New Technology

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New Technology
Harvey Dillon National Acoustic Laboratories,
Australian Hearing, CRC for Cochlear Implant and
Hearing Aid Innovation
ASA Brisbane 2004
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Aim of this talk

• To describe recent technology developments that
  have the potential to provide benefit to
  hearing-impaired people

Dillon, NAL
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This talk can be down-loaded from the NAL
Web-site, from May 27

• www.nal.gov.au
• Research_at_NAL.GOV.AU

Dillon, NAL
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Summary of features

• Old (but still worthwhile) features
• Tone controls
• Compression limiting
• Wide dynamic range compression
• Multi-channel compression
• Directional microphones
• Multi-memory
• Volume controls
• Programmability
• Bilateral fittings

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Summary of features

• Last five years
• Head level wireless receivers
• Feedback cancelling
• Multi-band adaptive noise suppression
• Adaptive directionality
• Highly directional hand-held
• Frequency transposition hearing aid

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Summary of features
Last two years Post-auricular canal aid Low
visibility open fitting Laser construction of
shells Automatic environment detection and
program switching (e.g. mic directionality) Multi-
band adaptive directionality Wind noise detection
and partial suppression Improved FM technology
Wall pilot, FM for APD kids Merging with
communications SoundPilot, Bluetooth
remote Adaptive dynamic range optimisation (o/p
prescription, compression, noise
suppression) More intelligent adaptive noise
suppression when, how much at each freq Choice
of compression speed and linkage to client
characteristics Automatic telecoil
selection Hearing loss simulator
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Suppressing noise adaptively
Hearing aid automatically alters its response
depending on the environment
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Adaptive noise suppression
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Adaptive noise suppression
Graphic equaliser
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6 dB
12 dB
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Adaptive noise suppression
Graphic equaliser
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6 dB
12 dB
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Adaptive noise suppression
Graphic equaliser
Graphic equaliser
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6 dB
12 dB
6 dB
12 dB
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Improving signal to noise ratioDirectional
microphones
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Effect of decreasing noise
BKB sentences Moore, Johnson, Clark Pluvinage,
1992
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The cardioid family
90
60
120
Super
150
30
-10
-20
-30
180
0
Hyper
330
210
Figure-8
300
240
270
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Adaptive directional microphone
Front
?
-

?
T
Output
Figure 7.4 A simple adaptive directional
microphone with steerable nulls.
Dillon, NAL
Source Dillon (2001) Hearing Aids
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Multi-band adaptive directional microphone
Front
?
-

?
Filter
Filter
T
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45 mm
Highly directional hand-held microphone
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Feedback cancelling
-
Internal feedback path
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Feedback cancelling

• Benefits
• Approximately 12 dB more gain before feedback
• More open ear -gt better own voice quality
• More gain -gt more intelligible speech
• Less whistling -gt less embarrassment

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Transposition
Figure 7.14 Input and output spectra for a
frequency transposition scheme in which the
output frequency equals half the input frequency.
The amplifier also provides some high frequency
pre-emphasis. The arrows show the reduction in
frequency of each formant.
Intensity
1000
250
4000
Frequency
Dillon, NAL
Source Dillon (2001) Hearing Aids
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Environmentally sensitive hearing aids
?
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Environmentally sensitive hearing aids

• Automatic variation of response between programs
• Microphone directionality
• Low frequency gain
• Degree of noise suppression
• Wind noise reduction (low cut, omni)
• Automatic telecoil selection
• Parallel processing to determine
• Implications for fitting fit, or auto-fit,
  multiple programs!
• Patient involvement in fitting
• simulated listening situations
• computer-based fine-tuning
• . Clinical time!

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Wireless / Direct audio input
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New FM features

• Compatibility improvement
• Wall pilot auto switching of channel
• FM for children with Auditory Processing Disorders

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Smarter compression

• Adaptive compression speed
• compression speed linked to client type
• Adaptive dynamic range optimization
• Output prescription
• Adaptive speed compression
• Multi-channel adaptive noise suppression

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• Hearing loss simulator

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Open fittings

• Combination of
• Feedback cancelling
• Open earmould

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Through-the-ear aid

• Potential advantages
• No occlusion effect of the aid in the canal
• No heat or moisture build-up in the ear
• No discomfort from an ear mold
• Cosmetic nothing in the canal
• Potential disadvantages
• Adverse directionality
• Minor surgery

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Another approach to reduced feedback and
occlusion

• Sebo-Tek Post-Auricular Canal
• separation of mic and receiver
• deep seated soft-mounted receiver
• CIC, ITC, ITE, BTE, PAC, TTE

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Integration with communication devices

• Blue-tooth connection between headset and
• mobile phone
• PDA
• . internal microphone ?
• Headset look-alike hearing aids (e.g. Microsound
  Pilot)
• Mobile telephone that can be programmed with
  multi-channel compression
• Telephone with bone-conduction output (Sanyo
  Tu-Ka whisper phone)

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Integration with communication devices

• Headset device as a hearing aid, with Bluetooth
  communication to
• mobile phone
• personal digital assistant

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Bone-anchored hearing aid
Figure 16.6 Bone-anchored hearing aid, showing
its attachment through the skin to the bone.
Amended by permission from Entific Medical
Systems.
Dillon, NAL
Source Dillon (2001) Hearing Aids
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Hybrid implants and hearing aids

• Hearing aids - most effective for low-frequency
  cues and pitch / timing
• Cochlear implants - most effective for high
  frequency cues and spectral shape
• Implanting does not destroy potential for
  conventional acoustic aiding

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Combining hearing aids and implants

• 1. Hearing aids and implants in opposite ears
• Now recommended practice
• Fine-tuning of hearing aid beneficial
• 2. Hearing aid and implant in same ear
• Separate devices
• Short electrode used so far

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Implantable hearing aids
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Implantable hearing aids
Output vibrator
Microphone
Magnet coil
Magnet
Coil
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Laser construction of earmolds and shells

• 1. Impression scanned at factory (now)
• Computer-assisted construction (reduced cost)
• Minimum size
• Retention
• 2. Impression scanned at clinic
• As above, plus
• Reduced turn-around time
• 3. Ear canal scanned
• Reduced clinical time

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Thats all Folks
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Web-site address WWW.NAL.gov.au

• Research_at_NAL.GOV.AU