Comparative performance of Comparative performance of an an adaptive directional microphoneadaptive directional microphone and and a a multi-channel noise reductionmulti-channel noise reduction systemsystem, , in a digital hearing instrumentin a digital hearing instrument

Kevin CP YuenKevin CP YuenInstitute of Human Communicative Research & Institute of Human Communicative Research & Division of Otolaryngology, Department of Surgery, Division of Otolaryngology, Department of Surgery, The Chinese University of Hong KongThe Chinese University of Hong Kong

Anna CS KamAnna CS KamPhonak Hong Kong Hearing CentrePhonak Hong Kong Hearing Centre

Polly SH LauPolly SH LauDivision of Speech and Hearing Sciences, Division of Speech and Hearing Sciences, The University of Hong KongThe University of Hong Kong 8 Oct 20058 Oct 2005

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ObjectivesObjectives

Compare the speech recognition in noise perfCompare the speech recognition in noise performance amongormance among Multi-channel noise reduction system (medium) (Multi-channel noise reduction system (medium) (FNCFNC),), Adaptive directional microphone (Adaptive directional microphone (DAZDAZ), &), & FNC + DAZFNC + DAZ

Compare the objective and subjective performCompare the objective and subjective performance betweenance between NAL-NL1NAL-NL1 in Perseo, & in Perseo, & Digital Perception Processing (Digital Perception Processing (DPPDPP) in Perseo) in Perseo

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Multi-channel noise reduction system -Multi-channel noise reduction system -Fine noise canceller, FNC (Medium)Fine noise canceller, FNC (Medium)

Courtesy of Phonak

Frequency-Frequency-dependent gain dependent gain reductionreduction

SNR-dependent SNR-dependent gain reductiongain reduction

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Att

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Noise only SNR 0 SNR+5 SNR+10 Signal only

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Adaptive directional microphone (DAZ)Adaptive directional microphone (DAZ) Polar patterns are Polar patterns are

switched switched adaptively in adaptively in response to the response to the direction of noisedirection of noise

Courtesy of Phonak

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NAL-NL1 & DPPNAL-NL1 & DPP NAL-NL1NAL-NL1, National Acoustics Laboratory – Non-linear , National Acoustics Laboratory – Non-linear

1 (Dillion, 1999)1 (Dillion, 1999) Provides gain-frequency response that maximizes speech intProvides gain-frequency response that maximizes speech int

elligibility for any input level of speech,elligibility for any input level of speech, while keeping overall loudness at a level no greater than that while keeping overall loudness at a level no greater than that

perceived by a normal hearing person, or at a lower level if it perceived by a normal hearing person, or at a lower level if it provides greater speech intelligibility.provides greater speech intelligibility.

DPPDPP, Digital Perception Processing, Digital Perception Processing Incorporates a psychoacoustic loudness mode of normal and Incorporates a psychoacoustic loudness mode of normal and

impaired cochlea function (Moore et al, 2003)impaired cochlea function (Moore et al, 2003) Calculates excitation patterns and specific loudness patterns Calculates excitation patterns and specific loudness patterns

evoked in a normal and impaired cochlear, from the incominevoked in a normal and impaired cochlear, from the incoming signal, and adjusts gain required to match the loudness pattg signal, and adjusts gain required to match the loudness patterns of impaired cochlea to those of normal cochleaerns of impaired cochlea to those of normal cochlea

Aims at restoring loudness perception to ‘normal’Aims at restoring loudness perception to ‘normal’

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Research DesignResearch Design

Group 1 (5 subjects)Group 1 (5 subjects)

OWN hearing aidOWN hearing aid → → Perseo DPPPerseo DPP →→ Perseo NAL-NL1Perseo NAL-NL1

1 1 wweekeek 1 week1 week

Group 2 (4 subjects) Group 2 (4 subjects)

OWN hearing aidOWN hearing aid → → Perseo NAL-NL1Perseo NAL-NL1 → → Perseo DPPPerseo DPP

Perseo DPPPerseo DPP == Digital Perception Processing targetDigital Perception Processing targetPerseo NAL-NL1Perseo NAL-NL1 = = NAL-NL1 targetNAL-NL1 target

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Assessment toolsAssessment tools

DPPDPP vs vs NAL-NL1 NAL-NL1 / / FNC+DAZFNC+DAZ vs vs DAZDAZ vs vs FNCFNC Cantonese Hearing-in-Noise Test (CHINT)Cantonese Hearing-in-Noise Test (CHINT)

(Wong & Soli, 2005)(Wong & Soli, 2005) Chinese translated version of Abbreviated Profile of HeChinese translated version of Abbreviated Profile of He

aring Aid Benefit (APHAB)aring Aid Benefit (APHAB) (Cox & Alexander, 1995)(Cox & Alexander, 1995)

DPPDPP vs vs NAL-NL1NAL-NL1 Sound quality paired comparison judgmentSound quality paired comparison judgment

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SubjectsSubjects

250 500 1000 2000 4000 8000Frequency, Hz

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Nine post-lingually deafened adults (39-79 yrNine post-lingually deafened adults (39-79 yrs)s)

Sensorineural hearing lossSensorineural hearing loss Native Cantonese-speakingNative Cantonese-speaking Hearing aid experience > 6 monthsHearing aid experience > 6 months

Own hearing aidPerseo hearing

aidMultiband noise redu

ction

Directional mic

Compression scheme

Ear

S1 OC L 211

S2 OC R 211

S3 OC R 211

S4 ✔ WDRC R 311

S5 OC L 311

S6 ✔ ✔ WDRC R 211

S7 WDRC L 211

S8 WDRC L 211

S9 ✔ ✔ WDRC R 211

Average unaided air-conduction threshold of the test ear (+/- 1 SD)

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Speech recognition in noise resultsSpeech recognition in noise results

Separately for Separately for Signal_Front/ Noise_Front & Signal_Front/ Noise_Front & Signal_Front/ Noise_SideSignal_Front/ Noise_Side

RunRunTwo-way repeated measures ANOVA forTwo-way repeated measures ANOVA for Noise suppression (Noise suppression (FNC+DAZFNC+DAZ vs vs DAZDAZ vs vs FNCFNC)) Prescription (Prescription (DPPDPP vs vs NAL-NL1NAL-NL1))

&&Post-hoc Tukey HSD testPost-hoc Tukey HSD test

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ResultsResults

Noise suppression optionsNoise suppression options

FNC+DAZFNC+DAZ vs vs DAZDAZ vs vs FNCFNC

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FNC+DAZDAZFNC

S3 S4 S5 S6 S7 S8 S9Subject

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S1S1 S2S2 S3S3 S4S4 S5S5 S6S6 S7S7 S8S8 S9S9

SNRSNR -- -- 00 00 +5+5 +10+10 +5+5 -5-5 +5+5

FNC+DAZFNC+DAZ vs vs DAZDAZ

FNC+DAZFNC+DAZ vs vs FNCFNC

DAZDAZ vs vs FNCFNC

FNC+DAZFNC+DAZ vs vs DAZDAZ vs vs FNCFNC Signal_Front / Noise_FrontSignal_Front / Noise_Front

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FNC+DAZDAZFNC

S3 S4 S5 S6 S7 S8 S9Subject

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S1S1 S2S2 S3S3 S4S4 S5S5 S6S6 S7S7 S8S8 S9S9

SNRSNR -- -- 00 00 +5+5 +10+10 +5+5 -5-5 +5+5FNC+DAZFNC+DAZ vs vs DAZDAZ DAZDAZ

FNC+DAZFNC+DAZ vs vs FNCFNC FNC+FNC+DAZDAZ

FNC+FNC+DAZDAZ

FNC+FNC+DAZDAZ

FNC+FNC+DAZDAZ

FNC+FNC+DAZDAZ

FNC+FNC+

DAZDAZ

DAZDAZ vs vs FNCFNC DAZDAZ DAZDAZ DAZDAZ DAZDAZ DAZDAZ DAZDAZ DAZDAZ DAZDAZ

FNC+DAZFNC+DAZ vs vs DAZDAZ vs vs FNCFNCSignal_Front / Noise_SideSignal_Front / Noise_Side

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ResultsResults

PrescriptionsPrescriptions

DPPDPP vs vs NAL-NL1NAL-NL1

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DPPNAL-NL1

S3 S4 S5 S6 S7 S8 S9Subject

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S1S1 S2S2 S3S3 S4S4 S5S5 S6S6 S7S7 S8S8 S9S9

SNRSNR -- -- 00 00 +5+5 +10+10 +5+5 -5-5 +5+5

DPP DPP vs vs

NAL-NL1NAL-NL1

DPPDPP

DPPDPP vs vs NAL-NL1NAL-NL1 Signal_Front / Noise_FrontSignal_Front / Noise_Front

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DPPNAL-NL1

S3 S4 S5 S6 S7 S8 S9Subject

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S1S1 S2S2 S3S3 S4S4 S5S5 S6S6 S7S7 S8S8 S9S9

SNRSNR -- -- 00 00 +5+5 +10+10 +5+5 -5-5 +5+5

DPPDPP vs vs

NAL-NL1NAL-NL1

DPPDPP DPPDPP DPPDPP DPPDPP

DPPDPP vs vs NAL-NL1NAL-NL1 Signal_Front / Noise_SideSignal_Front / Noise_Side

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APHAB APHAB DPPDPP vs vs NAL-NL1NAL-NL1 APHAB subscale

Sums of negative ranks

(NAL-NL1 > DPP)

Sums of positive ranks

(DPP > NAL-NL1)

p value

Ease of communication

323.0 343.0 0.87

Reverberation 70.5 205.5 0.04

Background noise

1129.5 950.5 0.55

Adversiveness 474.5 155.5 0.01

Wilcoxon Signed-Ranks Test

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Sound quality paired comparison judgmentSound quality paired comparison judgment DPPDPP vs vs NAL-NL1NAL-NL1

SOFT loudnessSOFT loudness MEDIUM loudnessMEDIUM loudness

so1so1 Bird singingBird singing m1m1 Alarm clockAlarm clock

so2so2 CatCat m2m2 Bird singingBird singing

so3so3 Clock tickingClock ticking m3m3 Church bellChurch bell

so4so4 Distant thunderDistant thunder m4m4 Classical musicClassical music

so5so5 Running waterRunning water m5m5 RainingRaining

so6so6 Male radio broadcastMale radio broadcast m6m6 Toilet flushingToilet flushing

so7so7 Female radio broadcastFemale radio broadcast m7m7 Male radio broadcastMale radio broadcast

so8so8 Female singingFemale singing m8m8 Female radio broadcastFemale radio broadcast

so9so9 Male singingMale singing m9m9 Female singingFemale singing

m10m10 Male singingMale singing

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Sound quality paired comparison judgmentSound quality paired comparison judgment DPPDPP vs vs NAL-NL1NAL-NL1

Track

Subject So1

So2

So3

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M1

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S1 - D N D N D N D N D D D D D D N D D N

S2 D N D N D D D D D N D D D N D N N N D

S3 N N N D D D D D D - D D N N D D D N N

S4 D D N D N N D D N - D D D D D N D D N

S5 - - D N N D D D D - N D D N D D D N N

S6 D N D N N N D D N - D D D N N N D D N

S7 N N D N D D N D N - D - N N N D N N D

S8 D N D D N D N N N - D D N N N N D D N

S9 D N D N N N D N N - N N D N N D N N D

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Sound quality paired comparison judgmentSound quality paired comparison judgment DPPDPP vs vs NAL-NL1NAL-NL1

N D

S1 NN NN NN NN NN NN DD DD DD DD DD DD DD DD DD DD DD DD - 6 12

S2 NN NN NN NN NN NN NN DD DD DD DD DD DD DD DD DD DD DD DD 77 1212

S3 NN NN NN NN NN NN NN DD DD DD DD DD DD DD DD DD DD DD - 7 11

S4 NN NN NN NN NN NN DD DD DD DD DD DD DD DD DD DD DD DD - 6 12

S5 NN NN NN NN NN NN DD DD DD DD DD DD DD DD DD DD - - - 6 10

S6 NN NN NN NN NN NN NN NN NN DD DD DD DD DD DD DD DD DD - 9 9

S7 NN NN NN NN NN NN NN NN NN NN DD DD DD DD DD DD DD - - 10 7

S8 NN NN NN NN NN NN NN NN NN NN DD DD DD DD DD DD DD DD - 10 8

S9 NN NN NN NN NN NN NN NN NN NN NN NN DD DD DD DD DD DD - 12 6

NNDD DPP NALWilcoxon Signed-Ranks Test , p =.26

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S1 S2 S3

S4 S5 S6

S7 S8 S9

DPP - NAL-NL1 @ 50 dBSPLDPP - NAL-NL1 @ 65 dBSPLDPP - NAL-NL1 @ 80 dBSPL

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Real ear SPL difference Real ear SPL difference DPPDPP minus minus NAL-NL1NAL-NL1

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ConclusionConclusion

Speech recognition in noiseSpeech recognition in noise With With signalsignal and and noisenoise from the from the frontfront,,

DPPDPP better than better than NAL-NL1NAL-NL1 in 1 subject in 1 subject FNCFNC, , DAZDAZ and and FNC+DAZFNC+DAZ were not different were not different

With With signalsignal from the from the frontfront, , noisenoise from the from the sideside DPPDPP better than better than NAL-NL1NAL-NL1 in 4 subjects in 4 subjects DAZDAZ better than better than FNCFNC in 8 subjects in 8 subjects FNC+DAZFNC+DAZ better than better than FNCFNC in 6 subjects in 6 subjects

Whenever there was a difference, Whenever there was a difference, DPPDPP was better than was better than NAL-NL1NAL-NL1 Adaptive Directional MicAdaptive Directional Mic better than better than Multiband noise reduction Multiband noise reduction

systemsystem, only for , only for signal_front/noise_sidesignal_front/noise_side but not for but not for signal_frontsignal_front/noise_front/noise_front

best speech recognition, measured AI-weighted directional pattern best speech recognition, measured AI-weighted directional pattern for for signal_front/noise_side signal_front/noise_side (Ricketts et al, 2002)(Ricketts et al, 2002)

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ConclusionConclusion

APHABAPHAB NAL-NL1NAL-NL1 > > DPP DPP (Adversiveness)(Adversiveness) DPPDPP > > NAL-NL1NAL-NL1 (Reverberation) (Reverberation)

Sound quality paired comparison judgmentSound quality paired comparison judgment 5/9 subjects had more preferences towards 5/9 subjects had more preferences towards DPPDPP th th

an NAL-NL1an NAL-NL1 3/9 subjects had more preference towards 3/9 subjects had more preference towards NAL-NL1NAL-NL1

than DPPthan DPP

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NAL-NL1NAL-NL1EnglishEnglish does not maximize speech does not maximize speech

intelligibility for intelligibility for CantoneseCantonese ? ?

Band importance functionBand importance function English sentence – peak at 2000Hz (Eisenberg et al, 1998)English sentence – peak at 2000Hz (Eisenberg et al, 1998) Cantonese sentence – peak at 800-1600Hz (Chua, 2004)Cantonese sentence – peak at 800-1600Hz (Chua, 2004)

Band importance functionBand importance function -> derive -> derive SIISII -> derive -> derive NAL-NL1NAL-NL1

Chua, 2004

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Kevin YuenKevin Yuen

Division of Otorhinolaryngology, Division of Otorhinolaryngology,

Department of SurgeryDepartment of Surgery

The Chinese University of Hong KongThe Chinese University of Hong Kong

Email: Email: kevinyuen@surgery.cuhk.edu.hkkevinyuen@surgery.cuhk.edu.hk

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2cc coupler gain response of the three hearing aid 2cc coupler gain response of the three hearing aid settings (front microphone @ 0 degree azimuth)settings (front microphone @ 0 degree azimuth)

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FNC DAZ FNC+DAZ