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Amplification II > 12 - CROS & BiCROS > Flashcards

12 - CROS & BiCROS Flashcards

1
Q

What are 3 hearing problems associated with unilateral hearing loss?

A

1) Speech and communication issues when sound is arriving to the poor ear
2) Background noise and group situations- increased challenges
3) Sound localization challenges

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2
Q

What is a CROS overcoming?

A

Frequency-specific decrease in SPL occurs when sound is presented to the contralateral side of the skull

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3
Q

The greatest decrease in frequency caused by the head shadow effect is?

A

Particularly above 1500 Hz

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4
Q

What does the head shadow effect compromise?

A

HF consonants (things aren’t clear)

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5
Q

What does CROS stand for?

A

Contralateral Routing Of Signals

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6
Q

What is a CROS used for?

A

For Single-Sided Deafness (SSD)

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7
Q

How does a CROS work?

A

CROS: Signal arrives at poor ear, the device picks up the signal and delivers it to the better ear

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8
Q

How does a BiCROS work?

A

BiCROS: Signal arrives at poor ear, the device picks up the signal and delivers it to the better ear (the better ear is also receiving amplification)

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9
Q

What does a CROS look like?

A

CROS devices appear to look like conventional hearing instruments, but they are only transmitting sound to be delivered to the better ear to a receiver device

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10
Q

A CROS communicates through ____

A

wireless transmission

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11
Q

Who is a candidate for a CROS?

A
  • Normal or near normal hearing in one ear
  • Other ear is “unaidable”
    • “Not enough” residual hearing
    • Extremely poor word recognition scores
    • Binaural interference
    • Medical condition preventing use of aid
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12
Q

CROS: mic transmitter on ____, amplifier and receiver on ____

A

poor side, good side

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13
Q

What type of a dome is used with a CROS?

A

Open ear tip/earmold on normal ear (want as open as possible)

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14
Q

What are 2 benefits of a CROS?

A

1) Easier to hear speech originating from the poor side
2) Most helpful when noise is on good side and speech on poor side

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15
Q

What are 2 limitations of a CROS?

A

1) Least helpful when noise is on poor side and speech on good side (better if unaided)
2) Generally, does not improve localization

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16
Q

What does BiCROS stand for?

A

Bilateral Loss/Contralateral Routing of Signals

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17
Q

Who is a candidate for a BiCROS?

A
  • For patients with bilateral hearing loss with one unaidable ear
  • Hearing aid on better ear, with an additional mic on the poor (unaidable) ear
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18
Q

With a BiCROS, both mics send signal to one receiver on ____

A

Better ear

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19
Q

What are the 3 CROS/BiCROS arrangements?

A

1) Wire along neck
2) Wireless transmission
3) Transcranial CROS

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20
Q

How common is the wire along neck arrangement?

A

ancient technology

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21
Q

How common is the wireless transmission arrangement and how does it work?

A
  • Commonly used
  • Transmitter-mic on poor side and receiver on good side.
  • Radio frequency transmission
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22
Q

How common is the transcranial CROS arrangement and how does it work?

A
  • Not commonly used
  • One normal ear & absolutely no residual hearing in other ear.
  • One powerful HA on ‘dead’ ear to provide crossover hearing to normal ear via bone conduction
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23
Q

What are 4 examples of a wireless CROS/BiCROS?

A

1) Phonak CROS P
2) Starkey Livio AI CROS System
3) Widex CROS
4) Signia CROS Z

24
Q

What are the fitting targets with a CROS?

A

1) The goal is to overcome the head shadow effect
2) The REUR is the target (in the better ear)

25
Q

What are the fitting targets with a BiCROS?

A

Targets for the better ear (DSL, NAL-NL2) are also the targets when the test signal is delivered from the poorer side (to the better side)

26
Q

What is the purpose of CROS and BiCROS verification?

A

Measure the effectiveness in overcoming the head shadow effect by measuring the response in the better ear receiving input from the transmitter side

27
Q

What are we measuring with CROS and BiCROS verification?

A

We are measuring transparency. We are measuring the ability to overcome the head shadow effect through the process of verification

28
Q

What are 3 key rules with CROS and BiCROS verification?

A

1) The probe tube/microphone is always in the better ear (not in the poor ear because we aren’t delivering sound to the poor ear)
2) Coupling to the “better” ear is key (we need to ensure that with CROS systems, the ear is not occluded). What measure could we use to ensure this? Look at the REOR (a decrease in SPL will mean we are occluding the ear)
3) The system you are using requires a way to separate the probe mic system from the reference mic

29
Q

What is a probe mic?

A

Measuring the response of sound delivered to the ear canal (always in the better ear)

30
Q

What is a reference mic?

A

Ensuring that what is being delivered is correct. Making sure the sound that you’re playing is the sound being delivered to the ear. Measuring the output from the loud speaker.

31
Q

When the “CROS” choice is selected; the system will use the ____ of the non-test ear to monitor the input signal being used for the test

A

Reference mic

32
Q

What are three verification measures for CROS and BiCROS?

A

1) Insertion gain (CROS)
2) speech mapping (CROS or BiCROS)
3) Pink noise (CROS)

33
Q

What are the 2 components we are trying to understand with the CROS insertion gain verification measure?

A

1) understand REUR in the better ear
2) understand individual head shadow effect

34
Q

What are the 6 steps to measure REUR in the better ear with the insertion gain verification measure?

A
  • This method is just for CROS
  • Want to make sure we are measuring the better ear
  • The reference mic is on the ear closest to the loud-speaker and the probe mic is in that same ear
  • R ear = better ear and we want to measure the SPL in the REUR
  • 65 dB pink noise
  • When we deliver the sound to the ear we will get a REIG measure
35
Q

What are the next 3 steps to measure the individual head shadow effect with the insertion gain verification measure?

A
  • Now the RM is on the poor ear and the PM is on the good ear (the RM is always on the ear that is facing the loud speaker)
  • Now we are going to turn our patient, so their poor ear is directed toward the loud-speaker
  • We will see if we overcame the head-shadow effect if the second measure matches the first measure
36
Q

What are the advantages to the insertion gain approach?

A

Fairly easy to run (in verefit), can see if you overcame the head shadow effect

37
Q

What are the disadvantages to the insertion gain approach?

A

Pink noise isn’t necessarily real world

38
Q

What is the expected performance for the patient with the insertion gain approach?

A

We should be able to show that we gave the patient access to sound from the poorer sound

39
Q

Verification using speech mapping REAR measures are most helpful for ____, but can be used for ____ too.

A

BiCROS, CROS

40
Q

What is the speech mapping REAR verification method looking at?

A
  • Speech Mapping results are displayed as output results, generally using comfortable levels of calibrated speech
  • This method can be used, like the REIG method to see output results, and confirm if indeed you are overcoming the Head Shadow effect (and also checking for occlusion on the better)
41
Q

What are the first 4 steps of verification of CROS with the speech mapping measure?

A
  • don’t want any targets
  • go to single view and set ourselves up with the better ear facing the speaker
  • PM and RM on same ear facing speaker
  • run just a response of the LTASS at a comfortable level (finding the individual ear canal resonance)
42
Q

What are the remainding 3 steps of verification of CROS with the speech mapping measure?

A
  • now separating cross in our drop down (PM in better ear, RM on poor ear but still facing loud-speaker)
  • with cross off, shows the head-shadow effect
  • when cross system is on, can see that we overcame the HS effect (just trying to match up the response to the better ear)
43
Q

Another way to verify CROS is through the use of ____

A

Pink noise

44
Q

If using pink noise in speech mapping turn off ____ system

A

NR

45
Q

What is the first step of verifying through speech mapping measures for BiCROS and what are the 3 steps?

A

Step 1: Need to verify the aided response, on the ear using a hearing aid (the better ear)
- better ear (RM and PM facing the speaker)
- fit to target as we normally would (fit to soft, mod, and loud inputs)
- now we want to verify what the cross transmitter is doing

46
Q

What are the remainding 5 steps of verifying through speech mapping measures for BiCROS?

A
  • Now that the hearing aid has been verified, we need to set the instrument to CROS, and measure the Head Shadow effect
  • select cross to separate PM and RM
  • turn cross system off (or mute it)
  • look at the same response: if its off we should see a lessened response because of HS effect
  • when we turn it on, we should see our targets are meeting the good ears targets (the response of the prescription)
47
Q

What are the advantages of the speech mapping approach?

A

Looking at speech mapping targets with our prescriptive formulas

48
Q

What are the disadvantages of the speech mapping approach?

A

No disadvantage (don’t have to turn off NR)

49
Q

What is the expected performance for the patient using the speech mapping approach?

A

Still not 2 ear hearing and doesn’t provide the ability to amplify sound.

50
Q

What are the full 10 steps of CROS verification with REMs?

A

1) Probe mic in good ear and reference mic on side of loudspeaker location (Verifit: probe modules with reference mic on each ear with probe mic only in good ear).
2) Set Verifit to BTE and position speaker 45-90˚ to good ear: Response is measured.
3) Position CROS transmitter on patient.
4) Set Verifit to CROS and position speaker at 45-90˚ to poor ear: Response is measured with device turned off, then on.
5) We are verifying that we have overcome the Head Shadow effect
6) Probe mic in better (aidable) ear & reference mic on side of loudspeaker location.
7) Verify the HA in the better ear using standard REM, as if verifying a monaural fit (REAR1). You are matching targets. Verifit set to device configuration, and match targets accordingly.
8) Set Verifit to CROS.
9) Then verify the BICROS system by positioning the speaker 45-90˚ to poor ear with the CROS transmitter: REAR2 should match REAR1 obtained with the HA alone.
10) We are verifying that we have overcome the Head Shadow effect, and that the hearing aid (also the CROS receiving device) is meeting targets

51
Q

How do we measure speech recognition in quiet and in noise using CROS verification with speech tests?

A
  • Speech ~ 50 dB HL; noise ~ 45 dB (+5 S/N)
  • Speech on poor side; noise on good side:
  • Unaided: challenging!
  • Aided: should show some improvement.
  • Speech-in-noise measures in soundfield may be useful for counselling
52
Q

In BiCROS fittings, consider setting additional programs to what?

A

1) HA only mode (no BiCROS) so that noise coming predominantly from the poor side is not routed to the better ear (a manual program where the CROS isn’t active). Ex) if there is just noise and the CROS is just sending that noise over to the good ear.

53
Q

Overall patient satisfaction with CROS and BiCROS is generally ____

A

High

54
Q

Hill and Colleagues (2006) conducted a study of 91 patients with severe-to-profound asymmetric hearing loss to assess their satisfaction with digital contralateral routing of signal (CROS) or bilateral contralateral routing of signal (BiCROS) hearing aid, and found that the satisfaction rate was over ____

A

70%

55
Q
A

Amplification II (13 decks)

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