Exam 2 Priority Flashcards
List 8 warning signs of ear disease that should be referred for medical evaluation before proceeding with amplification?
- Visible congenital or traumatic deformity of the ear.
- History of active drainage from the ear within the previous 90 days.
- History of sudden or rapidly progressive hearing loss within the previous 90 days.
- Acute or chronic dizziness.
- Unilateral hearing loss of sudden or recent onset within the previous 90 days.
- Audiometric air-bone gap equal to or greater than 15 decibels at 500 hertz (Hz), 1,000 Hz, and 2,000 Hz.
- Visible evidence of significant cerumen accumulation or a foreign body in the ear canal.
- Pain or discomfort in the ear.
act as a frequency specific volume “handle” to maximize audibility w/o changing compression
Frequency shaping bands
Define Frequency shaping bands
Frequency shaping bands acts as frequency specific volume “handle” to maximize audibility without changing compression
adjust compression ratios to shape output into the individual’s dynamic range
Compression shaping channels
Define Compression shaping channels
Compression shaping channels adjust compression ratios to shape output into the individuals dynamic range
The measurement of the absolute SPL level of an open ear canal resonance, across all frequencies, at the tympanic membrane (input+ gain+ resonance= output)
Real ear unaided response (REUR)
Measures the natural amplification created by the shape of the pinna & open ear canal.
Real ear unaided response (REUR)
Clinical Usefulness of REUR
Knowing an individual’s ear canal resonance improve accuracy of prescriptive fitting
REUR changes due differences in:
- Size, texture, shape, or presence of abnormal anatomy
- Age: Pediatric, adult, elderly
- One person can have 2 different REUR’s
Define REOR; Real Ear Occluded Response
A measurement of insertion loss caused by placing an earmold/dome in the ear canal.
The measurement of gain increase resulting from pinna, ear canal, and head diffraction effects, as measured in an open ear canal.
REUR - input level =
REUG; Real Ear Unaided Gain
A measurement of insertion loss caused by placing an earmold/dome in the ear canal.
REOR; Real Ear Occluded Response
A measurement of the attenuation of an input signal, across all frequencies, when a hearing aid is inserted and turned off
REOR; Real Ear Occluded Response
Clinical usefulness for REOR
- This measurement identifies which low frequencies are released due to the vent effect
- Programming tip: You will not be able to increase the output within the “vent effect” frequency range. Additional gain is be released through the vent!
- The measurement shows if the vent introduced undesired standing wave effects that would impact amplification characteristics?
- i.e., Vent-associated phase cancellation
What does REOR tell us
REOR tells us…
If the vent effect is releasing low frequencies as expected
If an open dome truly “open” (acoustically transparent”)?
- Large domes fold in small ear canals causing insertion loss
If closed vents or power domes supply needed LF gain?
- Research on power & closed domes suggests LF output is compromised in low and mid frequencies for losses > 35 dB HL
- It’s possible for an unexpected slit leak in an unvented mold to release of LF output
REAR; Real Ear Aided Response
The absolute aided output and frequency response when a hearing aid is turned on
The absolute aided output and frequency response when a hearing aid is turned on
REAR; Real Ear Aided Response
Clinical Usefulness of REAR
Why we do it …
To view device’s absolute aided output in a unique ear canal
- If you don’t measure it, you
don’t know if you’ve met your
objective!!!
DSL prescriptive targets specifies REAR (OUTPUT) targets for signals arriving to the TM
Assessment of MPO
REAR 85/90 (MPO); Real Ear Aided Response 85/90 (REAR85/90), AKA MPO,
REAR 85/90 (MPO); Real Ear Aided Response 85/90 (REAR85/90), AKA MPO,
Measures intensity of the output signal arriving at the TM, when the input signal is sufficiently intense to drive the device to its maximum power output level.
Measures intensity of the output signal arriving at the TM, when the input signal is sufficiently intense to drive the device to its maximum power output level.
REAR 85/90 (MPO); Real Ear Aided Response 85/90 (REAR85/90), AKA MPO,
REAR 85/90 (MPO) Clinical Usefulness
To document the maximum SPL that the hearing aid can deliver to the user’s ear for loud sounds
To ensure MPO settings do not exceed loudness discomfort levels
REAR 85/90 uses what type of signal?
Type 1 input signal
______ is the difference in decibels across frequencies, between an ear canal resonance and the resonance of the 2cc coupler
RECD; Real Ear to Coupler Difference
Define RECD
A sound generating transducer produces a signal in the ear canal and in a 2cc coupler to measure the resonance of each.
RECD is the difference in decibels across frequencies, between an ear canal resonance and the resonance of the 2cc coupler
Name two reasons for RECD measurement
- Accurately converts an individual’s HL audiometric thresholds, measured using inserts, to dB SPL values
- Arguably the most useful application of the RECD is in the prediction of real-ear output when hearing aid measurements are made in the test box.
the natural resonance resulting from the pinna and ear canal effect that the patient walked in the door with
REUR
the insertion loss that results from the mold/dome
REOR-
the output arriving to the TM when aid is turned on
REAR
the amount of gain added to the input signal when the aid is turned on
REIG
the MPO that’s arriving to the TM
MPO/RESR/REAR85/90
the difference between the SPL resonance of a 2cc coupler and the SPL resonance of the real ear
RECD
Digital technology is best measured with standardized __________
type II signals
True or False
Type II signals are pure tone signals swept over a variety of frequencies
FALSE
Thats type 1
Type II signals are complex “speech-like” signals
Pure tone signal swept over a variety of frequencies
Type I Test signal
Type I Test SIgnal
Pure tone signal swept over a variety of frequencies
TYpe II Test Signal
Type II signals are complex “speech-like” signals
Broadband signal consisting of random frequencies occurring at different intensities
Type II Test Signal Benefits
Its unpredictable moment-to-moment amplitude changes mimics speech
Type II Test Signal limitaions
Rapid gain changes may not truly show a device’s response to different spectral shapes in the succeeding sounds
Name Type II Test signal Types
Standardized; Speechmap, ISTS-, ICRA
non- Standardized ; Specch Live
speech signals filtered to provide the long-term average speech spectrum (LTASS)
Speechmap
Speechmap
speech signals filtered to provide the long-term average speech spectrum (LTASS)
6 female talkers reading the same passage in American English, Arabic, Chinese, French, German and Spanish
ISTS; International Speech Test Signal:
ISTS-
International Speech Test Signal: 6 female talkers reading the same passage in American English, Arabic, Chinese, French, German and Spanish
distorted speech signal is a recording of an English-speaking talker that has been digitally modified to make the speech largely unintelligible
ICRA; International Collegium for Rehabilitative Audiolog:
ICRA
International Collegium for Rehabilitative Audiolog: distorted speech signal is a recording of an English-speaking talker that has been digitally modified to make the speech largely unintelligible
Measures the LTASS and speech envelope of any audible signal over 10 seconds
Speech Live
Speech Live
Non - standardized signals
Measures the LTASS and speech envelope of any audible signal over 10 seconds
___________ signals are not used for programming amplification
Non-standardized signals
___________ signals are helpful in counseling, but cannot be used for prescriptive fittings
Noncalibrated
Type I Test Signal Benefit
Type I signals drive a higher output than speech signals
They’re used to accurately measure maximum loudness when verifying MPO
Type I Test Signal Limitations
Does not show affect of compression or channel interactions on the output signal
DFS signals attenuate Type I signals when its activated
What is the output requirements to achieve binaural benefit
Aided output must be 15dB
Why does the probe module calibration process result in an “acoustic transparency” b/w the reference mic and probe tube?
The probe microphone module cannot be physically located in the ear canal; the probe tube serves as an extension to the probe microphone
Describe the substitution method calibration protocol
A sound level measurement microphone is placed at subject’s position
Calibration is stored and used as a reference point
Describe Modified pressure using “concurrent equalization”
the reference mic constantly monitors the test signal throughout testing to equalize & adjust signal intensity
- Recalibration occurs automatically. The calibration signal replays every 10 seconds throughout measurement process
___________ the reference mic constantly monitors the test signal throughout testing to equalize & adjust signal intensity
Modified pressure using “concurrent equalization”
____________ the probe is calibrated one time on the patient’s ear, and it stored for the fitting process.
Modified pressure using “stored equalization”
When is Modified pressure using “stored equalization” used?
This method is used when amplified sound can leak out of open domes and interact with reference microphone
Modified pressure using “stored equalization” limitations
Limitation: head movement during measurement can impact final recording
Define reference microphone contamination
When does reference microphone contamination occur?
Reference microphone contamination occurs when amplified output escapes the ear canal though open domes
What Calibration Method is designed to overcome the issue
A modified pressure stored equalization calibration method stops microphone contamination
What does microphone contamination look like on LTASS
PROBE TUBE INSERTION: CONSTANT DEPTH METHOD
You choose a premeasured length on the probe tube BEFORE insertion
Move the probe tube marker to a premeasured position on the probe tube.
Distance from intertragal notch to TM is about:
Male: ~30 mm
Female: ~28 mm
Pediatric: move marker to ~20-25 mm
Using these measurements the tube tip will be within 2-5 mm of TM for the average patient
What is Dr.Dabrowski’s Prefered Method of Probe Insertion?
Combination of CONSTANT DEPTH & ACOUSTIC METHOD
PROBE TUBE INSERTION: ACOUSTIC METHOD
Present a 65 dB SPL pink noise signal while inserting probe tube.
Gently insert the probe tube while keeping an eye on the high frequency notch
The probe is w/i 5mm of the TN when the notch is no longer dragging the gain curve down in the high-frequencies (no > 5 dB at 6k Hz)
Once the measurement is stabilized move the probe tube marker into position.
GEOMETRIC POSITION METHOD
Typically used when patient is squirmy/not cooperative
Probe tube placed along the outer ridge of the intertragal notch of device
Probe tip extends 3- 5 mm beyond the tip of the earmold.
The extent to which this insertion depth is appropriate will also depend on the length of the earmold. For instance, shorter length canals (e.g., not beyond the second bend), it is likely that the probe tube will not be close enough to the eardrum to accurately assess the high frequencies.
Mark the probe tube length
what is Loudness normalization
Loudness normalization methods strives for an output that’s audible and comfortable
- It does not consider the relative importance of specific frequencies to speech recognition
DSL – Desired Sensation Level
What is loudness Equalization
Low frequency signals have more energy than high frequency. Loudness equalization increases the intensity of mid and high frequencies until their energy equals the lows.
NAL NL1 & NL2– National Acoustic Laboratory
Theory behindLoudness Normalization
This prescriptive approach theorizes aided loudness perception should be the same as normal loudness perception.
Theory behind Loudness Equalization
-Balances perception of loudness over range of frequencies
-Increases intensity of mid and high freq until their intensity matches the low frequencies.
-Recognizes audibility of mid and high is important for speech perception / intelligibility.
Which formula uses REAR targets, which one uses REIG targets?
Loudness Normalization
-Uses REAR “OUTPUT” targets
Which formula uses REAR targets, which one uses REIG targets?
Loudness Equalization
-Uses REIG targets.
Which formula uses REAR targets, which one uses REIG targets? Differentiate the use of output and gain targets.
Loudness Normalization
-Uses REAR “OUTPUT” targets
- Soft signals increased until audible and perceived as soft.
- Moderately loud signals increased until just perceived as comfortable
- Loud increased to loud but OK.
-Formula provides output targets for soft, moderate, loud, & MPO settings
Which formula uses REAR targets, which one uses REIG targets? Differentiate the use of output and gain targets.
Loudness Equalization
-Uses REIG targets.
-Looks at threshold and audibility then decides how much gain needs to be added.
-Equalizing energy, not intensity.
-Take HF energy which is weaker and vibrate less than LF and makes them stronger
Name DSL 5.0 differences
-DSL adult formula reduces mid-freq gain by 7dB
-Milder thresh = low TK (~30 dB SPL)
-Sev thresh = higher TK (~60 dB SPL)
-Too much gain of soft results in loss of intelligibility when loss is severe
-DSL for peds is louder in mids than in adults
-Limitation: doesn’t account for ABG that is common in child population
Name NAL-NL2 differences
-Early uses Lybarger ½ gain rule, calculates gain targets as 50% threshold loss
-Revised formula: calculates gain targets as 46% threshold loss, based on SII (more gain is added to sounds contributing most to speech intelligibility)
Which prescription provides targets for tonal languages?
-NAL – LF targets for tonal languages because tonal language is based more on LF than HF
Which formula supplies MPO targets?
-MPO targets are supplied by DSL
Which formula supplies targets for A/B gaps?
-NAL-NL2 provides Air Bone Gap targets.
-More gain added to overcome attenuation from mechanical loss
-25% of ABG is added
Name the formula used for severe to profound losses
DSL will shift TK to 60 dB SPL (Higher TK), expansion is applied to low input
-multi-stage WDRC applied to input to expand DR
I BELIEVE DSL IF WRONG TELL ME
Which formula supports language development?
THE DSL ALGORITHM MAXIMIZES AUDIBILITY TO ASSIST WITH LANGUAGE DEVELOPMENT
Name Programming Pitfalls
- Disregarding targets falling below thresholds
- Only adjust a frequency shaping band for 1 input intensity
- adjusting moderate channel input for 65dB signal during the initial fit
- Using too small a frequency range when adjusting to target
- If you increase gain without observing an increase in REM, stop adding gain
- Not realizing MPO headroom limitations can result in unintentionally high compression ratios
WHAT MAKES A LOSS ASYMMETRIC?
Asymmetric threshold loss
- 3 adjacent frequencies of >20 dB
- 1 frequency > 25 dB
Asymmetric speech intelligibility
- If you made the speech signal audible frequencies critical to understanding
Asymmetric SNR Loss
- 20% difference is significant enough to consider it, kind of a quick clinical rule of thumb, not researched. recommends quick sin to be done at the assessment phase part of comp audio
Asymmetric discomfort levels
Are tolerance levels significantly different
Types of NIHL
Type I: Normal or near normal to 2k Hz
Type II: Threshold loss extends into the lower frequencies (i.e., below 2000 Hz).
Type III: Threshold loss shows a precipitous slope into the high frequencies.
Type II & III Challenges
- OHC damage in the cochlea leads to abnormal loudness growth
- Potential distortion for patients with damaged or absent inner hair cells (IHC)- Dead regions
- High frequency output is limited by feedback.
- Full high frequency audibility is not a reasonable goal due to comfort and sound quality problems.
Recommendation for Frequency Lowering
Verify audibility of HF signals at time of initial fit
For adults do not enble at first fit; try after 4-6 wks
Management Dead regions (IHC loss)
Special fitting strategies aren’t need for the presence of 1-2 dead regions
Special fitting strategies MAY be needed when extensive dead regions are present:
- Do not assume this individual needs reduced high frequency output
Frequency Lowering programming steps
- Find the “Maximum Audible Output Frequency” (MAOF) with frequency lowering technology turned off!
- Asses FL candidacy
- Enable FL to verify if audibility of a calibrated /s/ is achievable
Reverse slope losses Fitting Strategies
Add only 15-20 dB of gain in low and mid frequencies initially
Add 10-15 dB at 2k Hz & above of gain for increased audibility!
Allow time for habituation before further increase
Conductive losses Fitting Strategies
Additional gain is needed to overcome the attenuation caused by the mechanical loss
Air/bone gaps attenuate the signal’s amplitude before it arrives to the cochlea
- A/B gaps with normal B/C
thresholds: compression is not
needed because the dynamic
range is normal.
* Use of 1:1 linear signal
processing (or very low
CR) is fine
A/B gaps with abnormal B/C thresholds (mixed loss):
- Compression is needed in
addition extra gain due to the
reduced dynamic range
And then probably fitting strategies for NIHL, IHC loss, Reverse slopes, CHL, perfs, andsevere to profound losses
Fitting Strategies Severe to profound losses
Don’t rely on a targeted approach; begin with very low CR’s & listen to your patient instead
If they complain that speech is ‘muddled’, or indistinct modifications are needed
- Change to slow acting
compression to maintain a
longer non-compressed state
- Slower acting compression
approaches maintain more of
the linear aspect of the speech
signal over a longer periods of
time.
- Reduce compression ratios
- Frequency lowering MAY help by shifting signal to lower frequencies (don’t use this strategy at first fit)
- Audibility of only the signal ABOVE the LTASS may be preferred
Perforations FR
Options
BC/Bone ancored devices
- Some dislike surgical recommendation or are not candidates
Ear level device (HA’s, etc.)
Will the pathology allow for an ear level device?
- What pathophysiologic concerns must be considered?
- Style considerations?
- Prescriptive considerations?
- Verification considerations
