problem can have many different causes. Hearing ability is reduced when one or more elements from the outer ear to the brain are affected (see Conductive Hearing Loss and Sensorineural Hearing Loss).
With the development of digitally programmable hearing instruments, it became possible to provide patients with a 2nd hearing program in addition to the basic instrument settings. For example, while the first hearing program is used for "speech in quiet" situations, the 2nd hearing program is used primarily for "speech in noise" situations. The patient can select which hearing program to use with the touch of a button. Current modern hearing instruments from Siemens have up to four different hearing programs that can be adapted individually to the user's requirements.
The cut-off point between being able to hear and not being able to hear. In other words, the intensity level of sound at which an average adult listener will just be able to hear a sound. For adults is given as a reference level of 0 dB. The hearing threshold for newborns does not apply because their threshold develops to a normal level at around three to five years of age. Generally, newborns begin to hear at levels higher than 0 dB.
Afraid of or hostile towards water; hydrophobic materials can hardly or not at all be dissolved by water. A hydrophobic surface is water repellent.
See Sensorineural Hearing Loss.
Usually means a surgical procedure.
Knowles Electronic Manikin for Acoustical Research. "Kemar" is a standardized mannequin used worldwide for auditory testing, especially those tests where the body or head plays a role, e.g., when measuring hearing instruments containing a directional microphone
A Manufacturing technology for ITE instruments which allows ensures exact modeling of the earmold impression.
Finding the azimuth (location in space) of a sound source by comparing time and intensity differences between the ears.
Loudness indicates the subjective perception of volume provoked by a signal. Physically identical sound levels can result in very different perceptions of loudness. The perception of loudness among people with normal hearing is calculated from the signal characteristics. During hearing instrument fitting, loudness is measured using a loudness scaling in categories.
In the case of loudness recruitment, the hearing impaired person first begins to hear at higher sound pressure levels; however, said person "catches up" in terms of sensitivity to loudness. This means the hearing-impaired person can have the same sensitivity to loud noises as a person with normal hearing.
Collection of past medical or psychological illnesses of a patient.
If one looks at the temporal display of a voice signal, one will note a temporal structure (modulation) in the envelope curve. The structure is formed by the temporal sequence of words, syllables, and phonemes. The speed at which the loud and soft portions follow in sequence is called modulation frequency. Language generally has a modulation frequency between 3 and 6 Hz.
A directional microphone system that is controlled by a digital signal processing algorithm that allows the processing of the signal in several frequency regions. Each frequency region can recognize a different noise source/masker. This allows the system to reduce the effects of up to four different noise maskers, provided they are separated in frequency.
A negative reduction in a frequency response.
The perception of increased loudness of a bone-conducted signal when the outer ear is somehow blocked (covered by earphone or earmold).
Afraid of or hostile towards oil or grease; oil and grease do not adhere to oleophobic surfaces. They can easily be wiped off.
A term from directional microphone technology indicating the mode of operation of microphones that receive sounds with the same sensitivity in all directions. If one turns a microphone 360° in front of a sound source and draws a diagram of the voltage produced by the microphone, the result is the spherical characteristic. These microphones are also called omnidirectional.
A term used to describe a microphone that records in all direction. This is also referred to as a spherical microphone. See the term Omnidirectional.
Ear mold created by the audiologist based on a three-dimensional ear impression of the auditory canal, the Concha, and a clip, up to the Triangular Depression. It is used to secure and provide soundproofing for the hearing instrument. Sound from the hearing instrument is sent through the auditory canal to the area before the eardrum. Soundproofing is important to prevent feedback whistling.
The hearing system is automatically turned on with a delay of 12 seconds, so that you may insert the hearing instrument into your ear without experiencing unpleasant feedback (whistling).
See Hearing Program
A device that can be used to control specific features of a hearing instrument system such as volume and program change. It may also provide read-out functions of the hearing instruments such as battery status.
The frequency at which something vibrates naturally when stimulated. When struck, for example, a tuning fork will resonate at a specific frequency.
In this type of hearing impairment, the hair cells in the inner ear are damaged or missing. As a result, acoustical impulses cannot be converted into neural excitation patterns. Usually treated with a hearing instrument. In cases of hearing impairment bordering on deafness and/or failure of a hearing instrument, a cochlear implant may also be considered.
The process of detecting the incoming signal to a hearing instrument and classifying it against known signal patterns to determine the optimal processing necessary for that listening environment.
Audiogram that is characterized by progressively increasing high frequency hearing loss.
Digital technology makes Speech & Noise management technology possible by using special listening programs, (algorithms) to offer personalized sound processing for specific listening needs such as listening to music. This technology automaticall helps minimize or reduce background noise in many hearing situations.
Events occurring at the same time. The process of a binaural hearing system using information from each ear to arrive at a common (synchronized) set of signal processing parameters.
In a hearing situation, the hearing instrument picks up sounds with the microphone. For this reason, most hearing instruments have an induction coil (telecoil) built in. It receives the inductive field emission the telephone receiver and transmits it to the amplifier. To activate the telecoil, the instrument must be set to telecoil mode using a switch (0-T-M). An induction coil may also be used to receive signals from an induction loop, such as those found in churches, schools, or lecture halls, resulting in improved transmission without ambient noise.
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