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What is the name of the difference in sensitivity between bone conduction and air conduction?
Air-Bone Gap
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Transmission of sound waves from air through bones to fluid?
Air conduction
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Sound waves in the air strike the skull, and transmit vibrations through the bones to the fluid-filled cochlea?
Bone Conduction
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Range of frequencies the normal ear can respond too?
20Hz - 20,000Hz
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Most sensitive frequencies the human ear can hear?
3,000-4,000Hz
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Measures equal loudness balance at differenct frequencies?
Phon
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What is audiometric zero?
Is the point where normal ears can hear at every frequency
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Procedure that measures the sensitivity of a person's hearing, relative to the sensitivity of average normal hearing?
Audiometry
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The quietest level the patient can hear a tone 50% of the time?
Threshold
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What is an octave?
When the higher frequency is double the lower frequency
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Classifications of hearing loss?
- 0-25 Normal
- 25-40 Mild
- 40-60 Moderate
- 60-80 Severe
- >80 Profound
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What shape does the audiogram make of a noise induced hearing loss?
"V" shaped
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Loss of acoustic energy of sound as it travels from the test ear, across the head, to the opposite ear?
Interaural Attenuation
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What is cross-over?
When you present a sound to the test ear, but the non-test ear hears the sound first.
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What is the interaural attenuation for pure tone air conduction testing?
40dB HL
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What is the occlusion effect?
The natural increase in loudness of a tone by bone conduction when a blockage is present
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What is a change in the threshold of hearing as a result of continuous exposure to sound?
Auditory Fatigue
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What is the Weber Test?
When you set the bone vibrator in the middle of the patients forehead. Set the frequency to 500Hz and the attenuator to 40dB or louder.
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What are the 3 possible results from the Weber Test?
- 1. The patient hears the tone in the ear with the greatest conductive loss at 50 Hz
- 2. If no conductive loss is present, the patient hears the tone in the ear with the best sensorieural loss at 500Hz
- 3. If the loss in both ears is identical at 500Hz, the patient hears the tone in the center of the forehead.
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What are the two definitions of Masking?
- 1. Masking occurs when an unwanted sound causes a wanted sound to be inaudible
- 2. Masking is required to keep a better ear busy while testing a poorer ear
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What is white noise?
A broad band of noise that contains equal amounts of energy in all frequencies, it is effective for both pure tone and speech testing.
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What type of noise consists of a narrow range of frequencies of equal intensity, this noise is not effective for masking speech?
Narrow Band
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White noise that is filtered to a low and middle frequency spectrum?
Speech Noise
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What type of audiogram occurs when the contour of the poorer ear follows the contour of the better ear with a 30dB or greater loss?
Shadow Curve or Mirror Audiogram
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What is the Interaural attenuation of bone conduction testing?
0db
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What is undermasking?
Occurs when the masking noise presented in the better is is not loud enough to eleminate cross-over or Interaural Attenuation
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What is overmasking?
Occurs when each 10dB increase in masking shifts the hearing threshold 10dB or more above the plateau.
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What is effective masking?
Occurs when the appropriate amount of noise is played in the non-test ear preventing it from taking part in the testing
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What is central masking?
A 5dB shift in the threshold of the test ear because of the effects of masking on the Central Nervous System
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Rule #1 of Masking?
Air Conduction. Masking is required when there is a 40dB or greater difference in the Air conduction scores between the ears.
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Rule #2 of Masking?
Bone Conduction. Masking is required when there is a 15dB or greater difference between the AC and the BC scores of the same ear
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Rule #3 of Masking?
Air Conduction. Masking is required when there is a 40dB difference between the AC score of the test ear and the BC score of the non-test ear
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Describe a what a typical sensorineural loss audiogram?
- -Thresholds are the same for both AC and BC.
- -Most of the thresholds are not within the normal range
- -There is no conductive component
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Describe a Conductive loss audiogram?
- -There is an over-all difference between the AC and the BC
- -The BC thresholds are within the normal limits
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Describe a Mixed loss audiogram?
- -There is an over-all difference between the BC and the AC thresholds
- -The BC thresholds are not within the normal range
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Describe a Flat Curve Audiogram?
Thresholds are approximately equal at all frequencies
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Describe a Gradually Falling Curve audiogram?
Thresholds fall off in the higher frequencies about 5-10dB be octave
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Describe a Marked Falling Curve audiogram?
Fall off is between 15-20dB per octave in the higher frequencies
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Describe a Rising Curve or Reverse Slope Audiogram?
Loss decreases in the higher frequencies by 5-10dB
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Describe the trough shaped curve, or "cookie bite" audiogram?
Less loss at the high and low frequencies then in the middle frequencies
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Describe a sudden drop or steep drop audiogram?
Normal or near normal up to 1000-2000 Hz with a steep drop to the next frequencies.
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Describe a Fragmentary Audiogram?
There are small islands of hearing at or or two frequencies
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What is the point at which spondaic words, spondees, can be repeated 50% of the time?
Speech Reception Threshold
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The range of useable hearing between the Speech Reception Threshold (SRT) and the Uncomfortable Level (UL)?
Dynamic Range
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For normal ears this limit is 130dB, anything above it causes discomfort and/or pain?
Uncomfortable Level
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What are the 5 types of information provided by Speech Audiometry?
- Speech Reception Threshold
- Most Comfortable Level
- Uncomfortable Level
- Dynamic Range
- Speech Discrimination Score
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What is the best level for patients to hear and understand speech?
Most Comfortable Level (MCL)
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What is the purpose of the Uncomfortable Level in Speech Audiometry?
To determine the upper limit where no further amplification will be permitted in a hearing instrument or accepted by the patient
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This uses single syllable word lists, chosen so they approximate a sample of speech sounds occurring in an ordinary conversation?
Speech Discrimination
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The Timbre or tonal quality of a complex sound depends on what 3 things?
- The number of frequencies in the complex sound
- the relative strength of each of these frequencies
- the resonance of the chamber surrounding the sound
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In a complex tone, this is the lowest frequency (loudest), that predominates?
Fundamental Frequency
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In a complex tone, this is the weaker, higher frequencies?
Overtones
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Overtones in exact multiples of the fundamental frequency?
Harmonics
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Range of frequencies in the spectrum of sound where certain harmonics are relatively loud, these give complex sounds there distinct characteristics?
Formants
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When does upward masking occur?
Whenever a low frequency sound masks out a higher frequency sound
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When does backward masking occur?
When a louder sound occurs immediately after a softer sound, causing the softer sound to be inaudible, even though it occurred first.
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When does forward masking occur?
When one sound follows another closely in time and the first sound reduces the sensitivity of recently stimulate cells
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This test identifies a measure of dynamic compliance of the tympanic membrane and reflect the algebraic sum of the factors influencing middle ear performance?
Tympanometry
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What is a Type A Tympanogram?
- It is lower on both ends, with a peak centered around 0. The height of the peak is between 0.3cc-cc
- Normal Middle Ear function
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What is a Type Ad Tympanogram?
- Similar to a Type A but, with a deep curve and a tall peak
- Potential causes: ossicular dislocation; loss of elastic fiber in the TM
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What is a Type As Typanogram?
- Flattened Type A, shallow curve
- Potential Causes: Otosclerosis; Thickening of the TM
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What is a Type B Typanogram?
- No steep peak, little or no variation in impedance over a wide range of pressures
- Potential Causes: Otitis Media; Heavy Debris; Hold in the TM
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What is a Type C Tympaogram?
- Looks like a Type A with the peak toward the negative side
- Potential Causes: Eustachian tube is not functioning properly
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