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Lynn Li Lim 1,2 , Karen Croot 1,2,3 , Sallyanne Palethorpe 1,2 , Max Coltheart 1,2

An Investigation of the Effect of Multiple Productions on the S ingle Word Production of People with Acquired Speech Sound Production Difficulties : An Analysis of 2 Cases. Lynn Li Lim 1,2 , Karen Croot 1,2,3 , Sallyanne Palethorpe 1,2 , Max Coltheart 1,2

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Lynn Li Lim 1,2 , Karen Croot 1,2,3 , Sallyanne Palethorpe 1,2 , Max Coltheart 1,2

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  1. An Investigation of the Effect of Multiple Productions onthe Single Word Production of People with Acquired Speech Sound Production Difficulties: An Analysis of 2 Cases Lynn Li Lim1,2, Karen Croot1,2,3, Sallyanne Palethorpe1,2, Max Coltheart1,2 1. Macquarie Centre for Cognitive Science (MACCS), Macquarie University 2. Speech Hearing and Language Research Centre (SHLRC), Macquarie University 3. School of Psychology, The University of Sydney

  2. Acoustic Analysis • Speech disorders may share similar symptoms of impaired speech production • To determine the speech disorder associated with the symptom  examine speech segment productions acoustically • Gives more concrete information on speech qualities attributed to phonological & articulatory deficits • More reliable than impressionistic phonetic transcription (Haley et al, 2001)

  3. Acoustic Speech Analysis • Most common acoustic investigations are on contrastive features to determine if speech segment errors are: • Phonemic – substitution of one phoneme for another • Phonetic – impaired articulation of a speech sound (Baum et al, 1990; Tuller, 1984)

  4. Variability in Speech Production • Unimpaired speech production can be somewhat variable (Auzou et al, 2000) • Acoustic studies usually rely on multiple productions of speech tokens to overcome this variability • People with speech disorders are far more variable in their productions than controls (Ryalls, 1986) • But disordered speech analyses have not addressed the issue of possible effects of multiple productions • And their results have been inconsistent

  5. Multiple Production • Not known if eliciting multiple word productions from these people affects their speech sound production difficulties • H1: Fatigue – deterioration of speech production • H2: Practice – improvement in speech production • H0: No effect on speech production

  6. Previous Studies • Some examples for Vowel Duration

  7. Multiple Production Implication: • If there are effects, then method of eliciting speech tokens may confound the investigation of the nature of the disorder

  8. Other Features of Speech Production • Previous acoustic studies address question of whether speakers produce phonemic or phonetic errors • Other information about speech production difficulties that are non-contrastive in nature • These are not usually reported in most acoustic studies

  9. Research Questions Q1: Does multiple repetition of target words affect phonetic parameters of the speech of people with impaired speech sound production? Q2: Are there other phonetic parameters in the speech of these individuals that might be indicative of the nature of the disorder but not usually reported?

  10. Speakers AR • 63 y.o., male • progressive aphasia with other mild cognitive deficits 2.5 years after presentation • impaired syntax & phoneme discrimination • semantic abilities just below control range • moderate hearing loss (35-50 dB loss at 4kHz, 55-70 dB loss at 6 kHz)

  11. Speakers HO • 62 y.o., male • left middle cerebral artery infarct early 1996 • unimpaired visuo-perceptual processing of pictures & words • semantic abilities just below control range • impaired receptive phonological processing • moderate hearing loss (45-55 dB loss at & above 4 kHz)

  12. Material

  13. Acoustic Procedure • Recordings digitised at 20,000 Hz • Spectrograms hand-labelled & analysed using the EMU speech database system & the R statistical analysis software • Acoustic dimensions analysed: • Burst Release Duration (BRDUR) • Vowel Duration (VDUR) • Fricative Spectral Moments (FSM) • First SM (SM1): average spectral frequency

  14. Q1: Statistical Analysis • Repeated Measures ANOVA • To investigate for any significant differences in the variance between sessions • Sphericity: assumption that variance is equal between pairs of scores (Field, 2000, p.324)

  15. Q1: Results - Error-bar Plots dark duck Example:Burst Release Duration of /d/ (AR)

  16. Q1: Results - Error-bar Plots Example:Burst Release Duration of /p/ (HO)

  17. Q1: Results - Error-bar Plots saw sea Example:1st Spectral Momentof /s/ (HO)

  18. Q1: Results - Error-bar Plots Example: Vowel Duration of /I/ (AR)

  19. Q1: Results - ANOVA Descriptive Statistics Vowel duration /I/ in “Big” (Speaker AR) Mauchly's Test of Sphericity Tests of Within-Subjects Effects

  20. Q1: Results - ANOVA

  21. Q1: Summary of Results • ANOVA: significant differences between sessions for only some words • Post-hoc: significant differences between session means were few • and no pattern of increase/decrease in differences across sessions • Results were similar for VDUR, BRDUR, Fricative SM1, the other words, both speakers • Results were also similar in 2nd experiment

  22. Q1: Summary of Results • No change across sessions = no effect (practice/fatigue) of multiple productions • Also, no. of repetitions in Exp 2 > Exp 1, yet no effect of increased repetition on speech production

  23. Implication of Results • method of eliciting multiple production may not confound investigation of nature of speech disorder • but for treatment – practice of this type elicited in this study may not contribute to improvement in speech production

  24. Q2: Other Speech Production Features • Pre-voicing (HO) Pre-voicing Figure 1a Figure 1b Example: Bug

  25. Q2: Other Speech Production Features • Pre-voicing (HO) • voicing preceding release of word initial /b/ & /d/ • Impaired laryngealcontrol – difficulty coordinating timing of stop release for voiced stops

  26. Q2: Other Speech Production Features Schwa • Schwa appended to final stop (HO) Example: Pad Figure 3

  27. Q2: Other Speech Production Features • Schwa appended to word-final stop (HO) • Voiced stops • Indicative of careful speech production • Or due to speech disorder • Or due to hearing loss

  28. Q2: Other Speech Production Features - Summary • No pattern in occurrence of these features over sessions • Not an effect of multiple production • May just be characteristic of disordered speech production

  29. Future Directions • Word-final consonants (stops) • Nasal consonants • Co-articulation • Analysis of the other speech production features • Analysis of control data

  30. Thank you for listening

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