slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
DEVELOPMENT OF NAL-NL2 Harvey Dillon, Gitte Keidser, Teresa Ching, Matt Flax, Scott Brewer PowerPoint Presentation
Download Presentation
DEVELOPMENT OF NAL-NL2 Harvey Dillon, Gitte Keidser, Teresa Ching, Matt Flax, Scott Brewer

Loading in 2 Seconds...

play fullscreen
1 / 28

DEVELOPMENT OF NAL-NL2 Harvey Dillon, Gitte Keidser, Teresa Ching, Matt Flax, Scott Brewer - PowerPoint PPT Presentation


  • 215 Views
  • Uploaded on

DEVELOPMENT OF NAL-NL2 Harvey Dillon, Gitte Keidser, Teresa Ching, Matt Flax, Scott Brewer The HEARing CRC & The National Acoustic Laboratories. creating sound value TM. www.hearingcrc.org. Make speech intelligible Make loudness comfortable. Prescribe hearing aids to:.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'DEVELOPMENT OF NAL-NL2 Harvey Dillon, Gitte Keidser, Teresa Ching, Matt Flax, Scott Brewer' - lars-valenzuela


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

DEVELOPMENT OF NAL-NL2

Harvey Dillon, Gitte Keidser, Teresa Ching,

Matt Flax, Scott Brewer

The HEARing CRC & The National Acoustic Laboratories

creatingsoundvalueTM

www.hearingcrc.org

prescribe hearing aids to
Make speech intelligible

Make loudness comfortable

Prescribe hearing aids to:
  • Prescription affected by other things
    • localization,
    • tonal quality,
    • detection of environmental sounds,
    • naturalness.
deriving optimal gains step 1

Loudness model

Normal loudness

Gain-frequency response

Compare

Intelligibility achieved

Loudness (hearing impaired)

Intelligibility model

Loudness model

Amplified speech spectrum

Audiogram

Deriving optimal gains - step 1

Speech spectrum & level

slide4

The audiograms

Rejection criterion :

  • -30<= G <=60 , where G is the slope
  • sum(H(f))/3 <=100 , where f is in the set {0.5, 1, 2} kHz

Inverted hearing loss profiles used

deriving optimal gains step 11

Audiogram 1

Audiogram 1

Audiogram 1

Audiogram 2

Speech level 1

Speech level 2

Speech level 3

Speech level 1

Optimal gain frequency response

Optimal gain frequency response

Optimal gain frequency response

Optimal gain frequency response

Deriving optimal gains - step 1

200 audiograms x 6 speech levels  1200 gain–frequency responses, each at 20 frequencies from 125 Hz to 10 kHz

overall prescription approach

Adjust

Final

formula

Compare

Overall prescription approach

Psychoacoustics

Theoretical

predictions

Assumptions,

rationale

Speech science

Empirical

observations

multi dimensional equation
A neural networkMulti-dimensional equation

H250

H500

H1000

H2000

H8k

SPL

G250

G500

G1000

G2000

G8k

the two key ingredients

Loudness model

Speech spectrum & level

Normal loudness

Gain-frequency response

Compare

Intelligibility achieved

Loudness (hearing impaired)

Intelligibility model

Loudness model

Amplified speech spectrum

Audiogram

The two key ingredients
why are hearing thresholds so useful

Frequency

selectivity

Temporal

resolution

Central auditory

processing

Other

Why are hearing thresholds so useful?

Speech

Perception

proficiency

Hearing

thresholds

Age

Cognitive ability

gain for adults low high input levels
Gain for adults: low & high input levels

Suggest that the compression ratio should be slightly higher,

at least for clients with mild and moderate hearing loss

empirical evidence variations from nal nl1

Children

Adults

Empirical evidence: variations from NAL-NL1

Output level

NAL-NL1

Input level

effect of language
Gain at each frequency depends on importance of each frequency

Low frequencies more important in tonal languages

Two versions of NAL-NL2

Tonal languages

Non-tonal languages

Effect of language
example audiogram moderate sloping

125

250

500

1k

2k

4k

8k

0

20

40

60

80

100

120

Example audiogram: moderate sloping

Frequency (Hz)

50 dB

65 dB

Hearing threshold (dB HL)

80 dB

slide22

125

250

500

1k

2k

4k

8k

0

20

40

60

80

100

120

Example audiogram: flat 60

Frequency (Hz)

50 dB

65 dB

Hearing threshold (dB HL)

80 dB

example audiogram steeply sloping

125

250

500

1k

2k

4k

8k

0

20

40

60

80

100

120

Example audiogram: steeply sloping

Frequency (Hz)

50 dB

65 dB

Hearing threshold (dB HL)

80 dB

example audiogram extreme ski slope

125

250

500

1k

2k

4k

8k

0

20

40

60

80

100

120

Example audiogram: extreme ski-slope

Frequency (Hz)

50 dB

65 dB

Hearing threshold (dB HL)

80 dB

example audiogram reverse sloping

125

250

500

1k

2k

4k

8k

0

20

40

60

80

100

120

Example audiogram: reverse sloping

Frequency (Hz)

50 dB

65 dB

Hearing threshold (dB HL)

80 dB

variables in nal nl2
Variables in NAL-NL2

Age

Vent

Tube

Comp speed

WBCT

N

Language

Depth

Gender

RECD

Bi-uni

CR

RECD

BWC

Experience

REUG

Aid type

UCT

I/O

REDD

MLE

REIG

REAG

Transducer

AC

CG

AC'

ABG

ESG

BC'

RESR

ESCD

BC

SSPL2cc

Blue = User i/p

Grey = internal variable

Red = effect of saturation

Dash-dot = alternatives

Green = stored data

SSPLES

Limiting

type

denis byrne 1998

“A challenge for the profession is to devise fitting procedures that are scientifically defensible and the challenge for the individual audiologist is to choose the best procedures from whatever are available”

Denis Byrne, 1998

slide28

creatingsoundvalueTM

Thanks for listening

Acknowledgements

www.hearingcrc.org

www.nal.gov.au

This research was financially supported by the HEARing CRC established and supported under the Australian Government’s Cooperative Research Centres Program