Hearing Dictionary

Term Definition
A/D (Analog to Digital) Converter The part of the digital chip that takes sound and converts it into a signal the chip can recognize.
Accuvoice System Used to control low frequency sounds so your voice does not sound hollow.
Activity Analyzer “Keeps track of listening environments to which you are exposed so your audiologist can better adjust the hearing aids for your needs.
Adaptability The ability of the hearing aid to change its’ settings based on the listening environment.
Adaptive Directional Microphone A directional microphone system capable of activating itself.
Adaptive Directional Microphone with Softswitching A directional microphone system capable of activating itself. Designed with special circuitry to make the change more transparent to the wearer.
Aditus The opening between the pneumaticized mastoid air cells and the middle ear space.
Advanced Noise Reduction A more technologically advanced noise reduction system.
Algorithm The procedure or formula a digital processor uses to calculate what needs to be done with sound as it goes through your hearing aid.
Aliasing Occurs when a sound is not converted properly from analog to digital. The sound is reconstructed at a different frequency causing distortion.
American Academy of Audiology A professional organizations for audiologists
American Speech Language Hearing Association (CCC-A) An organization that provides standards for certification of audiologists. CCC-A designates an ASHA certified audiologists.
American Speech-Language Hearing Association A professional organization for both speech-language pathologists and audiologists.
Amplifier A device that increases the intensity of the sound
Amplitude The amount of displacement of something; the amount of movement.
Ampulla The enlarged section of the semicircular canal in which the sense organ for head rotation is located.
Analog Hearing Aid A standard hearing aid that amplifies sound in an analog format.
Anatomy The study of the structures of the body.
Antagonistic Pulling in opposite directions. The contraction of the stapedial muscle and tensor tympani are antagonistic.
Anti-Aliasing Filter Filter within a digital chip that prevents aliasing.
Antihelix Part of the pinna that is just beyond the concha; it is a rim of cartilage.
Arch of Corti Also called pillars of Corti. Supporting structure located between the inner and outer hair cells within the organ of Corti.
Areal ratio “The relative difference in the size of the tympanic membrane to the stapes footplate. Because of this size difference sound is concentrated as it reaches the inner ear and the sound pressure is enhanced by about 27 dB.
Articulation Index Weighted Directivity Index (AI-DI) A means to calculate the benefit of a directional microphone system.
Assistive Devices “Tools and devices such as alarms alerting devices or FM systems used to help people hear to perform daily actions tasks and activities.
Asymmetrical Hearing Loss The degree of hearing loss in one ear is greater than the other.
Au.D. Professional doctoral degree designator for audiologists.
Audibility The level at which a sound can be heard.
Audiogram An audiogram is a standard way of representing a person’s hearing loss. Most audiograms cover a range of 250Hz to 8000Hz (8 kHz).
Audiologist “A hearing healthcare professional who has earned a Masters Degree (M.S. or M.A.) or Doctorate Degree (Au.D. or Ph.D.) in audiology. Audiologists are trained to evaluate hearing loss and related disorders including balance (vestibular) disorders and tinnitus and to rehabilitate people with hearing loss and related disorders. Audiologists use a variety of tests and procedures to assess hearing and balance function and to fit and dispense hearing aids and other assistive devices for hearing loss.
Audiology The science of the assessment and management of hearing and balance disorders.
Audiometer Electronic device used to assess hearing. Produces pure-tone signals at calibrated intensities and allows for controlled presentation of speech signals to the patientås ears.
Auditory Brainstem Response (ABR) Test “A test used to check the hearing of infants and young children or to test the functioning of the hearing nerve. This painless procedure involves attaching recording disks to the head to record electrical activity from the hearing nerve and brain stem.
Auditory Processing Disorder (APD) “Inability of an individual with normal hearing and intelligence to differentiate recognize or understand sounds normally.
Auricle Synonym for the pinna. Portion of the external ear that gathers sound waves and funnels them to the external auditory meatus.
Autoimmune Hearing Loss “Hearing loss when one’s immune system produces abnormal antibodies that react against the body’s healthy tissues. May be associated with tissue-causing disease such as rheumatoid arthritis or lupus.
Automatic Telecoil Programmable telecoil that activates automatically when a telephone is placed near.
Automatic Volume Control The hearing aid automatically adjusts the volume for the wearer.
Axon Portion of a neuron than conveys the neural impulse away from the cell body to the terminal button.
Background Noise Generally refers to the presence of other sound in an environment that is not the speech one is trying to hear.
Balance “A biological system that enables individuals to know where their bodies are in the environment and to maintain a desired position. Normal balance depends on information from the labyrinth in the inner ear from other senses such as sight and touch and from muscle movement.
Balance Disorder “Disruption in the labyrinth the inner ear organ that controls the balance system which allows individuals to know where their bodies are in the environment. The labyrinth works with other systems in the body such as the visual and skeletal systems to maintain posture.
Band A range of frequencies that can be adjusted in a hearing independent of other frequencies
Bandwidth The total area of frequency that a hearing amplifies generally from about 125Hz to 5500KHz.
Barotrauma Injury to the middle ear caused by a rapid change of air or water pressure.
Basilar membrane Membrane inside the cochlea that separates scala media and scala tympani; on this membrane rests the organ of Corti.
Battery The power source for a hearing aid.
Behind the Ear Hearing Aid (BTE) Style of hearing aid in which the components are placed behind the ear and the sound is delivered to the ear through a tube connect to an ear mold.
Bilateral Hearing Loss A hearing loss in both ears.
Bluetooth A type of wireless connection for electronic devices.
Bluetooth Technology “Bluetooth is a wireless technology which allows electronic devices to connect securely and talk to each other over a typical maximum range of 30 feet. Initially the two devices wishing to communicate with each other are ‘paired’. This creates a secure radio link between the devices which is encrypted and prevents un-paired devices from interfering or intercepting the data being transmitted between the devices.
Bone Conduction Hearing Aid A hearing aid that transfers sound through the skull instead of the ear canal.
Brainstem “Portion of the brain that is below the cerebrum and anterior to the cerebellum. It is a conduit of information to the “”brain”” and to the cerebellum (the cerebellum coordinates motor function.)
Calibration “The process of determining that an audiometer produces the desired signals at the proper intensities.
Captioning “Text display of spoken words presented on a television or a movie screen that allows deaf or hard-of-hearing viewers to follow the dialogue and the action of a program simultaneously.
Cartilaginous “Comprised of cartilage a dense but flexible connective tissue.
Cerebellopontine angle “Area where the VIII nerve enters the brainstem. At this location the auditory pathway takes a turn (angles) upward. This occurs at the junction of the cerebellum and pons portion of the brainstem ergo the name.
Cerumen Earwax. Substance produced by the glands under the hairs in the cartilaginous portion of the external auditory meatus. Comprised of the secretions of the apocrine and sebaceous glands.
Cerumen (Ear Wax) Yellow secretion from glands in the outer ear canal that keeps the skin of the ear canal dry and protected from infection.
Channel A section of frequencies controlled by the hearing aids compression circuitry. Hearing aids can have as few as 1 channel and as many as the manufacturer wants to use.
Cholesteatoma “An abnormal accumulation and pocketing of dead cells in the eardrum which can often be surgically repaired.
Cilia “Tiny hairlike projections on a cell. Ciliated cells are found in portions of the middle ear space the Eustachian tube and in the cochlea. Cilia are found on both outer and inner hair cells.
Circuit Board The piece inside the hearing aid that contains the digital chip.
Clinic A professional medically oriented office.
Clock Generator A circuit that provides the timing signal to synchronize the hearing aids operations.
Cochlea Spiral-shaped hole in the temporal bone. It is here that sound energy is received by the hair cells and the nerve impulses that encode hearing are created.
Cochlea Snail-shaped structure in the inner ear that contains the organ of hearing.
Cochlear Implant “Medical device that bypasses damaged structures in the inner ear and indirectly stimulates the auditory nerve allowing some deaf and hard of hearing individuals to learn to hear and interpret sounds and speech.
Cochlear Nucleus Group of nerve cells just medial to the VIII nerve. The first nucleus in the auditory pathway.
Completely-In-The-Canal Hearing Aid (CIC) A hearing aid that is designed so that most of the electronics are located in the ear canal. The smallest style of hearing aid currently available.
Compression A type of circuitry that is used to keep soft sounds audible and loud sounds comfortable.
Concha Portion of the pinna that is the recessed bowl.
Condensation Also called compression. The portion of a sound wave where the air molecules are most tightly packed together. See also the tutorial on acoustic review.
Conductive Hearing Loss “Conductive hearing loss is due to any condition that interferes with the transmission of sound through the outer and middle ear to the inner ear. This type of hearing loss can be successfully treated in most cases. Modern techniques make it possible to cure or at least improve the vast majority of cases involving problems with the outer or middle ear. Even if people with conductive hearing loss are not improved medically or surgically they stand to benefit greatly from a hearing aid because what they need most is amplification.
Cortex “Outside portion of the cerebrum consisting of gray matter (material that is mostly cell bodies rather than white matter which is mostly myelinated neurons).
Crus “Singular (crura is plura) from the Latin word meaning leg it is a side part of the stapes bone of the middle ear.
D/A (Digital to Analog) Converter Changes in the digital signal coming out of the amplifier into an analog sound that we can understand.
D3 Directional Microphones Sonic Innovations brand name for the directional microphone system used in their Innova product.
Data Logging “Feature in some digital products that keeps a record of what kind of environments the user has been exposed to battery life hours of usage etc. and may even make recommendations for adjustments.
dB HL “Decibels hearing level. 0 dB HL is the softest sound that can be heard by the average person with normal hearing. It is not the absence of sound as persons with better than average hearing will have thresholds lower than 0 dB HL (e.g. Ñ10 dB HL).
dB SPL “Decibels sound pressure level. The type of decibel used in sound level meters it compares the pressure of sound at the microphone of the sound level meter to the reference pressure of .0002 dynes/cm2.
Deaf “A person that is not able to perceive sound and / or understand speech even when amplified.
Decibel (dB) “A decibel or its abbreviation dB is a measurement of loudness that ranges from the threshold of hearing 0dB to the threshold of pain about 140dB. The term decibel is actually two words: deci meaning one-tenth and bel named after Alexander Graham Bell the inventor of the telephone which is why the ‘B’ is always written in upper case as in dB. So a decibel is actually one-tenth of a unit of sound measurement known as a bel. To put Decibel in context the volume of normal conversation is about 60dB and the roar of a jet engine is at least 120dB.
Decussation Crossing over of nerve fibers from one hemisphere of the brain to the opposite (contralateral) hemisphere. Auditory nerves will decussate at several places in the brainstem.
Dendrite Portion of the neuron that connects either to the sensory receptor (i.e. hair cell) or to the terminal button of the neuron that is transmitting information.
Digital A type of amplifier system that changes analog sound into a series of numbers for processing.
Digital Hearing Aid “A hearing aid with a digital processor that converts analog sound to digital and then back to analog.
Digital Processor See digital signal processor.
Digital Signal Processor A microprocessor that converts analog sound to digital signal.
Digital Speech Enhancement The enhancement of speech signals by a digital processor to make speech more readily distinguished from noise.
Direct Audio Input “Generally only available on BTE hearing aids enables the wearer to directly connect an electronic sound source to their hearing aid.
Directional Microphone Multiple microphone system that amplifies sound from the front more than sound from the rear for better hearing in noise.
Directional Polar Pattern The area in relation to the head in which a directional microphone provides full amplification.
Disposable Hearing Aid A hearing aid designed to be worn and then thrown away when the battery dies.
Dither Noise added to sound to reduce distortion
Dual Band Directional Microphone “A directional microphone system that separates high and low frequencies providing more emphasis on high frequency for better speech understanding.
Dynamic Range The range between wear a person begins to hear sound and sound becomes uncomfortable.
Ear “The organ of hearing comprised of the outer ear middle ear and inner ear but is more commonly used to refer to the portion of the ear that is visible the pinna.
Ear Canal Channel on the side of the head that the pinna directs sound down to the eardrum.
Ear Drum The tympanic membrane is a thin membrane that separates the outer ear from the middle ear; sound vibrates the membrane which transfers the energy to the bones of the middle ear.
Ear Wax (Cerumen) Glandular excretion in the ear canal which is designed to help keep foreign objects from entering the ear canal.
Eardrum “The eardrum (tympanic membrane) is a thin semi-transparent membranous wall that stretches across the ear canal and separates the outer ear from the middle ear. The side that faces outward into the ear canal is covered with skin and the inside is covered with mucous membrane. The eardrum vibrates when sound waves travel into the ear canal and strike it. One of the bones of the middle ear (the malleus) attaches to the center of the membrane and receives vibrations transmitting them to other bones (the incus and stapes) and the inner ear fluid and finally to nerves in the brain where sound is perceived.
Earmold The portion of a behind-the-ear style hearing aid that fits in the concha and directs the sound into the ear canal.
EEPROM (Electrical Erasable Programmable Read-Only Memory) The memory area of a hearing aids digital processor.
Endolymph “Fluid in the section of the cochlea known as scala media and in the membranous labyrinth of the vestibular system. This fluid is high in potassium and relatively low in sodium.
Eustachian Tube “Tube which is normally closed between the nasopharynx and the middle ear system. It is opened by contraction of the levator veli palatini and tensor veli palatini during swallowing and yawning.
External Ear Part of the auditory system comprised of the pinna and external auditory meatus.
Feedback The whistling sound that occurs when sound from a speaker loops back to the microphone.
Feedback Cancellation The removal of feedback by producing a signal exactly opposite of the feedback signal.
Feedback Suppression Control of feedback by reducing the frequency where the feedback has occurred.
Fluctuating Hearing Loss Hearing loss that does not stay constant but is improved on some days and worse on others.
Footplate Portion of the stapes bone that is attached to the two crura and that sits in the oval window.
Frequency The number of back and forth vibrations of a vibrating object in one second. Related to pitch; the larger the frequency of vibration the higher the pitch.
Frequency Band In hearing aids refers to the divisions of frequencies that can be adjusted for volume independently from other frequency bands.
Full Shell Hearing Aid (FS) Style of hearing aid that fills the bowl of the ear.
Gain The volume added to a sound after amplification.
Granulation Noise Audible distortion in amplified sound.
Group Delay The time delay between the input and output of a sound.
Half Shell Hearing Aid (HS) Style of hearing aid that fills approximately half of the bowl of the ear.
Hearing “The transfer of sound through the auditory system ( outer middle and inner ear ) to the brain.
Hearing Aid “A battery-powered electronic device that brings amplified sound to the ear. A hearing aid usually consists of a microphone amplifier and receiver.
Hearing Aid Dispenser “Person licensed by the state to dispense hearing aids but who does not have university training in audiology.
Hearing Loss “Disruption in the normal hearing process that may occur in either the outer middle or inner ear whereby sound waves are not conducted to the inner ear converted to electrical signals and/or nerve impulses are not transmitted to the brain to be interpreted as sound.
Hearing Test Series of tests performed with an audiometer that measures a persons hearing loss based on subjective response.
Helicotrema The portion at the apex of the cochlea where there is no scala media. The perilymph can flow between scala tympani and scala vestibuli at this location.
Helix The outside rim of cartilage that runs along the top of the ear.
Hertz (Hz) “Measurement of the speed of a sound wave one cycle per second = 1Hz
High Frequency “Sounds on the higher end of the speech frequency range. Perceived as high tone or treble soft consonants such as f and s.
High Power BTE Behind the ear hearing aid designed for hearing losses in the severe to profound range.
High Tone “High frequency sounds such as a soft s or f crickets children’s voices treble.
Impedance An object or medium’s resistance to energy flow. A high-impendance medium will reject energy; a low-impedance substance vibrates more freely.
Impression A silicon cast of the shape of the ear and canal used to make custom hearing aids and ear molds.
In-The-Canal Hearing Aid (ITC) “Smaller than an ITE hearing aid it usually fills up a portion of the ear canal and a small portion of the outer ear. A mini-canal attempts to make the hearing aid even smaller by using a smaller battery.
In-The-Ear Hearing Aid (ITE) A style of hearing aid in which all the parts of the hearing aid are fit into the concha or bowl area of the pinna and the ear canal. In-the-ear hearing aids typically serve clients with mild hearing losses.
Incus “One of the ossicles or bones of the middle ear. It is the middle bone located between the malleus and the stapes.
Inferior Colliculus “One of the nuclei of the auditory system it is located superior to the lateral lemniscus but before medial geniculate body.
Inner Ear Fluid-filled hole in the temporal bone containing the sense organs for hearing and balance.
Inner Hair Cells “The cells within the organ of Corti that are responsible for encoding neural impulses for sound. These ciliated cells are located on the medial side of the arch of Corti and are found spiraling the length of the cochlea. Only one hair cell is seen on any cross section of the cochlea where 3 to 5 outer hair cells are found sitting side by side.
Intelligibility “How easily a sound especially speech is understood.
Intensity The loudness of sound; related to the amplitude of the sound vibration.
Internal Auditory Meatus The hole in bone through which the nerves exit the cochlea on their way to the brainstem.
Inverted Phase Feedback Canceller A more advanced form of phase cancellation with improved performance.
Kilohertz (kHz). Thousands of hertz (cycles per second of vibration). A measure of the frequency of sound.
Labyrinth Organ of balance located in the inner ear. The labyrinth consists of three semicircular canals and the vestibule.
Labyrinthitis “Viral or bacterial infection or inflammation of the inner ear that can cause dizziness loss of balance and temporary hearing loss.
Lateral Lemniscus “Nucleus of the auditory system located after superior olive but prior to inferior colliculus.
Lateralization The perception that sound is in one ear or the other when presented by headphones or via bone conduction. See also localization.
Levator Veli Palatini “Muscle of the nasopharynx one of those responsible for opening the Eustachian tube.
Listening Environment Another term for listening program.
Listening Program An individual memory program in a digital hearing aid with multiple memories accessed through a push button or remote control.
Localization “The ability of a person to determine the location of a sound source that is present in soundfield (somewhere out in the room). See also lateralization a related term meaning to perceive the sound in one ear or the other when presented by earphones or bone conduction.
Low Frequency “Sounds on the lower end of the speech frequency range. Perceived as low tones or bass vowels are generally low frequency.
Low Frequency Roll Off Algorithm Circuitry that reduces low frequency amplification when activated to reduce background noise.
Low Tone “Low frequency sounds such as vowels and hard consonants bass.
Malleus “One of the ossicles or bones of the middle ear. It is the first bone and is attached to the tympanic membrane and connected to the incus.
Manual Volume Control The wearer adjusts the volume setting.
Manubrium of the Malleus “Portion of the malleus that attaches to the tympanic membrane; the “”handle”” of the malleus.
Mastoid “The mastoid bone is located behind the ear (felt as a hard bump behind the ear). Inside it looks like a honeycomb with the spaces filled with air. These air cells are connected to the middle ear through an air filled cavity called the mastoid antrum.
Mastoid Air Cells “Openings in bone filled with air that are linked to the middle ear space. The opening between the middle ear and pneumaticized (air-filled) mastoid cells is the aditus.
Mastoid Bone Portion of the temporal bone that is located behind the pinna.
Mastoid Process The dome-shaped portion of the mastoid bone that is behind the pinna. It is the location for the placement of bone-conduction oscillators.
Medial Geniculate Body “Auditory nucleus located in the brainstem above the inferior colliculus. It is the last nucleus before the auditory signal reaches the cortex.
Medium The substance through which sound travels. Sound is often defined as the vibration of the molecules of a medium. Air is the most common medium.
Megahertz (Mhz) 1 million hertz.
Memory (Memories) The area within the digital circuit that stores the information programmed for your hearing loss. Some hearing aids have more than one memory. The additional memories are programmed for specific situations such as noise or telephone use.
Memory Change Indicator A beep signal that is given to let the wearer know when the have pushed their button and changed memories.
Menieres Disease “Affects the membranous inner ear and is characterized by deafness dizziness (vertigo) and ringing in the ear (tinnitus).
Microphone “Device that is set into vibration by sound waves and will convert the sound energy into an electrical signal that represents the frequency and amplitude of the sound striking the microphoneås diaphragm (thin metal sheet that picks up the vibrations).
Middle Ear The air-filled hole in bone containing the ossicles and the tendons of the two muscles of the middle ear. Some people classify the tympanic membrane as being a part of the middle ear.
Mild Hearing Loss (20 -40 decibels) Where the softest sound perceptible at any frequency tested falls between 20 and 40 decibels.
Mini Canal Hearing Aid Style of hearing aid slightly larger than a CIC and smaller than an ITC.
Mixed Hearing Loss “A mixed hearing loss is a combination of a conductive and a sensorineural hearing loss. Hearing aids can be beneficial for persons with a mixed hearing loss but caution should be exercised.
Moderate Hearing Loss (40-60 decibels) Where the softest sound perceptible at any frequency tested falls between 40 and 60 decibels.
Modiolus The center core of the cochlea. The first-order neurons (VIII nerve) runs through modiolus before exiting via the internal auditory meatus.
Molecule “Smallest particle of a chemical element. Hydrogen nitrogen and oxygen are examples of molecules. Molecules are comprised of protons electrons and neutrons.
Mucous Membranes “Type of lining of the middle ear and nasopharynx. It secretes mucus a secretion of water salts skin tissue cells white blood cells and a protein called mucin.
Multi-Band Adaptive Directional Microphones Directional microphone systems that are capable of suppressing more than one sound source at a time in different frequencies.
Myelin “A fatty material that covers portions of some neurons’ axons. Myelin insulates nerves from each other and permits rapid transmission of neural impulses as neural signals (action potentials) “”skip”” across myelin sheathes jumping from one node of Ranvier to the next.
Nanoscience Studying and working with matter on an ultra small scale.
Node of Ranvier “Unmyelinated segments of axons between the myelin sheathes that cover the axon. The action potential is conducted from one node to the next allowing for a faster depolarization wave than would occur in the neuron were not myelinated.
Noise Sound perceived as unwanted.
Noise Induced Hearing Loss “Hearing loss caused by exposure to very loud sounds either very loud impulse sound(s) or repeated exposure to sounds over 90-decibel level over an extended period of time that damage the sensitive structures of the inner ear.
Noise Reduction Reducing the perception of noise.
Occlusion “The occlusion effect occurs when a hearing aid completely fills the outer part of the ear canal. It can cause the wearer’s voice to sound funny. Many people complain that they sound hollow or it’s like they are talking into a barrel. Chewing food can also sound odd and even cause discomfort to someone with occluded canals. Normally when people talk or chew the produced sound vibrations escape through the unblocked ear and little is heard. But when the ear is blocked by a hearing aid the vibrations cannot escape and are instead bounced back down to the eardrum which produces the louder hollow sound. Open Fit hearing aids are an answer to this problem as they do not occlude the canal. The in ear section of the aid is not molded to fit tightly in the way that other types of hearing aids are.
Omnidirectional Type of microphone that picks up sound from all around.
On-The-Ear (OTE) Or Open Ear Hearing Aid A more recently developed style of a BTE hearing aid that utilizes a thinner tubing and a placement of the electronics lower down behind the ear for better cosmetic appeal with less occlusion.
Open Ear Acoustics Method of fitting hearing aids so that the ear canal is left as open as possible.
Open Ear Hearing Aid “A hearing aid designed to fit over the ear with a thin tube or wire running into the ear and a small soft plastic tip. The tip has holes to keep from blocking the ear canal so that the user does not feel plugged. Open Ear hearing aids are primarily used for high frequency hearing loss.
Organ of Corti “The collection of cells sitting on basilar membrane that permit the sound waves to become coded as nerve impulses. The organ of Corti includes inner and outer hair cells the supporting cells including the arch of Corti the tectorial membrane and spiral limbus.
Osseous Spiral Lamina A ridge of bone projecting from the core of the cochlea (modiolus) inward towards basilar membrane.
Otolaryngologist “Physician who specializes in the medical disorders of the ears nose and throat also called an ENT physician.
Otologist “A medical doctors who has undergone extensive post medical school study and training to specialize in diagnosis treatment and surgery of the human ear.
Otosclerosis “Abnormal growth of bone around the ossicles and the inner ear. This bone prevents structures within the ear from working properly and causes hearing loss. For some people with otosclerosis the hearing loss may become severe but often the hearing can be improved by surgery or hearing aids.
Otoscope A magnifying and lighting tool utilized by health care workers to look into the ear canal.
Outer Ear Section of the ear that includes the pinna and external auditory meatus.
Outer Hair Cells “The cells within the organ of Corti that are responsible for increasing the amount of basilar membrane movement when soft sounds are present. These ciliated cells are located on the radial side of the arch of Corti and are found spiraling the length of the cochlea. Three to five outer hair cells sit side-by-side when viewing a cross section of the cochla. The cilia of the outer hair cells are embedded in tectorial membrane.
Oval Window Membrane-covered opening between the middle ear and scala vestibuli of the inner ear. Stapes footplate sits in oval window.
Pars Flaccida “The portion of the tympanic membrane that does not contain a fibrous middle layer but only has the skin and mucous membrane layers. It is located at the top of the tympanic membrane.
Pars Tensa Portion of the tympani membrane that contains the fibrous middle layer and comprises most of the area of the tympanic membrane. See also pars flaccida.
Perilymph The inner ear fluid found in scala vestibuli and scala tympani. This fluid is high in sodium and relatively low in potassium.
Period The time required for one complete cycle of vibration to occur.
Phase Describes the amount of compression or rarefaction of a sound. Sounds at 90 degrees phase are at maximal compression; those at 270 degrees phase are maximally rarefied. Phase cycles from 0 to 360 degrees.
Phase Cancellation Cancellation of sound by creating a sound exactly opposite.
Physics The study of the physical properties of matter and energy. Acoustics is a branch of physics that studies how sound vibration occurs.
Physiology “The study of the function of the body that is how things work.
Pinna Synonym for the auricle. Portion of the external ear that gathers sound waves and funnels them to the external auditory meatus.
Presbycusis Loss of hearing that gradually occurs because of changes in the inner or middle ear in individuals as they grow older. The type of hearing loss often associated with presbycusis is a sensorineural hearing loss.
Processing Power How fast a processor works.
Processor The part of a digital chip where information is interpreted and changed based on the instructions that have been programmed into the processor.
Profound Hearing Loss (over 80 Decibels) Where the softest sound perceptible at any frequency tested falls at 80 decibels or worse.
Program Refers to a set of instructions given to the processor.
Programmable Telecoil A telecoil that is connected to one of the memory slots of a hearing aid and can be programmed to the users needs apart from the other memories.
Programming Creating and sending the program to the processor.
Progressive Hearing Loss A hearing loss that becomes progressively worse over time.
PROM (Programmable Read-Only Memory) The memory portion of the hearing aid in which programming information is stored.
Pure Tone A sound that has only one frequency. It occurs when an object is vibrating in simple harmonic motion. See also tutorial on acoustics review.
Rarefaction The portion of a sound wave where the air molecules are most spread apart and have the lowest pressure. See also the tutorial on acoustic review.
Receiver The speaker of the hearing aid.
Reissner’s Membrane The membrane separating scala media and scala vestibuli in the cochlea.
Resonance “Enhancement of sound at a certain frequency because of the characteristics of the vibrating object or tube. Cavities of different lengths resonate or accentuate sound vibration at certain frequencies. Objects will vibrate best at a given frequency or frequency range depending upon the mass and stiffness of the object.
Reverberation Sound being reflected off of a surface.
Round Window Membrane-covered opening between the scala tympani of the inner ear and the middle ear.
Saccule “Located in the vestibule of the inner ear this structure along with the utricle sense “”straight line’ head motion.
Sampling Rate The rate at which incoming analog sounds are taken and converted to digital form.
Scala Media “The middle section of the cochlea which contains endolymph. Basilar membrane is at the bottom of scala media; Reissner’s membrane is at its top.
Scala Tympani “The section of the cochlea that is below basilar membrane and contains perilymph. If a cross section of one coil of the cochlea is examined scala tympani will be on the bottom.
Scala Vestibuli “The section of the cochlea that is above Reissner’s membrane and contains perilymph. If a cross section of one coil of the cochlea is examined scala vestibuli will be on the top.
Semicircular Canals The 3 channels in the vestibular section of the inner ear that permit neural encoding of head rotation.
Sensorineural Hearing Loss Hearing loss caused by damage to the sensory cells and/or nerve fibers of the inner ear. The most common type of hearing loss in adulthood.
Severe Hearing Loss Where the softest sound perceptible at any frequency tested falls between 60 and 80 decibels.
Shell The outer portion of the hearing aid that is custom formed to fit the ear.
Shrapnell’s Membrane A synonym for pars flaccida.
Simple Harmonic Motion “The vibration back and forth of an object or air molecules that results in a clean single tone a “”pure tone””. See also tutorial on acoustics review.
Soma The body of a nerve cell.
Sound Waves Sound is made up of molecules of air that move and when they push together the form waves.
Speech Understanding “Also called discrimination refers to the ability to understand speech when amplified to a comfortable level.
Speech-Language Pathologist Health care professional who assess speech and language development and treats language and speech disorders.
Spiral Limbus “A part of the organ of Corti that is one point of attachment for tectorial membrane. It is composed of periosteum the type of tissue that covers bone and is located on top of the bony ridge called osseous spiral lamina.
Stable Hearing Loss A hearing loss that has not changed for several years.
Stapedius A muscle residing in the pyramidal eminence on the posterior wall of the middle ear space whose tendon is attached to the neck of the stapes. Contraction of the stapedial muscle (e.g. in response to loud sound) increases the stiffness of the middle ear system and reduces the transmission of low-frequency sound through the middle ear.
Stapes “One of the ossicles or bones of the middle ear. It is the last bone located after the incus. The footplate of the stapes is attached to the oval window of the inner ear.
Stria Vascularis “A lining of the radial wall of scala media containing a rich network of vascularized tissue (containing networks of small veins and arteries). Endolymph is produced and nourished by stria vascularis.
Sudden Hearing Loss A hearing loss that occurs with a rapid onset requiring immediate medical treatment.
Superior Olivary Complex “A nucleus in the auditory central nervous system located just after cochlear nucleus and prior to lateral lemniscus.
Symmetrical Hearing Loss Hearing loss that is the same or very similar in both ears.
Tectorial Membrane A gelatinous tissue mass that is located above the hair cells. The cilia of the outer hair cells imbeds in tectorial membrane.
Telecoil Device in a hearing aid that can connect with the magnetic coils of a telephone and transgfer the sound through the hearing aid without feedback.
Temporomandibular Joint “(TMJ) The hinge joint for the jaw.
Tensor Tympani “A muscle residing in the semicanal of tensor tympani on the medial wall of the middle ear space whose tendon is attached to the malleus. Contraction of the tensor tympani muscle would move tympanic membrane inward and decrease the vibration of the TM by increasing the stiffness of the middle ear system. However in humans this muscle does not appear to contract in response to loud sounds.
Tensor Veli Palatini “Muscle of the nasopharynx one of those responsible for opening the Eustachian tube.
Tinnitus “The perception of sound in the head when no external sound is present. In addition to ringing head noises have been described as hissing roaring pulsing whooshing chirping whistling and clicking. The ringing or other sounds can be perceived in one or both ears as occurring inside or outside the ear.
Tone The perceived frequency of a note or sound.
Tonotopic Organization The property of a structure to be organized such that different locations within the structure respond to or encode different frequencies. (There is a different place within the structure for each frequency.)
Tragus The skin covered appendage in front of the pinna. The tragus can be pushed inward to cover the entrance of the ear canal.
Trapezoid Body “Nerve fiber pathway in the lower brainstem that decussates from one hemisphere to the other. The trapezoid body contains a nucleus called the nucleus of the trapezoid body.
Traveling Wave “An undulating up and down motion of basilar membrane in response to sound that increases in amplitude relatively gradually until it reaches a maximum displacement point and then decreases in amplitude rapidly just apical to that point of maximum vibration.
Tuning Fork Hand-held device that produces tones that are essentially pure tones. Tuning forks of different sizes produce different frequency tones.
Tunnel of Corti Space beneath the arch of Corti.
Tympanic Membrane “Also called the eardrum colloquially this membrane separates the outer and middle ear.
Umbo “The center-most point of the tympanic membrane and the point at which the tympanic membrane is most medially displaced. The manubrium of the malleus is attached at the umbo and its medial pull creates the cone shape of the eardrum.
Unilateral Hearing Loss Hearing loss in only one ear.
Utricle “Located in the vestibule of the inner ear this structure along with the saccule sense “”straight line”” head motion.
Vent An air channel in the hearing aid or earmold to alleviate pressure and reduce low frequency amplification.
Vertigo “Vertigo refers to a very distinct sensation that is similar to the feeling of spinning or motion that leads to dizziness. Vertigo is not lightheadedness or the dizziness associated with low blood pressure. Vertigo is more about the sensation of moving while the body is standing still. People with vertigo may feel as though they are moving or spinning or that the environment is actually moving or spinning and this sensation leads to dizziness. When there is a problem within the inner ear or the vestibular which connects the part of the inner ear that controls balance to the brainstem it is called peripheral vertigo.
Vestibular The medical term for all of the parts of the inner ear involved with balance is the Vestibular System.
Vestibular System Portion of the inner ear responsible for encoding information about head movement and head position.
Vestibule Portion of the inner ear that is between the cochlea and the semicircular canals. Oval window is located in the vestibule.
VIII nerve “Also called the acoustic nerve or more correctly the vestibulo-acoustic nerve. It conveys information from the cochlea utricle saccule and semicircular canals to the brainstem.
Voice Priority Processing “Processing strategy that combines adaptive directional microphones noise management and compression to provide maximum speech understanding and comfort.
Volume Control Component of the hearing aid that turns the volume up or down.
Warp Processing A type of digital processing that improves execution time and energy consumption.
Warranty The period of time for which a hearing is covered for repairs and/or loss and damage.
Wavelength “When a pure tone is produced the sound radiates outward. As it does different areas (of air) are in rarefaction and compression. Wavelength is the physical distance generally measured in feet between areas where the sound wave is in the same phase of vibration. For example if air molecules are in maximal compression at one place and then are rarefied one foot later then maximally compressed again two feet away from that original compression place then the wavelength is 2 feet. Wavelength is related to frequency and computed by dividing the speed of sound by the frequency.
Wide Dynamic Range Compression (WDRC) Hearing aid processing type that works to keep soft sounds audible and loud sounds comfortable.
Wind Noise Manager Device within a digital processor that reduces the sound of wind noise on the microphone.