Monday, 17 December 2012

How many channels should a hearing aid have?

My response to a statement made about the number of channels that were necessary in a modern hearing aid (on hearingaidforums.com):

This is the question:
 Quote:
Originally Posted by ed121 View Post
Lets get basic. A Channel should mean a slice of the hearable audio spectrum which the aid can control the loudness AND compression and possibly other parameters.. A Band is a slice that you can only control how loud it is (gain) and narrows the noise gate.

Many experts think that the majority of loss types require only 4 to 6 channels.

There is a penalty to more channels....more means increased processing time which can lead to conflict with the sound coming through the vent which has zero processing time. And each additional channel increases the amount of inter-channel distortion and phase shift to the input signal.

So more is not always better.

It is a rare patient that benifits from more than 4 to 6 channels (notching out distorting hair cells.)

For most losses the only benifit to lots of channels is increased cost and more profit for the manufacturers and retailers. Ed
My Answer.

However it does give the audiologist/dispenser more tools to deal with pitch specific problems. If you've ever programmed an aid, you'd realise that not having a gain 'handle' at a particular frequency can be quite debilitating to the process. (Like having occasional feedback just at 3Khz and only having 2KHz and 4 Khz controls.)

Just one caveat about the 'flat losses' as they appear on the audiogram: yes, that might look like you can just whack in one gain setting: in reality your canal resonance added to the insertion gain/loss of the device will produce a pretty squiggly line. Coupled with this, the output of the receiver is a damped sinusoid saw-tooth in it's natural state. Put all these things together and you have the potential to be massively askew at a particular frequency - in terms of the actual gain needed.

Now, as to the actual resolution: if you follow the articulation index measure that each octave contains roughly 20% of the speech cues (with a greater bias in the 2-4KHz area), you have a starting point. If you remove one of these octaves entirely to deal with a feedback issue, then you have eliminated the response from up to 20% of your potential speech area. I appreciate that there are other factors at play: including the roll-off between each channel and the efficacy of different feedback systems, but ultimately, if the aid is whistling, you have to turn down the gain a bit at that point - whether you do it obviously or not.

This leaves us with a trade off - how many channels is enough, how many is too much? - (NB Bernafon). Ultimately this is a design choice based on the parameters of the circuit, especially the clocking speed: going forward its going to be less of an issue due to Moore's Law. In a previous response on here I postulated that a 10-12 channels was probably enough, given that it adequately represents every conceivable audiogram, provides half octave accuracy for the feedback issue and allows frequency specific noise management to function properly with minimum disturbance of the adjoining channels. More than 12 channels is probably chewing more processor cycles than absolutely needed, but if you have the lateral capacity on your chip, why not, if there is a potential improvement in the end signal.

I'd like to address another point in relation to the alleged 'inter channel distortion' or 'compression artefacts'; you can bet your bottom dollar on the fact that whatever you think of the electronics engineers at a modern hearing aid factory/design house, they are doing their absolute utmost to prevent such issues. Likewise the delay within the circuit. Nobody benefits from more rubbish being thrown at their residual hearing.

Going forward, simultaneous binaural processing is pushing the aids to do more with the incoming signal on both sides, so the number of channels per aid will effectively double as the processing of the stereo signal can be done separately to improve performance in background noise with a combined decision on the output to each ear.

In conclusion a dozen channels is probably enough: that much used study illustrating the patient benefits of less than half a dozen channels doesn't actually have great credibility at all when you think about it, as the patient is unaware of what they are missing in all situations, therefore they can't tell relatively how effective an aid is being in those situations. It might sound prescriptive, but you can't ever appreciate the full effect of a view from inside, can you.

NB: Bernafon - Channel free or 10,000 channel technology has been around for a few years; having fitted quite a few in the past, some people really like the kind of performance, some don't. It's a shame that their not one of the 'main' manufacturers as this delivery mechanism will always be considered a bit 'second string' in the DeMant catalogue.
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Wednesday, 5 December 2012

Specsavers: where exactly do they pay tax?


Just a bit of a moan about the state of competition on the High Street: also posted in FB


Why is it that when you post a question regarding Specsavers Tax status on their home page it gets deleted?

Surely being registered here........Specsavers Optical Group Limited registered in Guernsey with company number 12294 and its registered office at La Villiaze, St Andrews, Guernsey GY6 8YP...... doesn't afford them any tax savings, by being offshore: does it?
Like ·  · 

Monday, 12 November 2012


From : http://hearingmojo.com

Unitron Max Super Power Hearing Aids Use Automatic Gain Reduction To Protect Against Over-Amplification

Posted by David Copithorne on Saturday, October 13, 2012 ·

New Unitron Max Super-Power hearing aids address one of the biggest dangers people with severe-to-profound hearing loss face — the temptation to turn up the volume to catch conversations in noisy settings to levels that can damage your hearing. Unitron Max is the first super power hearing instrument on the market with a Power Adaptation Manager that automatically moderates over-amplification while continuing to maximize speech intelligibility.
Over-amplification is a bigger concern than you might think. I find myself constantly turning up my hearing aids to follow conversations, even when the over-amplification of very noisy ambient sound bothers my ears. Worse, I’ll often forget to turn the volume down long after I need the extra boost. I’ve also been guilty of badgering my fitter for even more gain to let me tune into other people’s voices — even when I know that too much amplification can further degrade the hearing that I still do have.
In a recent survey of 200 hearing healthcare providers conducted by Unitron’s product development team, 87 percent of respondents indicated that over-amplification is a persisting issue in their practices and would welcome a means to address the potential harm it can cause to residual hearing while still meeting patient needs.
“While hearing healthcare providers recognize the need to reduce gain to maximize speech intelligibility and protect the long term hearing health of their clients with severe to profound loss, they typically face client rejection when they attempt to manually reduce gain,” Donald Hayes, Ph.D., Unitron’s Director of Audiology, said in a press release. “Power Adaptation Manager solves this challenge, by  automatically and imperceptibly reducing gain and output to safer levels,  gradually and deliberately.
It’s always gratifying when a major manufacturer makes special efforts to build high-end features into its highest power hearing aids. Super-power aids are for a much smaller market niche — consumers with severe-to-profound hearing loss who don’t  qualify for a cochlear implant but who need a lot more amplification and programming assistance — than the mass-market of consumers with age-related mild-to-moderate high-frequency hearing loss. So they often don’t get the same attention from developers and new-product mavens as the hot-selling hearing aids for mild-to-moderate loss.
Built on the next-generation Unitron Era sound processing platform, the Unitron Max super-power hearing aids provide high-end features that have been customized for the needs of users with severe hearing impairement. Unitron customized the Era “SmartFocus” feature with a unique integration of directional microphones, speech enhancement, noise reduction and gain work to optimum speech understanding without compromising awareness of ambient sounds.

Hearing Aids From the beginning of time.....Almost

Link to the article: Deafness in Disguise

Interesting article about hearing aid development from the earliest beginnings to current (2009) iPhone integration.

Friday, 2 November 2012

Unitron Automatic Acceptance manager

Don Hayes video

In the field I've found that the Moxi Pro still need to be started from a lowish level (70% or so) even when fitted to existing hearing aid wearers. Normally you'd expect not to have to throttle the full prescription as much, but the degree of sharpness from the Moxi seems to need to be delivered slowly for some: especially flatter losses IMHO. Extending the length of time works really well too, pushing out the full adaption over a year or more seems to fit some people's mental plasticity.

Saturday, 27 October 2012

Article on iPhone and hearing aid integration from 'the hearing aid blog'


Speculation started several weeks ago at Apple’s WWDC that the new API’s in iOS 6 would create some kind of linkage between the iPhone and hearing aids. This speculation was ramped up by this July 19th AppleInsider article revealing two key patent applications from January 2011. This article will examine these patent applications individually; and later we’ll provide our own SWAG (Silly Wild-Assed Guess) to add fuel to the fire.

First, a bit of history…

Users of hearing aids received their first big break in 1947 when the late Sam Lybarger, the Father of the Modern Hearing Aid, accidentally developed the telephone coil:¹ For the first time, deaf and hard-of-hearing people could hold the phone receiver over their (hot!) vacuum tube-powered hearing aid, switch on the T-coil, and through inductive magnetic coupling the baseband audio was picked up, amplified, and then transmitted to the button earphones… And it worked. However, two things conspired to break telephone compatibility: First, in the early 1960′s as the market shifted away from body aids and into transistorized behind-the-ear (BTE) instruments, the Electrical Engineers at the European hearing aid manufacturers seemed to have forgotten Maxwell’s Equations, namely that that the induced EMF in the telecoil magnetic pickup coil is proportional to (œ) the scalar dot product of the flux line vectors, which are oriented on the axis of the two coils, i.e. the EMF v, the vectors A & B, the absolute value of the vector magnitudes |A| & |B|, and the angle θ between A & B:
v  œ A • B = |A| * |B| * cosine (θ)
As a brief reminder from high school trig, cos (0°) = 1 & cos (90°) = 0
Cosine function as it applies to the scalar dot product of the angle between the axes of a hearing aid telecoil and the voice coil of a telephone receiver or room induction "hearing" loop
Cosine function as it applies to the scalar dot product of the angle between the axes of a hearing aid telecoil and the voice coil of a telephone receiver or room induction “hearing” loop
Click to enlarge
[Note: The actual value of electromotive force v  is a pretty complex calculation using Maxwell's Equations; but the important thing to note is the constituent relationship between the induced telecoil audio signal and the axes of the coil orientations.]
Although like a squirrel stumbling upon a nut, this vertical alignment of the hearing aid telecoil in fact works with horizontal room induction “hearing” loops on the floor or in the ceiling, in fact it broke telephone compatibility — Nice going, guys.
The second factor that conspired against hearing aid telecoil efficacy was that back in the late 1970′s, the Bell System and their Western Electric telephone manufacturing subsidiary came out with a new, lower cost receiver that was more efficient — In fact, it was a bit too efficient, as it did a better job of confining the magnetic flux to the voice coil — magnet gap area… And hence weakening by over 10dB the induced voltage in the hearing aid telecoil, which was already weakened to almost zero by the vertical alignment by the European BTE manufacturers. In fact, some American ITE manufacturers — notably Starkey, Telex, and Argosy — had Engineers who understood Maxwell’s Equations, and used either pancake coils glued to the faceplate, or long thin telecoils on a ferrite core stuffed down into the canal portion of the shell.
From A Look at the Telecoil — Its Development and Potential, by David A. Preves, the longtime Chief Engineer at Starkey Labs
After a huge outcry, a powerful consumer movement was started In Washington, D.C. by a lobbyist named David Saks and his organization — OUT  (Organization for Use of the Telephone) — to ensure that persons with hearing loss would be able to use their hearing aids with the telephone.
In 1982, the federal government passed the Telecommunications for the Disabled Act which required that telephones be labeled as to their hearing aid compatibility. The resulting legislation from the Federal Communications Commission (FCC) brought engineers from hearing aid companies and telephone companies together for the first time to work on the compatibility problem of telephones and hearing aids. The outcome of these meetings in the early 1980s was a new measurement standard for determining whether a particular telephone was compatible for coupling with hearing aids via induction pickup. A telephone that produced the proper amount of magnetic leakage In the proper direction, as specified in the standard, could be labelled and sold as “Hearing-Aid Compatible.” The law specified that coin-operated telephones in public places like airports were required to be hearing aid compatible. These hearing aid-compatible telephones were identified by a blue grommet at the junction of the cord and the telephone handset.
This consumer-driven movement on behalf of people with hearing loss went much further In 1989 when all telephones with cords sold in the United States were required to be hearing-aid-compatible, and in 1991, when all cordless telephones sold in the United States were required to be hearing aid compatible.
TIA-1083 LogoFast forward to 2007, and the Telecommunications Industry Association had introduced the TIA-1083 logo program for mass-produced phones: Just go to your local WalMart or Target and look for a box with this logo:


Moving on to mobile phone connectivity…

Getting a mobile phone to work directly with hearing aids has been a recurring nightmare, and more so on the AT&T, T-Mobile (Deutche Telekom), and European 2G & 3G GSM networks, and somewhat less so on the North American Sprint and Verizon CDMA networks. As it turns out, although the mobile phones work in the UHF portion of the radio spectrum, they “burst” their data differently, with GSM bursting at several hundred packets per second — Right smack in the audio range. This causes two distinct problems: First, with older hearing aids, one would hear a terrible screeching sound whether the microphone or telephone pickup coil was used. This was caused by inadequate shielding, and more importantly a lack of RF bypass around the semiconductor junctions: What would happen is that this strong RF signal would be rectified by the p-n semiconductor junctions, with the burst envelopes in the audio range being demodulated just like an AM signal would be… And then amplified to full power and faithfully reproduced loudly screeched by the output amplifier stage straight into the user’s ears.
About a decade ago, mobile phones started to incorporate IEEE 802.15.4 “Bluetooth” wireless Personal Area Network (PAN) connectivity both for synching to a user’s desktop PC, and for connecting to the ubiquitous headset (the ones that look like the wearer has a cockroach on their ear). You’ll notice that we spell out “IEEE 802.15.4″ instead of using the more generic “Bluetooth” for two distinct reasons:
• To emphasize that, in general, the IEEE 802.15 family is similar to TCP/IP in general, and moreso to IEEE 802.11 “WiFi” in that it is a two-way protocol, i.e. that the transmitting station sends a packet of data along with error correcting codes and a checksum, and then the receiving station decodes the packet, verifies and corrects what errors it can, and then transmit back an ACK(nowledgement) signal. If the sending station does not receive an ACK, then it will send the packet again. This presents issues with power consumption and up to 150 mSec latency, which will be discussed below;
• To separate out the commonly used 802.15.4 Personal Area Network (PAN) standard that we all know from the still-evolving 802.15.6 Body Area Network (BAN) standard that we believe Apple may be implementing in iOS 6.
Let’s look at how “Bluetooth” is currently implemented with hearing aids for connectivity, and the significant drawbacks.
First and foremost, we need to understand that any digital reception in a hearing aid is going to consume extra power — And lots of it, due to the decoding operation. Add to this the 802.15.4 overhead of transmitting ACK signalling, even occasionally in A2DP (Advanced Audio Distribution Protocol), and it makes for a real issue. Austin-based Audiotoniq has mostly sidestepped this with their hearing aids by using a Li-ION cell; but in fact their hearing aid wireless communications protocol is only really for phone use and not continuous streaming (though they have a clever workaround for it).
Most every other manufacturer uses a “Bluetooth streamer,” which acts as a “relay station” communicating via 802.15.4 to the phone or other Bluetooth -equipped device, and then using a second transmitter to broadcast a proprietary Hearing Instrument Body Area Network (HI-BAN) signal to the hearing aids. There are three basic ways this is accomplished, and it’s important to understand the distinction, as it is key in understanding what we speculate Apple will be doing:
• Widex and Phonak use a 28 meter (10.6 mHz) “near field” digital signal.² Phonak and Widex also use 10.6 mHz for ear-to-ear communication between the instruments for binaural coordination of directional microphone beam steering, compression to maintain binaural localization, and also program shift. Widex also uses it for binaural “Phone Plus” operation and Phonak for CROS and BiCROS communications; and both manufacturers also use it for wireless programming;
• Starkey uses a 33 cm (900 mHz) UHF digital signal for streaming and ear-to-ear communications; however they also have direct-to-instrument broadcasting through their SurfLink Media transmitter, i.e. unlike the Widex TV-Dex media transmitter, no additional relay is used. However, Starkey also just released their SurfLink Mobile device, which can be used as a Bluetooth relay, and also as a remote mic up to 20 feet away — But it’s on backorder until at least fall 2012 due to unanticipated demand;
• GN ReSound uses a variation of a 2.4 gHz 802.15.4 signal — An “unofficial” 802.15.6 HI-BAN — for direct, low (under 10 mSec) latency, direct-to-instrument broadcasting from various Unite accessories to their Alera series hearing aids, as well as for remote control and wireless programming (with inter-ear coordination available 4Q2012). It is this style of direct-to-hearing aid broadcasting that we believe Apple will be implementing in software in iOS 6, by essentially “hacking” the 802.15.4 Bluetooth stack and turning it into a de facto 802.15.6 HI-BAN stack for low latency broadcasting.³

 If this direct-to-instrument 802.15.6 2.4 gHz digital broadcasting standard is indeed brought out by Apple forcing the Big Six hearing aid manufacturers as well as chipmakers such as Intricon, ON Semi and others to agree on a single standard, we at The Hearing Blog cannot overstate the significance of this to those of us in the hearing impaired community, as well as to hearing care professionals and sound reinforcement engineers.

Here are just several reasons why this will vastly improve the life of us in the hearing impaired community — And not just those who use an iPhone with hearing aids:
• This will elegantly solve the issue of people needing to carry or even wear a Bluetooth streamer relay to use their mobile phones, wirelessly bringing the audio into both ears;
• This will allow for all hearing aid users to have a very effective and inexpensive alternative to FM assistive devices (ALD’s), as what ReSound is now doing with their very good Unite Mini Mic will be duplicated by other HA manufacturers. We cannot understate both the efficacy and cost aspects of this approach, especially with pediatric hearing aid (and eventually CI) users, as current 72 mHz, 168 mHz (H band) and 216 mHz (N band) analog narrowband FM (6F3 NBFM) systems are plagued with interference, as well as high current drain for headworn devices, messy and unreliable direct audio input (DAI) cables, and troublesome neckloops which are subject to head movement drop-outs and electromagnetic interference;
• This will open the door for hearing aid and sound reinforcement manufacturers to use inexpensive, off-the-shelf chips for direct-to-hearing aid room-sized broadcasting from entertainment devices such as TV’s, stereos, and game consoles;
• Most excitingly, at least for this writer, is this will enable inexpensive wide area direct-to-instrument broadcasting in large venues such as airports, lecture halls, theaters, arenas, and mass transit using an open source standard. What’s exciting about this is that there is already in place mass-produced high power data transmission chips that can easily be adapted via firmware to implement 802.15.6 broadcasting, and in fact there’s a good probability you’ve received this very page via IEEE 802.11 WiFi — That’s right: The technology to deliver the broadcast signal to a wide area is already being mass produced, and all it will take is a firmware update and an analog-to-digital converter (ADC) to turn a $39 WiFi-enabled Linksys router into a transmitter that covers up to several hundred yards.
• Once in place, gone will be the close call we are currently on the edge of experiencing with obsolete technology “lock-in” of baseband induction “hearing loops,” which are being forced upon those of us in the hearing impaired community by those with no technical background such HLAA’s  David Myers and Brenda Battat, and worse by Juliette Sterkens and Janice Schacter, who don’t even have to “eat their own dog food” because they don’t have hearing losses themselves. The problems with magnetic flux line alignment causing orientation problems with telephones (which is, umm, why it’s called a “telecoil”) has been documented above; while the very real problem of electromagnetic interference (EMI) that cannot be filtered out (because of the very nature of the baseband beast) is well documented, and is plainly evident to those who either are forced to use it or have an actual knowledge of electromagnetic and communication engineering.
We already know that Apple is in close consultation with the Big Six hearing aid manufacturers: Given their current state of haphazard connecting Apple (and hence other) mobile phones to their hearing aids, this is the most likely initial part of the roadmap ahead. This brings us to…

But just what about those two patents breathlessly cited in the AppleInsider article?

Glad you asked! Let’s look at them individually at first and then together, in the context of the S.W.A.G. we just laid out.
• Remotely updating a hearing aid profile, United States Patent Application 20120183165 (PDF here)
• Social network for sharing a hearing aid setting, United States Patent Application 20120183164 (PDF here)
Although at first blush these patents look sexy, let’s look at them individually:
Remotely updating a hearing aid program (or for that matter, cochlear implant MAP) is something that has already been done by America Hears (and their partner Australia Hears, now Blamey & Saunders) for over a decade, and what Audiotoniq is using through mobile handsets. In fact, there is a possibility that Apple’s patent application for this function is invalid, as it represents prior art and is henceforth not patentable.
Sharing hearing aid settings through GPS-based “Foursquare” social networking is indeed a possibility; however there are significant HIPAA (privacy) issues in play. However, this would still involve communications between the iPhone and hearing aids… Via 802.15.6, as described above.

UPDATE: Near-Field Communications will .NOT. be supported on the iPhone 5

We originally penned this article eight weeks ago; but held off because of the near-field communications (NFC) wild card Apple could have played. Unlike the software changes outlined above in iOS 6, NFC requires an additional hardware chip. What we didn’t know until the iPhone 5 release two days ago, the “Made for Apple” hearing aids will also work on the iPhone 4s — Which would have made it obvious that it did not involve the NFC protocol.
For more on what NFC is and why Apple did not include it, please see iPhone 5 NFC snub explained by Apple in c|net UK.

References & Footnotes:

2) This use of 10.6 mHz presents a problem for Phonak’s Advanced Bionics division’s CI’s, as their Clarion II and HiRes 90k implants also use a very weak 10.6 mHz signal for the reverse updates to monitor implant integrity and telemetry, the interference of it causing a loss-of-lock and instantaneous shutdown of the implant circuit. This means that “bimodal” (CI + HA) users cannot avail themselves of the iCom or other wireless 10.6mHz technology
3) There is also the possibility that Apple has plans for using the 802.15.6 standard for a more general body-area network for connecting other medical devices such as pulse monitors, blood glucose monitors, and other things; but the FDA Device Branch will have the final say~

Friday, 27 July 2012

optimisim bias

http://www.ted.com/talks/tali_sharot_the_optimism_bias.html

Understanding optimism: good tool for interpreting optimism of clients, especially 3-day period before fulfillment.

Thursday, 26 July 2012

The 'Art' of fitting, robbed from Hearing aid Forums.

THE ART OF FITTING Those of us who have been around the block have seen the focus of this topic before. Most if not all of us have had classes pertaining to this very subject, not to mention years of experience and basically know how it works. If this were in fact true, then why do we still see clients walk into our office complaining about the size, the comfort, difficult controls, cosmetics etc.? Why are there still “part time users” or people who have never given them a reasonable trial? Even with those patients who report good sound quality of his/her device often qualify their statement with a “but wish the aid was”… (fill in the blank!). Most of these complaints appear to be justified and are real concerns considering what is available in today’s market. The choices available these past several years is amazing with result being more and more people accepting hearing aids due to the better cosmetics and coupling options at hand. However, there are still an unacceptably high number of people unsatisfied with their hearing aids. Our choices then are somewhat critical towards whether a patient is more likely to be happy with the devices and accept the hearing aid(s) or not. What we recommend has to merge with the clients experience, expectations, perceptions and preferences. The inexperienced “first timer” quite often is wrought with anxiety and anticipation having to submit to yet another piece of hardware they have to wear just to get along in their “golden years”. Having little or no knowledge of hearing aids other than what they hear from friends and/or the media, they may defer any recommendation to YOU, the PROVIDER…the EXPERT. We all love the guy who comes in and says …“I don’t care what it looks like as long as it works”…but this happens well below 50% of those seeking hearing aids for the first time! And even those that do sing that “I don’t care as long as it works” song are often subject to a change in heart after the fitting if the device is not what they expected! Therefore the “art” in fitting hearing aids is still a huge part of the process. As is counseling and listening which is an integral part of this process from the second the person walks into your office until well after the fittings. Keep in mind, it is a jungle out there with all the manufacturers, choices in style, ever changing features and technology. As if this were not enough we have to contend with the media that makes our job harder with ads that promise hearing aids will do everything short of walking your dog and cooking you breakfast! Counseling the patient regarding benefits vs. drawbacks of one style/feature over another is therefore so important. I cannot emphasize enough that we are not just here to sell hearing aids but rather here to offer the best hearing solutions for the problems this person is having with his/her hearing. If done right, the device will sell itself. Don’t get me wrong folks, programming the aid(s) for sound quality perfection is without a doubt important but we need to shoot for total perfection and acceptance…nirvana if you will. THE CHALLENGE A. Location, Location, Location So there you are with a hearing aid candidate sitting in front of you. You ask him/her if they have a particular choice in style and they respond…”I don’t know, I never had one but please don’t give me one of those big honkers … but you’re the doc, what do you think”? First, you are looking at the patient thinking ITE vs. BTE… You look at the audiogram: 1. Configuration of loss – Sloping vs. flat 2. Degree of loss – What frequencies are normal/mild, moderate, severe 3. Shape of the ear – Close to head vs. open car doors vs. space behind pinnae. 4. Ability of the patient – Can he/she hold, insert and manipulate the device 5. Speech discrimination – Fair/good/poor 6. Tolerance concerns (acoustically and physically) 7. Active patient vs. not so active or maybe homebound. 8. Cerumen – Prone to large amounts of cerumen? Now remember, you must keep looking back and forth at least five times to make the patient think you are deep in thought about how best to solve the specific problems of hearing (when actually you are pondering what to have for dinner that night or when your next day off may be…) when all of a sudden...BAM!...the patient startles you back to the present by shoving a newspaper in your face with a full page ad about this “ultra invisible hearing aid that only amplifies the one person … what about this one”? After recovering to the task at hand (and deciding to have fajitas that night) you continue by addressing the issues listed above and decide if your choice is compatible with the one he just shoved in your face or another that is more suitable to their needs. Back to a little more counseling… Seriously though, we cannot look at each one of the above aspects without considering the others at the same time. Although my philosophy is to keep a fitting as open as possible with BTE aids (short of feedback) we do have to consider ITE aids at times when given the following conditions: a. Patients inability to handle BTE aids. Keep in mind that older patients may have tremors, neuropathy and spatial difficulties. Also some patients just cannot tolerate something on top of the ear. b. Shape or lack of space around the ear Lack of space behind and/or top of ear due to surgery or just plain genetics. c. Long term user of ITE aids (Unless the patient is really motivated to change to BTE’s). d. Degree/severity of loss. Unless fitting a BTE would be prohibitive due to surgical or traumatic injury to the outer ear, BTE aids will typically be recommended for those with severe/profound losses. B. COLOR First of all, let me vent a little about those color charts from certain manufacturers. Seems what looks good on paper is not always the same shade on the finished product. It is always better to have those little plastic samples on a keychain …much more accurate! Also, identifying some of these colors by name has gotten a bit out of hand over the years with some names better suited to a flavor of ice cream rather than the color of a hearing aid! Now that we are on the subject of color, how many of us have gotten ready to order a specific aid in a certain color just to find the color is not available with that particular model! OK...off the soapbox and ON TO THE ISSUES… So what are we trying to match? Skin tone, hair, ear shadow, glasses. I favor a flat taupe or dark grey as these tend to blend in with the shadow behind the ear, skin tone and glass frames/temples. This is where those little plastic samples come in handy. The patient will often choose a color based on skin tone until he/she is shown other choices. The spouse, if present, is often helpful in this regard as well. Call me biased as an audiologist or a maybe “pinnaephile” but when I am out and about in public my eyes are often drawn to a person’s ears and sometimes it appears I am staring at little “light bulbs” when in fact they are hearing aids up there. A few patients (severe losses) may actually like the fact that others see their hearing impairment thereby causing a louder than average (or shouting) conversation… but my experience tells me most want to keep the devices obscure if at all possible. True, color is becoming less critical these days with smaller/hidden hearing aids but many still need the larger aids with larger controls due to severity of loss, size of hands, neuropathy, tremors etc. …which leads to… C. DEXTERITY/AGE: When dexterity is a concern, I tend to look at ITE aids. Sometimes even CIC aids are a good choice when all he/she needs is amplification and speech discrimination and/or occlusion is not an issue. With CIC aids, all the patient has to do is reach up and push on his ear canal (button) to adjust volume. Lately, I have become a fan of remote controls. I say lately because some manufacturers made such devices almost as complicated as my TV remote (and almost as large!). My experience has been people do not want to carry around extra baggage if they don’t have to … hey, is that a remote control in your pocket …or are ya just happy to see me? These days, however, I see some very basic and simple remotes on the market that are not as intimidating to the patient. Again, remote controls can be a real lifesaver at times. As far as dexterity issues with BTE aids, there are other things to consider i.e. removal strings on earmolds, models with larger volume controls or raised volume controls and don’t forget the earmold as certain styles are easier to insert than others for example half shells versus skeleton molds. D. Comfort vs. Cosmetics Just as a mid size hearing aid can be cosmetically appealing for some, a mini/micro aid can be physically uncomfortable or unappealing to others. These two factors are not mutually exclusive. A patient’s ear can reveal the probability of success with one or the other. Deep/shallow concha, large/small concha, large pinnae/small pinnae, close to head/protrudes from head, small canals/larger canals. Open fit/close fit, slim tube/regular tube, ric/non ric and on and on and on… Choosing the ultimate aid for each individual requires thought and coordination. So putting all these concerns and issues into perspective is where the “art” still applies and if these things are not quite in alignment with what the patient has in mind then again … counseling, counseling, counseling! UNIQUE CHALENGES: Although every patient is unique, below are three patients recently fit at our facility where we had to think outside the box ever so slightly. Patient X. Mr. X, an active 84 Y.O. presents with a flat moderate to moderate-severe symmetrical loss from 250-6000Hz. Discrimination scores were 86% right ear and 80% left ear. Cerumen was not an issue as it is with many of our elderly population. Head had little hair and his ears protruded away from his head to such an extent that the devices were “wobbling” all over the place up there! He was previously fit with two BTE aids with standard half shell earmolds but found them to be “too big and difficult to put on, operate the volume control etc. Mr. X has limited us of his hands due to arthritis and can only use his thumb and index finger on one hand and thumb/ring finger on the other. Cosmetics were a moderate issue with this gentleman. Normally, an ITE aid would have been a good choice especially a half shell with 60dB gain but thought I would go a step further. Due to his discrimination being pretty fair, we decided to go with CIC aids with a button volume control and a remote control (although he was not convinced he needed this). After fitting and programming, he was ecstatic at the fact that he could hear well, insert devices with ease and change the volume by just putting a finger anywhere near his ear canal. He was in cosmetic heaven with the size of these rascals as well. He like the remote but felt he would use it at home if at all. Speech mapping targets were matched quite well. Patient Y: Mr. Y is a 70 Y.O active gentleman with a sloping mild to severe loss from 500-6000Hz bilaterally, slightly worse left ear. Speech discrimination scores were 76% right ear and 72% left ear. He had very small pinnae’s, close to his head with very little if any room behind his ear near the top where the hearing aid would be. In addition, his canals were quite small as well with a lot of dry cerumen. He had not experience with hearing aids but mentioned he saw an “ad” with a small apparently CIC aid. After some counseling about occlusion/comfort/cosmetics we decided to go with a BTE aid. Now, as mentioned, there was very little room behind the top of this gentlemans’s ears (he denied any otoplasty or injury) so normally an open fit BTE aid would have been the choice…and it was…however, it had to be a RIC since cosmetics was an issue. There were no cognitive or dexterity issues with Mr. Y so we ordered the absolute smallest BTE RIC on the market with the smallest canal mold, largest vent possible. We also ordered a slightly longer length RIC (wire) in order to place the hearing aid a little lower behind his ears where there was more room to hide and secure the aids. After fitting and programming, we found the molds too occluding and replaced both with medium tulip domes with no feedback or occlusion. Now, if he were a patient compromised due to cognitive or dexterity issues, RIC aids become less an option when cerumen is a problem. Standard or slim tubing seems to be easier to maintain with this population. Patient Z: Mr. Z is a 57 Y.O. active gentleman with a moderate to severe bilateral loss from 250-6000Hz, slightly worse left ear. Speech discrimination scores were 76% right ear and 64% left ear. He had tried CIC and BTE aids before but could not tolerate the noise due to recruitment both ears. He had not worn any amplification in five years and wants to try something “small like seen in the newspaper”…He was also worried about any amplified sound due to his previous experience. He knew all about compression due his many visits to his provider when he previously wore the aids years ago. He reported the hearing aids did not hurt with all the compression but that he could not hear under that condition…”everything sounded muddy, not clear”…Mr. Z could have been fit with either ITE or BTE aids. Cosmetics were a concern but he stated “I just want to hear clearly without any pain”. He had pinnae’s close to his head and a lot of hair. Cerumen was not an issue. We decided to go with BTE RIC aids with canal molds and 4.0 vents. Objective was to provide a mild/moderate amount of gain with little occlusion or feedback from earmold(s). After fitting and programming devices with a mild/moderate amount of gain, mid to high frequencies, very little compression and MPO reduced significantly, he reported the sound was good, clear without pain. He returned two months later stating some sounds were too sharp and therefore reduced the high frequency gain. Speech mapping targets met at full volume but just short at two thirds volume where he like it. Last report he was doing fine and wearing them every day. Now, it is not my intent to address electro acoustics and/or programming in this article but there is one concern where I would hope all healthcare professionals practice …that concern being to physically listen to each and every hearing aid (power aids excluded) before and during the fitting. We all hook up and listen to hearing aids when a patient comes in complaining about the sound quality, typically by connecting to a listening stethoscope. What we SHOULD be doing is listening to every hearing aid that comes into a clinic, especially new devices during the fitting/programming. Within the past three months I have found three new aids to be “dead”, intermittent, distorted and even the front/back microphones reversed! They were all from one respected manufacturer from whom I continue to place orders. Two of the patients having never worn hearing aid(s) before did not even detect any problem! With a long term users, the patient can usually tell you there is something not right with the sound, however, the new user is without any reference and may be unfamiliar with what amplification is supposed to sound like. Recently, a patient came in for a replacement on his left ear and when listening to his right aid I heard a slight distorted static like sound at the end of each word. Sound was amplified enough and the distortion was not that bad but definitely noticeable compared to his left aid. When questioned he stated the aid was put it through the wash, showered with it, took it to a nice dinner etc. Offered to get it repaired but he did not think it serious enough to part with the aid for 2 weeks! Point being, listen to these devices and get a “footprint” established regarding what sound is like through these devices, what compression sounds like, distortion sounds like, your programming adjustments sound like! Bottom line…the patient will be happier and you will be a better clinician for it.

Friday, 18 May 2012

BSHAA 2012

Bshaa conference 2012, Nottingham. Prof. Harvey Dillon via webcast, interesting study on Spatial Processing Disorder, not evidenced by hearing loss, but px experiencing issues with noise at 90 degrees to a forward facing sound source. The prof didn't seem to get that Unitron moxi pro is already doing fully binaural mic combination. Study on proper broadband hearing aids, power in 8-10 kHz very beneficial to improve the fidelity of sound. Practical application is going to be hard as the suggestion is to seal the canal to provide sufficient HF drive without feedback. More to follow..... Mead killion, two lectures on different aspects of hearing. First fit: lack of response on first fit levels; px are sometimes worse with the first fit levels than without aids at all. Also significant noise damage amongst musicians and the general public, with the appropriate level of protection. 20dB reduction allows 100 times longer safe exposure time. Identification of susceptibility: not all users suffer equally with the same levels of sound. Interesting talk on echolocation, fully blind individuals who can use a series of clicks to determine size, texture, shape and distance of items and their environment.

Friday, 20 April 2012

Good Article about dealing with more severe losses....

Here

From the Hearing Review. Explanation of how more care is required when dealing with severe-profound losses, both in terms of loudness and the avoidance of  hearing aid sound artefacts like distortion, compression issues and feedback.

Wednesday, 18 April 2012

Moxi Pro and Unitron Micro

Friday 13th: Not a bad launch......

I attended the Unitron launch at Heathrow. This was a pretty reasonable affair to update the Moxi range and the BTE's as well as add a couple more products in ITE.

Looks like Unitron have undertaken a fairly significant look at the ERA platform and it's underpinnings: I'm assuming this will be like the Spice-Spice + revision recently undertaken by Phonak. As it turns out the the new Moxi PRO benefits from the full array beamforming technology as part of the Automatic package rather than a discrete dispenser-selectable program. This is full spatial mapping as vaulted by Starkey, but I suspect in a better looking and better featured overall package.

Apparently the aids are now able to track principal voice sources bilaterally and beam-form onto them to the exclusion of background noise. Most of the presentation was light on actual improvements, but the ability of the aids to identify speech in noise was pretty good. Transitions to other sounds and music also sounded pretty effective during the demonstration. Moxi Pro's are ONLY sold as pairs, if you want one, you get a bog-standard Moxi. The technology is also available across the larger BTE (Quantum) range too.

Also new were some high power ITE models to strengthen the offering, but far more relevant was the introduction of the Micro - one of the smallest IIC I've seen. It's claimed to be smaller than the Phonak Nano, through a couple of neat touches and the smallest transducers available. I'm not going to quite agree with the 50% claimed volume reduction of transducers, but the receiver was the thinnest device I've ever seen - which makes me suspect that it doesn't use conventional coil technology at all, but panel excitation like the founding technology behind the Otolens. This essentially uses current to manipulate a crystalline surface quite rapidly - sort of like the way the numerals work on a digital watch. It's not capable of moving vast volumes of air, but it will move it quite quickly with lowish voltages: so assuming your residual canal volume is not too high (like an IIC) you can get enough pressure to make sound waves. Interestingly enough, this establishes the possibility of a wipe/clean back 'face' to future IIC aids which will simply remove lots of the issues we currently experience with wax.

And, to top it all off, Rula Lenska (the actress) gave an address thanking Unitron for their support with the latest products, which was quite encouraging.

Wednesday, 4 April 2012

Phonak Spice - Technical background.

After fitting the Spice and now Spice +, I chanced on this PDF from Phonak, covering the underpinning technology and features of the Spice system. Worth a read to get the gist of everything that is going on.

Here

The extra refinement of Spice + seems to have improved the timbre and initial user acceptance of the aid too. From a dispensing point of view, you have to ask whether the level of technology now available exceeds what can be understood by the average wearer (and average dispenser) to such an extent that they will never fully utilise some/most of the features. Yet the aid is still just as susceptible to basic 'plumbing failures' - wax blockage, mic screen issues, condensation - as it ever was. Even the H2O versions claims about water-proofing come with a caveat that you can still block the filters and the receiver units.

Friday, 23 March 2012

What has happened to Panasonic Hearing in the UK.

Just another small note, it seems like Panasonic has basically disappeared from the Hearing Aid market in the UK. Googling them just yields a couple of likes to product listed through companies like Hidden Hearing holding some legacy product from them - nothing about the new #13 battery RIC from any of the major suppliers.

It's all in stark contrast to the USA where, under the tenure of Delain Wright, they seem to have got off the ground in some way or another. I guess their presence at the AAA next week will show their intent. I'm wondering if this is a reflection of Delain's experience in both the US domestic market (and previously Europe).

So, Panasonic, if you want to start again in the UK with proper branded distribution centres - give me a call ;-)

Would the last person leaving Guilford please turn the lights out.......

Floating Point Linearity - my best layman's terms explanation.

This came up on the Hearing Aid Forums recently - after a bit of research, the response below was about the best way I could think of to explain it to a customer:


XXXXXXXXXX
I demo'ed a pair of Oticon Agil Pro's for 3 weeks.
At the end of the demo, the Audiologist advised I try the 'Acto Pro' first since
I can return them for the Agil Pro's if I'm not happy. (and save $1,600!).
The audi adjusted the Acto Pro's similar to the Agil Pro's (this is my uninformed perspective of what she did/said).
I don't like the Acto Pro's as well as I did the Agil Pro's. Here's why:
1. The sound seems less 'natural'.......not sure how to describe this but seems like the Agil Pro is easier/emphsizes conversation/voices, etc better. 2. The 'fidelity' of the sound of the Agil Pro's seem better.....almost like the Acto Pro's have too much 'treble' dialed in (sorry, don't know how to better describe it) The Acto Pro's are 'louder'......for example the Agil Pro's are 'perfect' at the 'home volume' whereas the Acto Pro's have to be turned down 1 notch , and 3. I can hear my own voice much louder than with the Agil Pro's.
I've had the Acto Pro's for 2 days.
Question(s)
1. Are the differences I'm noting something that can be adjusted by the audi?
2. Is it premature to judge after only 2 days?
3. Any tips on words and/or phrases to better describe what I'm experiencing?

Finally, would appreciate any thoughts/advice you might have for a 'newbie's' first use of hearing aids (they do make a dramatic difference for me). I feel like I'm a victim of having tried the 'cadillac' and now I won't be happy with anything less .
ME:

1. Yes + No, the differences you are noting are due to the way that the Agil pro processes. Imagine if you will that you are in a shopping mall and can't quite decide whether what you need is on one floor or the next.
The Agil Pro's system is like being on an escalator that constantly moves smoothly up or down controlled by your thoughts (the sound level) - though at any one point it always looks like you are in the middle of the escalator and the slope is the same either side of you.
The Acto is more like having several sets of stairs as your inclination to go up or down (sound level) changes, you move from a steeper to a shallower set of stairs. It never seems as natural as the escalator transitions.

2. 2 days is a very short time to judge whether you prefer the stairs or the escalator.

3. You're experiencing the processing benefit of what Oticon have called 'Floating point linearity', which I'm going to explain in terms of escalators and stairs from now on (c) Um bongo 2012.
__________

Saturday, 28 January 2012

Nano, Imini and Soundlens.

I've just taken a closer look at the smaller side of the business today and read around the detail of the smallest and most deep fitting aids.

Customers who still have such a hang-up about cosmetics are out there, but you get into a host of issues based around the customer experience of the mini CIC style of aids.

Traditionally failure rates for these aids are a problem; initial candidacy, lack of features and general flimsiness seem to be just as great barriers. That's before you even get into issues of manual dexterity and the like.

Of the three latest entrants I've only fitted the Soundlens (to a 33 year old Lawyer) who was adamant about the need for the aid to be hidden. He's an experienced wearer with a flat 40dB SN loss. He's also worn CIC for years - we tried to fit binaurally but his left canal was too small. This basically seems to be true of all the systems - you need a fairly unbroken 9x7mm oval cross section running cleanly down the canal or they just won't fit. In terms of average candidacy that pushes the 'people who can' figure under 50% before you start.

Next you have to consider the ability to handle and clean, the propensity for wax ingress at the mic and battery manipulation: all of which deteriorates from your forties. Or  to look at it another way you've just carved another half from the 50% of your market, so we're down to 25%.

Acoustically and clinically, the claims of the output are varied and variable - the driver/receiver at the end of a Soundlens is going to really struggle to deliver the maximum output in a large ear canal. That's before you've even considered the issues with occlusion, potential for infection and awkwardness of insertion.

Then there's the final aspect of price: the aids are going to have to be fitted with a reasonable margin as service work is highly likely over their life. The Soundlens launch pricing was right at the to of the high-end product range, though there are lesser models out now.

Putting all of this together it sums out at possibly one or two percent of the average customers fitted here will be interested and can afford this sector. With the growing popularity of the ever reliable RIC products combined with their fancy features, one wonders why the manufacturers are still heavily pushing the mini-CIC products. Perhaps they have heavily invested in the production line technology to make them, or is it a nod to the American market where the CIC (and ITE in general) has a greater foot-hold.

And, in any case it's counter-productive from an industry marketing point of view: as long as people continue to hide their loss with hidden CIC, the less widely accepted proper hearing aid solutions will be.