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31 Cards in this Set
- Front
- Back
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Sensorineural indicates that air-conducted thresholds equal _____________ thresholds; the ear is doing what it is supposed to be doing. However, when conductive problems arise, the ear is ______________________.
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Sensorineural indicates that air-conducted thresholds equal bone-conducted thresholds; the ear is doing what it is supposed to be doing. However, when conductive problems arise, the ear is not doing everything it is supposed to do.
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we define conductive loss as a ___________________—or interruption of sound transmission—in the mechanical system of the middle ear
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loss of efficiency
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Acoustic immitance testing is used to evaluate what?
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Immittance tests help diagnose middle ear disorders, lesions in the seventh (facial) or eighth (acoustic) cranial nerve, and Eustachian tube dysfunction. Immittance measures are used to determine the middle ear’s ability to transfer sound waves to the inner ears, as well as assess the impact of middle ear mechanisms that alter this ability.
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What affects immitance measures
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Mass, mobility, and resistance of the outer and middle ear systems
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otitis media (OM)
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he general term for middle ear diseases, is the single most-common health care problem in children. We have also come to recognize that chronic, recurrent, middle ear disease can potentially play a significant role in (or lead to) a delay in the acquisition of language—which leads to delays in speech, reading skills, and diminished academic performance.
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advantage of immitance testing
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Additional advantages of immittance testing is that it is non-invasive and nonbehavioral. In fact, the patient doesn’t even have to be conscious or feeling especially participatory—one more reason why this test is useful and effective, especially for special populations.
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what does immitance mean?
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Immittance is an all encompassing term to describe measurements made of tympanic membrane impedance, admittance or compliance. The word immittance, when applied to measurements at the tympanic membrane, is a combined form of the words impedance and admittance. Acoustic impedance is the opposition to the flow of acoustic energy to the middle ear. We'll also measure admittance or the flow of energy. Admittance is the ease of sound flow. It is the acoustic energy passed by the TM into the middle ear.
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what has a reciprocal relationship
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impedance/admittance
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Acoustic immittance tests include
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static compliance (which is a sub test of tympanometry), tympanometry, acoustic reflex testing and Eustachian tube function testing.
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The outer third of the ear canal is _____________, and the inner two-thirds is _________. Within the ear canal, there is very little _________, but there does exist a __________, as well as a network of ___________
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is the external auditory meatus, or ear canal. The outer third of the ear canal is skin over cartilage, and the inner two-thirds is skin over bone. Within the ear canal, there is very little fatty tissue, but there does exist a highly vascular network, as well as a network of neural end organs
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The ear canal of most adults is roughly about _____ in length from the concha opening to the tympanic membrane, but the canal can vary in diameter over that length from about a ________. The ear canal is not round, but rather _____, meaning it changes over its length.
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The ear canal of most adults is roughly about 1 inch in length from the concha opening to the tympanic membrane, but the canal can vary in diameter over that length from about a half to three-quarters of an inch. The ear canal is not round, but rather ovoid, meaning it changes over its length.
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The ossicles are not only connected to the medial wall of the TM, but are also connected to, and articulate with, _______. Each of these bones is ________ independently in the middle ear; if you removed one, the others would ______ their position.
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The ossicles are not only connected to the medial wall of the TM, but are also connected to, and articulate with, each other. Each of these bones is suspended independently in the middle ear; if you removed one, the others would retain their position.
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The ossicles perform a mechanical system that acts as a ________: the ratio of the work that goes in, compared to that of the work that goes out, is ________
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perform a mechanical system that acts as a Class II lever: the ratio of the work that goes in, compared to that of the work that goes out, is improved.
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purpose of the middle ear is to ____________ in order to overcome the higher impedance of the inner ear fluids, thus allowing the air-borne sound wave to be transferred into a __________ without being deflected.
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purpose of the middle ear is to enhance the incoming sound wave in order to overcome the higher impedance of the inner ear fluids, thus allowing the air-borne sound wave to be transferred into a liquid wave without being deflected.
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key landmarks of middle ear
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tympanic membrane, the three ossicular bones (malleus, incus, stapes), the Eustachian tube, the oval window, and the round window, and the promontory between them
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How is sound introduced to inner ear
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It is introduced via pressure waves at the oval window membrane by the motion of the footplate of the stapes, which moves in and out of the recess. The pressure wave is then released back out into the middle ear space at the round window.
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main mechanism used to achieve the sound wave transformation
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difference in surface area of the TM and the stapes footplate. Also, the lever action of the three middle ear bones adds to the sound pressure at the oval window.
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Results in sound waves being reflected back through the outer ear.
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Any alteration to the middle ear system, such as fluid or air pressure build up in the middle ear cavity or inhibition of the ossicular chain movements, will result in an inefficient transfer of acoustic energy through the middle ear.
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Note impedance is designated as capital __, admittance with capital __.
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Z; Y
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When we want to measure the acoustic admittance characteristics of the ear we use
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an electroacoustic immittance meter. The equipment includes the probe tone oscillator and loudspeaker, Monitor microphone, Pressure or air pump and manometer, ipsilateral reflex oscillator and loudspeaker, contralateral earphone and probe tip.
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* The acoustic immittance of the ear is measured by inserting an ear piece called the probe tip into the ear canal. The probe tip is encased in a flexible plastic cuff to create an airtight connection (hermetic seal) between the ear canal and the probe tip. The probe tip includes 4 tubes and a second ______, what are they?
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o One tube is connected to a receiver or a miniature loudspeaker, which is used to deliver a tone into the ear canal. This sound is called the probe tone. Usually this is an 85 dB SPL, 226 Hz pure-tone sound.
o The second tube is connected to a tiny measuring microphone and is used to monitor the probe sound within the ear canal. This sound is compromising both the incident wave introduced to the ear from the speaker and the reflected wave as it returns from the TM. This is how we measure the sound pressure in the cavity. o The third tube is connected to an air pressure pump and manometer, or a pressure meter. We create and remove pressure in the cavity to get a dynamic measure of the movement of the TM. o The fourth tube connects to another receiver used to present stimuli for testing the acoustic reflex. o In addition to the probe tip in one ear, a second earphone goes to the opposite ear and is used for acoustic reflex tests. |
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How do Mass, mobility, and resistance of the outer and middle ear systems affect the immittance measures.
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Think of a piston as the TM and a black box being the mass of all the bones, muscles and ligaments in the middle ear. When the sound waves strike the TM, the piston moves the mass of all the bones, muscles, and ligaments in the middle ear. The mass is connected to the piston on the left and to a spring on the right, which represents the resistance the mass encounters as it moves. The spring can be influenced by pressure on the footplate of the stapes or the stretching or movement of the ligaments and muscles of the middle ear. The saw tooth wave underneath the black box represents the reactance of the system, or conversely, the tendency of the system to remain at rest. This is the inertia—the tendency of a body to remain at rest—that has to be overcome, if the mass is to be set in motion.
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Through the air pump we create and remove ______ in the cavity to get a dynamic measure of the ______ of the TM.
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Through the air pump we create and remove pressure in the cavity to get a dynamic measure of the movement of the TM.
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We can exert ______ pressure, pushing the TM from us, or ______ pressure, creating a partial vacuum and pulling the TM _____ us
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postive-away,negative-toward
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air pump is calibrated in? What do we need to know about these measures?
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milliliters (ml), milliliters of water (MM H20), or dekapascals (daPa). The units of measurements are very similar- 1 daPa = 1.02 mm H20, and 1 mm H20 = 0.98 daPa- when measurements are made at standardized conditions of temperature and pressure. Because they are so similar, the measurements can be used interchangeably. So you may see milliliter (ml) in a measurement or milliliters of water (mmho) or dekapascals (daPa), but it is essentially the same.
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devices must be calibrated so that ___daPa (or mm H2O or ml) is equal to _____ ______ at the site where measurements are to be made
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0; atmospheric pressure
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how much pressure do most testing instruments use?
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+200 ml to -200 ml.
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How does stiffness of TM affect sound perception?
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As we make it stiffer, it reflects more sound back into the cavity and this allows less energy (less sound) through the TM. So, the sound is soft when we push the TM away from us. Then, we begin to remove the pressure in the cavity, a bit at a time. As we do, the TM becomes more compliant, lets more sound through, and the perception is that the sound gets louder.
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immitance measurements are made in
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measurements are made in dB SPL
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prior to any testing, an _____________ should be done on the patient
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otoscopic examination
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How do you prepare a patient for immitence test
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Seat the patient facing the iimmittance meter; do an otoscopic examination; give instructions to the patient, select a probe tip to fit the ear canal tightly (air tight seal); place a probe tip on the end of the probe and insert it into the ear canal-it should stay in place without holding it; run the immittance test.
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