Audiology-Modules 1-15
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Maggieandbrowbrow on May 23, 2011
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404 terms
Terms | Definitions |
|---|---|
 List the parts of the outer ear | Auricle (pinna), Top to Bottom-Helix, Scaphoid Fossa, Triangular Fossa, Antihelix, Crus of Helix, Cymba Concha, Cavum Concha, Tragus, Antitragus, Interagal Notch, Helix, and Lobe |
| What is the main function of the outer ear? What is another function of the outer ear? | Collects acoustic energy and enhances some frequencies |
| List the parts of the middle ear. | Medial TM Ossicles (ossicular chain-Malleus (hammer), Incus (anvil), Stapes (stirrup) Muscles:Stapedius, Tensor Tympani, Eustachain Tube Nerves:Cranial Nerve V (Trigeminal), Cranial Nerve VII (Facial) |
| What is the main function of the middle ear? | Transforms acoustic energy into mechanical energy; transfers mechanical energy, through oval window, to inner ear |
| How does the middle ear receive fresh air? | Normally the human Eustachian tube is closed, but it can open to let a small amount of air through to prevent damage by equalizing pressure between the middle ear and the atmosphere. |
| Name the parts of the inner ear. | Organ of Hearing: Cochlea Vestibular System (part of balance system): Semicircular Canals, Ampulla, and Saccule |
| What is the main function of the inner ear? | Transforms mechanical energy to hydraulic energy; then hydraulic energy into electrical energy. Inner ear also begins coding auditory and converts waves into messages which travel to the stem (base) of the brain via the auditory nerve |
| Explain which part of the cochlea is best tuned to respond to low frequencies? To high frequencies? | Hair Cells and neurons at apex tuned to lower frequencies Hair Cells and neurons at base tuned to high frequencies; |
| Explain how the auditory system transforms acoustic energy into other forms of energy. | Sound enters the ear canal as acoustic energy, hits the TM and the ossicles which transform the acoustic energy into mechanical energy. The stapes pushes the oval window, which pushes the fluid in the cochlea, transforming the energy from mechanical to hydraulic energy. The movement of the fluid in the cochlea causes the cilia of the hair cells to bend. When the cilia bend, there is an exchange between intracellular and extracellular sodium and potassium ions. This ion exchange starts the reaction for neurotransmitter release into the synaptic cleft or space, the space between the base of the hair cell and the VIIIth nerve ending, causing a conversion from hydraulic energy to electrical energy. The nerve fibers carry the information as an electrical impulse up through the medulla, midbrain, thalamus, and to the auditory cortex. The fibers take the information from each part of the cochlea that was stimulated depending on: the frequency components of the original acoustic signal (from 20 20,000 Hertz) The decibel level of the signal The timing components of the original sound (short sound, long sound, one syllable, multisyllabic, etc. |
| Explain the terms "afferent" and "efferent" | Efferent fibers take messages from the brain to the peripheral nervous system. They are almost always motor fibers. Afferent fibers take messages from the periphery back to the brain. They are almost always sensory fibers. |
| Explain the central auditory pathways. | Central Auditory Pathways: Brainstem, Medulla, Pons, Midbrain, Thalamus, Cortex, Temporal lobes |
| List common disorders that affect the outer ear | ... |
| The auditory system transforms... | energy as sound travels through the system |
| The auditory system transforms energy from: ... | Acoustic to mechanical to hydraulic to electrical, The outer ear collects acoustic energy then transfers acoustic energy to the middle ear, which receives acoustic energy then transfers mechanical energy to the inner ear, which receives mechanical energy then transforms it to hydraulic then electrical eneergy |
| The Pinna or the Auricle is made up of... and enhances frequencies about... | Skin & cartilage; 4500 Hz /~3 dB |
| The auditory meatus or canal (ear canal) is made up of... is approximately...long, has ...on the outer 1/3, and enhances frequencies... | skin, 1 inch long, tiny hairs, 2500 Hz by 10-12 dB |
| Yellowish-brown ... is produced in the lateral third of the canal. | cerumen (wax) |
| The eardrum is also referred to as the... | tympanic membrane (TM) |
| The Tympanic Membrane is... | Conical; typically thin, shiny, and pearly-white to light gray |
| Sound waves vibrate the... and it transfers these waves to the... | TM; Ossicles |
| The outer ear (auricle or pinna) collects ... energy and transfers ... energy | acoustic and acoustic |
| The middle ear transfers ... energy into ... energy and then transfers ... energy through the ... to the ... | acoustic, mechanical, mechanical, oval window, inner ear |
| The Middle Ear increases sound by approximately ... of the ... DB that are lost from air to fluid. | 27, 30 |
| The ... connects the Middle Ear with the... | Eustachian tube (ET), nasopahrynx |
| 2 Muscles associated with the eustachian tube are the ... and the ... | tensor veli palatini and levator veli palatini |
| The eustachian tube ... the middle ear space pronounced ..., it also maintains ... in the middle ear space equal to ..., and drains ... from the middle ear | Aerates (ventilates), 'air-rates', pressure, atmospheric pressure, secretions |
| The eustachian tube in children up to approximately 5 years of age is more ... than it is in adults, causing more ... in children than adults. | horizontal, ear infections due to fluid build up |
| Micrognathia is ... | Abnormal smallness of the jaws, especially of the mandible, and can be one cause of abnormal alignment of the teeth. |
| Micrognathia may be the only ... and can be caused by certain ... and ... | abnormality in a child, certain inherited disorders, syndromes. |
| Syndromes that may include Micrognathia are: | Cri du chat (small jaw and cry sounds like a cat), turner syndrome (developmental and lacking x chromosome), and Pierre Robin syndrome, which also is related to small jaw issues. |
| Why would micrognathia cause middle ear problems? | The Eustachian tube connects to the pharynx, which is affected by various motor movements of the mouth and jaw. If one has an abnormal sized jaw or is underdeveloped this may affect the motor movements of the mouth as well as placement of the eustachian tube or its vulnerability causing problems in the inner ear. |
| Cochlea's Auditory Process | Not quite 3 spiral turns Base connects with stapes via oval window Bony Labyrinth Membranous Labyrinth Organ of Corti Hair Cells: Outer and Inner When cilia bend chemical reaction starts Transduces hydraulic energy to electrical energy via CN VIII Hair Cells and neurons at base tuned to high frequencies; Hair Cells and neurons at apex tuned to lower frequencies |
| If there is hair cell damage what happens to the information that is transmitted? | ... |
| Inner Hair Cells are in a ..., there are a total of approximately ..., and they are mostly innervated by ... | Single Row, 3500 cells, afferent fibers |
| Outer Hair Cells are in ..., there are a total of approximately ..., and they are mostly innervated by ... | 3 Rows, 13,000 cells, efferent nerve fibers |
| The OHC serve mostly to ... | fine tune the information that the IHC have received and transmitted. For example, when a sound is very soft, the brain sends a signal back to the cochlea, to the OHC telling them to increase the gain or "volume" of those soft sounds. |
| The cochlear hair cells and their nerve endings respond best to certain frequencies, depending on where along the cochlear the cells/nerve endings are located. This is known as ... | tonotopic organization. |
| This ... organization remains the same throughout the structures of the central nervous system. | tonotopic |
| In order for that information to reach the language center in the left hemisphere, it has to be transmitted via the ... | commissure and c__________________________, which are the fibers that connect the right and left hemispheres to each other. |
| Process of Ascending or afferent pathways: | Superior Olivary Complex connects with CN VII to send efferent innervation to stapedius muscle when loud sound are present Pathways continue to lateral lemniscus in pons To inferior colliculus in midbrain To medidal geniculate body in thalamus Fanning out into auditory radiations to temporal lobes Inputs from both ears represented in both hemispheres Language information decoded in left hemisphere |
| Decussate | cross or intersect so as to form a cross-this nerve... with another |
| To hear sound, your ear has to do three basic things: | Direct the sound waves into the hearing part of the ear Sense the fluctuations in air pressure Translate these fluctuations into an electrical signal that your brain can understand |
| Explain how sound occurs. | An object produces sound when it vibrates in matter. This could be a solid, such as earth; a liquid, such as water; or a gas, such as air. Most of the time, we hear sounds traveling through the air in our atmosphere. When something vibrates in the atmosphere, it moves the air particles around it. Those air particles in turn move the air particles around them, carrying the pulse of the vibration through the air. |
| Explain compressions. | When you hit a bell, the metal vibrates -- flexes in and out. When it flexes out on one side, it pushes on the surrounding air particles on that side. These air particles then collide with the particles in front of them, which collide with the particles in front of them, and so on. |
| Explain rarefractions. | When the bell flexes away, it pulls in on the surrounding air particles. This creates a drop in pressure, which pulls in more surrounding air particles, creating another drop in pressure, which pulls in particles even farther out. |
| Explain frequencies. | A vibrating object sends a wave of pressure fluctuation through the atmosphere. We hear different sounds from different vibrating objects because of variations in the sound wave frequency. |
| Explain high wave frequencies. | air pressure fluctuation switches back and forth more quickly. We hear this as a higher pitch. |
| Explain low wave frequencies. | air pressure has fewer fluctuations in a period of time, the pitch is lower. The level of air pressure in each fluctuation, the wave's amplitude, determines how loud the sound is. |
| The tympanic membrane is positioned between the ear canal and the | middle ear |
| The middle ear is connected to the throat via the ... | eustachian tube |
| Explain the equal pressure allowing the eardrum to freely move back and forth | since the ear canal receives air from the outer ear and from the mouth, which connects to the eustachian tube which then connects to the middle ear |
| The tensor tympanic muscle serves as... | a diaphragm to the tympanic membrane pulling it inward and taut if needed |
| The Cochlea in the inner ear conducts sound through... instead of through... | fluid, air. |
| Explain the amplification process allowing air to be transferred to enough inertia to move fluid via the ossicles group (malleus, incus and stapes). | At the other end of the stapes -- its faceplate -- rests against the cochlea, through the oval window. When air-pressure compression pushes in on the eardrum, the ossicles move so that the faceplate of the stapes pushes in on the cochlear fluid. When air-pressure rarefaction pulls out on the eardrum, the ossicles move so that the faceplate of the stapes pulls in on the fluid. Essentially, the stapes acts as a piston, creating waves in the inner-ear fluid to represent the air-pressure fluctuations of the sound wave. |
| Describe the inertia of fluid vs. air. | is fluid has a much higher inertia than air -- that is, it is harder to move (think of pushing air versus pushing water). The small force felt at the eardrum is not strong enough to move this fluid. Before the sound passes on to the inner ear, the total pressure (force per unit of area) must be amplified. |
| Amplification of force by the ossicles occurs in two ways: | pressure from eardrum to the stapes, which travels from a larger space to a smaller space creating build-up of pressure as it goes from a larger space to a smaller one, when the malleus hits from a greater distance since it is larger, it hits the incus, which is smaller and therefore hits with greater force to the stapes. This force is great enough to transfer to the inner ear and to translate into nerve impulses to hit the brain |
| The cochlea's job is to take the physical vibrations caused by the sound wave and ... | translate them into electrical information the brain can recognize as distinct sound. |
| When the hair cells in the cochlea are moved ... | they send an electrical impulse through the cochlear nerve. The cochlear nerve sends these impulses on to the cerebral cortex, where the brain interprets them. The brain determines the pitch of the sound based on the position of the cells sending electrical impulses. Louder sounds release more energy at the resonant point along the membrane and so move a greater number of hair cells in that area. The brain knows a sound is louder because more hair cells are activated in an area. |
| Conductive Hearing Loss occurs... | when sound vibrations from the tympanic membrane to the inner ear are blocked. This may be caused by ear wax in the auditory canal, fluid buildup in the middle ear, ear infections or abnormal bone growth. |
| Sensorineural Hearing Loss occurs ... | occurs when there is damage to the vestibulocochlear (auditory) nerve. This type of hearing loss may be caused by head injury, birth defects, high blood pressure or stroke. |
| Tinnitus-people with tinnitus hear ... | a ringing or roaring sound. The cause of this ringing cannot always be found. Some cases of tinnitus are caused by ear wax, ear infections or a reaction to antibiotics, but there are many other possible causes of this disorder. |
| Prebycusis occurs ... | because of changes in the inner ear. This is a very common type of hearing loss that happens gradually in older age. |
| Describe how waves create sound | Hearing is all about a wave in the air pushing on the inside of the ear, specifically, on the ear drum. When a series of these waves pushes on the ear drum, a tone is heard. The number of times per second that a wave pushes on the ear drum is called the frequency of the sound. The frequency of a sound is measured in "hertz," abbreviated Hz. |
| Humans can hear frequencies between ... and ... Hz. | 20 and 20,000 |
| The audiometric speech frequencies (meaning the frequencies that are important for speech understanding) are | 500, 1000, 2000, & 4000 Hz. |
| Of the four audiometric speech frequencies, the most important ones for speech understanding are | 1000, 2000, & 4000 Hz |
| during a hearing screening, the frequencies tested are | 1000, 2000, & 4000 Hz. |
| During an audiological evaluation, typically, frequencies between ... are tested | 250-8000 Hz |
| Acoustics | the branch of physics that studies the physical characteristics or properties of sound |
| Decibel | the unit in which sound intensity or pressure is measured |
| Psychoacoustics, a branch of psychophysics | studies the psychological response to acoustical stimuli, i.e. the psychological correlates to the physical properties of sound (e.g.., frequency and pitch do not refer to the same concept and are not identical) |
| Psychophysics | is a branch of psychology that studies the relationships between physical stimuli and their psychological correlates. This science deals with quantifying our perceptions |
| Sound | Is a disturbance or vibration of molecules that propagates or transmits through an elastic medium such as air |
| Describe how sound works | A source of energy creates a disturbance or vibration The propagation occurs in the form of waves The propagation occurs in a medium The medium needs elasticity for the molecules to be able to move. (Different media transmit sound differently depending on the molecules from which the medium is composed (air, water, wood, metal, etc.). We are interested in how sounds travels through air). |
| Constituents of Sound (essential part or component) | Sound produces pressure waves, The vibrating source creates a disturbance and moves air molecules, A medium (e.g.., air, water) transmits the disturbance, If the disturbance is audible, there is sound. Sound is a pressure disturbance of particles in a medium Sound has physical characteristics as well as psychological correlates of those physical characteristics |
| Propagation of sound through air (spreading of sound) | the vibration of a tuning fork displaces air molecules/particles, These particles in turn displace adjacent particles . . . that displace adjacent particles, When a molecule vibrates, it moves from its original position, then touches its neighbor causing neighboring molecules to move also, then returns to its original position. Once disturbed, each particle continues to vibrate with the same frequency as the tuning fork |
| Rarefaction or rarified | When molecules are spread apart |
| Sound/Waves occur when | the succession of molecules being pushed together and then pulled apart |
| Compression or condensation | when molecules are pushed together (occurs first then rarefaction) |
| Sound waves can be | Simple or complex |
| Simple sound waves | one frequency only: a pure tone, tuning fork |
| Complex sound waves | multiple frequencies: all other sounds, including speech |
| Lis the 5 properties of sound/ waves | duration, amplitude intensity/pressure, frequency, phase, and quality=timbre |
| How is the duration of sound measured? | time units; sound occurs over time ,seconds (s), and milliseconds (ms) |
| How is the amplitude intensity/pressure of sound measured? | decibels |
| How is the frequency of sound measured? | cycles per second Hertz (Hz) |
| How is the phase of sound measured? | the time aspect of a wave, degrees e.g., 90 or 180 |
| Measurement of waves are calculated according to ... | period: number of seconds or milliseconds per cycle velocity: speed in a certain direction wavelength: distance in space occupied by one cycle:= velocity / frequency |
| Pure tones result from ... | simple harmonic motion (SHM) |
| A pure tone is a ... | simple harmonic motion |
| periodic | the pattern of vibration repeats itself |
| Constant | each cycle takes the same amount of time |
| Whenever the source of a wave's motion is a periodic motion, such as the motion of your hand moving up and down repeatedly, a ... is produced | periodic wave |
| A wave whose source vibrates with simple harmonic motion is called a | sine wave |
| Our vocal folds vibrate, depending on the age and sex of the person, at rates between ... and ... times per second =Hertz=Hz | 120, 265 |
| List characteristics of a sinusoidal waveform in regards to amplitude, frequency, wavelength, phase, and duration | ... |
| Amplitude, a physical characteristic of sound is | the maximum displacement of particles in a medium |
| List characteristics of amplitude | initially depends on the amount of force to start the movement and when it decreases over time, energy is lost and this is called "damping" |
| Resonant frequency | Every object or cavity has a frequency at which it vibrates the best, e.g.., when you strike a table, a pillow, a bottle, each sounds differently |
| shorter objects tend to vibrate at ... frequencies | higher |
| Longer objects tend to vibrate at ... frequencies | lower |
| The decibel (dB) is the unit used to measure the | intensity of a sound. |
| On the dB scale, the smallest audible sound (near total silence) is ... | 0 dB |
| List the dB for each of these sounds: a whisper, normal conversation, a lawnmower, car horn, rock concert or jet engine, gunshot or firecracker | 15 dB, 60 dB, 90 dB, 110 dB, 120 dB, 140 dB |
| Describe sound waves and their common attributes and express the way these characteristics are measured. | ... |
| State the difference between physical acoustics and psychoacoutics. | ... |
| Elasticity, or springiness, of any molecule is increased as the distance between the molecules is ... | decreased example-molecules in a solid have the most elasticity, then molecules in a liquid followed by those in gas. |
| Brownian motion | the random and rapid movement of air particles. it is also affected by the heat in the environment. As the heat is increased, the particle velocity is increased. |
| Vibrations | whenever air molecules are disturbed, they are set into ... moving from the point of disturbance, striking and bouncing off adjacent molecules. |
| List 3 kinds of waves | transverse, longitudinal, and sine |
| transverse waves | a wave in which the motion of the molecules of the medium is perpendicular to the direction of the wave (water) |
| Longitudinal Waves | a wave in which the particles of the medium move along the same axis as the wave (wheat blowing in the wind) |
| sine/sinusoidal waves | the waveform of a pure tone showing simple harmonic motion (bucket of paint hanging from a string)-compression is usu shown by curve upward and rarefaction is usu shown by the curve downward |
| Cycle | consisting of a compression and rarefaction |
| Frequency | the number of cycles that occur in one second, if two are completed in one second then the frequency is two cycles per second (cps) |
| Oscillation | a body moving back and forth beginning at any point on the wave and ending at the identical point of the next wave. |
| Pure tone | when a body oscillates sinusoidally showing only one frequency of vibration (oscillation) with no tones superimposed |
| Cosine Wave | when a wave begins at 90 degrees rather than 0 degrees |
| Period is | time (in seconds or milliseconds) to complete a cycle |
| Frequency is | measured in cycles per second = Hertz = Hz |
| If frequency=20 Hz (20 cycles per second), then: period = | 1/20th of a second |
| period = | 1/frequency |
| frequency (f) | 1/period |
| (f) = | frequency |
| (l) = | wavelegth |
| Wavelength represents the | length of the disturbance a wave creates in a medium |
| Sound velocity in air is ... | slower than in most media, independent of sound pressure and particle velocity, and varies a little with air conditions (e.g.., temperature), but is usually treated as a constant : |
| 344 meters / second = 1130 feet / second | 1130 feet / second |
| If frequency = 200 Hz: then (l)= speed of sound(344)/(f) | 344(sos)/200(f) = 1.72 meters |
| How do you calculate the distance of a storm from you? | Count the number of seconds between the time you see lightning until you hear thunder. Divide the number of seconds by 5 to calculate the distance in miles (or divide by 3 for kilometers). In other words if you counted 18 seconds from when you saw the lightning, the strike was 3.6 miles (6 kilometers) from your location. |
| Sound travels through air at | 1100-1200 feet (or 330-350 meters) per second (depending on altitude, relative humidity, pressure, etc.), |
| The behavior of different wavelengths around our head is one of the cues our brain uses to help us locate the direction of a sound. This effect is called the ... | "head shadow effect" |
| Higher frequencies have ... wavelengths (l) and ... | shorter, tend to reflect off barriers, e., a person's head |
| Lower frequencies have ... wavelengths (l) and ... | longer, travel well through barriers, e.g.., walls |
| Acoustics | a category within physics that focuses on the studies of the physical characteristics or properties of sound. |
| pure tone | when a sound wave oscillates sinusoidally showing only one frequency of vibration with no tones superimposed |
| frequency | the number of cycles (compressions and rarefaction) that occur in one second |
| simple harmonic motion (SHM) | Produces a sound wave that has only one frequency, which is a pure tone. |
| elasticity | It is the force that allows an object to be restored to its original size, shape, form and location after being pulled apart. |
| acoustic resonator | a container filled with air that serves to filter applied frequencies (such as a guitar or other musical instruments) |
| decibel | is the system of measurement for sound that takes into account our perceptions as affected by amplitudes and intensity |
| intensity | is the amount of energy expended within a specific time period and that is required to create a particular output. |
| resonance | forced vibration in which an object is set into motion of vibration by another vibration |
| compression | When molecules are pushed together |
| rarefaction | when molecules are spread apart |
| sine wave | the waveform of a pure tone showing simple harmonic motion |
| amplitude | this is the maximum displacement of molecules in a particular medium (solid, liquid, gas) |
| damping | decrease in amplitude |
| reverberation | is created when a sound is made in an enclosed space causing an echo effect or sound reflection |
| complex tone | A sound with more than one frequency. |
| periodic | the complex sound vibration that repeats overtime |
| aperiodic | a complex sound vibration that varies randomly overtime |
| quasiperiodic | a complex sound vibration that repeats overtime with a component of unpredictability. |
| fundamental frequency | the lowest frequency of a periodic sound |
| harmonic frequency or harmonics | frequencies that are higher than the fundamental frequency of a periodic sound |
| cycle | the complete sequence of events of a single sine wave |
| cycles per second = | the number of cycles of vibration occurring in one second, equivalent to frequency |
| Hertz (Hz) | the number of cycles in a second and the unit of measurement of frequency |
| wavelength | distance covered by one complete cycle of a wave |
| speed of sound | ... |
| phase | relative timing of compressions and rarefactions of waves |
| Brownian Motion | the rapid and random of movement of particles as affected by heat in the air (think teakettle) |
| transverse waves | the molecules in motion run perpendicular to the direction of the wave motion (think up and down waves) |
| Waves are created by | a vibration which is made up of molecular movement in compressions and rarefactions |
| There are ... kinds of waves. List them | 4, longitudinal, transverse, cosine, and sine or sinuous |
| Longitudinal waves | the molecules in motion move along the same axis as the wave itself (think kids moving forward in a line-one moves after the other and one follows or a slinky) |
| Sine or sinuous waves | the molecules in motion move forward in compressions and rarefactions oscillating and coming back to the same point in each cycle (think standing on an escalator-you are still but it continues to move fw) |
| a wave that completes one rarefaction and compression, has completed one ... | cycle |
| The number of cycles a wave completes in a second is referred to as its ... | frequency |
| A sine wave is an example of a ... tone | pure |
| oscillation is also referred to as | one cycle of vibration |
| cosine wave | a wave that starts at a 90 degree angle rather than at 0 degrees |
| There are ... kinds of vibrations. List them. | 2, free and forced |
| Energy affects sound waves. list the two kinds of energy. | kinetic (the energy of a mass that results from its motion-moving energy--swing) and potential (energy resulting from a fixed and relative position-coiled spring waiting to burst) |
| Free vibrations are | when no outside force is added to perpetuate te vibration (swing-push once then stop pushing) |
| Forced vibrations are | When an outside force is added to a swinging motion that controls the vibration (think pushing the swing again and again) |
| Damping (light, heavy, and critical) damping occurs when | when the vibrations begin to decay gradually (light), rapidly (heavy) or before a cycle is completed (critical) overtime. |
| Frequency | a measure of units as cycles per second (cps), otherwise referred to Hertz (Hz). A sounds frequency is the number of cycles completed in a second. |
| Period | the duration (time during which something exists or lasts) of one cycle in a repeating event, so the period is the reciprocal of the frequency. Frequency is the number of occurrences of a repeating event per unit time (second). |
| List three things that have an effect on frequency | length (as length decreases, frequency increases-think hanging from a string), mass (as mass increases, frequency decreases) and stiffness (as compliance-adaptability-increases, frequency decreases-think hard rubber ball turning into playdoh) |
| Resonant frequency | each mass has a frequency at which it vibrates or is set to vibrate most naturally. This is its natural rate of vibration |
| Sound Velocity | the speed at which a sound wave travels from the source to another point |
| The velocity of sound in air is | 344 meters per second (or 330-350 meters per second) |
| Factors that influence velocity are | density of a medium (solid, liquid or gas) |
| A Sound's velocity occurs more quickly when molecules are ... | packed together more closely, therefore sound of velocity tends to move more quickly in solids than in liquids, and in liquids more so than in gas (think bursting out of confinement) |
| wavelength | the length of a wave is measured from any point of a sinusoid (any degree from 0-360) to the same point on the next cycle of the wave |
| phase | when an oscillation has a beginning at 0 (or 360) degrees it is with the standard (0 degrees) |
| Two aspects of phase are | interference (an additional frequency-if the same as the first it will reinforce it and increase the amplitude, if identical but out of phase they will cancel each other out=0 amplitude) and beats (changes in amplitude as a result of two tones of almost identical frequency meet). |
| Outside of lab conditions, there are usually more than two frequencies, so complete cancellation and complete reinforcement ... | rarely occur |
| two aspects of complex sounds include | fundamental frequency and harmonics |
| periodic | complex sounds that repeat over time (ticking of a clock) |
| aperiodic | complex sounds that vary randomly over time and do not have fundamental frequencies (lowest rate of a sound's vibration) |
| fundamental frequency | the lowest rate of a sounds vibration |
| harmonics | in a periodic complex sound these occur the sound of the fundamental frequency (lowest rate of a sounds vibration) |
| spectrum | graph with frequency on the horizontal axis and amplitude on the vertical axis |
| line spectrum represents | periodic sounds |
| a continuous spectrum represents | aperiodic sounds |
| formant | the peak in a waveform |
| fourier analysis | a mathematical procedure to identify the individual sinusoids in a complex sound |
| Intensity | how far a body vibrates |
| force | the impetus required to institute or alter the velocity of a body |
| because of the human ear's extreme sensitivity to sound, only very small amounts of ... are required to stimulate hearing | force |
| dyne (d) | unit of measurement for quantifying small changes in force |
| one dyne is a force sufficient to accelerate one mass of 1 gram of ... | 1 centimeter per second |
| Newton (N) 4 | has been used more recently as a measurement of force in the U.S. |
| Pressure | is generated whenever force is distributed over a surface area |
| pascals (Pa)5 | a unit of pressure |
| work | when any mass is moved this is done (force exerted times the distance the mass has moved) |
| erg (e) | the amount of work done |
| joule | 1 joule (j)6 is = 10 million ergs |
| Power | is the capacity to exert physical force or energy and is expressed as the rate at which energy is expended (ergs are used to measure power)-ergs per second |
| Intensity of a sound wave | the amount of force per unit of area |
| decibel (dB) | a unit for expressing the ratio between two sound pressures or two sound powers; deci= 10 so it is one-tenth of a unit=1/10th of a Bel |
| logarithm | a convenient way of expressing a ratio between two lengthy numbers |
| Bel | unit of measurement of intensity used in acoustics and audiometrics |
| 5 Important aspects of the decibel include: | involves ratio, utilizes logarithm, nonlinear, may be expressed in terms of various reference levels, which must be specified, and is a relative unit of measure |
| Logarithmic scale | a scale by which successive units increase by increasing amounts |
| ratio | the mathematical result of a quantity divided by another quantity of the same kind; often expressed as a fraction |
| exponent | a logarithm, or power to which a number may be raised (10 to the 3rd power=10x10x10) |
| Intensity level (IL) | an expression of the power of a sound per unit of area |
| watts | a unit of power |
| sound pressure level (SPL) | an expression of the pressure of a sound. |
| microbar | pressure equal to one millionth of standard atmospheric pressure |
| sound level meters | a device designed for measurement of the intensity of sound waves in the air. |
| hearing level | the lowest sound intensity that stimulates normal hearing is called zero ... |
| american national standards institute (ANSI) | an organization established to oversee the creation and use of guidelines that impact all centers of U.S. business. including acoustical devices and accreditation |
| International organization for standardization (ISO) | a worldwide consortium of 148 nations, based in geneva switzerland, whose mandate is to oversee and set guidelines for literally thousands of devices, including audiometers |
| sensation level (SL) | the number of decibels above the hearing threshold of a given subject for a given signal |
| threshold | the level at which a stimulus is barely perceptible greatest tolerable sound |
| pitch is determined by | frequency |
| loudness is determined by | intensity |
| quality is determined by | spectrum |
| pitch is measured using a | mel |
| loudness is measured using a | sone |
| loudness level is measured using a | phon |
| human hearing intensity range from the smallest to the largest sound we can detect. this is called ... | dynamic range |
| human hearing ranges from a ratio of | being the softest sound we can detect (e.g., (~fingertip brushing paper), 1 to 1,000,000,000,000 = the loudest sound we can detect (if it is higher than that, the sensation becomes a "tickle" or pain) |
| Every 10 decibel increase equals a ten-fold increase in intensity Examples include: | 10 dB is 10 times greater than 0 dB (1 zero) 20 dB is 100 times greater than 0 dB (2 zeroes) 30 dB is 1000 times greater than 0 dB (3 zeroes) 40 dB is 10,000 times greater than 0 dB (4 zeroes) 50 dB is 100,000 times greater than 0 dB (5 zeroes 100 dB is 10,000,000,000 times greater than 0 dB (10 zeroes) |
| Logarithms (base 10) express quantities in powers of ten = scientific notation) The logarithm of: 1 = 0 (because the number 1 has no zeros behind it) 10 = 1 100 = 2 | Question: The log 10 of 10,000 = ___4__ think 10x10x10x10 (4 zeroes = 10 times itself 4 times) |
| The logarithm of 0.1 = -1 0.01 = -2 | Question: The log 10 of 0.000000000001 = -12___ 12 numbers behind the decimal point = -12 |
| If a ratio of 100:1 = 20 dB then a | ratio of 10,000:1 = 40 dB notice the number of zeroes 4 so = 40 |
| psychoacoustics | studies the psychological response to acoustical stimuli, i.e. the psychological correlates to the physical properties of sound (e.g.., frequency and pitch do not refer to the same concept and are not identical; similarly, intensity and loudness are not identical either) |
| PHYSICAL attributes or properties of sound: | 1.Intensity, 2. Frequency, 3. Duration, & 4. Phase |
| intensity is measured in | dB and spl (sound pressure level) |
| frequency is measured in | Hertz Hz |
| examples of intensity | 0 - 120: dB range of audibility 130 dB: tickle >140 dB: pain Quiet classroom: ~45 dB |
| examples of frequency | Cats 50 - 65,000 Dogs 20 - 45,000 Bats 2000 - 110,000 Whales 1000 - 123,000 Mice 1000 - 91,000 HUMANS: 20 to 20,000 Hz |
| pitch | term used to describe the subjective impression of the highness or lowness of a sound and relates to frequency pitch rises as the frequency increases |
| mel | the subjective aspect of pitch can be measured using this unit |
| Loudness | is the subjective experience, as contrasted with the purely physical force of intensity |
| Loudness level is measured using what unit | phon or sone scale |
| duration is measured in ... and are | seconds, ms, μs Short/long: Which one easier to hear? How long does a stimulus have to be for the auditory system to perceive it? |
| Temporal integration | Is the effect that the auditory threshold changes with changes in the duration of a stimulus |
| How many phonemes per second occur in speech production? | Answer: 12-15 |
| in psychoacoustics intensity is related to ... and frequency is related to ... | loudness and pitch |
| binaural hearing | hearing with two ears |
| sound localization | being able to tell the direction of a sound source - very important survival skill) |
| Separation of Signal from Noise or selective auditory attention | Improved ability to attend to certain sounds in the presence of other background noise |
| The factors involved in sound localization, i.e., the acoustic cues the brain uses to help us locate the direction of a sound source are the four components of sound: | amplitude, phase, timing, frequency |
| free field | an area in which there are no hard surfaces (mountain top) to cause reverberation |
| Binaural summation | Binaural thresholds are 3-6 dB better than monaural versus thresholds. It takes less dB SPL for us to detect a sound when we listen with both ears at the same time compared to when we are listening with only one ear |
| timbre | ... |
| outer ear | comprises a shell-like protrusion from each side of the head, a canal through which sound travels and the eardrum membrane |
| eardrum membrane /tympanic membrane | located at the end of the outer ear canal through which sound travels |
| middle ear | consists of an air-filled space with a chain of tiny bones, the third of which is the stapes, the smallest in the human body |
| inner ear | contains the cochlea, which is filled with fluids and many microscopic components, all of which serve to concert waves into a message that travels to the stem (base) of the brain via the auditory nerve. |
| cochlea | filled with fluids and many microscopic components all of which serve to convert waves into a message that travels to the stem (base) of the brain via the auditory nerve. |
| auditory nerve | located at the end of the inner ear, receives messages then sends them to the stem (base of the brain) where they will be received, analyzed and transmit pulses along the auditory pathway. |
| attenuation | decrease in the strength of sound |
| Conductive portion of the ear consists of ... | the outer ear and middle ear |
| Sensorineural portion of the ear consists of ... | the inner ear and auditory nerve |
| Hearing by air conduction depends on the functioning of the ... | outer, middle, and inner ear, and of the neural pathways beyond |
| Hearing by bone conduction depends on the functioning of the ... | inner ear and beyond |
| Any sound that courses through the outer ear, middle ear, inner ear, and beyond is heard by ... | air conduction |
| It is possible to vibrate the skull mechanically and stimulate the inner ear directly creating ... by bypassing the ... | bone conduction, outer and middle ears |
| List the 4 kinds of hearing loss | conductive, sensorineural, mixed, and nonorganic |
| conductive Hearing loss | impaired air conduction (which is usually a blockage in the outer or middle ear) with normal bone conduction (goes straight to the sensorineural structures) |
| We test human hearing by two pathways. They are: | bone conduction and air conduction |
| Tuning forks | are not modern means for testing but they can test both the air and bone conduction pathways |
| Sensorineural hearing loss | formerly called perceptive loss or nerve loss, this term refers to loss of hearing sensitivity produced by damage or alteration of the sensory mechanism of the cochlea or he neural structures that lie beyond. |
| Mixed hearing loss | a sensorineural hearing loss with superimposed conductive hearing loss. The air conduction level shows the entire loss; the bone conduction level , |
| Nonorganic hearing loss | the exaggerated elevation of auditory thresholds (malingering-feigning or exaggerating loss for profit) Psychogenic-a hearing loss produced at the unconscious level as by anxiety |
| List the two types of nonorganic hearing loss | malingering, and psychogenic hearing loss |
| Schwabach test is a ... | tuning fork test that compares the bone-conduction sensitivity of the patient to that of a presumed normal hearing person---a hearing test made, with the opposite ear masked, placing the stems of vibrating tuning forks on the mastoid process first of the patient and then of the examiner. If heard longer by the patient it indicates conductive hearing loss and if heard longer by the examiner it indicates sensorineural hearing loss in the patient. |
| Rinne tuning fork test compares ... | patient's own hearing by bone conduction to their hearing by air conduction in order to sample for conductive versus sensorineural loss--place the tuning fork on the mastoid ask if can hear and for how long, then in front of the ear canal and ask if can hear and which is louder |
| Bing tuning fork test | An auxiliary test closely related to the Weber and Rinne tests is the Bing Test, which is a qualitative test of bilateral conductive involvement. It begins by striking the fork handle and placing it against the mastoid, then asking the patient to indicate when they no longer hear the tone. When they indicate the tone has stopped, the examiner closes the patient's tragus over the entrance to the external auditory canal (EAC) to see if the tone comes back. If it does, on either side, there is no indication of conductive component, marked "Bing Negative". Theoretically, the closure (or collapse) of the EAC should cause an increase of energy conducted to the cochlea by about 10-14 dB |
| Weber tuning fork test | Its purpose was to detect possible unilateral conductive involvement in a hearing loss. With these newly unearthed tuning forks, however, the test is quick and safe. We present a tone, usually 512 Hz and/or 1024 Hz, to the frontal sinuses of the forehead, while the recipient is asked to indicate in which ear they hear the tone the loudest (Figure 3). If the tone gravitates to the ear with the worst air-conduction thresholds, a unilateral conductive loss is indicated, and the exam form is marked "Weber Positive", indicating a conductive involvement in the loss. If the tone is heard in the ear with the best air-conduction thresholds or heard equally in the case of symmetrical thresholds, the form is marked "Weber Negative", meaning that there is no apparent conductive loss indicated. |
| The otoscopic exam is ... | to inspect the external auditory canal. Evaluate tympanic membrane Note the color (red, white, yellow) and translucency (transparent, opaque) and position (retracted, neutral or bulging) of the drum Identify the pars tensa with its cone of light, the handle and short process of malleus, and the anterior and posterior folds of the pars flaccida and position of the malleus handle. |
| Air inflation otoscopy (pneumatic-otoscope) is ... | very useful to evaluate middle ear disease. Assess the mobility of tympanic membrane by applying positive and negative pressures with the rubber squeeze bulb. |
| A normal otoscopic exam would show ... | Auditory canal: Some hair, often with yellow to brown cerumen. Ear drum: Pinkish gray in color , translucent and in neutral position. Malleus lies in oblique position behind the upper part of drum. Mobile with air inflation. |
| An abnormal otoscopic exam may show ... | External auditory canal Tenderness on pulling auricle: (Otitis externa ) Canal swollen, narrowed, moist, with pus. (Otitis externa ) Yellow to brown, sticky to hard cerumen and obscuring drum: (Ear Wax) Foreign body Ear drum Color: Red and loss of landmarks (Acute purulent otitis media) Amber: Serous effusion (Barotrauma) Bulging: (Acute otitis media) Retraction: (Tympanosclerosis) Translucent: Air fluid level (Otitis media) Hemorrhagic vesicles: (Bullous meringitis) Hole: (Perforation) |
| Diseases affecting the external auditory canal include: | External Ottitis Wax Foreign body |
| Diseases affecting the ear drum include: | Perforation, Ottitis media, Red tympanic membrane, Bulging, Dull or absent light reflex, Diminished movement, Purulent material (air fluid level) |
| Behavioral responses to a hearing test | can be raising your hand, pushing a button, or some other response. |
| Objective responses to a hearing test | assessment methods where the response is obtained without a behavioral response from the patient. An example of an objective tests is measuring the electrical activity of hearing nerve/auditory pathways in response to a sound). |
| Why is an audiological behavioral assessment important to an SLP? | Better serve your patients Critically appraise audiological results What patient can and cannot hear may guide your therapy goals Collaboration with another profession Make appropriate referrals: Behavioral? ABR? Comprehensive Examinations |
| During an audiological assessment, the audiologist evaluates ... | the status of outer ear, middle ear, inner ear, & the central nervous system |
| In audiology diagnostics, the following questions are answered: | Is the hearing normal? Or, is there a hearing loss (or an auditory processing disorder)? If there is a hearing loss: What is the DEGREE of hearing loss (or how much hearing loss is there)? What is the CONFIGURATION of the hearing loss (or what frequencies are affected)? What is the TYPE of hearing loss (or what kind or where along the auditory system is the problem)? |
| Once a hearing loss is diagnosed, a ... | treatment plan is devised (recommendations, intervention): What medical recommendations need to be made? Amplification (hearing aids) or cochlear implants What patient education should be provided? What other recommendations need to be made, e.g., speech-language evaluation, genetics evaluation, etc. |
| Audiological assessments include: | Behavioral Evals., Objective Evals., Pediatric Evals. Auditory Processing Evals. |
| Basic audiological evaluations start with ... | Clinical Observations Obtain Case History information Otoscopy (inspection/examination of the outer ear) Immittance (An objective test of middle ear function) Speech Testing (how well can the patient hear speech stimuli) Pure-tone thresholds (how well can patient hear different frequencies) Results are plotted on a form called an Audiogram The audiologist interprets the results Finally, the audiologist reviews the results and recommendations with the patient-this is called Counseling |
| during the clinical observation portion of the basic audiological evaluation you want to determine ... | Responses to sounds?, Talking from behind? Lip reading?, Play skills, Speech-Language skills/level, Voice quality, and Family interactions |
| during the case history portion of the basic audiological evaluation you want to determine ... | patient's Main Concern, Hearing history (Hx), Medical Hx, Communication Hx, Noise Exposure, Birth Hx, Educational Hx, Hearing Handicap Inventory, Adult vs Child case history forms ASHA Self-Test |
| Otoscopy | oto=related to the ear, and speculum=scope |
| during the otoscopy portion of the basic audiological evaluation you want check ... | Pinna size, shape, placement, symmetry, Pre-auricular pits or tags, Surgical scars, Signs of trauma, Condition of the skin, and the pinna should be lined up with the corner of the eye--if it is lower it could be indicative of a syndrome. |
| During the otoscopy make sure to ... | Since our ear canals are curved, in order to see well into the ear canal: In adults: Pull pinna up & back In children: Pull pinna down & back Keep tip of speculum in center of canal Watch your angle- do not jab pt. Insert the tip of the speculum just past the hairs the tip of the speculum should be pointing toward the face and upwards toward the eye |
| During an otoscopy check for ... | Canal: Present? Small? Look for cerumen (ear wax): Is it occluding the canal? Any foreign objects, blood, drainage? TM and its landmarks: Normal color: pearly white/gray Intact versus perforation Cone of light Ossicles |
| Audibility Index (AI) | is a measure of the proportion (between 0 and 1.0) of speech cues that are audible. It was referred to as the articulation index and now is sometimes referred to as the speech intelligibility index or count the dots |
| The AI (audible index) has 3 useful clinical applications, what are they? | 1. serve as a tool to explain to the patient the impact of hearing loss on the ability to understand speech. 2.Has a known relationship to word recognition 3?? |
| The measurement of hearing consists of two parameters: | the frequency or pitch of the sound and the intensity or loudness of a sound. |
| the device uses to measure responses to sound is called an | audiometer |
| responses to the tones/sounds presented through an audiometer are recorded on a graph called an | audiogram |
| when testing hearing the audiologist presents tones/sounds at either ... or ... | ear-level (or through speakers) or soundfield |
| When tones are presented at ear-level, they come through ... | earphones (a headset with TDK earmuffs or earphones that insert into each ear canal) or a bone conduction oscillator. |
| When tones are presented soundfield, ... | speakers are placed approximately 3 feet from each ear to assure equal balance of the presentations. |
| An audiogram is a graph ghat charts the way a person responds to specific sounds canned puretones. It is designed to ... | record the responses for the mechanical part of hearing. |
| The audiologist measures a client's hearing threshold at each frequency. Auditory threshold is the ... | intensity at which a puretone is barely detected 50% of the time, often in two out of three presentations. |
| All audiograms have an audiogram ... | key, or legend at the bottom of the form to remind them of what the symbols mean |
| Earphones are used to evaluate hearing of the outer, middle, and inner ear. A response at any frequency is called the | air conduction response (AC). The type of earphone (TDK or insert) should be noted as part of the audiogram |
| A bone conduction oscillator stimulates the inner ear directly and is placed by the audiologist on the mastoid bone. The use of the bone oscillator bypasses the outer ear and middle ear and stimulates the cochlea (inner ear) directly. A response at any frequency is called the | bone conduction response (BC). |
| When an individual cannot wear earphones, hearing levels are evaluated by presenting tones or noise through speakers in a soundproof room. This is called the ... | Soundfield Response. |
| When there is suspicion or confirmation that one cochlea hears better than the other cochlea at a given frequency, masking (narrow band or speech noise) is presented to the better ear to keep it "occupied." Masking is ... | generally presented through one earphone and a puretone or speech is presented through the opposite earphone or a bone oscillator. |
| The responses charted on the audiogram define levels of hearing for each ear. For adults, normal hearing and degree of hearing loss fall into the following categories: | 0 dB - 20 dB ....... normal hearing 20 dB - 40 dB ..... mild hearing loss 40 dB - 55 dB ..... moderate hearing loss 55 dB - 70 dB ..... moderately severe hearing loss 70 dB - 90 dB ..... severe hearing loss >90 dB.................profound hearing loss |
| The audiogram indicates where along the auditory system hearing loss occurs. For most adults, hearing loss is confined to the inner ear and is called | sensorineural hearing loss. |
| Hearing loss that is the result of blockage, damage, or disease to the outer and/or middle ear, with the cochlea hearing normally, is called | conductive hearing loss |
| Hearing loss that includes diminished air conduction responses and both normal and diminished bone conduction responses is called | mixed hearing loss. This means that a person has both conductive hearing loss and sensorineural hearing loss: that there is an air-bone gap of at least 10 dB, generally in the low to mid frequencies, but no air-bone gap at the mid to high frequencies. |
| While valuable, an audiogram only tells the way a person responds to basic sounds—or how loud a sound needs to be for an individual to be aware of it. The audiogram has value when determining financial compensation for handicap; however, it only suggests | the way a person might function in a quiet environment and gives little valuable information about how one functions in the real world. Most people with hearing loss have hearing threshold levels that cross a range of categories; consequenctly, further word and speech testing must be conducted in order to determine function and amplification needs. |
| What Test Environment is necessary to test hearing? | Sound-proof booth is necessary for thresholds A quiet room for screening (as when children's hearing is screened at a school or at a physician's office)Very small booth with the audiology equipment outside This is a double-chamber booth: one side for the patient and another side for the audiologist (notice window inside the booth, between the two chambers). Inside of a sound-proof booth. Audiologist with equipment (audiometer) |
| What equipment do audiologist's use? | a clinical audiometer used for diagnostics or a portable audiometer-used for hearing screenings , tranducers-for air conduction include:hearphones, insert earphones or speakers for field sound, for bone conduction equipment includes:a bone conductor or bone oscillator |
| What are the Instructions to the Patient? | You will hear some tones (beeps), first in one ear, then in the other. I want you to raise your hand (or push a button) as soon as you hear the tones, no mater how faint they may be. Keep your hand up (or the button pushed) as long as you hear the tone and lower your hand (or release the button) immediately when it goes away. |
| What Patient Responses are expected? | Patient may give: "false positive" responses (responding when there is no tone) "false negative" responses(deliberately not responding when they have, in fact, heard the tone) |
| What is the Role of the Audiologist during the audiological evaluation? | Do not give visual cues Patterned presentations must be avoided Proper transducer placement Check for collapsing canals: In the very young or much older, the pressure of a headphone may push the ear canal closed and cause a false hearing loss; insert earphones are best in these cases Obtain pt.'s thresholds Accurately record information obtained |
| Clinically, thresholds to sounds are obtained in the following manner: | Present a sound that is supra-threshold (louder than the softest sound that person can hear) which the person can hear comfortably Change the dB presentation level as follows: When the pt. responds, turn the dB down by 10 Continue turning the dB down by 10 until the person no longer hears the sound and stops responding When the pt. does not respond, turn the dB level up by 5 until the pt. responds The threshold will be the LOWEST dB level at which the patient responds to 3 out of 6 presentations |
| Medical abbreviations: | AD=right ear AS= left ear AU=both ears DNT=Did not test; CNT= Could not test WNL=Within Normal Limits Frequencies (X-Axis) Intensity (dB HL) (Y-Axis) Air conduction (AC) Bone Conduction (BC) SPL-sound pressure level HL-hearing level |
| on an audiogram, on the horizontal axis, the frequencies double, e..g, 125, 500, 1000, 2000 Hz, etc. A doubling of frequency is called an . | octave. |
| On the audiogram you see solid vertical lines at each octave. You also see dashed vertical lines between the octaves, e.g., at 750, 1500, 3000, & 6000 Hz; these are called | inter-octaves |
| On an audiogram, there should always be: | A key showing the symbols used to represent the thresholds of each ear using which transducer. Remember Red-Right-Round"? The "Round" is a circle represents the hearing thresholds of the right ear. Test reliability: Usually marked as "good, "fair", or "poor". This is a judgment the audiologist makes regarding how accurate the obtained responses were during the eval. session. If the individual being tested paid good attention and there were scarce or no false positive or false negative responses, then the test reliability is considered "good". On the other had, if there were many false responses and frequent reinstruction was necessary to keep the individual on task, the test reliability is considered "fair" or "poor". |
| On audiogram forms, there are usually places to record the results of: | speech audiometry" (using speech stimuli, instead of pure-tones, as the test stimuli). Tympanometry: Acoustic Stapedial Reflexes: |
| A common measure in audiology is called the Pure-tone average (PTA). It is equal to the sum of the thresholds at 500, 1000, and 2000 Hz, divided by 3. Since the frequencies of 500, 1000, and 2000 Hz are important speech frequencies, the average of the thresholds at those 3 frequencies s | should be fairly equal to the Speech Recognition Threshold (SRT) (more on SRT later). |
| Listen to Audiometric Test Frequencies: You will hear 6 frequencies: | 250, 500, 1000, 2000, 4000, and 8000 Hz. |
| Pure-tone Average (PTA): | Threshold 500+Thr1000+Thr2000/3 |
| Audiometric symbols: | Notice air conduction (AC) bone conduction (BC) symbols for R (circle) and L ears: Unmasked means only the test stimulus was presented, whether a tone or speech Masked means the test stimulus was presented to the "test ear" and noise was presented to the opposite ear -the "non-test ear" more on masking later Sound Field ("S") means the test stimuli were presented through loudspeakers Aided: responses obtained with the person wearing his/her hearing aid(s) |
| Audiological abbreviations | CNT - Could not test DNT - Did not test HA - Hearing aid HAE - Hearing aid evaluation NR - No response SNHL - Sensorineural hearing loss WNL - Within normal limits AU - Both sides (ears) AS - Left AD - Right VT - Vibrotactile response RTC - Return to clinic PRN - As needed BC - Bone conduction AC - Air conduction PTA - Pure-tone average UCL - Uncomfortable loudness level MCL - Most comfortable loudness level HFA - High frequency average HL - Hearing level SPL - Sound pressure level SRT - Speech reception threshold SAT - Speech awareness threshold |
| Masking | when two sounds are heard simultaneously, the intensity of one sound may be sufficient to cause the other sound to be inaudible. This change in the threshold of a sound caused by a second sound with which it coexists is called masking. The noise that causes the interference is called the masker. |
| Cross hearing refers to the concept that there are | certain situations when sounds presented to one ear may cross-over and stimulate the opposite ear To obtain a correct diagnosis of the hearing status of each ear, the audiologist must always bear in mind that cross-hearing may be taking place. |
| Since we know that a sound presented to one ear may cross over to the opposite ear, the question is: "How much of the sound crosses over?" This will depend on | The type of transducer that is used: Headphone Insert earphone, or Bone conductor |
| "inter-aural attenuation" -IA- (to attenuate means "to lessen"): IA is a phenomenon whereby the | skull bones and the structures inside the skull may absorb some of the sound energy being presented. Therefore, some sound energy is lost by the time the sound reaches the opposite ear. |
| Air conduction: The Inter-aural attenuation for headphones is about 40 dB. This means that the skull and tissues inside the skull absorb about | 40 dB of the sound presented through a headphone. |
| Air conduction: At presentation levels greater than 40 dB, sounds cross over from the | TEST-EAR to the NON-TEST EAR "Test -Ear": The ear which is being tested "Non-test Ear": The ear opposite the one being tested. |
| Air conduction: Through headphones, at presentation levels less than 40 dB, sounds | do not cross over. |
| Air conduction: if a graphic shows a 50 dB signal presented via a headphone to the "test ear": Since the skulls absorbs 40 dB , this leaves ... | 10 dB crossing over to the non-test ear |
| Air conduction: If a graphic shows a 80 dB signal presented via a headphone to the test ear: since skulls absorb 40 dB this leaves | 40 dB crossing over to the non-test ear In this case, it so happens that both the IA and the amount of sound that crossed over are 40 dB |
| Air conduction: The Inter-aural atttenuation for insert earphones is about 70 dB. This means ... | that the skull and tissues inside the skull absorb 70 dB of the sound presented through an insert phone |
| Airconduction: At presentation levels greater than 70dB from the insert earphones, sounds ... | cross over from the test-ear to the non-test ear |
| Airconduction:If a graphic shows a 80 dB signal presented to one ear via a headphone to the test ear, the skull would absorb 70 dB as mentioned leaving | 10 dB crossing over to the non-test ear |
| Air conduction:At presentation levels in this example of 70 dB being presented to the test ear via insert earphones levels less than | 70 dB, sounds do not cross over. |
| Air conduction:The IA for headphones is ... and for insert earphones ... | 40 dB, 70 dB |
| Sounds presented by bone conduction (BC) stimulate both cochleas by micro-vibrating the entire skull, Therefore, the IA by bone conduction is | ZERO. This means that the skull and tissues inside the skull do not lessen or attenuate the sound. Through BC, at ANY presentation level, sounds DO cross over from the TEST-EAR to the NON-TEST EAR |
| The graphic shows an 50 dB signal presented to one ear via a bone conduction to the test ear, Since the skulls absorbs nothing, this leaves the ... | whole 50 dB crossing over to the non-test ear |
| BC thresholds (whether the bone vibrator is placed on the mastoid bone or on the forehead) obtained without presenting some noise to the opposite ear (unmasked bc thresholds) represent | the hearing of the better cochlea |
| BC thresholds obtained without presenting some noise to the opposite ear are called | unmasked BC thresholds |
| Unmasked bone conduction thresholds are denoted on an audiogram with: | <, if the bone conductor was placed on the right mastoid >, if placed on the left mastoid, or , if placed on the forehead |
| Bone conduction-The amount of sound energy received by opposite ear by cross-hearing after interaural attenuation has taken place is | zero, since IA by BC is 0 no energy is lost sound is heard in the other ear which will require masking but nothing is absorbed between |
| If sound is crossing over from the test ear to the non-test ear, the audiologist must present a noise to the non-test ear: To keep non-test ear "out of the picture" and To obtain the true threshold of the test ear, whether the stimuli being used are pure tones or words (speech) The introduction of this noise s called | MASKING |
| Audiology students need to know masking very well, If cross-hearing is suspected , then There are several formulas and "styles" for audiologists to know how much masking is needed (how loud the masking noise needs to be) | masking is necessary |
| There are several formulas and styles for audiologists to know how much masking is needed (how loud the masking noise needs to be). There must be | enough noise presented to the non-test ear to keep it busy, but not too much noise or the noise will cross back over to the test ear. Different kinds of noise are used to mask pure tones and speech stimuli. |
| The idea of masking in audiology is similar to the procedure used by optometrists when testing vision: How? | To test the right eye, the left eye is covered; to test the left eye, the right eye is covered If the audiologist is interested in knowing the hearing thresholds of the right ear and cross-hearing is suspected, the audiologist must "cover" the opposite ear by introducing a noise into the opposite ear |
| So: if a signal greater than 40 dB is presented via a headphone, the audiologist must be aware of | cross-over hearing and the possibility of the need for masking |
| If the same 40 dB signal is presented via an insert earphone, there is no cross over, so the audiologist does not have to think about cross-over hearing or masking; only when signals are presented at greater than | 70 dB, does the audiologist need to be aware of cross-over hearing and the possibility of the need for masking |
| When sounds are presented via bone conduction, the audiologist must | always be aware of cross-over hearing and the possibility of the need for masking |
| Masking via air conduction--By placing noise (via headphone or earphone insert) in the non-test ear that is loud enough to distract it (non-test ear) from hearing the test signal, the test ear's threshold can | be accurately determined without the possibility of the non-test ear being involved in the patient's response. |
| In air conduction the test signal is usually presented via tones in | a headphone or earphone insert in the test ear |
| In bone conduction the test signal is presented via | a bone conductor on the mastoid or forehead of the testing ear |
| The same masking procedure is used for bone conduction testing, except only one headphone or insert earphone is used and placed in the | non-testing ear to introduce the making noise |
| If masking was used to determine any of the thresholds in a test, the masked symbols for either air and/or bone conduction must be drawn on the audiogram. | ^ (triangle)= RE AC Masked=right ear air conduction masked [] (square) = LE AC Masked [ = RE BC Masked ] = LE BC Masked |
| Remember these symbols are for unmasked hearing thresholds | O = RE AC (circle =right) air conduction X = LE AC (x=left) < = RE BC (<=right mastoid) bone conduction > = LE BC (>=left mastoid) , if placed on the forehead |
| Speech testing in audiology does not mean testing articulation, it means ... | using speech stimuli (as opposed to pure tones) Test Environment should be a sound-proof booth Equipment: Audiometer/tape-CD player /microphone Role of the Audiologist: no visual cues, determine pt. response method Recording responses in appropriate places Cross-hearing applies Masking applies: Need to mask if cross-hearing is suspected SPEECH NOISE is used: similar spectrum to speech - greater intensity in the low frequencies; lower intensity in the high frequencies |
| What do the following acronyms mean? WRS, UCL, MCL | ... |
| SRT | A Speech Recognition Threshold is defined as the lowest dB level at which 50% of words are repeated correctly (without visual cues) The SRT provides estimate of hearing sensitivity in the speech frequencies (20-55 dB) Stimuli used are called spondees. Spondees are 2-syllable words pronounced with equal stress on each syllable: air-plane; ice-cream , etc. The words can be recorded or spoken by the audiologist. The SRT should be very similar to the pure-tone average: (PTA) they should be within ± 6 to 10 dB of each other |
| What are the patient instructions for the SRT? | We need to find out what is the softest level at which you can understand words. You will hear 2-syllable words, just repeat them back to me, even if they sound very soft. Guess if you are not sure The audiologist must familiarize the pt. with words that will be used during testing The "down by 10, up by 5" procedure applies (recall that pure-tone thresholds are also obtained using the "down by 10, up by 5" procedure SRT can be obtained unaided or aided (while wearing hearing aids) |
| What happens if a patient admits to an SRT of 20 dB HL and to all pure tone thresholds at 55 dB HL? | What happens if pt. admits to an SRT of 20 dB HL and to all pure tone thresholds at , say 55 dB HL? This may be indicative of a diagnosis of Pesudohypacusis , also called "functional" hearing loss, also called "non-organic HL" also called malingering = faking a hearing loss |
| Why do you think a much lower SRT than a PTA may suggest that the pt. is faking a hearing loss? | because these two tests should only be within 10 dB difference of each other |
| SDT is known as speech detection threshold or SAT speech awareness threshold. | Speech is presented to the pt. The pt. does not have to repeat words correctly. They indicate whether they detect the presence of speech stimuli SDT/SAT is used if an SRT cannot be obtained due to pt,'s ability or degree of hearing loss: a very young child may no be able to repeat words, but if they detect speech, they may look to see where the speech is coming from A person who has a profound hearing loss may not be able to understand words but they may be able to just detect speech. An SDT/SAT can also be obtained unaided or aided |
| Question: Would an SDT be louder or softer than SRT? Why? | Answer: An SDT will be softer than an SRT: It will take a few more dB for the word to actually be intelligible. Think about a time when you have detected that someone is talking but you can't make out what they are saying because it was to soft: That was an SDT. |
| Audibility "versus "Intelligibility": | Because a sound is audible, it is not automatically intelligible. To a child in a classroom (or an adult) who has an undiagnosed hearing loss, voices may be audible but not intelligible. ALWAYS have a hearing screening (testing to see if the person can hear the speech frequencies normally). Remember: KNOW THE STATUS OF YOUR PATIENT'S HEARING BEFORE YOU EVALUATE OR TREAT |
| Word Recognition Scores/Word Identification Score/Speech Recognition Score | The audiologist presents single-syllable words using a "carrier phrase" such as "You will say......" or "Say the word......." The words can be recorded or spoken by the audiologist. The words are presented at a "MCL" (most comfortable loudness level) or at a certain dB level above SRT (dB SL) (SL = Sensation Level) MCL for a person with normal hearing (hearing thresholds between 0-20 dB HL) would be about 40-50 dB HL; |
| Question: Would MCL for a person who has a hearing loss be louder or softer than 40-50 dB HL? Masking usually needed because the words are being presented at dB levels where cross-over hearing is likely to occur W | ... |
| ... | WRS's are reported in % correct scores at whatever presentation levels and masking levels were use: 90-100% excellent, 80-89% good; 70-79% fair; 6-0-69% poor (at given presentation/masking dB levels) Pt. Instructions: "You will hear a sentence at a comfortable listening level- repeat only the last word" Usually, the audiologist presents 25-50 words per ear WRS can also be obtained unaided or aided WRS is a measure used in hearing aid counseling: since the words are presented at a comfortable listening level, it is sort of simulating what a hearing aid would do |
| Latency | the time between stimulus onset and the appearance of the response of each electrical potential generated by the auditory system. |
| Interpeak Latency | ... |
| Define OAE | Otoacoustic Emissions Test-tests is to determine cochlear status, specifically hair cell function. This information can be used to (1) screen hearing (particularly in neonates, infants, or individuals with developmental disabilities), (2) partially estimate hearing sensitivity within a limited range, (3) differentiate between the sensory and neural components of sensorineural hearing loss, and (4) test for functional (feigned) hearing loss. The information can be obtained from patients who are sleeping or even comatose because no behavioral response is required. |
| List the types of OAEs | Spontaneous and evoked tests; of the evoked tests there are two kinds: transient and distortion product |
| How are the OAE tests performed TOAE? | Transient (TOAEs):The stimulus is a broad-band or wide-band sound, the sound contains a large number of frequencies, stimulating much of the cochlea—emission lines need to be above the black area of the noise to pass • The environment needs to be quiet, and the patient should be still. Takes approx. 10-30 seconds • A small probe rubber tip in the canal sends sound into the ear • The sound presented to evoke an OAE response travels through the outer, middle, and inner ears into the cochlea • The probe has a microphone that picks up the cochlear emission coming back through the outer hair cells and middle ear |
| How are the OAE tests performed DPOAE? | Distortion-Product (DPOAEs):Two pure tones are presented at the same time, causing a third portion of the cochlea to respond; then another pair of pure tones, causing another area of the cochlea to respond, and so forth. The pairs of tones increase in frequency testing the cochlear regions from around 1000-8000—emission lines need to be above the gray norm area to pass • The environment needs to be quiet, and the patient should be still. Takes approx. 10-30 seconds • A small probe rubber tip in the canal sends sound into the ear • The sound presented to evoke an OAE response travels through the outer, middle, and inner ears into the cochlea • The probe has a microphone that picks up the cochlear emission coming back through the outer hair cells and middle ear |
| What do OAEs measure? | cochlear status and health of the outer hair cell function, but does not provide a measure of the function of the cranial nerve VIII or auditory pathways beyond |
| List and describe how OAE tests are used or what are their uses? | Because they are objective and do not require participation or a behavioral response, OAEs are used with • Faking Patients-(pseudohypacusis) • Not used with School Children • Early Head Start Programs • Newborn hearing screenings |
| What are patient instructions for OAEs? | •The environment needs to be quiet, and the patient should be still. Takes approx. 10-30 seconds •A small probe rubber tip in the canal sends sound into the ear •The sound presented to evoke an OAE response travels through the outer, middle, and inner ears into the cochlea •The probe has a microphone that picks up the cochlear emission coming back through the outer hair cells and middle ear |
| What are the outcomes of OAE testing? | •If the cochlea is healthy, AND the outer and middle ear are also in their normal state (unobstructed), and hearing is 30 dB HL o better, then OAEs will be present. •If outer and middle ears are normal and OAEs are absent, the loss is cochlear or sensory •If outer and middle ear are normal, OAEs are present , and neural conduction is impaired (measured by using an "ABR Test", the hearing loss is neural •The outcome of an OAE test is either "pass" or "fail": either you meet criteria for passing the test, or you don't. If you don't pass, a referral to an audiologist is warranted so the person may receive a complete evaluation of the status of their hearing •OAEs DO NOT yield hearing thresholds or degree or type of hearing loss |
| Define ABR | Auditory Brainstem Response test that measures the electrical potentials generated in the inner ear, lower brainstem, and upper brainstem in response to stimulation by sound. |
| How is an ABR test performed (transducers, electrode placements, types of stimuli used)? | Surface electrodes are placed on pt.'s head with tape (nothing hurts the pt.) Sound goes through outer, middle, inner ear, VIIIth cranial nerve, and brainstem About 1000-2000 or more clicks must be presented to get a good read out. As one click goes through, electrical activity is sequentially generated at the: Cochlea then VIIIth cranial nerve, then Lower brainstem and finally the Upper brainstem. The sound continues to travel through the midbrain to the cortex but an ABR test does not show that (because it is an auditory BRAINSTEM response test). At the start of the next click the process repeats. |
| Does an ABR measure "hearing" directly? Technically, what does an ABR measure? | electrical potentials generated in the inner ear, lower brainstem and upper brainstem in response to sound |
| List and describe the types of ABR tests: | newborn hearing screenings, threshold eval and to assist in neurological hearing loss diagnosis |
| When are ABR tests used in children - there are two reasons? With adults -one reason? | for newborns and if threshold eval and for adults if neurological hearing loss is suspected, |
| What are pt. instructions for an ABR test for the parents of a young child? For an adult? | Pt. must be absolutely still (if the pt. is a child, sedation or anesthesia may be needed) Surface electrodes are placed on pt.'s head with tape (nothing hurts the pt.) and earphones in their ears |
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