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Electroacoustic Evaluation
Hearing Aid 2
33
Audiology
Graduate
03/14/2018

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Cards

Term
sound pressure level at the microphone opening of the HA
Definition
Input SPL
Term
the difference between the output SPL in a coupler and the input SPL (output SPL-input SPL = this)
Definition
Acoustic gain
Term
a manual or electronic adjustment for overall gain
Definition
gain control
Term
What are key components of probe-mic equipment?
Definition
Tone/noise generator, amplifier, loudspeakers (generate stimuli), reference mic (monitors the SPL reaching the aid from the loudspeaker & adjusts the sound’s volume if the level is too high or too low).
Term
Where is the reference microphone placed?
Definition
placed next to HA microphone
Term
Describe the importance of calibration
Definition
To check that the correct input levels are generated
Term
Describe the importance of electroacoustic analysis:
-What: obtaining various measures of ___ ___ ___ in a test box
-Why: For ___ control; provides a standard way to check hearing aid ___; can compare results to how aid ___ worked
-How: We connect hearing aid to a ___, place it in a small ___, then run a test in the test box.
Definition
hearing aid function; quality; function; originally; coupler; chamber
Term
Appropriate settings for electroacoustic analysis:
-___ coupler: small cavity that connects a hearing aid to a measurement microphone
-BTE = use ___ coupler
-ITEs & ITCs = use ___ coupler (attach with putty)
-RIC = use ___. May need to use an “adapter”
Definition
2-cc; HA-2; HA-1; HA-1
Term
How to set up HA appropriately for EC:
-Plug ___ on faceplate side of aid
-Set aid to ___-directional mode, ___ frequency response, greatest HFA-OSPL90, greatest HFA-FOG.
-Disable ___ features (i.e. noise reduction, feedback suppression).
-All tests performed with AGC set for ___ effect. Except for attack and release time tests and input-output tests.
-There is no standard coupler for ___-fit HAs. Most are specified as BTEs using an earhook.
Definition
vent; omni; widest; adaptive; minimum; open
Term
has several cavities to simulate a real adult’s ear (i.e. to mimic change of impedance as freq changes)
Definition
Ear simulator
Term
What is an example of an ear simulator?
Definition
Zwislocki coupler. Main cavity(0.6cc) is connected to 4 other cavities (0.1 to 0.22 cc) by small tubes & dampers
Term
ANSI specifies measuring HAs in __ ___ and IEC standards specifies measuring HAs in ___ ___
Definition
2-cc coupler; ear simulator (but allows coupler)
Term
Name two companies that make test boxes for electrocoustic analyses
Definition
Audioscan and Fonix
Term
Telecoil:
-An inductive pick-up coil used to sense changing ___ fields
-Converts magnetic energy into ___ energy
-Mic converts acoustic energy to ___ energy
Definition
magnetic; electrical; electrical
Term
generation of an electric current or magnetic state by proximity to a different source of electricity or magnetism
Definition
induction
Term
conductor wound into a spiral to create a high concentration of material into which current flow is induced when a magnetic field enters its vicinity
Definition
Induction coil
Term
In a hearing aid, the ___ is the induction coil and the ___ produces the magnetic field
Definition
telecoil; telephone
Term
continuous wire surrounding a room that conducts electrical
energy from an amplifier
Definition
induction loop
Term
coupler SPL for an inductive telephone simulator
Definition
SPLITS
Term
coupler SPL in a vertical magnetic field
Definition
SPLIV
Term
The average of values at 1000, 1600, and 2500 Hz
Definition
high frequency average
Term
Coupler SPL as a function of frequency for 90 dB input SPL
Definition
OSPL90 curve
Term
The maximum value of the OSPL90 curve
Definition
Maximum OSPL90
Term
Average of the OSPL90 values
Definition
HFA-OSPL90
Term
Average of the full on gain at the HFA frequencies
Definition
HFA full-on gain (HFA-FOG); input is 50 dB SPL
Term
What are the tolerances for maximum OSPL90, HFA-OSPL90, HFA full on gain (HFA-FOG),
Definition
OSPL90=plus or minus 3
HFA-OSPL90=plus or minus 4
HFA full on gain (HFA-FOG)=plus or minus 5
Term
gain control (VC or overall gain control) setting to produce an HFA-gain within +/- 1.5 dB of the HFA-OSPL90 minus 77 dB for a 60 dB SPL input
Definition
Reference test setting (RTS)
Term
If HFA FOG for a 60 dB SPL input is less than HFA-OSPL90-77 dB, then RTS is ___-___ ___ of gain control
Definition
full-on setting
Term
average of the gain at HFA freqs for a 60 dB SPL input, with gain control set at RTS
Definition
Reference test gain (RTG)
Term
range between the lowest & highest freqs. at which the freq. response curve is 20 dB below its HFA value
Definition
Frequency range
Term
distortion components relative to the total power of the signal (expressed in dB or a percentage)
Definition
Total Harmonic Distortion (THD)
Term
THD is measured by putting a ___ dB SPL pure tone into HA (set to RTS) & analyzing the output waveform
Definition
70
Term
quantifies the internal noise of HA
Definition
Equivalent Input Noise (EIN)
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