Pure Tone Audiometry Flashcards
The quietest level the pt can hear tone 50% of the time
Threshold
How do you find the Sensation Level
Presentation Level- PT’s Threshold= Sensation Level
Presented at 40dB- Pt’s TH is 20dB= 20dB SL
Both of these decibels compare the hearing of the patient to normal ears at audiometric zero. ANSI Standards
HTL- Hearing Threshold Level
HL- Hearing Level
Compares this level to where the best human ears can hear
Sound Pressure Level SPL
The amount of sound above the threshold of the pt. The sound the pt hears
Sensation Level
The loss of acoustic energy of a sound as it travels from the test ear, across the head, to the opposite ear
IA- Interaural Attenuation
Occurs when you present a sound to the test ear but the non test ear hears the sound first
Cross- over or IA
Interaural Attenuation for pure tone air conduction testing is____
40dB
The natural increase in the loudness of a tone by bone conduction when a blockage is present. It is greatest at 250Hz, about 20dB
The Occlusion Effect
Designed to measure the auditory fatigue of the VIII Nerve
Tone Decay Tests
3 Hearing Loss Characteristics
Type of Hearing Loss (Sensorineural, Conductive, Mixed)
Degree of HL (mild, Moderate, Severe)
Configuration of HL ( reverse slope, cookie-bite, flat)
Always presents with better hearing from by BC, indicates a blockage or impairment to the conductive portion of the hearing mechanism, if 15dB or more at all frequencies there is a conductive loss/component. What do all these traits identify?
Air- Bone Gap/ Conductive HL
When the AC thresholds and BC thresholds are the same (right on top of each other)
Sensorineural HL
When there is a separation between the AC thresholds and the BC thresholds in addition to abnormal BC thresholds (worse than 20dB on Audio)
Mixed HL
The 5 degrees of HL
Normal- 0-20dB Mild- 21-40dB Moderate 41-70dB Severe 71-90dB Profound 91+
A configuration of HL that Generally varies within 10-15dB at all frequencies
Flat Loss
A configuration of HL that has a gradual reduction from lower to higher Frequencies
Gently Sloping or gradual slope
A configuration of HL that has a greater HL in the LF’s better hearing in the HF’s
Reverse or Rising slope
Severe to profound loss in the LF’s and no response in the mid or HF’s
Corner Audiogram
Better Hearing in the LF range to a severe drop in the highs
Ski-Slope or HF, or precipitous Loss
A Hearing loss due to noise exposure and illustrates a V notch between 3k-6kHz and a sensorineural HL
Noise induced HL
All Bone conduction thresholds are in normal range while AC have a reverse slope and type B Tymp…what HL would this indicate?
Otitis Media
Early stages will exhibit that of otitis media on the audiogram but with this the BC thresholds drop at 2k (carhart notch) Tymps are type As
Otosclerosis- with surgery BC and AC will return to normal (stapedectomy) W/O surgery loss gets worse
Produces a purely conductive loss with up to 60dB air bone gap.
Missing Drum or Ossicular Chain
Occurs when a lower frequency sound masks out a higher frequency stimulus
Upward spread of masking
A masking noise that can be used for both pure tone and speech
White Noise
More effective masking noise and easily tolerated than white noise for pure tones but not speech tests
Narrow Band Noise
Interaural Attenuation for Bone Conduction is ___ for the sound to be audible in the opposite ear
0dB
Eliminates cross over from occurring. Determines the appropriate noise needed to cover up or keep the non test ear busy.
Effective Masking
occurs when an effective masking noise in the non-test ear isolates the test from cross over or IA and the Central Nervous system causes the test ear threshold to be 5dB lower without masking.
Central Masking
When is masking required
- Required in the better ear when the difference in air conduction thresholds between ears is 40dB or more.
- Whenever the masked or unmasked BC threshold of the better ear is 40dB better than AC threshold of the poorer ear, mask the poorer ear thresholds by AC
How to determine the proper amount of masking noise and the starting level for the test tone
Start masking noise in the better ear at AC threshold plus 10
When to mask for BC
When a 15dB or more difference occurs between the BC and the better ear and AC of the poorer ear
In pure tone testing, threshold means
The lowest intensity the client hears 50% of the time
What is the meaning of 40dB threshold re: audiometric zero, at 500 Hz
Subject could barely hear a 500Hz tone at 40dB about 50% of the time
The problems produced by excessive ambient noise are
Greater for the lower frequencies than the higher frequencies
What should be done before testing is performed
The Pt’s ears should be carefully examined using an otoscope
The descending technique in pure tone Audiometry is preformed because it:
It’s easier to hear when a sound stops than when it begins
Why is beginning testing with the 1000Hz tone conducted
It is the center of frequency of those most important to understanding speech
Has good test, re-test reliability
Provides the pt to become accustomed to the procedure
Individuals with a noise induced hearing impairment can have a V notch at which frequencies
3000, 4000, 6000Hz
The loss of acoustic energy as it travels from the test ear in the non-test ear is a definition of:
Interaural attenuation
To begin testing for air or bone conduction thresholds, test should begin at which frequency
1000 Hz
If the outer and middle ear parts are normal
Air thresholds will equal the bone thresholds
In bone conduction testing the receiver should be
Placed at the most sensitive spot on the mastoid of the test ear
Sound from the bone conduction receiver may stimulate the non-test ear at
10dB or less
A source of information that helps to identify which ear is responding in bone conduction stimuli is
Tympanometry
Acoustic reflex testing
Bone conduction with masking
Bone conduction testing directly stimulates the:
Cochlea
Ambient noise in the environment during bone conduction testing will
Affect the test results in the lower frequencies
During the testing process it is best to test bone conduction
After air conduction testing
A conductive loss may be caused by
Perforation of TM
Immobile Middel ear ossicles
Otitis media
Bone condition thresholds worse than Air conduction thresholds may be caused by
Poor placement of the vibrator
Skull fracture
Thickness of the skull
Sound being presented to one ear and then routed to the opposite ear is known as
Cross hearing
Trans cranial hearing
Shadow hearing
When the better ear answers for the poorer ear what occurs
Shadow curve
Which noise is best for masking during pure tone air and bone conduction testing
Narrow band noise
Effective masking may be described as
An increased masking noise that does not shift the threshold tone
A formula method to determine how much masking noise is appropriate
A psychoacoustic method like the one proposed by hood
Masking is performed during air conduction testing when
A
Masking is performed during bone conduction testing whenever
A 15dB or more difference occurs between the obtained bone conduction threshold of the better ear and the obtained air conduction threshold of the poorer ear
The occlusion effect occurs during
Bone conduction testing causing thresholds to shift due to headphones being placed over the ear
A masking dilemma occurs when
It is impossible to mask
The patient displays a bilateral conductive loss
Masking can not be completed due to over masking
Under masking is defined as
Occurring more often during air conduction testing
Central masking can effect a threshold by
5dB