Amplification 1 Flashcards
(129 cards)
1
Q
To verify that an instrument is functioning properly, that is, according to the manufacturer’s specifications
A
Electroacoustic testing
2
Q
To verify that a HA/instrument is functioning appropriately, delivering sound in an individuals ear canal. It measures the actual output of a HA while it is worn by the patient
A
Real Ear Measurement (REM)
3
Q
Testing the electroacoustic performance of hearing instruments servers two general purposes
A
electroacoustic testing and real ear measurement (REM)
4
Q
Small sound-isolating pressure box containing a substantially anechoic space, signal generator, an amplifier, a loudspeaker that provides the test signals, and a control microphone/reference microphone
A
hearing aid test box
5
Q
What type of sounds go into the HA when in the hearing aid test box
A
pure tones across frequencies, or complex/broadband sounds which are meaningful with nonlinear HA’s
6
Q
Acoustic Mannequin
A
can also be used to asses HAs
7
Q
- HA gain/output across freq range at diff input levels
- HA output versus input at diff freqs
- HA output across freq range for 90 dB SPL input
- distortion
- internal noise
- HA response to magnetic field
- battery drain of the HA (disposable batteries)
A
test box measures
8
Q
A device (a cavity) that joins one part of an acoustic system to another. Used to measure the HA’s performance without the need to have the patient wear the HAs.
A
couplers
9
Q
Couplers connects the HA to a _____ via cavity to measure HA’s performance, without sound leaking out
A
microphone (which is connected to a sound level meter)
10
Q
Why are couplers known as artificial ears?
A
are approx the volume of adult ear canal past the earmold
11
Q
Larger than the average adult ear canal with a HA in place, so the HA generates low SPL in this than the average ear.
A
standard 2 cc coupler
12
Q
The difference in SPL between 2 cc coupler and a real ear is known as? Accounts for individual ear acoustics.
A
the real ear to coupler difference (RECD)
13
Q
To better simulate the acoustics of the human ear, a more complex measurement device can be used
A
ear simulator
14
Q
Who specify how HAs should be tested
A
ANSI and IEC
15
Q
Over time, dust, humidity, microphone aging, or movement of the reference mic can introduce small inaccuracies. If not calibrated, these errors could lead to:
A
- Incorrect real-ear measurements
- Misalignment with fitting targets
- Reduced confidence in verification results
16
Q
traditional measurement signal, automatically sweeps in freq over the desired freq range
A
pure tone
17
Q
more appropriate for modern hearing aids. Wide range of freq are present simultaneously
A
broadband
18
Q
broadband signals are the most appropriate, because they more closely resemble real-world inputs that the hearing aid would encounter
A
nonlinear hearing aids
19
Q
Non-linear HA allow all the following except:
1. Engaging the compression circuits realistically
2. Allowing for test across soft, average, and loud input levels, which is key for verifying compression behavior
3. No needed calibrations for equipment usuage
4. Show HA processes as complex, multifrequency inputs
A
3
20
Q
Purpose to confirm that a HA meets manufacturer specifications and commonly used for quality control, troubleshooting, and repairs
A
ANSI/IEC Test Box Testing, AKA electroacoustic analysis
21
Q
What is ANSI/IEC Test Box Testing standardized protocols outlined by all except:
1. ANSI S3.22 (U.S.)
2. ASHA 2024 (U.S.)
3. IEC 60118-7 (INTERNATIONAL)
A
2
22
Q
Measures the hearing aid’s output for a 90 dB SPL input
A
OSPL90 (maximum output)
23
Q
Assesses the gain with all settings at maximum.
A
Full-On Gain
24
Q
an ANSI HA specification expressed
as the average SPL at 1000 Hz, 1600 Hz, and 2500 Hz.
A
High-Frequency Average (HFA)
25
Plots output levels across frequencies.
Frequency Response Curve
26
Assesses sound quality by measuring unwanted harmonic distortion.
Total Harmonic Distortion (THD)
27
Measures the internal noise generated by the aid.
Equivalent Input Noise (EIN)
28
Assesses power usage
Battery current drain
29
On a gain-freq response graph:
x-axis
y-axis
right hand side of graph
x- freq
y- coupler output level
righ- coupler gain
30
Only one hearing aid is tested at a time.
Monaural testing
31
Connects the hearing aid to a microphone that measures output. (HA1 for BTE, HA2 for ITE)
Standard 2cc coupler
32
Typically tests up to 6000 Hz (unlike
wideband testing).
Limited frequency range
33
Pure tones, warble tones, and speech-like signals (usually fixed at 65 or 70 dB SPL).
Standardized input signals
34
True or False. Text Box Measures:
HA gain across frequency range at different output levels
False it is input levels
35
True or False. Text Box Measures:
HA output across frequency range at different input levels
True
36
True or False. Text Box Measures:
HA output versus input at different frequencies
True
37
True or False. Text Box Measures:
HA output across frequency range for 180 dB SPL input
False. for 90 dB SPL
38
True or False. Text Box Measures:
HA distortion, HA internal noise and HA response to magnetic field
True
39
True or False. Text Box Measures: the battery drain of the HA (disposable batteries)
true
40
When should test box calibrations be preformed to ensure that the reference microphone and test signals used in real-ear and test box measurements are accurate
weekly
41
ANSI Electroacoustic Analysis-HA Settings. All volume and gain controls at maximum, known as...
Full-on gain (FOG)
42
ANSI Electroacoustic Analysis-HA Settings. Set aid for maximum output, known as...
maximum output (OSPL90)
43
ANSI Electroacoustic Analysis-HA Settings. The disable or bypass adaptive features include: (FNDC)
feedback cancellation
noise reduction
directionality
compression (if possible)
44
ANSI Electroacoustic Analysis-HA Settings. Required for accurate comparison to spec., known as...
omnidirectional mode
45
ANSI Electroacoustic Analysis-HA Settings. Use test mode if available, known as...
program/memory
46
Purpose of ANSI Electroacoustic Analysis-HA Settings
to assess the raw electroacoustic performance, not how the aid behaves in real life. You're replicating the test conditions the manufacturer used
47
For ANSI/IEC testing which coupler for in the ear HA which are connected via putty, all vents must be sealed
HA1 coupler
48
For ANSI/IEC testing which coupler for BTE and body worn, it has a tube to connect to the BTE
HA2 coupler
49
Steps for _____?
1. HA1 and HA2 coupler is connected to the measuring microphone
2. the measuring microphone measures the output from the HA
3. the control microphone is placed next to the HA microphone
4. control mic monitors the SPL reaching the HA from the loudspeaker
ANSI/IEC
50
An advanced form of test box verification. Simulates real-world, binaural listening conditions using broadband, speech-like stimuli. Helping assess modern HA features (compression, directional wireless ear-to-ear processing)
Wideband/binaural test box testing
51
Examples of speech-like stimuli used in wideband/binaural test box testing
ISTS and speech-weighted noise
52
Wideband/binaural Test box testing allows evaluation of...
compression behavior (at soft, average, loud input levels)
speech mapping
directionality
binaural features (beamforming, synchronization)
53
What broader freq range does wideband testing in the test box use
up to 10k Hz or more
54
True or false. The difference between wideband testing in the test box than the original is the wideband noise stimulus rather than the traditional filter warble tones or narrowband signals
true
55
True or false. Wideband testing captures low-freq responses better
false. captures high-freq better-- important for speech sounds like /s/ and /sh/, and for pediatric fittings
56
True or false. The wideband testing in the test box is more realistic representation of how speech sounds across the freq range allowing better evaluation of features like freq lowering or extended bandwidth HA
true
57
What is wideband testing in the test box tested using
0.2 cc coupler with test box open
58
Audioscan Verifit2 supports ____________. Traditional systems topped out around ____ Hz, while wideband measurements can reach ____ Hz.
wideband SPL measurements, 6000 Hz, 10000 Hz
59
Involves verifying both HAs at the same time (saving time) in the test box, with synchronized stimulus presentations and measurements
binaural testing in the test box
60
True or false. Earlier models of test box testing could also test both HA at the same time
false earlier models and many
traditional verification systems could only test one hearing aid at a time.
61
*User program: Use the patient’s everyday listening program.
*All features ON: Leave compression, noise reduction, and directionality ON (as
they would be used in daily life).
*Omnidirectional mode if testing with a single speaker (e.g., in a test box).
*Volume/gain: Leave at user’s default settings.
*Linked or binaural mode: When using binaural test box testing, ensure both aids
are communicating as they would on the patient (e.g., for beamforming, syncing).
You want to simulate how the hearing aids perform in real-world environments,
not just in lab conditions.
How HA should be set during wideband/binaural test HA
62
GOAL of wideband/binaural test
Verify that the hearing aid meets prescriptive targets and performs well in real-world conditions.
63
Tolerance known for the reading must be no more than 3 dB higher than the manufacturer’s specification.
maximum OSPL90
64
Tolerance known for being within ±4 dB of the manufacturer’s
specification.
HFA OSPL90
65
Tolerance known for being within ±5 dB of the manufacturer’s
specification.
HFA Full on gain
66
Tolerance known for the low-band portion of the frequency
response curve (<2 kHz) must fall within ±4 dB of the specified curve.
The high-band portion of the frequency response curve (>2 kHz) must fall within ±6 dB of the specified curve.
The frequency response curve
67
The measured values must be less than or equal to the published values plus 3%
≤ 3% at ___Hz
≤ 2% at ___Hz
≤ 1% at ___Hz
Total harmonic distortion (%THD)
3 - 500
2- 800
1 - 1600
68
This level must be less than or equal to the highest value specified by the manufacturer plus 3 dB
equivalent input noise
69
Norm: Varies depending on the power level of the aid (e.g.,
0.5–2.5 mA). Acceptable: Within ±20% of manufacturer spec
battery drain
70
The difference, in dB, between the output levels, generated as a function of freq, for a fixed input level is known as
acoustic gain or gain
71
A freq response is a set of output levels, generated as a function of freq, for a fixed input level
freq response
72
The gain control of the HA is at its maximum position is known as
full-on position
73
Technically correct term for what is commonly called "volume control"
gain control
74
A set of output levels, generated as a function of input level, for a fixed input frequency (or frequency band). I/O testing is done only on AGC instruments
Input-output (I/O) characteristics
75
The SPL at the inlet of the hearing aid microphone
The input sound pressure level (also called input level)
76
The SPL measured by the coupler microphone
the output sound pressure level (also called output level)
77
The output level of a hearing aid when the input level is 90 dB SPL and the gain control is full-on
OUTPUT SOUND PRESSURE LEVEL FOR 90 dB INPUT SPL
(OSPL90)
78
The position of the gain control necessary to yield the reference-test gain
reference test setting (RTS)
79
The gain of the HA when the gain control is set so that a 60 dB SPL input signal yields an HFA value that is 17 dB below the HFA OSPHL90 value
reference test gain
80
If the actual HFA output level for the full-on position is already lower than 17 dB below the OSPL90 level, then the full-on gain is considered the reference-test gain (As in some AGC)
exceptions
81
Measuring sound pressure level (SPL) in the ear canal with the HA in place
REM
82
REM Acronym Cheats: term ends in "G" it refers to...? Ends in "R"
G=gain (difference measure)
R=response (absolute measure)
83
the input level used to generate the response has been subtracted from the absolute output level across frequencies.
G Rem acronym
84
there is no consideration given to the input level used to generate the response
R rem acronym
85
REUR (real-ear unaided response)
baseline SPL in the open ear canal
( no HA)
86
REAR (real-ear aided response)
SPL in the canal with the HA turned on and delivering sound
87
REAG (real-ear aided gain)
the amount of gain provided by the HA = REAR - input level
88
REIG (real-ear insertion gain)
gain added by the HA = REAR - REUR (less commonly used now) or REAG-REUG
89
True or false. REM is not supported by research or professional guidelines as an essential part of best-practice hearing aid fitting
false it is supported especially by AAA & ASHA
90
REM is golden standard for what 5 things :
* Verifying that the hearing aid matches the patient’s prescription targets
* Ensuring speech sounds fall within the patient’s audible range
* Identifying under-or over-amplification
* Customizing the fit based on the patient’s individual ear acoustics
* Avoiding reliance on manufacturer’s first-fit settings, which often miss targets
91
Functional assessment, requires acclimatization, often performed binaurally, subjective, requires patient cooperation
validation
92
hearing aid assessment, no delay, assessed monaurally, objective, minimal cooperation needed
verification
93
Manufacturers' proprietary targets/formulas
developed for particular hearing devices by it manufacturers
not available in verification software
94
Generic targets/formulas
NAL (national acoustic labs), DSL i/o (desired sensation level input/output), & CAMEQ (Cambridge loudness equalization methods)
95
When should the probe tube be calibrated
prior to conducting REM
96
True or false. Probe tube calibration accounts for the acoustic effects the probe tube introduces as sound travels through it to the probe microphone during actual use conditions
true
97
In probe tube calibration, the probe tube and mic are "acoustically invisible" why?
calibration removes the acoustic effects the probe tube and mic introduce during real-ear measurement
98
Probe tube calibration values will be applied to all probe mic readings via
mathematical correction
99
How to calibrate probe tube
1. hold headset .5m from the loudspeaker
2. mic and probe should be facing loudspeaker
3. hand should not be placed b/w the mic and loudspeaker
4. run calibration
100
How should a patient be prepared
sit still maintaining head position, inform may interrupt any time due to discomfort, otoscopic examination must always precede REM, seated test ear distance 0.5m from loudspeaker, 0 degree azimuth infront of facing the speaker
101
What is the typical length of the adult ear canal and distance from the ear canal opening to the intertragal notch
25mm and 8mm
102
What is the insertion depth past the tragus should result in placement within 5mm of the eardrum for the average adult
28 mm
103
The probe tube should be inserted into the ear canal until the mark approaches the
intertragal notch
104
True or false. Guidelines regarding how far to insert the probe tube has nothing to do with the age and gender of the patient.
false it does
105
What is the length of a children's ear canal, adult males, adult females
20mm and 25mm (0.8 to 1 inch), 30mm, 28mm
106
which way should the reference mic face when performing REM
outwards
107
Similar to lubricant and help reduce friction between the probe tube and earmold, and to assist in providing a good acoustic seal
otoferm
108
The level, in dB SPL, as a function of freq, measured in an open (unaided) ear canal. Uses a 65dB SPL broad band stimulus. Normal variation in length and diameter of EAC change center freq and level of resonant peak
REUR/REUG
109
The level, in dB SPL, as a function of frequency, measured in the ear canal with the hearing in place, and turned on.
REAR/REAG
110
Characterized by descriptions of peoples with low freq thresholds less than 40 dB HL. Complaints of voice sounding hollow, boomy, echoic, or tunnel like. It is caused by bone-conducted sound vibrations reverberating off the object filling the ear canal
occlusion effect
111
When the ear canal is blocked, the vibrations are reflected
back toward the eardrum
112
When talking or chewing, these vibrations normally
escape through an open ear canal, most people unaware of their existence
113
Completely open ear canal, the occlusion effect can boost ____ freq sound pressure in the ear canal by ______
low, 20 dB or more
114
Primary purpose of REOR measurements is to determine
venting characteristics, determine whether the vent is performing as expected by allowing certain freqs to pass through it
115
REOR has a reduction of the peak around ____ and record using _____ broad band stimulus
2000-3000, 65 dB SPL
116
True or false. REOR can be measured by placing a probe mic in the ear canal with their HA in the ear canal but turned off
True
117
Difference in decibels, as a function of frequency, across frequencies, between the SPL at a specified measurement point in the real-ear (canal) and in a 2cc coupler, produced by a transducer generating the same input signal.
RECD (real-ear-to-coupler difference)
118
True or false. RECD will vary substantially across age groups (adults typically having larger RECDs than adults)
false, children have larger
119
Indicate an inadequate seal of the transducer to the ear (foam ear tip), a larger than average ear, or a perforated eardrum
neg RECD
120
Given that the RECD allows us to know the difference between output in the real-ear and the 2cc coupler, real-ear hearing aid output (e.g., REAR, RESR) can be accurately predicted to within approximately
2 dB
121
Aided on REM terms? Aided off?
REAR, REIR, REIG, RESR (real-ear saturation response); REUR,REOR
122
Aided in ear REM term? Aided not in ear?
REAR, REOR, REIR, REIG, RESR; REUR, RECD (uses probe)
123
REUR purpose
measures natural ear canal resonance; baseline for calculating insertion gain
124
REAR purpose
measures total amplified sound; used in target matching verification
125
REOR purpose
shows acoustic effect of earmold or dome; evaluates occlusion effect
126
REIR purpose
measures added amplification over unaided ear; insertion gain fitting method
127
REIG purpose
show amount of gain applied; compared against prescriptive targets
128
RESR purpose
verifies hearing aid MPO; usually with a loud input at 85 dB SPL; prevents over amplification
129
RECD purpose
accounts for individual ear acoustics; Important in pediatric fitting
