IHS ILE EXAM QUESTIONS AND
ANSWERS
What does decreasing the compression ratio do, and when would you use this? -
Answer-Soft sound amplification is unaltered, but gain is increased for moderate/loud
sounds. Most often used if a PT complains loud sounds aren't loud enough or sound
"mushy"
What does increasing the compression ratio do, and when would you use this? -
Answer-Soft sound gain is unaltered, but gain for moderate/loud sounds is lowered.
Most often used if a PT complains loud/moderate sounds are too loud or background
noise is too loud. ** sometimes you use this on just certain frequencies, for example,
high frequencies if they complain dishes are too loud, or low frequencies if they
complain their voice is echo-y
What happens when you raise a knee point, and when would you do this? - Answer-
You will decrease gain for soft sounds and raise gain for moderate/loud sounds.
Most often used if they hear soft sounds better than moderate ones ( like hearing the
table across from them better than their own in a restaurant) or when they complain
about hearing a HA's circuit noise.
What does lowering the kneepoint do, and when would you do this? - Answer-
Lowering the KP will lower gain for moderate and loud sounds, and increase gain for
soft sounds below the original KP. Mostly used when a PT complains they can't hear
soft sounds like soft voices, bird chirping, or ticking clocks.
What are the two types of compression? - Answer-Input compression - when the
input level of a HA determines when compression is activated.
Output compression - when the output (input + gain) of the HA determines when
compression is activated.
What is Wide Dynamic Range Compression? - Answer-(WDRC) This is what most
HA's utilize today, and allows the signal to be packaged withing a user's DR.
Typically WDRC HA's have low (35-55 dB SPL) KPs and low (1:1 - 1:4) ratios
What is the Compression Ratio? - Answer-The ratio of change between the input
and output of a HA. This determines how much compression will occur.
What is the Kneepoint? (KP) - Answer-The lowest level at which compression is
applied
What is Harmonic Distortion? - Answer-Harmonic distortion occurs when a single
frequency is presented to the input of a hearing aid and the output contains the
original frequency plus additional undesired frequencies that are harmonically related
to the original frequency.
ANSI uses a harmonic distortion test that measures the distortion rate at specific Hz.
,Frequency Response Curve - Answer-Used in ANSI testing. A gain curve is run with
the input sound at 60 dB SPL to simulate conversation level. You get the frequency
range calculation from this test.
Reference Test Gain (RTG) - Answer-Used in ANSI testing. Input sound is set at 60
dB SPL to simulate conversation level; and then the HFA gain is adjusted to HFA-
OSPL90 -77 dB. The answer is the RTG.
Full On Gain (FOG)? - Answer-Used in ANSI testing. The HFA-FOG is measured
and recorded w/ the input set at 50 dB SPL
Maximum Output Curve ( OSPL90) - Answer-Used in ANSI testing. It's the max
output of a HA. Input is set to 90 dB SPL to test. Notes the max at each tested
frequency. HFA is noted from this test.
What must be done to an aid before ANSI testing? - Answer-1- Occlude all vents on
outside of aid
2- Set to test mode with gain full on, output at max, and bandwidth to max
3-Telecoil should be turned off and only turned back on when testing SPLITS
What couplers do do you use with what instruments when ANSI testing? - Answer-
HA-1 = ITE
SB-1 = RIC and thin tube BTE's
HA-2 = BTE
What is a coupler? - Answer-A joiner for a HA that is designed off the vol of an
average ear (2cc). Used to connect the HA to a testing box for ANSI tests.
What is Adaptive Feedback Supression? - Answer-This allows a HA to detect and
minimize feedback on it's own.
** There is also static feedback supression.
What is Digital Noise Reduction (DNR)? - Answer-This is an algorithm which allows
a HA to seperate desired signals ( like speech) from undesired ones ( like noise)
What are Multiple Memories? - Answer-A HA feature that allows saved programes to
optimize preformance is multiple enviorments, like the car, church, ect.
What are Directional Microphones? - Answer-Directional Mics are mics facing
multiple directions in a HA. This allows better signal to noise ratio gain as sound to
the front of the PT is louder than that towards the rear. They can be adaptive, fixed,
automatic, or manual.
What are the most common HA battery sizes? - Answer-675 - used for Power BTE's
and cochlear implants
13 - Smaller BTE's and ITE's
312 - Canal and Mini BTEs
10 - CIC/IICs
,What is Output? - Answer-The level of sound (expressed in dB) the hearing aid
plays.
Sometimes also used to refer to the highest intensity a HA can produce. Usually
expressed in dB SPL. Referred to as OSPL (output sound pressure level) or MPO
(max power output)
What is Gain? - Answer-The amount of amplification an instrument provides
What are Channels? - Answer-A frequency range that can have the gain
independently adjusted. The more channels a HA has, the more tailored it can be to
a specific loss.
What is Frequency Response? - Answer-A representation of relative gain over an
entire range of frequencies. Since all frequencies are not amplified equally, it's
typically curved rather than flat.
What benefits does compression provide to a PT? - Answer-Limits distortion of
sounds.
Can improve experience for recruitment sufferers.
Prevents further hearing loss from noise exposure.
Optimizes DR
Maximizes speech recognition
Reduces background noise
Provides more listening comfort.
What is Expansion? - Answer-This prevents the HA from amplifying very soft
sounds, such as circuit noise.
What is Compression? - Answer-The ability of a HA to adjust channels/bands to fit a
PT's specific hearing loss.
What are Wireless Connections? - Answer-The ability of a HA to pair with a device
and act as a headset, such as to a cell phone through bluetooth. This should be a
consideration when fitting a PT with issues listening on a cellphone.
What is Signal Identification & Classification? - Answer-The ability of a HA to identify
a sound (such as background or wind noise) and adapt (such as by enabling a front
directional mic)
What is Data Logging? - Answer-The ability of a HA to log data such as usage time,
program changes, listening environments, ect. This can help a HHP fine tune fittings.
What is Frequency Transposition? - Answer-This enables a HA to move a higher
frequency sound into a lower frequency sound that a wearer can hear. Used for
some profound HL or recruitment sufferers.
What is a Transducer? - Answer-A device taht converts energy. HA's have two
types, mics and rec's. Some also have a telecoil.
, What is a microphone? - Answer-An input transducer. Converts sound pressure into
an electric signal that is sent to the amplifier
What is a Reciever? - Answer-Transducer that connects electrical energy back into
sound pressure and delivers it to the wearer. AKA a "speaker"
What is a Telecoil? - Answer-Transducer which converts electromagnetic energy.
Used for some telephones and looped systems. AKA an induction coil.
What is an Ampifier? - Answer-Increases the amplitude of electric signal, providing
acoustic gain. Amplifier's effectiveness is dependant on programming adjustments.
What is Slope? - Answer-A HA performance term - the rise in curve (dB) between
500 Hz and the first peak
How do we express HA's performance (terms)? - Answer-In terms of gain, output,
and frequency response. It is usually expressed in a matrix of peak
output/FOG/Slope
What are the 8 main types of HA styles? - Answer-Standard BTE
Mini or Thintube BTE
BTE-RIC
Full Shell ITE
Half Shell ITE
ITC (In the canal)
CIC (concealed in the canal)
IIC (invisible in the canal)
When can we consider a thin tube BTE vs a standard? - Answer-When a PT's TH is
60 dB or higher
How does a BTE-RIC differ from a standard BTE? - Answer-The Reciever is in the
canal vs built into the aid.
What are the 5 considerations for fitting a HA? - Answer-Audiometric results
Lifestyle
Manual Deterity
Canal Size/Configuration
Cosmetic concerns
What effect does choosing an occluded fitting have on a PT's perception of sound? -
Answer-They may notice internal sounds like coughing, chewing, and speaking
much more than normal due to increased amplification by bone conduction.
What can we do to allieviate symptoms of the OE when fitting? - Answer-Choose a
more open fit or customize an ITE that extends past the 2nd bend
What amplification options are there for an unaidable ear? - Answer-CROS or
BiCROS
ANSWERS
What does decreasing the compression ratio do, and when would you use this? -
Answer-Soft sound amplification is unaltered, but gain is increased for moderate/loud
sounds. Most often used if a PT complains loud sounds aren't loud enough or sound
"mushy"
What does increasing the compression ratio do, and when would you use this? -
Answer-Soft sound gain is unaltered, but gain for moderate/loud sounds is lowered.
Most often used if a PT complains loud/moderate sounds are too loud or background
noise is too loud. ** sometimes you use this on just certain frequencies, for example,
high frequencies if they complain dishes are too loud, or low frequencies if they
complain their voice is echo-y
What happens when you raise a knee point, and when would you do this? - Answer-
You will decrease gain for soft sounds and raise gain for moderate/loud sounds.
Most often used if they hear soft sounds better than moderate ones ( like hearing the
table across from them better than their own in a restaurant) or when they complain
about hearing a HA's circuit noise.
What does lowering the kneepoint do, and when would you do this? - Answer-
Lowering the KP will lower gain for moderate and loud sounds, and increase gain for
soft sounds below the original KP. Mostly used when a PT complains they can't hear
soft sounds like soft voices, bird chirping, or ticking clocks.
What are the two types of compression? - Answer-Input compression - when the
input level of a HA determines when compression is activated.
Output compression - when the output (input + gain) of the HA determines when
compression is activated.
What is Wide Dynamic Range Compression? - Answer-(WDRC) This is what most
HA's utilize today, and allows the signal to be packaged withing a user's DR.
Typically WDRC HA's have low (35-55 dB SPL) KPs and low (1:1 - 1:4) ratios
What is the Compression Ratio? - Answer-The ratio of change between the input
and output of a HA. This determines how much compression will occur.
What is the Kneepoint? (KP) - Answer-The lowest level at which compression is
applied
What is Harmonic Distortion? - Answer-Harmonic distortion occurs when a single
frequency is presented to the input of a hearing aid and the output contains the
original frequency plus additional undesired frequencies that are harmonically related
to the original frequency.
ANSI uses a harmonic distortion test that measures the distortion rate at specific Hz.
,Frequency Response Curve - Answer-Used in ANSI testing. A gain curve is run with
the input sound at 60 dB SPL to simulate conversation level. You get the frequency
range calculation from this test.
Reference Test Gain (RTG) - Answer-Used in ANSI testing. Input sound is set at 60
dB SPL to simulate conversation level; and then the HFA gain is adjusted to HFA-
OSPL90 -77 dB. The answer is the RTG.
Full On Gain (FOG)? - Answer-Used in ANSI testing. The HFA-FOG is measured
and recorded w/ the input set at 50 dB SPL
Maximum Output Curve ( OSPL90) - Answer-Used in ANSI testing. It's the max
output of a HA. Input is set to 90 dB SPL to test. Notes the max at each tested
frequency. HFA is noted from this test.
What must be done to an aid before ANSI testing? - Answer-1- Occlude all vents on
outside of aid
2- Set to test mode with gain full on, output at max, and bandwidth to max
3-Telecoil should be turned off and only turned back on when testing SPLITS
What couplers do do you use with what instruments when ANSI testing? - Answer-
HA-1 = ITE
SB-1 = RIC and thin tube BTE's
HA-2 = BTE
What is a coupler? - Answer-A joiner for a HA that is designed off the vol of an
average ear (2cc). Used to connect the HA to a testing box for ANSI tests.
What is Adaptive Feedback Supression? - Answer-This allows a HA to detect and
minimize feedback on it's own.
** There is also static feedback supression.
What is Digital Noise Reduction (DNR)? - Answer-This is an algorithm which allows
a HA to seperate desired signals ( like speech) from undesired ones ( like noise)
What are Multiple Memories? - Answer-A HA feature that allows saved programes to
optimize preformance is multiple enviorments, like the car, church, ect.
What are Directional Microphones? - Answer-Directional Mics are mics facing
multiple directions in a HA. This allows better signal to noise ratio gain as sound to
the front of the PT is louder than that towards the rear. They can be adaptive, fixed,
automatic, or manual.
What are the most common HA battery sizes? - Answer-675 - used for Power BTE's
and cochlear implants
13 - Smaller BTE's and ITE's
312 - Canal and Mini BTEs
10 - CIC/IICs
,What is Output? - Answer-The level of sound (expressed in dB) the hearing aid
plays.
Sometimes also used to refer to the highest intensity a HA can produce. Usually
expressed in dB SPL. Referred to as OSPL (output sound pressure level) or MPO
(max power output)
What is Gain? - Answer-The amount of amplification an instrument provides
What are Channels? - Answer-A frequency range that can have the gain
independently adjusted. The more channels a HA has, the more tailored it can be to
a specific loss.
What is Frequency Response? - Answer-A representation of relative gain over an
entire range of frequencies. Since all frequencies are not amplified equally, it's
typically curved rather than flat.
What benefits does compression provide to a PT? - Answer-Limits distortion of
sounds.
Can improve experience for recruitment sufferers.
Prevents further hearing loss from noise exposure.
Optimizes DR
Maximizes speech recognition
Reduces background noise
Provides more listening comfort.
What is Expansion? - Answer-This prevents the HA from amplifying very soft
sounds, such as circuit noise.
What is Compression? - Answer-The ability of a HA to adjust channels/bands to fit a
PT's specific hearing loss.
What are Wireless Connections? - Answer-The ability of a HA to pair with a device
and act as a headset, such as to a cell phone through bluetooth. This should be a
consideration when fitting a PT with issues listening on a cellphone.
What is Signal Identification & Classification? - Answer-The ability of a HA to identify
a sound (such as background or wind noise) and adapt (such as by enabling a front
directional mic)
What is Data Logging? - Answer-The ability of a HA to log data such as usage time,
program changes, listening environments, ect. This can help a HHP fine tune fittings.
What is Frequency Transposition? - Answer-This enables a HA to move a higher
frequency sound into a lower frequency sound that a wearer can hear. Used for
some profound HL or recruitment sufferers.
What is a Transducer? - Answer-A device taht converts energy. HA's have two
types, mics and rec's. Some also have a telecoil.
, What is a microphone? - Answer-An input transducer. Converts sound pressure into
an electric signal that is sent to the amplifier
What is a Reciever? - Answer-Transducer that connects electrical energy back into
sound pressure and delivers it to the wearer. AKA a "speaker"
What is a Telecoil? - Answer-Transducer which converts electromagnetic energy.
Used for some telephones and looped systems. AKA an induction coil.
What is an Ampifier? - Answer-Increases the amplitude of electric signal, providing
acoustic gain. Amplifier's effectiveness is dependant on programming adjustments.
What is Slope? - Answer-A HA performance term - the rise in curve (dB) between
500 Hz and the first peak
How do we express HA's performance (terms)? - Answer-In terms of gain, output,
and frequency response. It is usually expressed in a matrix of peak
output/FOG/Slope
What are the 8 main types of HA styles? - Answer-Standard BTE
Mini or Thintube BTE
BTE-RIC
Full Shell ITE
Half Shell ITE
ITC (In the canal)
CIC (concealed in the canal)
IIC (invisible in the canal)
When can we consider a thin tube BTE vs a standard? - Answer-When a PT's TH is
60 dB or higher
How does a BTE-RIC differ from a standard BTE? - Answer-The Reciever is in the
canal vs built into the aid.
What are the 5 considerations for fitting a HA? - Answer-Audiometric results
Lifestyle
Manual Deterity
Canal Size/Configuration
Cosmetic concerns
What effect does choosing an occluded fitting have on a PT's perception of sound? -
Answer-They may notice internal sounds like coughing, chewing, and speaking
much more than normal due to increased amplification by bone conduction.
What can we do to allieviate symptoms of the OE when fitting? - Answer-Choose a
more open fit or customize an ITE that extends past the 2nd bend
What amplification options are there for an unaidable ear? - Answer-CROS or
BiCROS
