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Interview with Donald Hayes Ph.D., Manager of Audiology, Research and Training, Unitron Hearing

Donald Hayes, PhD

October 4, 2004

Topic: CROS & WiFi Technologies from Unitron Hearing
Beck: Hi Don. Thanks for your time today.

Hayes: Hi Doug. Happy to meet with you.

Beck: Don before we get to WiFi Mic and related issues, I understand you earned your Ph.D. at the University of Cincinnati?

Hayes: Yes, that's right, in 2002. I completed that a few years ago, but I had worked 11 years as a clinical audiologist at Sunnybrook Health Science Centre in Toronto before that. I was an Assistant Professor at the University of Cincinnati and was a Lecturer in the Department of Speech Pathology at the University of Toronto. I also worked as an Audiologist Consultant for the Canadian Ministry of Health and.

Beck: What was the topic of your dissertation?

Hayes: The Effect of Crossover Frequency on Aided Speech Perception in the Presence of Environmental Sounds.

Beck: Very good, seems like an excellent background for the work you're doing! Don, would you please define "WiFi" as it relates to your products?

Hayes: Sure. WiFi is an abbreviation for wireless fidelity. Products referred to as "Wi-Fi Certified" can communicate with each other "wirelessly," even if they are from different manufacturers. WiFi technology is available in our new BTEs and BTE shells, meaning all the Liaison™ and Unison™ models, and soon it'll be available in the Conversa™ too. Our goal is to make WiFi technology available on the bulk of our digital hearing aid lines. The traditional CROS units had a wireless system on an analog hearing aid, but now the WiFi Mic devices are avaialable on 100 percent digital, so they have a broader range of capabilities. So the principal advantage of the WiFi technology is that it applies wireless signals to digital technology.

Beck: Of course, the term CROS refers to "contralateral routing of signal. " For CROS and BiCROS options, I usually try to teach students to remember which is which, by noting that the CROS has one microphone, and BiCROS has two mics. But the question always comes up...which one is more common?

Hayes: The BiCROS represents the overwhelming majority of these types of fittings. Regarding CROS versus Bi-CROS, another thing to remember is the volume control (VC) issue. The CROS has the VC on the transmitter side, which is the side with the mic enabled, and on the BiCROS, both mics and both VCs are operational.

Beck: Who is the ideal candidate for the WiFi Mic CROS and BiCROS products?

Hayes: The ideal candidate is really the same as has been true historically. For the CROS, someone with an "unaidable" ear on one side, meaning no usable hearing on that ear, and normal or near normal hearing in the low to mid frequencies on the other side. The ideal candidate for the BiCROS is someone with one unaidable ear, and the other ear has a mild to moderately-severe hearing loss. The mics for the BiCROS hearing aids would serve both sides of the head, but the receiving side is the better ear only.

Beck: And sometimes the wearer of the BiCROS uses one mic only, depending on the situation?

Hayes: Yes, that's true. So for example....the BiCROS in the Unison has three programmable memories, and you could program the first program to be a CROS system only, and then programs 2 and 3 could both be a BiCROS system and perhaps a totally different program. It just depends on the needs of the individual and their listening environment. However, this should not be attempted with an open CROS mold as it may lead to problems with acoustic feedback.

Beck: Don, this is really exciting. It's great to see this technology applied in the specialized CROS and BiCROS arenas.

Hayes: Yes, I agree. The flexibility of these digital aids allows much more precise control of a wireless fitting where you can get large variations in the signal being transmitted across the head. Changes in the orientation of the transmitter and receiver coils due to the shape of the external ears or tubing length can have a large impact on the signal received from the transmitter. Using multichannel compression instruments we obtain very fine control to correct for the effects of the separation distance between the two units. We also get a better spectral response from the hearing aids. We can program these far more accurately, and with many more options than the previous generations. The other very important development is that the fitting software can really guide you through these fittings, and the software is intuitive, yet very sophisticated. This is really a nice advancement because many people only fit one or two BiCROS aids a year, and frankly it's hard to remember the details and the protocols when you're not doing this daily.

Beck: Excellent news Don. Thanks for sharing this with us.

Hayes: My pleasure Doug.

Beck: I'd like to hyperlink to the Unitron Hearing brochure on WiFi Mic Digital Wireless CROS /BiCROS, and I should note that you are accessible via e-mail if anyone has questions they'd like to address to you directly.

Hayes: Yes Doug. I can be reached at


WiFi Mic information is now live on the Unitron website Here are some additional links where you can read more about WiFi Mic:

To view the WiFi Mic brochure for hearing professionals, CLICK HERE.

Information for Hearing Healthcare Professionals:

WiFi Mic Technical Data:

Customer Testimonial:

Information for Consumers:

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donald hayes

Donald Hayes, PhD

Director of Audiology at Unitron Hearing Ltd. in Kitchener, Ontario

Donald Hayes, Ph.D. has been an audiologist for 18 years. He is the Director of Audiology at Unitron Hearing Ltd. in Kitchener, Ontario. Don Hayes is the Director of Audiology at Unitron Hearing Ltd. in Kitchener, Ontario.

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