Exam 2 Flashcards
The audiogram is used to describe what?
Degree of hearing loss, type of hearing loss, if referral is needed, and to predict ability to listen and communicate.
What is the range of hertz that the audiogram measures?
250-8000Hz
Give three examples of a diagnostic and computer based audiometer.
1.) interacoustic Model AC40
2.) Grason-Stradler Inc, Model 61
3.) Aurial
(*Diagnostic Audiometers must always have two separate channels with all of the functions duplicated.)
What was the original automatic audiometer?
Bekesy audiometer–hold to raise and release to lower.
Screening audiometer
Uses limited pure tones.
Used in schools and hospitals.
(20dB screened at 1000, 2000, and 4000Hz)
FM (frequency modulated) or warble tones (types of stimuli)
Typically used with peds population and holds the interest of this population more.
Pulsed-tones (type of stimuli)
Typically used with adults and increases patients awareness of the stimuli (distinguishes btwn tinnitus and the stimulus.)
Narrow band noise
Used as a master for pure tone stimuli and used for peds testing.
Speech noise
Used as a basket for speech stimuli
Transducers
Device capable of vibrating when activated by an electrical signal from the oscillator, converts the electrical signal into a vibration that can be heard.
Types of transducers
Insert earphones, super-aural headphones, high frequency earphones, speakers, and bone conduction vibrator
Insert earphones
-Acoustic diaphragm housed in a case, Sent through a small tube, and placed in the ear by a disposable foam cuff -Disposable -Placement is important -Test 250-8000Hz
Supra-aural headphones
- Standard use before inserts were developed.
- Position is important
- Can cause collapsed canal
- Tests 250-8000Hz
- 5dB higher output than inserts
High frequency earphones
- Used to test frequencies above 8000Hz
- Placement is important
Sound field speakers
- Test patients with hearing aids
- Test young children
- Not ear specific
- –Best to use narrowband noises or warble tones
Bone conduction vibrator
- Placed on mastoid, doesn’t touch auricle, and placed under hair
- Placed on one side of the head at a time
- Both ears receive vibration
- Masking must be used to get ear specific thresholds
What is the range (in Hz) that bone conduction tests?
250-4000Hz
What is the limited intensity range of bone conduction and is it frequency dependent?
50-80dB
Yes, it is frequency dependent
Vibro-tactile response
Low-frequency (500Hz or lower and high intensity 55dB+)
Bone conduction (unmasked) gives threshold from which ear?
The BEST hearing ear NOT the ear the bone vibrator is closest to
How to avoid the occlusion effect
EACs must be uncovered (unmasked thresholds)
How often do the Audiometers have to be calibrated?
Annually through special equipment and usually through an outside company.
(Sound booths/rooms are also tested annually for acceptable noise levels)
What are air conduction and speech testing transducers?
Insert earphones or headphones
Air conduction tests what frequencies?
125-20,000Hz (250-8000 most common)
-10 to 110/120dB
Speech testing (CD or MP3 files)
- Speech reception thresholds (STRs)
- Word discrimination scores
- Speech in noise testing
- Auditory processing tests
What does bone conduction test (in terms of frequency and decibels)
250-4000Hz
-10 to 50-80dB
Air conduction and bone conduction
- Patients hearing loss is basses on AC results
- AC looks at the entire auditory system
- BC looks at the inner ear
- The combination of AC and BC helps identify where the hearing loss occurs
Normal hearing loss
- All parts of the ear function normally
- No air-bone gap: within 10dB (air/bone essentially the same) AND all thresholds are equal or better than 25 dB HL
Sensorineural hearing loss (SNHL)
- Problem in the inner ear
- No air bone gap: within 10dB (air/bone are essentially the same) and at least some thresholds (air and bone) are worse than 25dB HL
Conductive hearing loss (CHL)
- Problem in the outer or middle ear
- Air bone gap present: >10dB AND bone conduction is equal to or better than 25dB
Mixed hearing loss
- Problem in the outer OR middle ear AND the inner ear
- Air bone gap present: >10dB AND bone conduction thresholds are >25dB HL
Procedure for obtaining pure tone thresholds
- ) Directions to the patient
- ) Put transducer on ears
- ) Test better ear first
- ) Test AC before BC
What are the frequencies tested for AC when testing for pure tone?
250, 500, 1000, 2000, 3000, 4000, 6000, 8000Hz
*1000Hz is recommended starting frequency
When must you test half octaves?
(Half octaves: 750, 1500Hz)
When 20dB difference or more btwn octaves
What are the frequencies tested for BC when testing pure tone?
250, 500, 1000, 2000, 3000, and 4000
Pure tone testing: level of first presentation?
10dB below the level of the listener’s response to the familiarization presentation
Modified Hughson Westlake technique
Start up 5dB down 10dB
Ascending threshold procedure
Threshold
Softest level a patient can accurately identify 2/3 of the time
False positive
Patient responds when no sound is present
False negative
Patient does not respond even when a sound is audible
Techniques for testing infants and toddlers
- Having an assistant is easiest
- Try to use headphones for ear specific information
- Newborns to 5-6 months test via physiologic measures–Immittance, OAEs, ABRs
- Visual reinforcement audiometry (ages 6 months to 2 years)
- Conditioned play audiometry (ages 2-4 years)
Visual reinforcement audiometry
6 months to 2 years
- mechanical toy in tinted box lights up when sound is played
- child is then distracted away from mechanical toy and then it is presented again
- only turns on when head is turned
Conditioned play audiometry
Ages 2-4 years
- can be tested by AC and BC
- child performs fun activity when pure tone is heard
