Improving Hearing Aid Performance in Noise
Most people agree that hearing aids work pretty well in a quiet
environment. It's the noisy environments, where people with hearing loss
really need help, that hearing aids have a difficult time dealing with. The
advent of advanced digital technologies are showing promise in the struggle
to provide better speech understanding in the presence of noise.
June 2004 - Directional microphones don't work very well because the
physical devices are just too small. It's a law of physics - or at least
it was until scientists studied an amazing little fly
that defies physical laws!
October 2005 - Dynamic Hearing Pty Ltd has
announced that it will be developing and commercializing noise
cancellation technology developed by the House Ear Institute.
January 2006 - New aid more effective in noise
July 2006 -
An Assessment of Everyday Noises and Their Annoyance
July 2008 -
New Hearing Aid Technology Works in Noise!
August 2009 - New Software Promises Better
Speech Recognition for Hearing Aids and Cochlear Implants
March 2010 - New Technology Improves Speech
Intelligibility in Noise
April 2010 -
Should We Eliminate Noise or Embrace Sound?
April 2010 -
Reducing Noise Interference in Hearing Aids
September 2010 -
Real-World Listening Preference for an Optimized Digital
Noise Reduction Algorithm
September 2010 - Evidence of the Effectiveness of a
Spatial Noise Management System
November 2011 - Improving Hearing Aid Function in Noisy
Situations
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January 2006
The aid helps people not only
work out what is being said, but from where the sound is coming. Sydney
University researchers, led by Dr Craig Jin, a senior lecturer in the
Electrical and Information Engineering School, have developed a more
effective way of solving the biggest problem of the hearing impaired-how
to carry on a conversation with more than one person or in a noisy
environment. Full
Story
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July 2006
A recent
study finds that annoyance ratings for new wearers of digital hearing
instruments are equally distributed across intensity and duration. This
supports the concept that signal processing algorithms designed to reduce
annoyance of noise should not only address stationary noise but also be
able to efficiently attenuate transient noises.
Fingernails
scraping down a chalkboard. A squealing smoke alarm. A jackhammer pounding
through concrete. These are just a few of the images that come to mind
when we think of sounds that are annoying. But this is just the tip of the
auditory iceberg for new wearers of amplification. Annoyance of sounds
comes in many forms and at many different loudness levels.
Full Story
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July 2008
The sound of a noisy Chicago restaurant during the
breakfast rush the clang of plates and silverware and the clamor of many
voices was the crucial test of new hearing aid technology in a study
conducted by researchers at Washington University School of Medicine in St.
Louis. The study showed that the hearing aids worked well in a noisy
environment the most challenging test for a hearing aid. But the patients
wearing the devices didn't need to fly from St. Louis to Chicago to
participate in the test. Instead, the restaurant came to the clinic of
Michael Valente, Ph.D., director of the Division of Adult Audiology in the
Department of Otolaryngology at the School of Medicine. Or at least its
sounds did.
Full Story
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April 2010
As audiologists, we have been persuaded to develop a
distinct disdain for noise. Noise is bad. Noise causes hearing loss. Noise
is something to avoid. The industry has even worked very hard to "cancel"
noise. Our patients have somehow come to expect hearing aids to eliminate
noise altogether and often become frustrated to the point of giving up on
the idea of hearing aids when those expectations are not met. [snip] So,
what is the difference between sound and noise? Many dictionaries define
sound as "the particular auditory effect produced by a given cause." Noise,
then, can be defined as sound that is unwanted, unexpected or undesired. But
who's to say when a sound is a noise? In the same vein that "beauty is in
the eye of the beholder," shouldn't noise be defined by the ear of the
be-hearer? Full
Story
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April 2010
Listening in background noise can be a challenge for
people with hearing loss because they often need a higher signal-to-noise
ratio (SNR) than people with normal hearing to understand the same amount of
speech. Many high-performance hearing aids are implemented with digital
signal processing algorithms to reduce the interference of continuous,
transient, and wind noise. Distinguishing between different technologies is
essential for effective hearing aid fitting, but can be confusing and
difficult because the launch of new technologies is rarely accompanied by
detailed explanations of their rationales and mechanisms. In addition,
different marketing names may be used to describe algorithms that are
implemented with similar functions and/or computational methods, or similar
names may be used to describe different algorithms. Several major types of
noise reduction strategies are available that can potentially help hearing
aid users improve speech understanding and enhance perceived sound quality.
Full Story
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September 2010
As with numerous algorithms in modern hearing aids,
digital noise reduction (DNR) can be implemented through the use of fast or
slow time constants. The function of DNR algorithms is to reduce prescribed
gain in response to high levels of environmental noise. The time constants
of these systems control how quickly gain is changed in response to acoustic
changes around the patient. Systems with slow time constants estimate a
long-term signal-to-noise ratio (SNR) and reduce gain in a gradual manner,
over seconds or hundreds of milliseconds. This method has been shown to
improve sound quality and comfort. In contrast, DNR with fast time constants
will manage the reduction and application of gain very quickly, over
milliseconds. A challenge to the design of any DNR algorithm is the fact
that speech quality may be compromised, for instance, if gain is reduced in
the presence of noise and not accurately reapplied when speech is the
dominant signal; this may result in distortion of the speech. With
slow-acting DNR, the result is a system that must be inactive when speech is
the dominant signal, with the disadvantage of not reducing the perception of
noise.
Full Story
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September 2010
Imagine yourself sitting in a fairly crowded
restaurant. You are trying to listen to the person next to you on the right
while there is a lot of interfering noise coming from the tables on the
left. The speech signal from the talker would, no doubt, be stronger at the
right ear than at the left ear due to head-shadow effect. Even then, with
disturbing noise emanating from the left, the listener is likely to lean
toward the speaker on the right, attempting to receive speech on the right
side and ignore noise on the left. People with hearing loss would presumably
have a greater need to segregate the desired speech signals from the
constant stream of competing noise in such a situation. To date, this
complex need is yet to be fulfilled by advanced hearing instrument
technology. In today's bilateral fittings, noise reduction is applied to
hearing instruments in both ears so long as noise is detected in both
instruments. An undesirable consequence of this is that the gain for speech
can be turned down on the side where the user has a speaker he or she wants
to focus on. Even with wireless synchronization of noise management between
ears, there is a possibility that the amount of noise attenuation on the
noisy side may not be adequate to achieve optimal comfort and ease of
listening.
Full Story
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November 2011
Even with today's sophisticated hearing aid advances
in microphone directionality and noise-reduction circuitry (Chung, 2010),
hearing-instrument users still experience difficulties in some challenging
environments, such as in restaurants and at parties. Almost half of
hearing-aid users who return their devices cite problems with hearing over
background noise (Kochkin, 2007). It is no surprise that use in noisy
situations is listed as one of the top 10 factors pertaining to hearing aid
user dissatisfaction (Kochkin, 2010). Innovative approaches to facilitating
hearing in noise, therefore, may further increase hearing- instrument users'
satisfaction. These approaches include strategic microphone placement in
non- directional devices and the use of wireless accessories that stream the
speaker's voice directly to the listener's hearing aids.
Full Story
