BUCNI Meeting

BUCNI Meeting Aug. 28 2008

Effects of spectral detail and tonal variation

on speech intelligibility

Kyong, Scott, Eisner and Rosen

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Rationale

• Languages differ in acoustic features they employ;

• How much is tonal variation ‘worth’ in terms of

intelligibility and will this be reflected accordingly in the neural representation?

• Pitch employed activations dominantly in the right (Scott et al., 2000).

Increasing intelligibility with increased spectral variation correlates with the activities in the left STS and the IFG

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Behavioural results

Fig.1 A logistic regression model comparing the coefficient for tonal variation to that for spectral detail

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Mandarin adult listeners: female talker (tone 'worth' 1.0 octave)

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English adult listeners: female talker (tone 'worth' 0.44 octave)

1 2 3 4 5 6 8 16 (in number of channels)

2 4 6 8 (in number of channels)

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Proposed scanning design

• 12-14 Native speakers of English, right-handed without speech/hearing problem

• Factorial (3 x 2) + controls (2) or + 1 (mini block of silence)

3 different spectral variations (2, 4, 6)

2 pitch conditions (natural/flat pitch variation)

2 controls for complex acoustic spectral variations (2, 6; ½ with and without tone)

• Sparse sampling with 8 s TR

Stimulus ~1.8 s Volume acquisition 3 s

We expect to• see the effect of intelligibility • know if increasing intelligibility with tonal variations uses the same neural substrates – main effect of tone• examine different contributions of spectral and tonal variations• confirm that potentially, reduced clarity invites IFG involvement

Thank you very much