1
Q
How is candidacy relevant to us as practicing audiologists?
A
to avoid understimulation (not enough gain) and overstimulation (too much gain), and to tune HAs within the patients dynamic range using a holistic approach
2
Q
Name special populations relevant to HA candidacy
A
Pediatrics, SSD, Asymmetrical HL, Conductive HL, CAPD
3
Q
What is HA ownership rate?
A
% of total population that owns HAs
*2-4% in developing countries
4
Q
What is HA penetration rate?
A
of HA owners (divided) by # of people with HL
*more relevant clinically
5
Q
Of those who believe they have HL, how many own HAs
A
14-31%, increases with HL degree
6
Q
At what point does HA penetration rate reach 50%?
A
when 4-frequency average in the better ear > 40 dB HL
7
Q
What societal goal exists for HA ownership?
A
At least 50% of people with HL have access to HAs
8
Q
Besides the audiogram, what info do clinicians need for candidacy?
A
-Attitude and motivation
-Acknowledgement of HL
-Communication needs
-Consequences of HL
-Self-image
-Expected benefit
-Fear/uncertainty
-cost-benefit ratio
-Influence of others
9
Q
What is the expected benefit?
A
How beneficial the patient believes HAs will be, based on others’ experiences or counseling
10
Q
How do operation/dexterity issues affect candidacy?
A
May prevent HA use –> clinicians must assess body language and concerns about handling devices
11
Q
What is the cost-benefit ratio in candidacy?
A
Patient’s perceived costs vs. perceived benefits of HA use
12
Q
Who influences candidacy besides the patient?
A
Family, significant others, professionals (can be positive or negative)
13
Q
What does PTA tell us in candidacy
A
Good indicator of impairment, moderate for activity limitation, poo for participation restriction
14
Q
Why can HAs hurt normal hearing listeners?
A
Internal HA mic noise makes soft sounds harder to detect in quiet
15
Q
What model explains patient decision-making for HA use?
A
Health Belief Model
16
Q
How does PTA relate to HA ownership?
A
As PTA increases (greater HL), ownership/use increases
17
Q
Which configuration causes more disability: LF vs HF loss?
A
LF HL is more strongly related to disability
18
Q
Who is less likely to use HAs (speech identification in quiet)?
A
Those with better speech identification in quiet, because they can manage without amplification
19
Q
Who is less likely to benefit from HAs (speech identification in noise)?
A
Those with poor speech identification in noise, since HAs may not improve their performance
20
Q
Who is more likely to benefit from HAs (self-reported disability)?
A
Those reporting higher disability are more likley to use HAs and report benefit
21
Q
What tools measure self-reported disability?
A
APHAB, HHIE
22
Q
What is ANL?
A
Acceptable Noise Level = MCL for speech - background noise level (BNL)
23
Q
How does ANL predict HA use?
A
ANL < 7 dB = likely full-time user
ANL > 13 dB = unlikely full-time user
24
Q
Ex of ANL
MCL = 80 dB
BNL = 75 dB
What is ANL and candidacy?
A
ANL = 5 dB
Good candidate (likely benefit)
25
What environmental factors influence candidacy?
Listening needs, expectations, communication environments
26
How does stigma affect HA use?
Concerns about looking old, HA size, social perceptions
May reduce candidacy
27
How does dexterity affect HA management?
Reduced use if patient struggles with insertion, removal, or controls
28
Does age directly affect candidacy?
No indirectly does
e.g., earlier HA use = better adaptation in later life
29
Which personality traits predict better HA use/benefit?
Internal locus of control, extroversion, agreealeness
30
Which traits predict worse HA use/benefit?
obsession, high neuroticism
31
How does openness affect HA use
Patients who are more open (variety-seeking, curious, insightful, broad-minded, analytical) are less likely to obtain hearing aids, perhaps because they use their open nature to reduce the problems their hearing loss causes in ways that do not require the use of hearing aids
32
What about CAPD and HA benefit?
Mixed results. not contraindicated. Directional mics and wireless may help
33
Do HAs cause tinnitus?
No, but they can supress it
34
What are the purposes of prescription procedures?
1. Amplify speech enough for audibility
2. Do not exceed UCL
3. Maximize intelligibility
4. Keep listening comfortable
35
What are the four categories of prescription methods?
Linear, Nonlinear, Special-purpose, Proprietary
36
Who introduced the 1/2 gain rule?
Lybarger
37
What is the 1/2 gain rule?
Gain = 1/2 of the HL (dB HL)
38
What were the limitations of early linear prescriptions?
Did not consider LDL or real-ear acoustics
39
What did NAL-R improve?
Max intelligibility at MCL; loudness equalization across frequencies
40
What does loudness equalization mean?
Equal loudness across speech frequencies
41
What is the goal of DSL?
Audible, comfortable, intelligible sounds, especially for children
42
How does DSL differ from NAL?
DSL prioritizes audibility (children)
NAL prioritizes intelligibility (Adults)
43
What are examples of nonlear prescriptions?
NAL-NL1,
NAL-NL2,
DSL[i/o]
44
Which prescribes more gain DSL[i/o] or NAL-NL1?
DSL[i/o]
45
What adjustments did NAL-NL2 add?
Factors like age, gender, tonal vs non-tonal language
46
What is the goal of nonlinear prescriptions?
To adjust the gain differently depending on input level (soft, medium, loud sounds)
47
How does NAL-NL1 determine gain?
Prescribes gain to maximize intelligibility while keeping loudness comfortable
48
What is a common issue with NAL-NL1
It prescribes less overall gain than DSL, sometimes under-amplifying children
49
What population is DSL [i/o] especially suited for?
Children (focus on the audibility of speech sounds)
50
How does NAL-NL2 improve over NL1?
Adjust for listener characteristics:
Age (children need more audibility)
Gender (females may prefer less gain)
Tonal vs non-tonal language (Mandarin speakers need more LF audibility for tones)
51
Which formula is best for a 12-year-old Mandarin-speaking child with bilateral severe SNHL
NAL-NL2 → accounts for tonal language and age.
52
Why not NAL-NL1 for the Mandarin-speaking child?
NAL-NL1 does not adjust for tonal languages or children.
53
Why not DSL for the Mandarin-speaking child?
DSL focuses on audibility, but NAL-NL2 provides a better balance between audibility and loudness for tonal language speakers.
54
What is the purpose of verification?
To ensure HA output matches prescribed targets in the patient's ear canal
55
What is REUG?
Real Ear Unaided Gain - natural ear canal resonance
56
What is REAG
Real Ear Aided Gain - response with HA in ear
57
What is REIG?
Real Ear Insertion Gain = REAG - REUG
58
What is REAR
Real ear aided response - output in dB SPL in the ear canal
59
What is RECD?
Real Ear to Coupler difference - difference between 2cc coupler and real ear response
60
Why is RECD especially important in pediatrics?
Children's ear canals are smaller --> need corrections to ensure proper amplification
61
How does linear amplification work?
Provides same amout of gain regardless of input level
62
What problem occurs with linear HAs?
Loud sounds may become uncomfortably loud
63
What is the purpose of compression in nonlinear HAs?
Reduces gain for louder sounds while keeping soft sounds audible
64
What are common compression ratios?
Mild: 1.5:1
Moderate: 2:1
High: 3:1+
65
What is WDRC?
Wide dynamic range compression - provides more gain for soft inputs and less gain for loud inputs
66
Why is WDRC useful?
Fits amplified sounds into the patients reduced dynamic range
67
Why is music more challenging to amplify than speech?
Wider dynamic range, higher peaks, broader frequency content
68
What HA feature can distort music?
Too much compression (flattens dynamics)
69
What HA feature improves music listening?
Wide input dynamic range (high input limiters ~115-120 dB SPL)
Low compression ratios
Reduced noise reduction/directional mic activity
70
What special program is often needed for music?
Dedicated "music program" with different settings from speech
71
What factors influence HA style selection?
Degree of HL
Ear canal size
Dextarity
Cosmetics
Comfort
72
Which HA style is good for severe HL?
BTE with earmold (more power, less feedback)
73
Which style is good for cosmetic concerns?
CIC
74
What style is best for children?
BTE (easier earmold replacement, durability)
75
What do multiple programs in HAs allow?
Different settings for quiet, noise, music, etc.
76
What is data logging in HAs?
Records HA use, environments, and settings to help with counseling and fine-tuning
77
What is directional microphone technology?
Mics that reduce sounds from behind, imrpove SNR for speech in noise
78
What is adaptive directionality?
HA automatically changes the mic pattern depending on the environment
79
What is feedback cancellation?
Digital processing that removes acoustic feedback (whistling)
80
What is frequency compression/transposition?
Moves high-frequency sounds in lower frequency regions for audibility
81
Who benefits from frequency lowering?
Patients with severe-profound HF loss (e.g., cannot access /s/,/sh/)
82
What is tinnitus therapy in HAs
Sound generators or masking programs to reduce tinnitus perception
83
What are the three main goals of compression?
1. Prevent loudness discomfort
2. restore normal loudness perception
3. improve audibility of soft sounds
84
What is the compression threshold (CT)
Input level at which compression starts
85
What is compression ratio (CR)
Change in input divided by change in output (e.g., 2:1)
86
What is attack time?
How quickly compression reacts when input suddenly increases
87
What is release time
How quickly compression recovers when input decreases
88
Why are fast attack/release times sometimes bad?
Can distort speech envelope
89
Why are slow times sometimes bad ?
May not protect against sudden loud sounds
90
What are the 3 main reasons we care about spatial analysis and binaural effects?
1. Localization
2. Speech perception in quiet and noise
3. Preventing auditory deprivation
91
For symmetrical HL, should we fot 1 HA or 2?
Generally, 2 HAs for binaural benefits
92
If fitting 2 HAs, should they be fitted simultaneously or sequentially?
Simultaneous fitting is preferred
93
If the patient disagrees with binaural fitting, should you convince them otherwise?
No - educate, demonstrate, and offer trial, but don't force
94
For asymmetrical HL, what's the decision process
If only 1 HA, fit the better ear unless special circumstances
95
Define monaural
Stimulation of one ear
96
Define binaural
Stimulation of both ears
97
Define unilateral
Fitting or loss with one HA
98
Define bilateral
Fitting or loss with two HA
99
What does diotic mean
The same sound is presented to both ears at the same time
100
What does dichotic mean
Different sounds presented to the two ears at the same time
101
What is head diffraction
External effect caused by the way ears are situated --> greatest effect in high frequencies
102
What type of effect is binaural squelch
Internal effect at the brainstem level
103
Which frequencies are most involved in squelch/MLDs
Low frequencies
104
Explain the notations S0N0, SπN0, S0Nπ
S = Signal
N = Noise
0 = same phase, same time
π = 180 degrees out of phase
105
What is binaural redundancy / diotic summation?
Slight improvement 1-2 dB in SNR when the same signal is presented to both ears
106
What is binaural loudness summation at threshold?
2-3 dB increase
107
At MCL (most comfortable level), how much is binaural loudness summation?
4-6 dB increase
108
At high levels, how much is binaural loudness summation?
6-10 dB increase
109
What is ITD and what frequencies use it?
Interaural Time Difference → LF sounds (<1500 Hz).
Range: 0 ms at 0° azimuth to ~0.7 ms at 90° azimuth
110
What is IID/ILD and what frequencies use it?
Interaural intensity difference (aka level difference) --> HF sounds (>1500 Hz)
Max ~ 20 dB at 7 kHz
111
Which HL benefits most from the bilateral localization advantage?
Moderate to severe-profound HL
112
When should localization be measured
At follow-up visits, not immediately after fitting
113
Why wait for localization testing
Patients need time to adapt and recalibrate spatial hearing
114
How does binaural amplification improve sound quality?
Improved clarity, fullness, spaciousness, and smaller JNDs
115
What is late-onset auditory deprivation?
Deterioration of speech recognition abilities in the unaided ear, can begin as early as 7 months
116
Is recovery possible if amplification is delayed?
May not be possible even if an HA is fit later
117
How do bilateral vs. unilateral HAs impact tinnitus?
66% of bilateral tinnitus patients reported reduced effects with 2 HAs
Only 13% reported reduced effects with 1 HA
118
What is the conclusion for tinnitus management
Bilateral HAs are more effective
119
What is the gain adjustment for low-level inputs
3 dB less gain for bilateral vs unilateral
120
What is the gain adjustment for mid-level inputs
4 dB
121
What is the gain adjustment for high-level inputs
5 dB less
122
What compression ratio adjustment is recommended for bilateral fittings
Slightly higher CR
123
Why might mild HL patients have worse localization with HAs
HAs may obscure natural anatomical cues that normally assist with localization
124
What frequency range is key for vertical localization
~3° for frequencies >4 kHz
125
Which HA styles may worsen vertical localization cues?
BTE, ITE, ITC - due to alteration of natural pinna effects
126
What plane is vertical localization measured in?
The midsagittal plane
127
What is binaural interference?
A condition where binaural listening results in poorer speech discrimination than monaural listening
128
How common is binaural interference?
About 10% of the geriatric population
129
What causes binaural interference
Signals from the poorer ear interfere with central processing.
Differential aging of hemispheres.
Inefficient interhemispheric transmission.
130
What non-auditory factors influence HA decisions
Cost (initial & recurring) and self-image
131
How can counseling help with self-image concerns?
Explain research showing greater alertness and environmental awareness with 2 HAs - makes useres appear younger and more responsive
132
Amplification II
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