How Do You Know You Need a Wireless Microphone?


In my last blog posting, I spoke about the technologies available to help you hear better in noise.  These included:

  1. Directional Microphones
  2. Fixed Gain Wireless Systems.
  3. Dynamic Wireless Systems. ZoomLink+ Transmitter

But how do you know what technology you need?  This is a very important question that needs to be answered right away before you decide what kind of hearing devices you wish to purchase.  Let’s say you need Dynamic Wireless system in addition to hearing aids.  If you have sufficient financial resources at your disposal, you may wish to purchase a premium hearing and a wireless system.  This is the best of all worlds.  But if you have limited resources, you may wish to spend less money on your hearing aids in order to have enough money left over for a wireless system.

It is also important to know this in order to have realistic expectations about your hearing instruments.  If your hearing loss requires that you use a wireless microphone system in order to hear in a noisy environment, you can do countless hours of hearing aid fine tuning with your Hearing Care Professional and you are still not going to hear better in noise.  Its simple physics: a Dynamic Wireless microphone placed in close proximity to a speaker’s mouth will always outperform a microphone at the ear level.

Ideally you will have answered this question early in your hearing device selection process.  Here’s how this question can be answered:

  1. Experience with Existing Hearing Devices.  If you already have hearing aids or a CI equipped with directional microphones and you are still struggling to hear better in a noisy environment, you will have answered your question about the need for a wireless system.
  2. Experience with a Bluetooth Wireless Microphone.  As I mentioned in my previous blog posting, a Bluetooth Wireless Microphone will provide better performance than a directional microphone on your hearing devices.  But if you are still struggling with the Bluetooth mic, there are still significant improvements that can be obtained with a Dynamic Wireless System.  The microphones cut noise better, and the dynamic nature of the system will reduce the amount of noise your hearing aid or CI microphones will pick up.
  3. Experience with a Fixed Gain Wireless System.  Similar to the above, if you already have tried a fixed gain system (Eg Phonak Campus, SmartLink SX, ZoomLink or EasyLink; Oticon Amigo, Comfort Audio Digisystem) and are still having trouble, then a Dynamic System will provide additional benefits particularly at noise levels at around 70 dB or greater.  This is about the level of a restaurant.
  4. Audiogram Approach.  Most people with moderate-severe hearing loss or greater will require more than a directional microphone on the hearing instruments.
  5. Direct Assessment of Hearing in Noise Abilities.  There are several tests that your Hearing Care Professional can perform to help determine right away what kind of technology you need.  The one I am most familiar with is the LiSN-S PGA test and as such I will highlight this test in the remainder of this blog posting.

LiSN-S PGA stands for Listening in Spatialized Noise.  Performed under headphones, a virtual 3D space is created with target sentences coming from the front and distracting sentences are coming from the left and the right.  The PGA stands Prescribed Gain Amplifier.  The stimuli are amplified according your hearing test results.  So it simulates the way you would hear in a noisy environment if you had hearing aids and an omni-directional microphone.

LISN-S PGA

LiSN-S PGA accurately measures your ability to understand speech in noise as if you were wearing hearing instruments (amplification), and by your performance on LiSN-S PGA with normative data stored in the software, LiSN-S PGA predicts accurately the your performance in noisy situations compared to normal hearing listeners of the same age, and if the predicted performance is not good, LiSN-S PGA gives you clear, individual, technology recommendations how to improve speech understanding in noise. So based on your responses to the sentences, you get an evidence based recommendation.

The test takes about 5 minutes to perform.  You will hear noise first coming into both ears.  It will seem like the noise is coming from the sides.  Then you will hear a sentence that sounds like it is coming from in front of you.  Your task is simply to repeat back the sentence.  Your Hearing Care Professional simply needs to click on how many words you repeated correctly.  The computer will then automatically make the next sentence softer or louder depending on how well you did.  The test stops when the software has sufficient results to make a recommendation for you.

Condition 1

Here is what the recommendations screen looks like:

recommendation

Personally I find it interesting that difficulty hearing in noise is one of the most common complaints that a person reports when getting a hearing test, yet most hearing care professionals never assess this.  Far too often we wait for a patient to fail with the hearing devices before we explore additional noise reduction technologies.  This is unacceptable.  Why frustrate people with hearing loss unnecessarily?

I know many Hearing Care Professionals are thinking, “Yes Peter, but many patients won’t use additional microphones, so I don’t bother introducing this technology”.  This thinking is also unacceptable.  You are making a pre-determination and denying people hearing loss technology that is critical to helping them function in our noisy world.   Our duty, as Hearing care Professionals is to help people with hearing loss make an informed decision.  Yes, some may reject such technologies initially, but it is still their right to be informed.

For more information about the LiSN-S PGA, click here.

For more information about the development of the LiSN-S PGA test click this link here.

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15 thoughts on “How Do You Know You Need a Wireless Microphone?

  1. To your knowledge, Peter, are there places that use LiSN-S PGA? I think the information that this assessment provide would be great for me considering the severity of my hearing loss.

    Thank you or sharing this.

    • Peter, who puts out this test?

      Incidentally, the ReSound Mini Mic is awesome; and I now make it mandatory with all of my fittings.

      • Good question. I edited the blog posting and added links to get more information about the LiSN-S PGA. It was developed by Dr. Harvey Dillon and Dr. Sharon Cameron at the National Acoustics Laboratory in Australia. It is distributed world-wide by Phonak.

        I am glad to hear that you are incorporating a Bluetooth Microphone in your fittings. I wish more hearing care professionals were like you. For many patients, this will give them sufficient reduction of noise in many situations. However, more severe losses or people with poor hearing in noise (as indicated by the LiSN-S test results) will require the higher SNR’s that can only be obtained by a Dynamic Wireless System as I indicated in my previous blog posting.

      • No, Peter: The ReSound Unite Mini Mic does NOT use IEEE 802.15.4 Bluetooth transmission: It uses a proprietary 2.4 gHz digital signal, to hold the latency down to a few mSec. The Bluetooth mini mics used with streamers employs BT2.1 A2DP transmission, which has up to 150 mSec latency, leading to feedforward comb filtering distortion, echo, and loss of synchrony with lipreading cues.

        As for Dynamic FM, ReSound goes one better with the Phone Clip Plus and Control iPhone app, as it allows the user to separately adjust the HA and wireless streaming levels (or even mute the HA mics at the touch of the screen), to get the precise mix ratio needed. Phonak’s Dynamic FM is a very expensive solution only really for people who don’t want to be bothered with a remote (and they probably won’t use the FM, either); and it’s only really for users who have the IQ of a potted plant, who aren’t capable of making the adjustments themselves.

        Oh, And By The Way, the Unite Mini Mic is less than 1/10th the cost of Phonak’s FM system; and since it uses N-band (216 mHz 6F3 analog transmission) at a weak 10mW power level, it is HIGHLY susceptible to interference, especially when CI’s are used.

      • Yes, I am aware of the Resound Mic. Indeed it is not Bluetooth, but it is still nonetheless a fixed gain solution, not dynamic. Studies still clearly show the advantages of an adaptive dynamic system over fixed gain. This paper by Linda Thibodeau shows the advantage of a dynamic system over fixed gain in hearing aids. This also applies to cochlear implants as can be seen in this paper by Jace Wolfe et al.

        Many patients may be get sufficient benefit from a lower cost fixed gain wireless microphone, which is fantastic. And you are correct, the price difference between these solutions and the FM solutions provided by Phonak, Oticon, and Comfort Audio is quite significant.

        But the point of this posting, and others in my blog, is to get people thinking more about hearing in noise issues and utilizing the many solutions that hearing aid companies such as Phonak and Resound already have made available. Far too many patients are not achieving full participation in all of life’s activities because these technologies are under utilized. Once again, I commend you for bucking the trend and encouraging greater use with your patients.

  2. I would love to see an opportunity for more consumers with hearing loss to try out the different kinds of FM systems for themselves, like at the national conventions for people with hearing loss. Will Phonak provide a way for consumers to try out the Dynamic Wireless Systems at the HLAA and ALDA conventions this year?

      • @Dana: The problem is threefold:

        1) Using a neckloop is a non-starter, as if a person is having a problem (highly likely on an electrically noisy Expo hall floor), it makes the FM itself look bad, and will be a turn-off: It has to work right 100% of the time;

        2) There are a whole plethora of hearing aid and CI audio input shoes & connectors;

        3) Even once you have the proper hardware, you still have to go into the HA or CI programming to enable the DAI port.

        This is why you saw me with my laptop and NOAHlink programmer at the DC and Providence HLAA Conventions, specifically so I could try out hearing aids, and reprogram mine for various ALD trials.

        [Needless to say, it was quite a bit of fun when I called the bluff of various hearing aid mfr reps when I asked to try their hearing aids: They would provide the stock answer of : “It’s not programmed for you;” and then I’d whip out my NOAHlink to their shocked faces!]

      • I agree. Unless you already have a hearing aid programmed for FM + M along with your own audio shoe, its tough to do. For some CI’s, the receivers need different gain than hearing aids. Even the neck loop approach is hard. In addition to what Dan said, many folks don’t even have a manually accessible telecoil program.

  3. Greetings, Have just found your blog and enjoy it immensely, thank you for it. A couple of places in your postings you mention that it can be too late to move to FM systems. After looking through your postings I don’t find an expanation of why that is. Can you explain, please.
    Joe

    • Hi Joe. This is only for people who have such a significant hearing loss, that they will likely need a cochlear implant (CI). If one has very little hearing left, adding an FM system won’t change that fact. Now after you get a cochlear implant, I then strongly encourage adding an FM system to the CI. People with CI’s also have difficulty hearing in noise and definitely benefit from FM systems.

      • Thank you Peter for your explanation. I guess you are saying if they had been using the FM system before their hearing loss further degraded, that they could have benefited from it, but if it gets to the point that the CI is needed, then adding an FM system will increase the benefit from the CI.
        thanks again,
        Joe

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