Weighting of acoustic cues shifts to frication duration in identification of fricatives/affricates when auditory

properties are degraded due to aging

Keiichi Yasu, Takayuki Arai, Kei Kobayashi, Mitsuko Shindo

Sophia University

2013/08/29 1

Degradation of auditory property by aging

• Difficulty in consonant identification by elderly people

• Degradation of auditory property is one of the causes

– Elevation of hearing levels

– Deficit of temporal resolution

– Loudness recruitment

• And so on.

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Identification of fricative and affricate (CV)

• Extending total duration of fricatives (T)

→ Identification shifts from affricates to fricatives.

• (Howell and Rosen, 1983; Kluender and Walsh, 1992)

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T (ms)

60 80 100 120 140 160 180 200

# 1 2 3 4 5 6 7 8

Gradient of amplitude of frication: ⊿ Total duration of frication: TYoung Elderly

Identification of fricative and affricate (VCV)

• Extending silent interval (SI) between V1 and C-> Identified from fricative to affricate

– (Dorman et al.,1980; Gordon-Salant et al., 2006)

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SI (ms) 0 20 40 60 80 100

# 1 2 3 4 5 6

Total duration of frication: T Silent interval: SIYoung Elderly

Weighting shift

• Multiple cues exists:– Longer T tend to perceived as fricative– Shorter SI tend to perceived as fricative

– Shorter T tend to perceived as affricate– Shorter SI tend to perceived as fricative

• Confusing condition– Depends on listeners perception– Weighting of cues shifts especially for elderly

listeners (Yasu et al. 2011, 2012)

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cue-trading(Repp et al. 1978)

typical consonant

Goal

• Identification tests of fricative and affricate

– Degradation of auditory property by aging

• (Yasu et al., 2011, 2012, Gordon-Salant et al., 2006)

• The weighting of acoustic cues

– Re-analysis and discussing in this study

• Weighting Shift to Total duration of frication T

– Unified in different cues in CV and VCV stimuli in simple framework

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Experiments(Yasu et al. 2011, 2012)

• Participants– 19 young listeners and 55 elderly listeners – Auditory property measurement for elderly listeners

• Absolute threshold (f), temporal resolution (t), loudness recruitment (r)

• Stimuli– Continuum of CV (changing gradient of amplitude

and T) – Continuum of VCV (changing SI and T)

• Procedure– 2AFC

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Result of CV: Gradient and T

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Res

po

nse

rat

e o

f [

∫ ]

1.0

0.5

0

Gradient of frication

1.0

0.5

0 2080

140

200

T (ms)

Phonetic boundary

Phonetic boundary (p=0.5) in CV

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Gra

die

nt

of

fric

atio

n

T (ms)

1.0

0.5

00 100 200

Eftr

Weighting shift from gradientto frication duration T

• Elderly listeners with a degradation in auditory properties are less influenced by the gradient of the amplitude of frication

• Aging and degradation of auditory properties affect cue trading

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Group Y E Eftr

θ [deg] 85.2 90.8 89.5

Angle θ [deg] at phonetic boundary

Result of VCV: SI and T

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Res

po

nse

rat

e o

f [

∫ ]

1.0

0.5

0

T (ms)SI (ms)

0

short

middle

long

3060

90

Phonetic boundary

Phonetic boundary (p=0.5) in VCV

2013/08/29 12T (ms)

SI(m

s)

0short middle long

50

100

Weighting shift from SIto frication duration T

• Elderly people with auditory degradations tend to clue into frication duration T, increasingly as the auditory degradations complete, rather than SI

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Group Y E Eftr

θ [deg] 30.1 25.3 80.5

Angle θ [deg] at phonetic boundary

General discussion and conclusion

• Weighting shifts to the total duration of frication (T) by aging

– CV: gradient of frication(⊿) to total duration (T)

– VCV: silent interval (SI) to total duration (T)

• Possible to unify into single framework-> Total duration of frication

– for identification of fricative and affricate

2013/08/29 14

Acknowledgment:Sophia University Open Research Center from MEXT, Japan