Thursday, July 9, 2009

iPhone for hearing loss?


Apparently, now you can cure your hearing loss with a $9.99 gadget that works to turn your iPhone into a hearing aid according to this CNET article. Huh? Why is everyone with an acquired hearing loss then spending thousands of dollars to get state-of-the-art hearing aids? The article is ludicrous. Obviously what we have all missed was that a combo of a simple volume amplifier and an equalizer is enough to restore one's hearing to optimal levels. Ginger Labs claim that "For those with a hearing loss, soundAMP reawakens your sense of hearing; sounds comes to life and you hear better again." For some reason this excerpt reminds me of these bogus $5 "hearing aids" ads you see in the back pages of pop U.S. magazines.

SoundAMP offers a feature that repeats the last seconds of the recorded sound. For a person with acquired
hearing loss, this is actually a useless feature! Let me first note that repeating "recorded sounds" is not the same
as repeating speech/conversation (which is what the article says this feature does). "Pure tone" sounds are usually
no problem for people who use hearing aids; all you need to "perceive" these sounds is an amplifier and any
hearing aid can fit that bill. Speech is much more complex and presents a problem of a taller order. Deciphering
speech involves -beyond capacity for perceiving plain sensory input- recognition, processing and understanding,
all very different cognitive processes in the brain.

The article states: "According to the developers, SoundAMP improves your hearing quality in a variety of
environments, including lecture halls and noisy restaurants. Thus, it has the potential to help students as well as the
hearing-impaired." This quote is just as vague as they come!! How exactly are students and "the hearing impaired"
similar audiences? It just shows the author's blatant ignorance of the mechanics and complexities of hearing loss
and related hearing aid technology. For sure, if hearing loss could improve in as simple a manner as turning up the volume
in an iPhone, none of us would be spending so much money in buying *actual* hearing aids, nor would the government
bother with research into hearing loss, and related brain, speech and signal processing tech. Let's set the record
straight: simply amplifying the volume may help about 5-15% of people with acquired hearing loss. The same
people can actually perform a simple surgery which restores their (conductive) hearing loss into "normal" levels.
The majority of people with acquired hearing loss need much more than a $5 amplifier with equalizing and recording
options.

They need a state-of-the-art speech processor. Of course such a feature could potentially improve its usefulness
if it could repeat sounds after a (slight) frequency mapping procedure, where a shift is made around areas where
people have reduced sensitivity for certain frequencies. However, that's exactly what hearing aids are (supposed
to be) doing! At least in theory, they are programmed to tweak your auditory input to match your audiogram's levels.
However, both the audiogram and the 'tweaking' process have severe limitations. For instance, audiograms are not
exact science! And hearing aids, depending on their underlying digital or analog platform, may not allow you any type
or level of 'tweaking'. And of course even if you had the perfect hearing aid to match your individualized (perfectly
measured) audiogram, there is always the X-factor of how your brain works with all this. Some people are unable to
benefit by state-of-the-art hearing aids despite their best efforts.

Maybe an improvement could be seen in replaying the recorded sound after applying a noise filter for specific problem
frequencies, e.g. a white noise filter, or every freq > 5000 Hz? I would never trust a machine to provide any noise filters
for me, beyond when applied in the extremes of the sound band. Speech is so much more complex than that.
Current state-of-the-art hearing aids offer a number of programmable channels. Users can try and test any one of
those channels that functions as an automatic noise filter; such a channel adjusts environmental sounds and speech input
to the user's audiogram and decides which frequencies to filter out based on indications in your audiogram. For many
of the reasons I mentioned above, this is utterly useless! Real speech and real brains are multifaceted dynamic systems;
no tech has come to address that level of complexity yet.

In an older post of mine posted in this blog last summer, I complained how the new iPhone was not hearing aid
compatible like most popular cell phones are. iPhone doesn't come with a hearing aid compatibility standard, so
you have no way to tell how well it fares with the microphone and telecoil of a modern hearing aid.

Incidentally, if you're curious about the hearing-aid compatibility standards for various popular hearing aids, go
to Phonescoop Phone Finder and choose a weighted search showing all options, where you can search for phones with high hearing aid compatibility. Anything about M3/T3 is what most people with acquired hearing loss need (M4/T4 is the top score and most phone may not accommodate the same rates for both M(icrophone) and T(elecoil)). The telecoil switch is what offers elimination of background noise in modern hearing aids and it's very useful for speaking on the phone while in the middle of the street or some other public area. When you have your telecoil switch on, though, you lose the volume of the microphone so you usually need pretty good phone compatibility with both your hearing aid's microphone and telecoil. Without a hearing aid compatibility (HAC) standard, you cannot tell if your new phone will work with your hearing aid without interference. In terms of usability, inference is critical since it renders hearing aids useless and the phones by extension become anything but a nuisance to people with acquired hearing loss. For the hearing impaired, speech perception is near impossible with the aid picking up buzzing, humming of whining noise when the user is on the phone.

Although it's nice to see anything like an improvement of sound clarity on iPhone, this is still nowhere near what customers with acquired hearing loss need to see in order to use an iPhone for listening purposes (not just music but also for speech).




2 comments:

dancilhoney said...

Hi I have iphone how can I use this application? I also have
hearing amplifier and I think it's really great.

Anonymous said...

>They need a state-of-the-art speech processor

I know microprocessor design and embedded circuits, there is no way anything currently in production that can fit into a hearing aid housing could not be replicated with the VASTLY more powerful computational power inside the iphone.

This App may not fit the bill 100%, but manufacturers of "specialized" hardware need to see the competitive horizon that this brings.

Buy a top of the line stereo bluetooth headset for a few $100, invest some app development time that any graduate student with signal processing experience has ... and you could market and app for $20 - $40 that would EASILY match the ludicrous $4000 - $15,000 hearing aids sold now.