By Jenny Groth
Hearing aid wearers who must use stethoscopes in their jobs have long been challenged by how to make them work with their hearing aids. Today, hearing aids and stethoscopes are commercially available that each advertise Bluetooth® capabilities, which would lead one to believe that a convenient solution has finally arrived. So, can Bluetooth stethoscopes be used together with digital wireless hearing aids? While the technical answer to this question is “yes, depending on the stethoscope”, the convenience may not compensate for the poorer audibility and sound quality afforded by a streaming solution.
But let’s talk about the technical part first. An audiologist recently fit a doctor with ReSound Verso™ hearing aids and a Phone Clip+. The doctor uses the Littman Model 3200 Bluetooth stethoscope, and had looked forward to being able to stream the sound from the stethoscope to the hearing aids. He brought his stethoscope with him to the fitting, but try as they might, they could not get the stethoscope to pair to the Phone Clip+. The audiologist naturally asked the question “If the stethoscope transmits a Bluetooth signal then why wouldn’t the Phone Clip+ pick up that signal?”
The reason that the stethoscope and Phone Clip+ did not communicate was that they are not using the same Bluetooth profile. The profile specifies an aspect of the wireless communication between devices that manufacturers follow to use Bluetooth in a particular manner. The information about the Bluetooth profile that is supported is usually buried somewhere in the technical specifications of the product. For example, information regarding the supported Bluetooth profiles for the Phone Clip+ appears in the data sheet as shown below. Information on which Bluetooth profiles are supported by the stethoscope in question does not seem to be readily available, but the manufacturer does explicitly state that the product is not compatible with wireless hearing aids. Indirectly, this means that this product does not use the same profiles as wireless hearing aids.
We have only been able to find one Bluetooth stethoscope currently on the market in the US that is compatible with the Phone Clip+ (and presumably other digital wireless hearing aid streamers). This is the Piezo Wireless Bluetooth Stethoscope from Sedation Resources. While it is possible to stream sound via the Phone Clip+ to ReSound wireless hearing aids from this stethoscope, the sound quality and audibility of the auscultation sounds with this solution were not impressive and could be expected to be inadequate for someone with hearing impairment.
An alternative to using a Bluetooth stethoscope to stream sound to the hearing aids is to use a hard-wired connection to the Mini Microphone, and stream from that accessory instead. Any amplified stethoscope that has a line out can be hooked up to the Mini Microphone just like an MP3 and the sound streamed to the ReSound Alera® or Verso hearing aids. There are at least three we know of with this capability from Cardionics, Sedation Resources, and Thinklabs Medical. While we found that this worked better than streaming over the Bluetooth connection with the Piezo Wireless Bluetooth Stethoscope, it was still far from ideal.
Generally speaking, streaming stethoscope sounds will not have the same integrity of sound quality as listening directly from an amplified stethoscope. This is primarily due to the low frequency bandwidth limitations of hearing aid receivers as well as the effective low frequency bandwidth limitations of vented and open fittings. These limitations may preclude accurate stethoscope diagnosis. If at all possible, an amplified stethoscope would be better than streamed stethoscope functionality for diagnosis.
For a review of options for how hearing impaired professionals can use stethoscopes with and without hearing aids, see Bankaitis’ article on Audiology Online. A treasure trove of information on using stethoscopes with hearing aids is also provided on the Association of Medical Professionals with Hearing Loss website.
© 2014 The GN ReSound Group, all rights reserved. Bluetooth is a trademark of Bluetooth SIG, Inc.