1
Q
What problem does compression solve in hearing loss
A
People with SNHL have reduced dynamic range
soft - inaudible
loud - become uncomfortable due to recruitment
Compression squeezes sounds into their smaller comfortable window
2
Q
Define compression in hearing aids
A
Compression automatically adjusts gain so soft sounds are amplified more and loud sounds are amplified less
3
Q
What are low level signals
A
Soft inputs (consonants) that need more gain to be audible
4
Q
What are high level signals?
A
loud inputs that must be compressed to stay comfortable
Avoid discomfort or exceeding the listeners loudness discomfort levels
5
Q
What is WDRC
A
Low CT + Low CR to make soft speech audible
6
Q
what is CT
What is CR
A
Point where compression starts
Degree of squeezing (Input:output change)
7
Q
What is level detection
A
How the HA measures input intensity for compression
8
Q
What is rectification?
A
Converting signal to positive only for level measurement
“In full-wave rectification the magnitude of both positive and negative half cycles is used to estimate the input level”
9
Q
Why is rectification needed?
A
So the HA can measure a smooth energy envelope for compression
“requires a unipolar signal to derive an accurate level estimate”
10
Q
What is smoothing?
A
Averaging fluctuation so compressor does not respond too fast
“prevent the compressor from responding to rapid fluctuation that are not perceptually relevant”
11
Q
What is AT
A
How fast gain decreases after a sudden loud sound
“Reduce gain after the input level has exceeded the compression threshold”
12
Q
What happens if AT is too slow?
A
Loud sounds may exceed LDL before compressor reacts
“if attack time is too slow, the listener may experience discomfort from sudden loud sounds before gain is reduced”
13
Q
What is RT
A
How quickly gain rises again when sound becomes softer
“gain to return to its previous value after the input signal falls below the theshold”
14
Q
What happens is RT is too fast?
A
Amplifies noise in gaps –> reducing SNR
“excessively fast RT can cause the compressor to follow rapid fluctuations thereby increasing background noise audibility”
15
Q
What happens is RT is too slow?
A
Soft consonants after loud sounds may remain inaudible
“very slow release time may fail to restore sufficient gain for softer sounds following loud outputs”
16
Q
What is ADRO (adaptive dynamic range optimization)
A
Adaptive system that maintains sounds inside preferred listening range
“ADRO adjusts gain to keep outputs within a defined preferred listening range optimizing comfort and audiblity”
17
Q
AGC-I vs AGC-O
A
- early stage compression
- final stage output limiting
“inout controlled compression occurs before volume control, whereas output controlled compression limits the final output to prevent discomfort”
18
Q
When is AGC-I preferred?
A
When maintaining consistent gain before volume control changes is important
(ADVANTAGE)
“preserves the relationship between input level and gain regardless of volume control setting”
19
Q
When is AGC-O preferred?
A
When preventing output from exceeding MPO is critical
(ADVANTAGE)
“Ensures the output does no exceed a predetermined maximum level, providing protection from loud sounds”
20
Q
What is multichannel compression
Why is multichannel compression useful for sloping hearing losses
A
A HA splits the incoming signal into frequency bands, and each band has its own compressor, allowing different gain, kneepoints, and compression rations across frequencies
Answer:
Because different frequencies have different degrees of HL, each channel can apply different compression to match frequency specific thresholds
21
Q
Intrinsic reason to multichannel compression
Which characteristic of SNHL makes multichannel compression intrinsically necessary?
A
HL varies by frequency –> compression requirements vary by frequency
Answer:
The audiogram slopes —> thresholds differ across frequency, so compression must differ across bands
22
Q
Extrinsic reason for multichannel compression
Give an EX. of an extrinsic reason multichannel compression is needed
A
Environmental noise and speech energy vary across frequency, so each channel can react appropriately without affecting unrelated bands
Low-frequency noise (AC unit, traffic) can be compressed without reducing high frequency speech cues
23
Q
What does multichannel compression allow clinically?
Why might a patient in restaurant noise benefit from multichannel compression
A
- Boost audibility in one frequency region
- Reduce loudness discomfort in another
- Improve comfort in noise
- Enhance soft speech audibility
Low-frequency noise can be compressed more than high frequency consonants improving SNR for speech
24
Q
How does multichannel compression work?
What happens if high-frequency channels have faster attack times than low frequency channels?
A
- Kneepoint
- CR
- AT & RT based on the acoustic scene
High-frequency consonants recover gain faster after noise, improving clarity of speech
25
What is TILL and when does gain increase?
TILL= treble increase at low levels
Gain is applied to higher frequencies above the cutoff
As input levels decrease, gain increases
Only applicable to high-intensity sounds as they go down
26
Why is TILL used clinically?
Applies more gain to high frequencies when input levels are soft
Improves audibility of consonants (/s/, /f/, /th/)
Helps patients with high frequency hearing loss
As sound gets louder, gain decreases to prevent discomfort and distortion
27
Which hearing loss configuration benefits most from TILL?
Often used for sloping SNHL
Emphasizes clarity cues
Avoids over-amplifying bass
28
What is BILL and how does gain change?
BILL= Bass increase at low levels
Occurs only for frequencies below the cutoff
as input intensity decreases, low frequency gain increases
As sounds get louder, low frequency gain decreases
29
What does BIL improve for the listener?
Applies additional gain to low frequencies when the signal is soft
Improves audibility of vowels
Improves overall loudness perception at soft levels
30
How can BILL help speech clarity?
Reduced bass gain at higher levels can reduce upward spread of masking
Helps keep speech clearer
31
What is PILL
PILL= Programmatic increase at low levels
A combination of TILL & BILL depending on input levels
32
How does PIL work in real time?
Dynamically applies TILL, BILL, or both
Depends on the acoustic environment
Shapes frequency response using real-time analysis of speech and background noise
33
Why is PILL used in modern hearing aids?
Used in automatic programs
Listener does not need manual adjutsments
34
What happen to the incoming signal in multichannel compression?
The incoming signal is split into frequency bands, each passing through a different channel
35
What processing occurs in each channel of a multichannel HA
Each channel has its own compressor
36
What are multiple compressors advatageous? (intrinsic reason)
Intrinsic: HL is different at different frequencies
37
Why are multiple compressors advantagepus (Extinsic reason)
Extrinsic: Ambient noise levels differ at different frequencies
38
What does multichannel compression allow the HA to do
It allows different frequency regions to be processed independently
39
Give an example of how multichannel compression works in a complex environment
The HA can increase audibility in one band (e.g., high freq for speech while preventing loudness discomfort in another (e.g., low frequency noise like an AC unit)
40
How many channels do modern HA typically have?
8-24 channels
41
What are the benefits of having many channels?
Fine-tuning gain and compression, better personalization, and improved speech understanding in complex listening settings
42
Why do we use multichannel compression
To match fain to the clients frequency specific thresholds
To control loud sounds in certain frequency regions without affecting others
To improve comfort in noise
To enhance soft speech audibility
43
How does multichannel compression work
Each channel applies its own kneepoint, ratio, attack, and release time based on acoustic environment
44
Rational: discomfort, distortion, and damage avoidance
Implementation???
Advantages???
Disadvantage???
Fast-acting wideband or multi channel compression limiting
No discomfort
Little distortion
Less OSPL90 possible than with peak clipping
45
Rational: Reduction of inter-syllabic intensity differences
Implementation???
Advantages???
Disadvantages???
Fast-acting wideband or multichannel compression with low compression thresholds
Signal kept in audible range without volume control for a wider range of levels and soft/weak phonemes
-Decreased SNR for noises in speech gaps
-Increased Chance of feedback
-Useful intensity cues may be disrupted
46
Rational: Long-term dynamic range reduction
Implementation???
Advantages???
Disadvantages???
Slow-acting wideband or multichannel compression with low compression threshold
Less need to vary volume control
No disruption of intensity cues to different phonemes
-Need further compression to avoid discomfort
-Increased change of feedback
-Soft phonemes may be inaudible
-Loud sounds may fall outside most comfortable range
47
Rational: comfort increase?
Implementation???
Advantages???
Disadvantages???
Slow or fast-acting wideband or multichannel compression with a medium compression threshold
Increased comfort in noisy places without decreasing volume control
Decreased SNR for noises occurring within speech gaps
48
Rational: Loudness normalization
Implementation???
Advantages???
Disadvantages???
Slow or fast-acting multichannel compression, or adaptive high-pass filter (steeper at low input levels)
Signal kept in audible range without volume control for a wider range of levels (and soft phonemes if fast-acting)
-Decreased SNR in speech gaps
-Increased chance of feedback
-Intensity cues may be disrupted (if fast-acting)
49
Rational: Noise reduction
Implementation???
Advantages???
Disadvantages???
Slow or fast-acting compression in low frequency band, or adaptive high pass filter (steeper at high input levels)
-Less masking/annoyance by low-frequency noise
-Signal useable over wider level range without volume control
-Signal attenuated along with noise
-Abnormal tonal balance
-Intensity cues may be disrupted (if fast-acting)
-Signal quality may vary as noise spectrum changes
50
What is advanced signal processing concerned with?
Noise
Feedback
Occlusion
Telephone conversations
High-freq HL
51
Why do we care about advanced signal processing
To address noise, feedback, occlusion, telephone conversations, and HF hearing loss
52
What are bands in HA?
What do bands control?
Bands are the number of gain adjustment handles
e.g., 250, 500, 1000 Hz
They control gain adjustments at specific frequencies
53
What are channels in HAs
Channels are frequency ranges needed to modify advanced signal processing strategies
54
Give examples of processing strategies that rely on channels?
Adaptive Noise Reduction (ANR)
Feedback cancellation
55
Key difference between bands and channels?
Bands = gain adjustment handles
Channels = frequency ranges for advanced signal processing
56
What is adaptive noise reduction (ANR)
Noise reduction at the micro level using one microphone to separate speech from noise
57
What are synonyms (means same thing) for ANR
Noise supression
Fine-scale noise cancelling
Single microphone noise reduction
Digital noise reduction
58
What is the main aim of ANR
To provide less amplification to noise than to speech
59
How does ANR work?
It identifies frequency segments where ANR is poor and reduces gain in those segments
60
How is speech identified in ANR
Speech is identifies by its amplitudes and frequency modulations
61
What is the modulation rate of speech used for detection
The amplitude and envelope of speech vary at 3-6 Hz, corresponding to syllable and word production
62
What component of the HA detects speech modulations?
The Voice Activity Detector (VAD)
63
What is onset time in ANR
The time from when noise starts to when gain is reduced to within 3 dB of the final value
64
What is the typical onset time range?
2-30 seconds
65
What is the offset time in ANR?
The time from when noise stops to when gain is restored to within 3 dB of the quiet value
66
What is the typical offset time range?
5 ms to several seconds
67
What are the advantages of ANR?
Increased comfort
Ease of listening
Improved overall sound quality
68
What additional performance benefits can ANR provide?
Improved performance in secondary tasks, such as memorizing and speed of response
69
What is a key limitation of ANR
Noise cannot always be reduced alone; speech and noise may both be reduced in a segment
70
How can this limitation affect speech understanding?
Speech intelligibility may not always improve
71
What is feedback in a hearing aid?
Feedback occurs when gain from the receiver outlet into the ear canal is greater than attenuation from the ear canal back to the microphone at a frequency
72
What is the main aim of feedback reduction?
To decrease gain only at frequencies where feedback oscillation is possible
73
Give examples of basic feedback reduction approaches
Acoustic damping
Use of multichannel HA
74
What is the main problem with feeback frequencies
Frequencies at which feedback occurs do not remain fixed over time
75
What is search and destroy feedback control?
Disadvantage???
Continuous monitoring by the HA to detect feedback oscillation,measure oscillation frequency, and automatically adjust the gain frequency response
Gain is still reduced
76
What is feedback path cancellation?
Intentionally creating a second feedback path with the correct gain and phase response inside the HA to cancel the external leakage path
77
How common is feedback path cancellation in modern HAs?
It is the most effective and widely used technique in digital HAs
78
What advantages does feedback path cancellation have regarding gain?
No reduction in gain
79
When does feedback path cancellation begin working?
It starts before the HA oscillates continuously
80
How does feedback path cancellation affect phone use?
It improves speech intelligibility over the phone
81
What happens to speech quality when feedback path cancellation starts?
There may be speech distortion during the first second while the filter adapts
82
What other sounds might feedback path cancellation affect?
It may cancel other periodic signals, such as whistling or music
83
What is frequency lowering?
A signal processing strategy used when high frequency information cannot be accessed through amplification alone
84
Who is a candidate for frequency lowering?
Individuals with greater high -frequency HL than low-frequency HL
85
Why an excessive high-frequency amplification be a problem for these individuals
Excessive HF amplification may distort low-frequency sounds
86
What is frequency transposition?
Taking something from one frequency region and relocating it to another
87
How is frequency transposition applied across frequencies
All information is reduced by a constant number of Hz
88
Give an example of frequency transposition across bands
.25-.5 --> .5-1 --> 1-2 --> 2-4 --> 4-8 moved to 2-4
89
What is n example of constant frequency reduction?
All incoming information is reduced by 2 kHz
90
What is the problem with frequency transposition at low frequencies
Information in the 0-2 kHz range cannot be lowered further and remains in the original range
91
What is a disadvantage of frequency transposition?
Overlap of information, which may lead to confusion in differentiating speech cues
92
What is the solution to the overlap problem in frequency transposition?
Linear frequency compression
93
What is linear frequency compression
Output frequency is a constant fraction of the inout frequency
94
Give an example of linear frequency compression
Every output frequency equals half the corresponding input frequency
95
What is a disadvantage of linear frequency compression
Incorrect voice identification
96
What is the solution to the disadvantage of linear frequency compression>
Non-linear frequency compression
97
What is non-linear frequency compression
Output frequency is not a constant fraction of the input frequency and changes with frequency
98
How does non-linear frequency compression differ across frequencies
It applies different ratios for lowering high frequencies above the cutoff compared to low frequencies below the cutoff
99
What is an advantage of non-linear frequency compression
Improves intelligibility
100
How does Widex VS Phonak implement Frequency lowering
Based on frequency transposition; dominant spectral peaks above the cutoff frequency are lowered by one octave
Based on non-linear frequency compression; frequency bands above the cutoff are analyzed and re-synthesized to lower frequencies
101
What is a key fitting guideline for frequency lowering?
The patient should be able to detect the difference between /s/ and /sh/
102
What is speech cue enhancement?
A signal processing strategy that enhances important speech cues
103
What are other names for speech cue enhancement?
Spectral contrast enhancement
Spectral sharpening
104
What is the process of speech cue enhancement ?
Prominent spectral peaks of speech sounds (usually formants) are detected and given greater amplification than the spectral valleys
105
How does speech cue enhancement affect the consonant-to-vowel ratio?
it is increased
106
what is the main advantage of speech cue enhancement
Improved speech intelligibility
107
What is automatic telephone detection?
Detection of telephone use via a wireless link between HA and telephones
108
What is data logging in HAs?
A feature where HAs store information about usage and listening situations
109
What listening information can HAs store?
How long HAs were used in specific listening situations
110
What patient actions can data logging record?
How the patient adjusted the HA in each situation (e.g., volume increased in noise)
111
What automatic HA actions can data logging record?
How the HA self-adjusted in each situation (e.g., ANR used in noise)
112
What overall usage information can data logging store?
Total usage of each HA
Daily patterns of usage
113
What are trainable HAs?
HA that use data logging information to perform self learning based on patient preferences
114
How do trainable HAs learn?
They analyze repeated patient adjustments made in specific listening situations
115
What is the problem address by active occlusion reduction?
The HA WEARERS OWN VOICE CREATES excessive low-frequency sound in occluded ear canal
116
What is the basic solution for active occlusion reduction?
Place an additional microphone in the ear canal to detect occlusion-induced sound
117
What happens to the detected occlusion-induced sound?
The sound is inverted
how is it used?
is output back into the ear canal
118
Why does active occlusion reduction work?
The original sound and the reintroduced sound have opposite polarity, so they cancel each other
119
Why do we care about verification
Verification
Objectivity
Actual vs projected gain
Fine tuning
120
Why do we care about validation?
Qualitative
Patient feedback
Patient satisfaction
121
What is one possible method or verification?
Aided thresholds
122
What are the disadvantages of aided thresholds?
Slower
Less accurate
Less detailed (discrete frequencies)
Limited input levels (comparison effect on gain)
Invalid if threshold is masked by ambient noise
123
When are aided thresholds used?
Used instead of REIG when REIG is not possible
124
How is verification performed in adults?
Measure REIG at 3 input levels (soft, averg, loud) and compare to prescribed target levels
125
How are compression characteristics verified in adults?
Measure I/O curves at each channel and measure gain frequency for narrowband vs broadband stimuli
126
How is verification performed in infants
Compare measurements to coupler gain targets calculated using RECD
127
What is used if REIG is not avaliable for infants?
Ling's 6 sound test at a soft speaking level for low-to-high frequency assessment
128
How are directional microphones verified using a test box
Present noise from the front vs back of the HA and measure gain difference (front-back ratio)
129
How can directional microphones be verified without a test box?
Use a stethoclip, place HA near a noise source, flip HA so noise is presented from front vs back
130
What indicates ADR is working?
Lower gain for high-level unmodulated noise than for a modulated signal at the same level
130
When should output be less during stethoclip directional testing?
When noise is presented from the back of the HA
131
What should be noted when verifying adaptive noise reduction
It may take several seconds for the ANR circuit to activate
132
How can ANR be verified without a test box?
Using a stethoclip
133
How is impulse noise reduction verified?
Listening test
134
Give examples of impulse sounds used for testing
Spoon hitting a cup
Hammer hitting a desk
135
Why verify frequency lowering
To assess detection and recognition of fricatives
136
How is frequency lowering verified?
/s/ and /sh/ spoken at conversational level should be detected by the patient
137
What is OSPL90 / RESR
Output sound pressure level when the input is 90 dB
138
Why measure OSPL90/ RESR
When should it be measured?
First impression and ensuring sounds are not too loud
First appointment
Whenever changes are made to acoustic coupling, gain, or compression characteristics
139
How is OSPL90 / RESR assessed?
By judging loudness of intense sounds
140
Where is OSPL90 / RESR assessment relevant?
Both in the clinic and real life
*contour test
141
What does validation assess?
Outcome domains
Activity limitation
participation restriction
listening effort
Emotional consequences
use
Satisfaction
142
What are paired comparisons?
A method where two listening conditions are compared directly
143
How are paired comparisons conducted?
Via multiple memories
10-30 seconds for judgment
<2 seconds between stimuli
144
What are disadvantages of paired comparisons?
Comparison is better vs worse, but no quantification of sound quality
multiple conditions require many paired comparisons
145
What is absolute rating of sound quality?
A method where sound quality is rated independently, not compared to another condition
146
What is a systematic selection?
A structured comparison of multiple conditions
147
What is comparison to the baseline?
Each condition is compared to a baseline; useful when there is an a priori hypothesis
148
round robin
tournament method
adaptive paired
forced choice
Each condition is compared to all other conditions; the condition preferred most often wins.
Each condition is compared to all other conditions; the condition preferred most often wins
A comparison method similar to PTA, where judgments guide subsequent comparisons.
The patient must choose one condition.
149
What is a no-difference response?
The patient indicates no perceived difference, which increases test-retest reliability
150
What is strength of preference?
Rating how much better one condition is (e.g., slightly better, much better)
151
What is adaptive gain adjustment?
A validation approach where gain is adjusted based on listener judgment
152
How should intense and weak speech be judged in camadapt
Intense speech at 80 dB SPL (loud)
Weak speech at 50 dB SPL (quiet)
153
What is CAM2Adapt? (camadapt)
A tool from the university of cambridge assessing gain-frequency response and compression characteristics of multichannel HAs
154
How should speech and music sound in camadapt?
They should have a preferred tonal quality
155
What are state measures?
How are state measures administered?
Indirect estimation of benefit in a designated situation
Twice: unaided vs aided
156
Give 2 examples of state measures
APHAB & HHIE
157
What are direct change measures?
Direct estimation of benefit in a designated situation
158
How are direct change measures administered?
Whats an example?
Once
HAPI
159
What are disadvantages of state & direct change measures?
Some items may be irrelevant
May not cover specific situations
Can be complex, especially for geriatric patients
160
What is COSI
How does it work?
A patient-driven validation tool
Patient identifies situation they want to hear clearly
situation are prioritized
ranking 1-5
pre-post comparison
161
How is a HA use measured?
how is patient satisfaction measured
data logging
Questionnaires
162
How is the quality of like (QOL) measured?
using standardized QOL questionaires
163
What is SF-36
Medical Outcomes study short from 23 a QOL measure
164
What physical domains are included in the SF-36
Physical functioning
Impact of physical dysfunction
pain
general health
165
What energy and social domains are included in the SF-36
Vitality
Social functioning
166
What emotional and mental domains are included in the SF36
Emotional impact
mental health
167
What is the EQ-5D
EuroQol - a quality of life measure
168
What mobility-related domain is included in the EQ-5D
Mobility
169
What self-function domain is included in the EQ-5D
What activity-related domain is included in the EQ-5D?
What symptom-related domains are included in the EQ-5D?
Self-care
Ability to undertake usual activities.
Pain/discomfort
Anxiety/depression
170
Why do we care about a protocol for fitting and verification of ALDs?
Need in challenging listening situations
171
What does an ALD fitting protocol include?
Fitting standard
Optimization of features
Verification
Objectivity
Validity
172
How does a personal FM system work?
Speakers voice --> FM mic (transmitter) --> acoustic to electric conversion via frequency modulation --> single FM receiver --> amplification --> electric to acoustic conversion (demodulation)
173
What SNR improvement is provided by personal FM systems?
15-25 dB high SNR
174
What FCC frequency range was originally used for FM systems?
Why were additional FM frequencies added?
What newer frequency range is used for FM systems?
72.025 - 75.975 MHz
The original band became congested, especially due to cell phone usage
216-217 MHz
175
What are two ways FM receivers can be coupled to HA?
Wireless receiver mounted inside the HA
Wireless receiver mounted in a boot that plugs into the HA
176
Arrange microphone signals in ascending order of clarity
Combined signal from both
Signal from HA mic
Signal from FM
Same order goes for microphone signals in order of preference
1. Signal from FM - most clear
2. combined signal from both
3. Signal from HA mic - least clear
177
What is the FM advantage / priority / precedence?
The FM signal is more intense than the HA mic signal in certain situations
178
Give an example where FM advantage is used?
Noisy classroom
179
Fm advantage is similar to what cochlear implant concept?
Mixing ratio of a CI (mic + direct audio input)
180
What automatic switching methods are used with FM systems?
Speech-operated switching (SOX)
Voice-operated switching (VOX)
181
What is the impact of FM advantage?
Better SNR
182
What are advantages of personal FM system?
Portable
Flexible (fits wider DR)
Simultaneous multiple transmission possible (separate channels)
183
What are disadvantages of a personal FM system?
Additional mic/receiver devices (stigma)
FM interference
Risk of picking up another FM user's voice
Must ensure FM does not negatively affect HA output characteristics
184
How does a sound-field FM system work?
Speakers voice --> FM mic --> acoustic to electric conversion --> multiple FM speakers --> amplification --> electric to acoustic conversion
185
What SNR improvement is provided by sound-field FM?
8-10 dB improvement
186
What populations benefit from sound-field FM?
Children with NH, HL, and at-risk populations, adults
187
What are advantages of sound-field FM systems?
Benefit to all listeners
Interim device when HAs are being repaired
Cost-effective
Less stigma
Less vocal strain for instructor
Easier approval (used for all students)
188
What are disdvantages of sound field FM systems
Increased reverberation in reverberant classrooms
Uneven loudness
Not suitable for severe recruitment
Not optimally portable
189
What should be checked when troubleshooting FM systems?
Batteries
Cables
Microphones
Channels
Room orientation
190
What common channel issue can prevent FM output?
Receiver is on a different channel than the transmitter
191
What is the rational for sound-field amplification?
SPL and SNR decrease with distance from the talker; placing the mic near age talker and speaker near the listener improves SNR
192
What are the components of sound-field amplification system?
Microphone
Amplifier
Loudspeaker(s)
193
What is the primary application of sound-field amplification?
Classroom
194
What are advantages of sound-field amplification?
No special equipment
Improved SNR for all
Temporary conductive HL
Immediate troubleshooting
Less vocal stain for instructor
195
What are disadvantages for sound-field amplification?
Feedback
May increase reverberation
196
What verification methods are used for FM systems?
Listening check
Electroacoustic characteristics
REM - AIM?
- Match the performance of the FM system to that of the HA (ref mic placed at the location of the trans mic)
197
What is the aim of REM verification for FM systems?
To match FM system performance to the HA (transparency)
198
Where is the reference microphone placed during FM verification?
At the location of the transmitting mic
199
What signal level should be used during FM verification?
A higher signal level, since the transmitting mic is close to the speaker's mouth
200
What type of signal should be used for FM verification?
A speech-erighted signal
201
What does transparency mean in FM systems?
A 65 dB SPL to the HA with FM muted produces the SAME output as a 65 dB SPL input to the FM transmitter (averaged across frequencies)
202
What is a result of achieiving FM transparency?
A 10 dB FM advantage
203
Why do we care about tinnitus?
Cost - veterns
High prevalence
Program
Pathology
204
\What are the two major mechanism categories of tinnitus?
Cochlear
Retrocochlear (beyond the cochlea, including the 8th nerve and CANS)
205
What are spontaneous otoacoustic emissions (SOAEs)
Sounds generated by the cochlea (OHC)s, present all the time, measurable with a vary small microphone in the ear canal
206
How common are SOAEs as a cause of tinnitus?
Present in 50% of people
only 4% of people with tinnitus have tinnitus due to SOAEs
Not a common cause
207
What happens to tinnitus caused by SOAEs?
Tinnitus disappears after SOAE suppression; OAEs can be contralaterally suppressed
208
Which hair cells are more likely to be damaged?
Outer hair cells (OHCs) are more likely to be damaged than inner hair cells (IHCs)
209
Why is isolated IHC damage an unlikely cause of tinnitus?
Because IHCs are more resilient than OHCs
210
What is cochlear synaptopathy?
Loss of synaptic connections between hair cells and auditory nerve fibers, leading to tinnitus and hidden hearing loss
211
How is hidden hearing loss assessed?
Using extended high-frequency audiometry (10, 12, 14, 16, up to 20 kHz)
212
What mechanical change contributes to tinnitus when OHCs are damaged?
Loss of coupling between the basilar membrane (BM) and tectorial membrane (TM), leading to abnormal shearing
213
Describe cochlear mechanism scenario A
Describe cochlear mechanism scenario B
Describe cochlear mechanism scenario C
IHCs damaged, OHCs intact
Unlikely
Associated with synaptopathy and hidden HL
OHCs damaged, IHCs intact
Loss of coupling between BM and TM
Associated with tinnitus
Both OHCs and IHCs damaged
Reduced afferent output to CANS
Reduced efferent inhibition
Increased afferent output from surrounding regions --> tinnitus
214
What neural structures are involved in retrocochlear tinnitus?
Dorsal cochlear nucleus (DCN)
IF
MGB
AC
Frontal, limbic, and cerebellar areas
215
What neural phenomenon contributes to tinnitus centrally?
Synchronization of spontaneous neural activity, non-stochastic, around 200 Hz
216
What is somatic modulation of tinnitus?
Tinnitus influenced o=by somatosensory input due to connections between the medullary somatosensory nucleus and DCN
217
What is cortical reorganization in tinnitus?
Changed in tonotopic maps due to auditory deprivation, including edge frequency theory
218
What is the Dangerous Decibels Program?
An educational program aimed at preventing noise-induced hearing loss and tinnitus
219
What are the key educational messages of Dangerous Decibels?
Sources of dangerous sounds
Consequences of exposure
Hearing protection strategies
220
What formats are used in the Dangerous Decibels program?
Classroom program
Museum exhibition
Internet-based activities
221
Which Dangerous Decibels format is most effective?
The classroom program
222
What is emphasized when taking tinnitus history
Evidence based to help us formulate our goals and next steps
223
What audiologic measures are used in tinnitus assessment?
Otoscopy
PTA (extended frequencies)
LDLs (important for hyperacusis)
SRT
WRS (SRS)
Immittance
224
What tinnitus psychoacoustic measures are used?
Pitch match
Loudness match
Minimum masking level
Residual inhibition
225
How should tinnitus measures be obtained?
Baseline measures with multiple trials and multiple sessions
226
What rating scales are used for tinnitus?
Numerical Rating Scale (NRS)
Visual Analog Scale (VAS)
227
Which tinnitus questionnaires are commonly used?
THI
THQ
TFI
TRQ
RPFQ
228
Which questionnaires assess anxiety and depression?
Anxiety: STAI
Depression: BDI
229
Which questionnaire assesses general health?
SF-12
230
What is a key limitation when selecting questionnaires?
Time constraints versus using a full test battery
231
What domains must tinnitus assessment cover?
Mechanisms
Prevention
History
Audiologic measures
Tinnitus measures
Rating scales
Questionnaires
232
Patient presents with tinnitus + HL
What is your FIRST step?
Perform audiologic evaluation
(PTA including extended high frequencies, speech testing, LDLs)
233
Patient reports tinnitus with normal audiogram.
What should you consider
Extended high-frequency audiometry
Hidden hearing loss / synaptopathy
234
Patient reports tinnitus that changes with a jaw or neck movement. what mechanism does this suggest?
Somatic modulation
(connection between somatosensory system and DCN)
235
Patients reports tinnitus + dizziness + unilateral symptoms.
What is your concern?
Retrocochlear pathology --> refer to medical evaluation
236
Patient reports tinnitus that interferes with sleep. What should be addressed in history?
Sleep disturbance
237
Patient reports tinnitus but minimal distress.
What is an appropriate management approach?
Education
Reassurance
Monitoring (no aggressive intervention needed)
238
Patient reports severe distress, anxiety, or depression related to tinnitus.
What should be added?
Questionnaires (THI, TFI)
Mental health screening (STAI, SDI)
239
What is tinnitus?
The perception of sound without an external acoustic stimulus
240
What is subjective tinnitus?
Tinnitus perceived only by the patient (most common type)
241
What is objective tinnitus?
Tinnitus that can be heard or measured by an examiner (rare)
242
What is hyperacusis?
Reduced tolerance to sound, often assessed using LDs
243
Why are LDLs important in tinnitus patients?
To identify hyperacusis and guide safe programming
244
Why are multiple tinnitus measures take across sessions?
To improve reliability, establish baseline, and track change over time
245
Why use both questionnaires and psychoacoustic measures?
Questionnaires --> impact/distress
Measures --> perceptual characteristics
246
Why is tinnitus assessment multidisciplinary?
Because tinnitus involves auditory, neurologic, emotional, and cognitive components
Amplification II
flashcards
Decks in class (3)
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