1
Q
Why is verification of hearing instruments an important measure?
A
- When patients are fitted with this best practice they have higher satisfaction with their HAs
- Take up less clinic time because they are more satisfied
- Maximizing potential of audibility and benefit of the HAs we have selected
- There is no HA at a premium level that will outperform poor audibility and poor fitting (if we cant verify to target we are reducing benefit)
- Audibility is key
2
Q
What does the verification of hearing instruments confirm?
A
Verification of hearing instruments (real ear measurements/REMs) is a practical procedure used to confirm that the hearing instruments are performing in a certain manner to provide appropriate benefit to the patient based on their audiological needs
3
Q
What are the 3 verification measures?
A
- Objective
- Measured in Real-Time
- Provide Monaural data (vs. binaural benefits reported by patient)
4
Q
How is validation different from verification?
A
- Validation: subjective measures (are you hearing better in a context that is important to you)
- Verification allows us to look at two hearing aids and how they are working to better performance together
5
Q
Define Real Ear Unaided Responses/Gain
A
(SPL at the TM): looking at the response of the ear itself with no amplification present (what is the ear bringing to the table)
6
Q
Define Real Ear Aided Responses/Gain
A
(Aided SPL at the TM): looking at sound delivered to the TM with the HA in place
7
Q
How do you use REAR to determine fit to target?
A
- Solid line: long term average speech spectrum (want to see the range going directly through the targets)
- Bubble: shows 30th and 99th percentile
- LDL: what are the loudness discomfort levels
8
Q
What is REAR really determining?
A
How much gain is being provided for soft, loud, and average inputs
9
Q
How do you use REIG to determine fit to target?
A
This is what an insertion gain target might look like (not the most popular view of measurement)
10
Q
What is the speech intelligibility index (SII)
A
- The Speech Intelligibility Index (SII) measures the amount of a given speech signal that is audible to the listener
- Ideal to use as a counselling tool, integrated into verification software, and helps to understand how much speech is available with and without the hearing aids. In combination with our matching to “target, the SII can be used to understand if the hearing aids are providing appropriate amount of audibility.
- The calculation of the aided SII is is done by evaluating the recorded aided response curve and the points where the aided response curve is higher (above) the hearing threshold of the patient.
- Different frequencies are given a different weight. For example, frequencies that are more important for speech intelligibility (e.g, 1500 to 3000 Hz), will have a greater impact on the SII.
11
Q
SSI - what is percentile SII (picture)
A
- Percentile SSI: the score is a way of quantifying the intelligibility of speech based on the proportion of speech cues that are available
- This is a likely predication based on aided and unaided conditions
- SII of 20, predicted speech score in words and sentences is pretty low
- SII of 90 is better because getting 90% of words in sentences
12
Q
SSI with and without aided thresholds (picture)
A
Without aided thresholds, SSI was 45, but with, its 75
13
Q
What are the 5 pieces of equipment needed for verification equipment?
A
- Hearing Aid/Real-Ear Analyzer
- Sound Source
- Test Box
- Probe mic and probe tube
- Reference Mic
14
Q
Explain how the probe mic and probe tube placement works
A
- Probe Mic measures the response, in the ear canal, in dB SPL (ideal for REUR, and REAR finding)
- Correct Placement of probe tube is essential for accurate REMs
- Placed to approximately 5mm of the TM (black marker to inter-tragal notch)
15
Q
What happens if a probe tube isn’t in the correct place?
A
A probe tube not in the right place, the frequency response will tell you that you cannot reach gain
16
Q
4 tips for probe mic and probe tube placement
A
- Clear Ear Canal (cerumen management if needed)
- Infection Control on retention cord and probe module
- Reference Mic facing outward
- Probe to to the front-side of the retention cord- stability and holding placement
17
Q
How do you place a hearing aid in the ear with a probe tube
A
- The probe tube should not easily slide
- The dome should be sitting on top of the probe tube, but not pushing on it
18
Q
What is the reference mic?
A
- Reference Microphone monitors the input from the loudspeaker to ensure that the signal delivered remains accurate and stable
- Reference microphones are in both the test box, and the on-ear probe module
- Reference microphones are active during the process of REM to monitor the signal
- Before each speech stimuli is presented, there is a “pssshhhh” sound that will be audible. This is the calibration for the reference mic
19
Q
How do you set up a measurement in the verification device?
A
- This will include audiogram, fitting rationales, hearing aid form, coupling/venting options.
- Select test signals (sound and level) Special consideration for “open fit” (equalization)
20
Q
What are the 6 procedural guidelines for completing a REM?
A
- Setting up measurement in verification device
- Positioning the patient comfortably (0° azimuth, directly in front of loudspeaker, within 45 to 90 cm ideally)
- Perform otoscopy: determine the need for cerumen management
- Probe tube insertion (placing probe tube, ideally in a clear canal, to appropriately depth)
- Reference mic positioning (facing outward)
- Checking in with patient (are they seated comfortably, ready to proceed?)
21
Q
What are 2 reference mic considerations
A
- Open-fit devices require equalization prior to performing REMs
- Devices are on the patient, but are on “mute” (or turned off)
Why? Sound leaking out may effect the stimulus from the loudspeaker
22
Q
Is an open-fit really an open-fit?
A
- REUR can provide insight
- If the two curves match up, it means with the HA in place, the two responses match up
- The second pic is showing what happens when the HAs are muted
- Generally run this when the patient is using a cap dome
23
Q
What features do we have to select when doing a REM?
A
- Target: which rational are we using (make sure this is a match to what we programed in software)
- HL transducer: how was the HL measured in a sound booth (sound field, insert, headphone)
24
Q
Why is it important to select the transducer type when doing a REM?
A
- How was the hearing loss measured in testing?
- To measures REMs, there is a conversion that occurs between the dB HL thresholds obtained, and the measured dB SPL at the eardrum.
- The conversion is partially based on the RETSPLs
25
What can impact probe-mic measures? Why?
- Cerumen in the ear canal can impact probe-mic measures
- Pathways of sound is modified (residual canal volume)
- Probe tube may be blocked by cerumen
- May be impossible to place the probe tube in the correct position depending on the location and amount of the wax
- Managing cerumen prior to REMs when necessary is the best way to get an accurate result
26
Explain how the loud speaker and patient location works
- Ideally away from reflective surfaces (right in a corner, reverberant surfaces)
- Ambient noise measurement tool to ensure room is quiet (should not be louder than soft speech inputs)
- Also to note: verification system should be placed where the audiologist can access all equipment, and move around the patient easily
27
What are the 3 types of speech stimuli test signals?
1. International speech testing signal (ISTS)
2. Standard speech signals
3. International collegium for rehabilitative audiology signal (ICRA)
Top two are the most popular
28
What is the ISTS
- International Speech Testing Signal (ISTS)
- Internationally recognized test signal based on non-intelligible speech.
- The signal is female speaker featuring six different languages (American English, Arabic, Chinese, French, German, and Spanish)
- Shaped according to the Long Term Average Speech Spectrum (LTASS)
29
What is the standard speech signal?
- Standard Speech Signals (Primarily used in North America with English speakers).
- The carrot story or the ear/eye story.
- Shaped according the LTASS
30
What is the ICRA?
- International Collegium for Rehabilitative Audiology Signal (ICRA):
- Noise signals that can be used for hearing aid testing (including real-ear measurements)
31
What is the problem with the standard speech signal?
With standard speech signals, sometimes people get hung up on content and try to understand the story (when they don’t have too)
32
What level are signals for testing presented at?
- Signals for testing are usually presented at: 55, 65, and 75 dB SPL (+/- 5 dB SPL)
- Soft speech should be above the test room’s ambient noise level
33
How does feedback management work with speech stimuli test signals?
Speech signals are preferential to prevent the hearing aid from classifying the signal as feedback. Generally, this is why pure-tone sweeps, pink/white noise signals are NOT used for “speech-mapping”
34
Should DM and noise reduction algorithms be turned off?
- By using speech noise stimuli during REM, the advanced features do not necessarily need to be turned off to obtain an accurate representation of the performance
- Some softwares have a verification mode (i.e. Resound’s “REM test” and Phonak’s “Verification Mode”)
35
What are the 3 trouble shooting techniques when the REAR has an unusually low output and is flat
1. Is the hearing aid muted?
2. Is the probe tube clogged with cerumen or other debris?
3. Is the probe tube pinched by the earmold?
36
What should you do if I am unable to meet high frequency targets, even though the hearing aid software is indicating that I can?
1. Is the probe tube in the correct position? (a shallow insertion can greatly effect the measured output)
- Will often see a really poor response on RECD
2. Is there a considerable amount of cerumen in the canal that is effecting the response?
37
What are the 5 guidelines for determining when to perform REMs?
1. Upon first dispensing new hearing aids
2. When re-programming hearing aids is warranted due to a change in audiometric thresholds (targets changed)
3. When the acoustic coupling has been changed/altered (i.e. moving from an open to a closed dome, changing the venting of an earmold, etc.)
4. When hearing aids arrive back from the manufacturer from repair (**particularly is the settings have not been saved to the device)
5. When you are concerned of a function issue or if a patient reports a decrease in hearing aid benefit (**possible audiological testing warranted as well)
38
When do you NOT perform REMs?
1. Active drainage from the ear (infection)
2. Abrasions and bleeding in the ear canal that will create discomfort
3. Perforations that my lead to the probe tube being placed in the middle ear space
4. Reports of significant pain/discomfort during otoscopy or probe-tube placement
39
When in doubt...
Refer out!
40
What are the limitations of a first-fit without verification
- Multiple research studies have found that “first-fit” under amplifies high frequencies and can negatively affect speech recognition ability
- First-fit programming alone leads to lower patient satisfaction with hearing aids
- Not performing REM is an ethical dilemma
41
What are the benefits of probe-mic measures?
- 79% of the study participants preferred programmed fittings using REM versus the first-fit.
- The “programmed fit” using REMs an average of 15% better word recognition, and a significant improvement in background noise (4.2%)
42
How do automatic REMs work?
- Automatic fine tuning integration with verification system (verifit link)
- Many manufacturers have an “automatic” REM protocol that is used in conjunction with verification equipment
- Can usually be done in test box or in an on-ear measurement
- Gain for various inputs are automatically adjusted to match the targets in real time
- Research on this is being done on the accuracy of this- there are camps of research to suggest this is a valid measure
43
How many clinicians routinely perform REMs? Why?
35-55% (there is a gap because of the time it takes, complexity of the task, and lack of understanding the benefit)
44
What are 4 special considerations for pediatric patients?
1. Compared to adult patients with acquired hearing losses that can often “fill-in-the gaps” when listening to language.
2. Young children who are learning auditory language need access to sounds to differentiate and integrate speech sounds.
3. Facilitate the development of auditory listening, speech, and language skills
4. Reduce the effects of auditory deprivation (sooner is better when considering amplifying speech for pediatric children with HL)
45
Should HAs be provided to pediatric patients with mild or slight hearing loss?
Multi-disciplinary approach
46
Should HAs be provided to pediatric patients with unilateral hearing loss?
SAC 2020 position statement guidelines UHL
47
Should HAs be provided to pediatric patients with profound hearing loss?
SAC 2018 position statement guidelines CI
48
Should HAs be provided to pediatric patients with auditory neuropathy?
CISG 2012 guidelines
49
Should HAs be provided to pediatric patients with recurrent otitis media?
ENT consultation
50
What are the 4 candidacy considerations for pediatric patients?
1. Case-by-case/results of testing
2. Communication development
3. Performance in school
4. Supports in place
51
What are 5 reasons for choosing a BTE hearing aid for a pediatric patients?
Preference for BTE hearing aids for several reasons:
1. Durability
2. Less chance of feedback (*if molds are fitting well*)
3. Earmolds can be made of various material, and replaced as the ear grows
4. Ideal connection to accessories (like FM system)
5. If a hearing aid goes for repair, generally easy to provide loaner to use with an existing earmold
52
What 6 things do we consider when deciding on a hearing aid style for pediatric patients?
1. Select a small hearing aid to best fit a small ear**
2. Use of pediatric earhooks
3. Use of retention/protection tools like “Huggies” and “Ear Gear”
4. VC deactivation
5. Tamper-resistant battery doors
6. Color choices for earmolds, casings, ear hooks
53
What are the 6 challenges with infants and young children?
1. Complete audiometric information may be unavailable
2. Relying on limited data obtained from soundbooth (limited data points)
3. Relying on the results of ABR
4. Difficult to obtain supra threshold measurements (LDLs)
5. Difficult to physically fit the hearing aid on ear, or earmolds in ears
6. Difficult getting subjective feedback on the hearing aid performance (validation)
54
Compared to adults, children's ears show differences in what 2 things?
RECD and REUR
55
Why do the RECD values change in children?
As the ear canal is growing and getting larger
56
Explain the REUR in children?
- The resonance frequency is much higher in young children than it is for adults (about 2-3 times higher)
- As a child ages, the peak begins to decrease/ shift to a lower resonant frequency
- The most rapid changes occur in the first 20 months of life, stabilizing after 24 months
- This is due to the changes in the physical properties of a growing ear canal!
57
DSL-v5 Fitting Rationale
- Generally the preferred fitting rationale for pediatric fittings
- The DSLv5 method is a well researched, validated, science-based approach to pediatric fittings aiming to...
- Optimize speech recognition for children with hearing loss, bring speech to a desired sensation level to maximize intelligibility
- Speech is amplified across a broad range of frequencies to support auditory learning and make speech cues audible
- This is a normalization approach
58
What are the two ways to verify HA function in pediatric patients?
- REMs and sREMs (test box)
- Benefits and Challenges of both? May struggle to get a pediatric patient to sit still to get the REM, Better to measure in textbox
59
What are 3 considerations for advanced features for pediatric patients?
1. Directional Microphones?
2. Digital Noise Reduction?
3. Automatic vs. Manual Programs?
60
What are the 3 strategies for digital noise reduction in pediatric HAs?
1. Directional microphone technology
2. Automatic noise reduction algorithms (reducing gain)
3. Multiple programs in hearing aids (automated switching)
61
DM - Think about how children hear in the environment? Could DM be a problem? Could children be “missing out” on environmental sounds?
Current practice guidelines recommend against full-time use of fixed/strong directional hearing aid programs and encourage the facilitation of overhearing in younger children
62
Automatic noise reduction algorithms - What noise do we want to reduce? Is there a negative aspect of noise reduction?
- Recent studies show that mild to moderate noise reduction do not necessarily degrade speech recognition for children who are hearing aid users and may provide easier listening and loudness relief
- Wide variability with automatic noise reduction (ANR) processing.
- No set protocol presently
63
Is automated switching between programs a good thing to have in pediatric HAs?
- Automatic activation of “age-appropriate” automatic programs are recommended for most children.
- It is important to note and monitor through discussion, follow-up, and datalogging how much time a child spends in noisy environments
- Proceed with caution when providing access to manual programs.
64
How do you validate pediatric fittings?
- On-going process
- Observation of auditory behaviours (such as detection and localization)
- Outcome Measures specific to children (for example, the LittlEars and PEACH questionnaires)
- Team approach with parents/caregivers
- Multi-disciplinary input
65
What is the general post-fitting follow-up guideline for pediatric patients?
- Every 3 months during the first two years, and every 6 months following
- “Open-door” to providers for assistance when needed
Amplification I
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