1
Q
What are the 9 HA styles (smallest to largest)?
A
- Extended wear devices (i.e Phonak Lyric)
- IIC (invisible in-the-canal)
- CIC (completely in-the-canal)
- ITC (in-the-canal)
- Half-shell
- ITE (in-the-ear)
- RIC/RITE (receiver in-canal/receiver in-the-ear)
- RITA (receiver in-the-aid)
- BTE (behind-the-ear)
2
Q
What is the difference between a half-shell and an ITE?
A
A half-shell doesn’t fill up the whole concha
3
Q
____ is the largest and most powerful HA
A
BTE
4
Q
What are 5 differences between hearing aid models?
A
- Cosmetic appearance
- Different ability to provide gain (more or less power)
- Different venting ability
- Feedback susceptibility (squeal)
- Maintenance (cleaning, care)
5
Q
Where is the serial number typically located?
A
- Inside the battery door
- Underside of the casing
- Under a colour marking
- Imprinted on the shell of a custom device
6
Q
What is feedback?
A
“Feedback” occurs as a result of sound (attempting to be delivered to the ear canal) leaks either around or through the earpiece, gets picked up, and re-amplified by the microphone system, and re-amplified again, and again, and again
7
Q
How do HAs avoid feedback?
A
Hearing aids often have “feedback management systems” to avoid feedback
8
Q
We can minimize feedback by doing what 3 things?
A
- Coupling: how the HA is put on the ear
- Venting: air flow
- Physical fitting of device or earmold to the ear
9
Q
Explain the feedback loop?
A
- Input coming to microphone
- Amplifier provides gain
- Reciever puts sound into canal
- Output gets re-picked up by microphone
- Gain keeps increasing in phase which gives us the oscillation of feedback
10
Q
What 3 ways do we address feedback?
A
- Close the canal
- Minimize venting
- Create a “snug” fit in ear
11
Q
Why does the occlusion effect happen?
A
- Low frequency sounds (vowels in particular) have high SPL level (100dB in the back of our throat)
- Those high intensity sounds conduct through the mandible, and condyle to the cartilaginous portion of the ear, causing vibration in the ear canal itself
- Without any physical obstruction on the ear canal (i.e. a hearing aid), those sounds would escape through the canal.
- With a device in place, energy can be trapped, and redirected to the tympanic membrane, and transmit through the auditory system, perceived as a increase in low frequency sounds
12
Q
The increase the level of sounds in the ____ when the canal is occluded
A
Low frequencies (greatest at 500 Hz and below)
13
Q
This increase can be between ____dB in an occluded canal vs. “open” canal
A
20-30
14
Q
What does the occlusion effect result in?
A
Own voice sounds “loud”, “hollow”, “boomy”, chewing becomes aggravating
15
Q
Why is the occlusion effect and feedback a balancing game?
A
If we open the canal to reduce the occlusion effect, it increases the possibility of feedback
16
Q
What 3 ways to we address occlusion?
A
- Modify to enlarge the vent
- “Open” the fitting
- Adjust low frequency gain
17
Q
Explain how HA batteries work?
A
- Zinc-Air batteries provide power to hearing aids
- Zinc-air preferred for safety and efficacy
- Voltage stays consistent over the battery life (1.25 V)
- Activated by removing tab
- Capacity (in mAH hours) dependant on the size
- Typically last 7-10 days (depending on amount of time worn)
18
Q
Why should you let a battery sit for 2 min after peeling off the tab?
A
Allow the voltage potential to come up
19
Q
A 675 battery is in a ____ power battery
A
High
20
Q
The battery door is often the ____ of the HA
A
On/off
21
Q
Why might a person choose a rechargeable HA?
A
- Increasing in popularity (ease of use, and minimizing waste in)
- Designed for “full day of use”, devices to be recharged at night
22
Q
Pros and cons of disposable batteries
A
- Good for someone who doesn’t have a power source available (traveling)
- Can be ingested (cognitive issues)
- Can they open and close the battery door?
23
Q
Pros and cons of rechargeable HAs
A
- Don’t have to worry about batteries
- A friendlier environment option
- Ease of use
24
Q
Mic, amplifier, receiver location - BTE
A
- The microphones, amplifier, and receiver are in the device sitting behind the ear.
- The sound is delivered to the ear through an earmold, attached to the device by tubing (either standard or slim tube); No electronics in the earmold
25
Mic, amplifier, receiver location - RIC/RITE
- The microphones and amplifier in the device sitting behind the ear
- The receiver ( the speaker ) sits in the ear canal.
- A custom shell or dome is attached to the end of the receiver
26
Mic, amplifier, receiver location - custom devices in the ear (IIC, CIC, ITC, ITE)
The microphone, amplifier, and receiver are built into a custom shell
27
How does a standard BTE with earmold work?
- Behind the ear devices with an earmold feature the microphone, amplifier, and receiver is in the device behind the ear
- Sound is delivered to the ear via a tube with a tube attached to a custom ear piece
28
What different materials can an earmold be made from?
Silicone, lucite, polyethylene
29
Why might a different material be chosen for an earmold?
Based on skin condition, ear texture, comfort, and sensitivity
30
Earmold styles have both ____ and ____ properties
aesthetic, acoustic
31
____ refers to the channel through the earmold which allows ____ between the medial and lateral side of the mold
Venting, airflow
32
A hard ear typically needs a ____ earmold
Soft
33
A soft ear typically needs a ____ earmold
Hard
34
How does a BTE with a slimt tube (RITA) work?
- Behind the ear devices with a slim tube feature the microphone, amplifier, and receiver in the device behind the ear
- Sound is delivered to the ear via a thin tube attached to a non-custom dome (*in many cases)
35
Who are the 5 ideal candidates for a BTE?
1. Pediatrics* (earmolds, robustness, retention)
- Earmolds need to be changed every 4-6 weeks
- Robust = can hold up to their lifestyle
- These devices stay the best on the ear
2. Adults with configurations up to profound hearing losses
3. Patients who require more of a physical device to “handle”
4. Patients with excessive moisture and cerumen (electronic are not in the ear, earmold can be cleaned)
5. Molds can be made from a variety of material for optimal comfort
36
BTE earmolds - landmarks & coupling to the ear
37
____ are the most powerful HA option
BTEs
38
Why are BTEs less susceptible to feedback?
- Separation of sound outport and microphone
- Tubing and earmolds can be modified to further separate this
39
What range of HL can use a BTE?
Mild - profound
40
How do RICs work?
- RIC/RITE boast the microphones and amplifier in the device sitting behind the ear
- The receiver (the speaker) sits in the ear canal
- A custom shell or dome is attached to the end of the receiver
41
What are the 7 HA components of a RIC?
1. Optional program or volume button
2. Microphone port 1
3. Microphone port 2
4. Battery door
5. Receiver wire (can occasionally be a thin tube)
6. Dome (various types)
7. Receiver
42
Different types of RIC domes
43
Custom RIC molds
44
RIC - Pick receiver size depending on the ____
Power
45
Why are RICs cosmetically appealing?
- Small casing behind the ear
- Receiver wire is discreet
46
What range can a RIC fit?
Generally can fit up to a moderately-severe hearing loss (dependant on the receiver and coupling)
47
RICs - Receivers can be interchanged to accommodate different ____ (or changing hearing thresholds)
Configurations
48
RICs can be stocked for ____
Same day fitting if custom shell is not required
49
RICs have less gain compared to standard ____
BTEs
50
What are the 4 custom HAs?
1. IICs
2. CICs
3. ITCs
4. ITEs
51
What are the 5 components of a ITC/ITE?
1. Earshell
2. Battery door
3. Microphone
4. Removal string
5. Vent
52
The larger the custom hearing aid, the greater the ____ it can accommodate
Hearing loss
53
What range of HL can custom HAs accomodate?
Mild-severe (dependent on the receiver power selected)
54
Why might require want a custom HA:?
- Patients who cannot support and aid on the ear, or have a preference for the full device off the pinna (glasses, masks, helmets, etc.)
- Patients whose dexterity limits them from handing two components
55
Can those with OE abnormalities get a custom HA?
Custom hearing aids need to be placed in canals are that of a certain shape, with no abnormalities, and whose shape directs sound towards the TM
56
Custom hearing aid shells must be made from a ____ material
Solid
57
What are shells typically made from?
- Acrylic material (sometimes titanium)
58
What are ITE HAs great at reducing?
Wind noise
59
What range of HL can ITE HAs accommodate?
Mild-severe
60
Does ear canal volume matter with ITE HAs?
Yes, residual ear canal volume- depth of device matters
61
What is an extended wear device?
- Phonak Lyric
- HAs that get placed deep with in the EAC and stay there for a couple of months
- Sit within 4mm of the TM
- The device is only 12 mm
62
Ideal candidates for an extended wear device
- Fitting range
- Contraindications (head/neck surgery cannot)
- Health considerations (diabetes, regular MRIs cannot)
- Lifestyle considerations (skydivers cannot)
63
What 4 audiological factors that help select the appropriate style of HA for a patient?
1. Audiogram configuration dictates the amount of amplification required (i.e the amount of gain we require to meet a targets at frequencies to make speech audible and comfortable)
2. Health of the ear
3. Cerumen, moisture
4. Physical shape of the ear
64
What 4 non-audiological factors that help select the appropriate style of HA for a patient?
1. Preference and comfort of the patient
2. Dexterity of the patient
3. Other features desired (bluetooth, FM systems, partner microphones, TV connectors, etc.)
4. Face masks, glasses, helmets
65
Selection of hearing aids is complex, and involves many ____
Considerations
66
Some HA selections can be ruled out based on ____ of hearing loss
Degree
67
What are OTC HAs?
- OTC (over-the-counter) hearing aids are devices that may be purchased without the oversight of a hearing dispenser, or physician
- Not available in Canada yet (Health Canada), Federal Drug Administration has approved these devices for those in the USA
- Over the age of 18
- “Perceived” mild to moderate hearing loss
Amplification I
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