BEHAVIORAL AUDIOMETRIC EVALUATION Flashcards
Principles of Air and Bone Pure Tone Audiometry
Pathways of Sound
* Types of Hearing Loss
* Tuning Fork Tests
2 Pathways to Stimulate Hearing
- __Air___ conduction pathway
- Consists of __outer______, ____middle_______ (conductive mechanism) and
____inner______ ear. (sensorineural mechanism) - ___Bone___ conduction pathway
- Consists of ____cochlea_______ and ___auditory nerve________. (sensorineural
mechanism
Types of Hearing Loss
- Sensorineural Hearing Loss
Occurs along ____both_________pathway(s) - Conductive Hearing Loss
Occurs along ___air_______pathway(s) - Mixed Hearing Loss
Occurs along __both_______ pathway(s)
Tuning Fork Tests
- Rinne
- Weber
- Bing
Differentiates between CHL and SNHL
Rinne Tuning Fork Test
Compares hearing by BC to hearing by AC
* Physiologically air conduction is more efficient than Bone Conduction
* NH or SNHL
▫ AC is always more efficient than BC
- CHL
▫ BC more efficient than AC
(Conductive blockage prevents sound from
being heard through AC.)
Weber Tuning Fork Test
- Test of lateralization for unilateral hearing loss
- TF is placed on midline (forehead or vertex) of head
- Patient indicates ‘weber’ s/he hears the signal righ ear, left ear or
midline.
▫ Unilateral SNHL – signal lateralizes to better ear
▫ Unilateral CHL – signal lateralizes to poorer ear
▫ Midline – signal heard in both ears.
Bing Tuning Fork Test
- Measures the occlusion effect - Loudness of a low frequency bone conducted signal
increases when the ear is occluded. - Vibrating TF is placed on mastoid while examiner alternatively closes and opens the ear canal
by pressing the tragus inward and then releasing. - Normal Hearing or SNHL
▫ Positive Bing – pulsating sound
▫ Signal is louder when ear is occluded and softer when the canal is open - Conductive HL
▫ Negative Bing – no pulsating signal
▫ No change in loudness when opening and closing ear canal.
.
Evaluation Process
▫ Case History – Process of Differential Diagnosis
▫ Otoscopic inspection
▫ Audiometric equipment
▫ Performing pure tone audiometry
Air Conduction
Bone Conducton
Referral Source
❖Self referral
❖Family Member
❖Professional referral
❖Physician
❖SLP
❖Educator
❖Insurance referral
❖Hearing Screening
Case History – Differential Dx
- Autism Spectrum Disorder or severe
– profound HL or both?
▫ Poor response when called
▫ Delays in language acquisition - ADHD/Hyperactivity or HL or both?
▫ Inability to listen or follow through with
directions
▫ Difficulty with academic work
▫ Poor social skills
Depression or HL or both?
▫ Withdrawn and isolation
▫ Poor self esteem
▫ Trouble concentrating and paying
attention
- Dementia or HL or both?
▫ Decline in memory, cognition,
attention, languag
Case History
- Patient interview, case hx form. Informal observation
- Helps identify possible medical conditions that would require physician
referral. - Influences which test procedures will be administered and how testing
will be conducted - Provides the audiologist with the information necessary to diagnose the
hearing los
Hearing Case History
- Hearing/Communication
History - Medical/Otological History
- Noise History
- Family History
- Rehabilitation History
Pediatric Hearing Case History
- Pregnancy/birth history
- Speech and language development
- Physical development
- Psychosocial development
- Academic Achievement
Interdisciplinary Collaboration
If significant medical history exists:
* Obtain signed release of records
* Contact primary care physician
* Contact any allied health professional
Otoscopy and Medical Referral Conditions
- Inspection of EAM, TM and surrounding
structures - Primary purpose is to ensure that the ear
canal is clear and the tympanic membrane
can be visualized in order to proceed with
testing - Rule out ear canal collapse
- Cerumen Impaction
- Foreign Matter Blockage
- Active Drainage
- Blood in EC
- Perforation
- Growths
Pure Tone Audiometry
- Measures degree and type of hearing loss
- Air Conduction –Determines degree and
configuration of HL - Bone Conduction – Determines type of HL
Audiometer
Whats the range from frequencies that are tested ?
- Electronic device that generates pure tone stimulus at varying
frequencies and intensities
▫ Test Frequencies: 125 to 8000 Hz
▫ Test Intensities: -10 to 110/120 dB HL - Oscillator – Frequency Selector
- Attenuator –dial to change intensity level
Audiometer
Input
* Stimulus
▫ Pure Tones
▫ Narrowband Noise
▫ Speech
Output
* Transducer
▫ Earphones (R or L)
Inserts
Conventional earphones
▫ Bone
▫ Speaker (R or L)
Patient Position
- Avoid giving inadvertent visual cues to the
participant. - Enable easy observation of participant
responses to stimuli. - Allow for the monitoring and reinforcement
of responses. - Permit observation of participant comfort,
safety, and health.
Instructions (ASHA 2005)
- Indicate the purpose of the test, that is, to find the faintest tone that
can be heard. - Emphasize that it is necessary to sit quietly, without talking, during the
test. - Indicate that the participant is to respond whenever the tone is heard,
no matter how faint it may be.
My Instructions
- You are going to hear some tones (or beeps).
- Raise your hand as soon as you hear the tones and put your
hand down when the tone goes away. - The tones will become very soft and sound far away.
- No matter how faint or distant the tone is, if you think you
hear it, raise your hand.
Response Mode
Hand raising
Index finger
Signal button
Verbal Response
Response Difficulties
- False Positive
- False Negative
- Inconsistent Responses
- Reinstruction
- Varying time between tones
- Use pulsed or warbled tone
- Present at supra threshold level
to reinforce signal
Air Conduction Testing
- Determine degree of hearing loss
- Tests the total auditory system
Earphone Selection
NSERT EARPHONES
Increase comfort
Prevents collapsed ear canals
Reduces need for masking
Attenuates BGN
SUPRA AURAL HEADPHONES
False conductive HL with
collapsible canals
Does not attenuate BGN
Uncomfortable for extended
period of time
Earphone Placement
RED – RIGHT EAR BLUE – LEFT EAR
Headphones (supra – aural)
Diaphragm of earphone should be directly over ear canal
Insert earphones
Compress foam and insert into ear
Test Procedure
- Familiarization
▫ 1000Hz @ 30dBHL
▫ If no response, present at 50dBHL
▫ If no response, raise in 10dB increments until response is achieved - Threshold Determination (Hughson-Westlake method)
▫ down 10, up 5
When patient responds, ____10 down_________ dB
When no response, ______5 up__________ dB
Threshold - Level at which persons hears 50% of time or at least 2 out of 3 ascending
trials
Signal Presentation
- Test better ear or right ear if no difference between the ears
- Test in ascending order:
▫ 1000, 2000, 3000, 4000, 6000, 8000Hz
▫ Retest 1000Hz to confirm test reliability
▫ 500, 250Hz - Switch to other ear and repeat but do not perform 1000Hz retest.
- Test inter-octave if there is a 20dB or greater difference between
successive octave frequencies
Signal Presentation
- Tone duration
▫ present pure tone 1-2 seconds’ duration - Interval between tones
▫ Vary interval of successive tone presentations - Tinnitus Interference
▫ Pulse the pure tone stimuli
Bone Conduction Audiometry
- Evaluates inner ear status
- Vibration of skull stimulates fluid-filled cochlea
- Determines type of hearing loss
▫ Conductive, Sensorineural, or Mixed - Frequency sequence (ASHA 2005):
▫ 1000Hz, 2000Hz, 3000Hz, 4000Hz, 500Hz, 250Hz
BC Oscillator Placement
- Mastoid
- Forehead
Bone Oscillator Placement
- No matter where you place the bone oscillator, both cochleas will
be stimulated. - If there is a difference in hearing between cochleas, the better
cochlea will respond. - Instructions and responses are the same as air conduction testing.
Bone Conduction Audiometry
How it works
▫ Distortional Bone Conduction
Compression / Distortion - Cochlea’s shape is distorted as the skull vibrates back
and forth, creating movement of the cochlear fluids
▫ Inertial Bone Conduction
Ossicular lag – Movement of the stapes footplate lags behind the vibrating cochlear
shell
▫ Osseotympanic Bone Conduction
BC by air conduction – Bony sides of the EAM are vibrating. This creates an air
conducted sound which travels outward and towards the TM and into the ME.
Masking
- Cross Hearing
- Interaural Attenuation
- Masker (Masking Noise)
CROSSHEARING
- Sound presented to the
test ear (TE) crosses
over and is perceived in
the cochlea of the non
test ear - Given enough intensity any transducer can stimulate the opposite cochlea
Interaural Attenuation
Reduction of sound energy as it crosses from one ear to the other (via bone conduction)
Supra-aural headphones
IA = 40dB
Insert earphones
IA = 70dB
Bone Conduction
IA= 0dB
Clinically – 15dB
When to Mask
- Apply masking to NTE when the AC of the TE exceeds the BC for the NT
cochlea by the amount of the minimum IA values. - Minimum IA values
▫ Supraaural phones: ABG = > 40 dB
▫ Insert phones: ABG = > 70 dB
▫ Bone conduction: ABG = > 15 dB
MASKING DEFINITION
- Masking in our Environment
- The presence of noise that interferes with the audibility of another
- Masking in Audiology
- The presentation of noise to the non- test ear (NTE) to raise the
threshold of audibility and thus eliminate its participation when
testing the hearing threshold of the test ear (TE).
Masking the NTE
- Keep the non-test ear “busy” while establishing true threshold
results for the test ear. - Present narrow band noise to the non-test ear (NTE) to eliminate
cross hearing. - Narrow band noise – sound energy within a critical band of noise
that is centered at a pure tone frequency.
