karolina smeds, phd director of research widex orca europe ... · [email protected]....

The impact of auditory ecology on hearing-aid design and testing

Karolina Smeds, PhD

Director of research

Widex ORCA Europe, Stockholm, Sweden

www.orca-eu.info

[email protected]

http://www.orca-eu.info/

Auditory Ecology describes the relationship between the acoustical environments experienced in everyday life and the perceptual demands of different people in these environments.

Gatehouse interpreted by Søgaard Jensen 2005

Why is it useful to focus on auditory ecology?1. Development of hearing aids2. Evaluation of hearing aids (development and clinically)3. Fitting and fine-tuning hearing aids4. Demonstration of hearing aid features5. …

A journey towards a stronger focus on auditory ecology

A 10 year thought process…

Widex ORCA Europe

Widex HQ

Outline

1. Noise reduction in hearing aids ”NR”

2. Realistic signal-to-noise ratios ”SNR”– Example: noise reduction study

– Example: speech testing

3. Common Sound Scenarios ”CoSS”

4. Summary

NR SummaryCoSSSNR Speech testNR

”How does Widex’ SII-based Noise Reduction system, the Speech Enhancer, compare to other noise reduction systems?”

ISAAR. Binaural processing and spatial hearing. Helsingør, Denmark: 445-452.


Method

• 12 modern hearing aids

• Three audiograms

• Long-term average test box gain

measurements

• Speech in stationary speech-shaped

noise

– Signal-to-noise ratios (SNRs) varied from

+6 to -12 dB in 3-dB steps (plus one

condition with “pure speech”)

• Measurements with NR ON and OFF

• Gain reduction =

Gain(NR_ON) – Gain(NR_OFF)

• Reduction contours to facilitate comparisons


Pure speecch

Decreasing SNR

Increased gain

Effect of noise reduction in 12 hearing aids

-8

-8

-6

-6

-6

-6

-6 -4

-4-4

-4

-4 -2

-2-2

-2

00

0

0 0

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-14

-12

-12

-12

-10-1

0

-10

-10

-8

-8

-8

-8

-8

-8

-8

-6-6

-6

-6

-6

-4

-4

-4

-4

-4

-4

-2

-2

-2-2-2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-10

-10-10

-8

-8

-8-8

-6

-6

-6-6

-4

-4

-4-4

-2

-2-2-2

0

0

0

00

0

0

0

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-4

-4

-2

-2

-2-2

-4

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-6

-6

-4

-4

-4

-4

-2

-2

-2

-2 0

0

0

0

00

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-2-2

-2

-2

-2

-2

-2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-4

-4

-4

-2-2-2

-2

-2

-2 -2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-4

-4

-4

-4

-2

-2

-2-2

-2

-2

-2

-2

-2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-10

-10

-10

-10

-10

-8-8

-8-8

-6

-6

-6-6

-4

-4

-4-4

-2

-2

-2

-2-2

0

0

0

0

2

2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-8-8

-6

-6

-4

-4

-4

-4

-2-2

-2

-2

-2

0

0

0

0

2

2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-4

-4

-4

-4

-4-4-4

-2-2

-2

-2

-6

-6

-6

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-2

-2

-2-2-2

-2

-2

-2

-2

-2

0

0

0

0 2

-2

-2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

SNR

(d

B)

0.5 21 4

∞630

-3-6-9

-12

0.5 21 4

∞630

-3-6-9

-12

0.5 21 4Frequency (kHz)

∞630

-3-6-9

-12 0.5 21 4Frequency (kHz)

∞630

-3-6-9

-12

0.5 21 4

∞630

-3-6-9

-12

0.5 21 4

∞630

-3-6-9

-12


∞630

-3-6-9

-12

0.5 21 4

∞630

-3-6-9

-12


∞630

-3-6-9

-12

0.5 21 4

∞630

-3-6-9

-12

0.5 21 4

∞630

-3-6-9

-12

0.5 21 4

∞630

-3-6-9

-12SN

R (

dB

)SN

R (

dB

)

LKJI

HGFE

DCBA


Learnings and new questions

• Large difference in NR characteristics– as a function of frequency

– as a function of SNR

• Hearing (speech) in background noise is oftendescribed as the most difficult listening situation(e.g., Kochkin, 2010)

• What are the SNRs in the those situations?– Is it appropriate for a NR system to be active at positive SNRs?

– Is it enough if a NR system is active only at negative SNRs?

• There was a lack of studies describing realistic SNRs– Pearsons et al. 1977

– Teder 1990

-10

-10-10

-8

-8

-8-8

-6

-6

-6-6

-4

-4

-4-4

-2

-2-2-2

0

0

0

00

0

0

0

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-10

-10

-10

-10

-10

-8-8

-8-8

-6

-6

-6-6

-4

-4

-4-4

-2

-2

-2

-2-2

0

0

0

0

2

2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-2-2

-2

-2

-2

-2

-2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

-10

-10

-10

-10

-10

-8-8

-8-8

-6

-6

-6-6

-4

-4

-4-4

-2

-2

-2

-2-2

0

0

0

0

2

2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS


”What are the SNRs in real life?”


Recorded data

Wagener, Hansen & Ludvigsen, JAAA 2008– 20 experienced and satisfied HA users

– Encouraged to record ”situations in daily life” for 3–4 days

– Lab evaluation of own recordings under headphones 3 w – 4 m after recordings

– Participants recorded relevant everyday situations

– Situations of varying difficulty


Manual SNR estimation method


Example: In a car

Speech +Noise

Noiseonly


Manual SNR estimation method

135 recordings

minus 7 recordingsdue to recording artifacts

minus 5 recordingsdue to dissimilarnoise characteristics

minus 22 recordingsno

minus 14 recordingsno

no


Summary results

-12 recordings due to category mismatch

In total 75 recordings included


Summary results


Results Babble


Results Car


Results Kitchen


Discussion and Conclusion

Main result

Estimated SNRs generally positive (very few situations with negative SNRs)

DiscussionBehavioural

– Avoidance of too difficult situations?

– Raised vocal effort when talking to hearing-impaired person?

Methodological

– Short recording time (3-4 days)

– Short excerpts of speech and noise used for analysis

– Estimation bias, dissimilar noise characteristics

Important result?


Short-term gain reduction HA F

Ga

in r

eduction (

NR

ON

–N

R O

FF

) (d

B)

Frequency (kHz)

SNR: +6 dB SNR: +3 dB SNR: 0 dB

SNR: -3 dB SNR: -6 dB SNR: -9 dB

-6

-6

-4

-4

-4

-4

-2

-2

-2

-2 0

0

0

0

00

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS


Gain

reduction

(NR

ON

–N

R O

FF

) (d

B)

Frequency (kHz)

Short-term gain reduction

SNR = +6 dB SNR = +3 dB SNR = 0 dB

SNR = -3 dB SNR = -6 dB SNR = -9 dB

-10

-10

-10

-10

-10

-8-8

-8-8

-6

-6

-6-6

-4

-4

-4-4

-2

-2

-2

-2-2

0

0

0

0

2

2

Frequency [Hz]

SNR [dB]

250 500 1000 2000 4000 6300-12

-9

-6

-3

0

+3

+6

ISTS

HA I


Speech testing – Psychometric function

• Describes performance as a function of some parameter– Presentation level (SPL)

– Signal-to-noise ratio (SNR)


Speech testing at fixed SNRs


Floor effects

Ceiling effects

10 test persons

Adaptive speech tests

To avoid floor and ceiling effects: Adaptive speech tests

Search for instance 50% correct by – Adjust the noise level (constant speech level)

– Adjust the speech level (constant noise level)

0

50

100

SNR

Perc

enta

ge

corr

ect

(%

)


10 test persons

On potential disadvantages: Test participants will perform the test at different SNRs

This is a potential confounding factor when interpreting the results of signal-processing studies

Smeds, Leijon, Wolters,

Hammarstedt, Båsjö,

Hertzman, JASA 2014

Example



• SNR determined for various background noises

• SNRs positive and medians in 5-10 dB range, but reported to vary in difficulty

• ”Kitchen” shared some acoustical characteristics, but also context (limited visual cues and/or moving targets)

• A purely acoustical characterization of a listening situation is not enough to fully describe the situation!


”How can listening situations be described in order to understand why they differ in difficulty despite similar acoustics – at leastsimilar SNRs?”


Aim and goal

Aim

• Investigate the acoustic environments and listening situations people encounter

Goal

• Deliver a structured framework of common sound scenarios1. Development of hearing-aid signal-processing features

2. Evaluation of such features in realistic laboratory tests

3. Demonstration of feature effects to hearing-device wearers


Method

1. General literature search: identify research expertise in the area of acoustic environments and everyday listening

2. Specific literature search: find studies for data extraction

3. Data were then extracted and categorized in a systematic way

4. A set of common sound scenarios was selected


1. General literature search

• Soundscape ecology, soundscapes, or acoustic ecology


ISO-12913-1 Sound Scape Framework

Intentions

Activities

Tasks

Experiences

Attitudes


”Making senseof sound”

Specific literature search


Only from the ”audiological field”

Questionnaire

Ecological Momentary Assessment (EMA)

Recordings

Dosimeter

Specific literature search


7 published, 3 unpublished papers

Common Sound Scenarios

Common– Happens often (everyday scenarios, rather than on extraordinary ones)

– General and widespread (recognized and shared by many people)

Sound– Main focus

– Physical and psychoacoustical characteristics

Scenario– Sum of physical environment and context

– Emphasizes a hypothetical aspect, indicates something created theoretically (with intentions and tasks as building blocks)


170 situations from the 10 studies

Work process


CoSS Framework

Intention

Scenario #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14

Occurrence

Difficulty

Importance

Scenario

Convers

atio

nat

hom

e

Convers

atio

non

metro

Meetin

gin

an

offic

e

Car

ride

with

fam

ily

Phone

call

at

hom

e

Mobile

call

in th

estre

et

Lectu

re

At

aconcert

Watc

hin

gT

V

Lis

tenin

g to

car

radio

Vacuum

cle

anin

g

City

walk

Rela

xin

gw

itha

book

Rela

xin

gon tra

in

Non-specific

Task 2 people2 people

More than Through

deviceLive sounds

Two people having a

conversation

Several people

having a shared

conversation

Two or more people

having a shared

conversation through

a communication

device

Focused listening to

sound without being

able to control the

sound source


sound while being

able to control the

sound source

Conscious or

unconscious

screening of sound of

relevance to current

activity

surroundings

Unconscious

perception of

environmental

sounds, without


activity

media device listening

MonitoringThrough Passive

Speech communication Focused listening


Discussion

Literature search– Few studies

– All studies from North America and North-Western Europe

– Only one study included NH informants

CoSS validity– Dillon et al (1999) COSI: 1 770 participants.

– EuroTrak (EHIMA, 2015): Importance to hear well in predefined situations.

– Dahlquist et al (2015): CoSS concept tried, 20 participants, 2-week field trial using a diary.

Current work on– Detailed prose descriptions of the sound scenarios

– Detailed technical descriptions (SPL, SNR, reverberation…)



• People can categorize their listening situations in the CoSS categories

• The categorization seems useful when interpreting comments from hearing-aidusers’ real life

HA setting preference per CoSS category


Setting A

Setting B

Ecological MomentaryAssessment (EMA)


• People can categorize their listening situations in the CoSS categories

• The categorization seems useful when interpreting comments from hearing-aidusers’ real life

• How can we combine context and acoustics to get– a broad picture of peoples’ auditory reality

– in order to create best hearing-aid settings?


We’ll be back!

Summary of presentation:Why is this research important?

1. Development of hearing aids

2. Evaluation of hearing aids



We need a thorough understanding of peoples’ real life!

Examples:– A noise reduction system should work in commonly experienced ”noisy” situations

Frequency (kHz)

SNR: +6 dB SNR: +3 dB SNR: 0 dB

SNR: -3 dB SNR: -6 dB SNR: -9 dB



Development of hearing aids: We need a thorough understanding of peoples’ real life!


– All development focus cannot be geared towards difficult speech-in-noise situations

30%

23%

47%

CoSS Intention Category Distribution

SpeechCommunication

Focused Listening

Non-specificSmall internal ORCA Europestudy, reported at poster session yesterday



Development of hearing aids: We need a thorough understanding of peoples’ real life!


– All development focus cannot be geared towards difficult speech-in-noise situations

– Hearing aid programs could still be useful in order to deal with peoples’ varying intentions

Sit and relax”Isn’t this lovely?”

Leaves rustlingDistant trafficFootsteps on gravel

Children playing

Monitoring the kids”Did she hurt herself?”


Solve difficult problem”Aren’t the kids noisy?”


We need to evaluate hearing aids in an ecologically valid way!

Examples:– Ecological momentary assessments: Paired comparisons between two settings




Examples:– Ecological momentary assessments: Paired comparisons between two settings.

– Laboratory tests: Need appropriate acoustical settings for the feature/system being evaluated




Examples:– Ecological momentary assessments: Paired comparisons between two settings

– Laboratory tests: Need appropriate acoustical settings for the feature/system being evaluated

– Laboratory tests: Need to test also other intentions than focused listening using artificial tasks

Intention

Scenario #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14

Occurrence

Difficulty

Importance

Scenario

Convers

atio

nat

hom

e

Convers

atio

non

metro

Meetin

gin

an

offic

e

Car

ride

with

fam

ily

Phone

call

at

hom

e

Mobile

call

in th

estre

et

Lectu

re

At

aconcert

Watc

hin

gT

V

Lis

tenin

g to

car

radio

Vacuum

cle

anin

g

City

walk

Rela

xin

gw

itha

book

Rela

xin

gon tra

in

Non-specific

Task 2 people2 people

More than Through

deviceLive sounds

Two people having a

conversation

Several people

having a shared

conversation

Two or more people

having a shared

conversation through

a communication

device


sound without being

able to control the

sound source


sound while being

able to control the

sound source

Conscious or

unconscious

screening of sound of


activity

surroundings

Unconscious

perception of

environmental

sounds, without


activity

media device listening

MonitoringThrough Passive

Speech communication Focused listening


Aligned focus on Auditory Ecology at Widex

Auditory Ecology

Best HAs for end-users’

real-life needs

Develop-ment

EvaluationEvidence

Dispensing(HA fittingand fine-tuning)

Marke-ting

Thank you for your attention!

[email protected]

www.orca-eu.info

mailto:[email protected]

karolina smeds, phd director of research widex orca europe ... · [email protected]....

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