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79 Cards in this Set
- Front
- Back
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Air-bon gap (ABG)
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The amount by which the air-conduction threshold of a patient exceeds the bone-conduction threshold at any frequency in the same ear.
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Air conduction
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The course of sounds that are conducted to the inner ear by way of the outer ear and middle ear.
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Audiogram
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A graphic representation of audiometric findings showing hearing thresholds as a function of frequency.
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Audiometer (pure tone)
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A device for determining the thresholds of hearing. Pure tones at various frequencies are generated, and their levels are increased and decreased until thresholds are found. Outputs may include earphones for air-conduction testing, a bone-conduction vibrator for bone-conduction testing, and one or more loudspeakers for sound-field testing.
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Audiometric Weber test
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An extension of the tuning-fork Weber test. The bone-conduction vibrator of the audiometer is applied to the forehead of a patient, and tones are presented above threshold. The patient is directed to respond by stating whether the tone was heard in the right ear, the left ear, or the midline.
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Bekesy audiometry
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Automatic audiometry wherein patients track their own auditory thresholds for both pulsed and continuous pure tones by depressing a switch when the tone becomes audible and releasing it when the tone is inaudible. Results are traced on a special audiogram blank. This test is no longer popular.
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Bone conduction
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The course of sounds that are conducted to the inner ear by way of the bones of the skull.
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Calibration
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The electroacoustic or psychoacoustic determination that an audiometer is performing properly in terms of its acoustic output, attenuator linearity, frequency accuracy, harmonic distortion, and so on.
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Central masking
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The shift in the auditory threshold of a tone produced by a noise in the opposite ear when the level of the noise is not sufficient to cause peripheral masking by cross-conduction.
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Computerized audiometry
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The process of testing human hearing sensitivity by having computers programmed to present the stimuli and interpret the threshold results.
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Critical band
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A portion of a continuous band of noise surrounding a pure tone. When the sound-pressure level of this narrow band is the same as the sound-pressure level of the tone, the tone is barely perceptible.
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Cross-hearing
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The reception of a sound signal during a hearing test (either by air conduction or bone conduction) at the ear opposite the ear under test.
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Distortional bone conduction
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The response to a sound stimulus evoked when the skull is deformed by a bone-conduction vibrator, distorting the cochlea and giving rise to electorchemical activity within the cochlea.
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Effective masking (EM)
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The minimum amount of noise required just to mask out a signal (under the same earphone) at a given hearing level. For example, 40 dB EM will just mask out a 40 dB HL signal.
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Electronic voltmeter
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A device for measuring differences in decibels and voltages.
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Inertial bone conduction
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Stimulation of the cochlea caused by lag of the chain of middle ear bones, or inner ear fluids, when the skull is deformed, resulting in movement of the stapes in and out of the oval window.
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Initial masking (IM)
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The lowest level of effective masking presented to the nontest ear. For air=conduction tests, this level is equal to the threshold of the masked ear; for bone-conduction tests the IM is equal to the air=conduction threshold of the masked ear plus the occlusion effect at each frequency.
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Interaural attenuation (IA)
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The loss of energy of a sound presented by either air conduction or bone conduction as it travels from the test ear to the nontest ear; the number of decibels lost in cross hearing.
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Masking
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The process by which the threshold of a sound is elevated by the simultaneous introduction of another sound.
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Maximum masking
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The highest level of noise that can be presented to one ear through an earphone before the noise crosses the skull and shifts the threshold of the opposite ear.
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Occlusion effect (OE)
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The impression of increased loudness of a bone-conducted tone when the outer ear is tightly covered or occluded.
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Osseotympanic bone conduction
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The contribution to hearing by bone conduction created when the vibrating skull sets the air in the external ear canal into vibration, causing sound waves to pass down the canal, impinging on the eardrum membrane, and being conducted through the middle ear to the cochlea.
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Overmasking (OM)
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Occurs when a masking noise presented to the nontest ear is of sufficient intensity to shift the threshold in the test ear beyond its true value. In overmasking, the masking noise crosses from the masked ear to the test ear by bone conduction.
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Plateau
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The theoretical point in clinical masking at which the level of noise in the nontest ear may be raised or lowered about 15 dB without affecting the threshold of the signal in the test ear; the levels between undermasking and overmasking at which the true threshold of the test ear may be seen.
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Pure-tone average (PTA)
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The average of the hearing levels at frequencies 500, 1000, and 2000 Hz for each ear, as obtained on a pure-tone hearing test. Sometimes the pure-tone average is computed by averaging the two lowest thresholds obtained at 500, 1000, and 2000 Hz.
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Tactile response
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The response obtained during bone-conduction (and occasionally air-conduction) audiometry that signals have been felt, rather than heard, by the patient.
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Threshold
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In audiometry, the level at which a stimulus, such as a pure tone, is barely perceptible. Usual clinical criteria demand that the level be just high enough for the subject to be aware of the sound at least 50% of the times it is presented.
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Undermasking
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Occurs when a masking noise presented to the nontest ear is of insufficient intensity to prevent the test signal from being heard in that ear
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White noise
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A broadband noise with approximately equal energy per cycle.
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What are the 5 factors to be aware of when performing audiometric testing?
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1. the test equipment
2. the environment 3. the patient 4. the clinician 5. the test procedure |
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What is the name of the equipment used to test hearing?
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audiometer
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What is a diagnostic audiometer?
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An audiometer that has the capability of delivering a number of audiometric tests for the examiner.
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What are the output limits of the audiometer?
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The intensity limits (either lower or higher) that an audiometer can deliver.
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What are the lower intensity limits of an audiometer?
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0 dB to -10 dB
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What are the upper limits of an audiometer?
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Depends on the frequency.
Lower frequencies of 125 and 250 Hz have a lower intensity maximum, as well as 8000 Hz. 500, 1000, 2000, & 4000 maximum is usually 100 dB. |
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Why are bone conduction intensity limits lower than air conduction?
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More power is needed to drive a bone conduction oscillator than the diaphragm in the air conduction outputs. When bone conduction is driven at high intensity levels, harmonic distortion can result.
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Name 3 ways that ambient noise in the room can be attenuated:
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1. earphone enclosures
2. receiver inserts 3. sound treated chambers. |
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T/F: every precaution should be taken to ensure that the test environment is as quiet as possible.
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TRUE!
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What are sound treated booths?
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An environment that has been designed, manufacture, and available for audiometric testing. They can be single walled or double walled. There are also one room and two room audiometric suites.
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What are some of the features of audiometric booths?
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1. a window that provides visual communication between the two rooms.
2. electrical connections that pass through the two rooms. 3. a talkback device - microphone, amplifier and speaker, and/or earphone - that enables the examiner to hear the patient when they speak. |
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What age are most patients?
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All ages - very young to very old.
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What is exam reliability?
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An indication of the reliability of the audiogram. Indicated with good, fair, or poor. This indicates whether the patient was really performing adequately or whether there was doubt as to the validity of the test result.
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Name four ways a patient can indicate if they've heard the auditory stimulus?
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1. raise hand
2. raise a finger 3. push a signal button 4. verbally answer |
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Who gives hearing examinations and what are their qualifications?
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Usually an audiologist. At least someone who has been properly trained, understands all of the factors that come into play on a successful audiometric test result - the patient, the equipment, the test procedure - and other factors that may come to bear.
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What should an examiner obtain before conducting threshold testing?
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A complete case history needs to be obtained and an otoscopy performed.
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Otoscopy
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visual examination of the auditory canal and the eardrum with an otoscope.
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Why is an otoscopy performed?
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to rule out active pathological conditions and the potential for ear canal collapse caused by audiometric earphones.
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What is the correct position for the patient to be sitting during an examination?
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The patient should sit facing slightly away from the clinician and the audiometer. The patient should not be able to observe visual cues from the clinician while they are being tested. A right angle to the clinician is best.
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Why is it so important to give proper instructions to a patient?
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Depending on the instructions given, the patient's audiogram can differ by as much as 10 dB.
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When should the patient be instructed?
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Prior to putting on the headphones or through the microphone.
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What language should be used during instructions?
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Understandable language! Avoid professional language that the client may not have knowledge of. Use words like "pitch" rather than "frequency" and "loudness" rather than "intensity".
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What ear is tested first?
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Usually the better ear, if it is known. If not, begin with the right ear.
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What is a negative response?
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When a patient fails to respond to a stimulus.
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What is the difference between a true negative and a false negative response?
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True negative - the signal is actually not heard.
False negative - the patient hears the signal but does not respond. Can be caused by a variety of factors. |
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Where should the center of the earphone be placed on the patient?
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Over the external auditory meatus or ear canal. Make sure the ear canal is not pressed up against a portion of the pinna or another part of the head. Also, make sure the tragus is not pushed inward blocking the sound.
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Infection control
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Adherence to universal precautions and appropriate infection control procedures should be in place. Instrumentation coming into physical contact with the patient must be cleaned and disinfected after each use. The use of disposable acoustically transparent earphone covers or disposable insert earphone tips is recommended. Hand washing should be routine for the audiologist between patients.
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What is the purpose of audiometric testing?
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To determine the threshold of the patient at every test frequency.
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What is the minimum number of responses needed to determine the threshold of hearing?
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Two responses out of three presentations at a single level.
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What is used to chart a threshold?
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An audiogram.
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The x-axis is also called..
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the abscissa.
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The y-axis is also called...
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the ordinate.
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What basic information is included on an audiogram?
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Information about the clinic - name, address, telephone number. Information about the patient - name, address, phone number, date of birth, date of examination, test results.
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What is a symbol legend?
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the key to symbols used on an audiogram.
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How are thresholds marked on an audiogram?
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A circle "O" in red for the right ear.
An "X" in blue for the left ear. 3 Rs - red, right, round |
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Air unmasked symbols
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Right: O
Left: X |
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Air masked symbols
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Right: triangle
Left: square |
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Bone unmasked symbols
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Right: <
Left: > |
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Bone masked symbols
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Right: [
Left: ] |
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Sound field symbol
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S
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Symbol for "Aided" (patient is wearing hearing aides).
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A
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What are "no response" symbols
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An arrow pointing down to the left or the right attached to the audiogram symbols indicting that you've reached the limit of the audiometer for that frequency and you have not been able to obtain a response from the patient.
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Where do you record the symbols on the audiogram?
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The threshold is recorded on the frequency line where the frequency and the intensity in dB HL intersect.
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What are the speech frequencies?
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between 500 to 2000 Hz
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Why is the Pure Tone Average (PTA) useful?
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For predicting the threshold for speech as well as establishing the degree of communication impact imposed by a hearing loss.
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What is one of the ways we us the Pure Tone Average?
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To help define the degree of hearing loss.
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What is the classification of loss?
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How we quantify the degree of a patient's hearing loss in terms of the level of the stimulus needed for them to respond to it.
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What is the classification of loss used for?
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Used for reporting the degree of hearing loss to the patient and also in the diagnostic reports that are written.
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How do we classify the degree of hearing loss?
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Normal hearing: 0-15 dB
Slight Loss: 16-25 dB Mild Hearing Loss: 26-40 dB Moderate Loss: 41-55 dB Moderately Severe Loss: 56-70 dB Sever Hearing Loss: 71-90 dB Profound Hearing Loss: >90 dB |
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What is a sloping loss?
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A person with hearing loss usually has a different amount of loss at each frequency across the range of hearing. For example: a person may have normal hearing in the lower frequencies, a moderate loss in the mid-frequencies and a severe hearing loss in the higher frequencies.
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