Folia Phoniatr Logop 2007;59:306–317
(DOI:10.1159/000108337)

Effects of Speech Stimuli and Dysarthria Severity on Intelligibility Scores and Listener Confidence Ratings for Speakers with Cerebral Palsy

Hustad K.C.
Department of Communicative Disorders and Waisman Center, University of Wisconsin, Madison, Wisc., USA
email Corresponding Author


 goto top of outline Key Words

  • Speech intelligibility
  • Cerebral palsy
  • Dysarthria

 goto top of outline Abstract

This study examined differences among transcription intelligibility scores and listener confidence ratings for three different types of speech stimuli – single words, unrelated sentences, and sentences forming a narrative – all produced by speakers with dysarthria. Twelve speakers with dysarthria of varying severity secondary to cerebral palsy and 144 listeners participated in this study. Results showed that both intelligibility scores and confidence ratings were differentially affected by both stimuli and severity. For speakers with mild, moderate, and severe dysarthria, intelligibility scores were higher for narratives than for either of the other two types of speech stimuli. For speakers with mild dysarthria, sentences were substantially more intelligible than single words. However, for speakers with moderate, severe, and profound dysarthria, the difference in intelligibility scores for sentences and single words was small or nonsignificant. Confidence ratings did not follow the same pattern as intelligibility data, suggesting a mismatch between listeners’ perception of their performance and their actual performance on intelligibility tasks.

Copyright © 2007 S. Karger AG, Basel


 goto top of outline References
  1. Miller GA, Heise GA, Lichten W: The intelligibility of speech as a function of the context of the test materials. J Exp Psychol 1951;41:329–335.
  2. O’Neil JJ: Recognition of intelligibility test materials in context and isolation. J Speech Hear Disord 1957;22:87–90.

    External Resources

  3. Yorkston K, Beukelman D: A comparison of techniques for measuring intelligibility of dysarthric speech. J Commun Disord 1978;11:499–512.
  4. Yorkston K, Beukelman D: Communication efficiency of dysarthric speakers as measured by sentence intelligibility and speaking rate. J Speech Hear Disord 1981;46:296–301.
  5. Sitler RW, Schiavetti N, Metz DE: Contextual effects in the measurement of hearing-impaired speakers’ intelligibility. J Commun Disord 1983;11:22–30.
  6. Dongilli P: Semantic context and speech intelligibility; in Till J, Yorkston K, Beukelman D (eds): Motor Speech Disorders: Advance in Assessment and Treatment. Baltimore, Brookes, 1994, pp 175–191.
  7. Giolas T, Epstein A: Comparative intelligibility of word lists and continuous discourse. JSHR 1963;6:349–358.
  8. Giolas TG: Comparative intelligibility scores of sentence lists and continuous discourse. J Aud Res 1965;6:31–38.
  9. Beukelman DR, Yorkston K: The relationship between information transfer and speech intelligibility of dysarthric speakers. J Commun Disord 1979;12:189–196.
  10. Drager KDR, Reichle JE: Effects of discourse context on the intelligibility of synthesized speech for young adult and older adult listeners: applications for AAC. J Speech Lang Hear Res 2001;44:1052–1057.
  11. Hustad KC, Beukelman DR: Effects of linguistic cues and stimulus cohesion on intelligibility of severely dysarthric speech. J Speech Lang Hear Res 2001;44:497–510.
  12. Hustad KC: Estimating the intelligibility of speakers with dysarthria. Folia Phoniatr Logop 2006;58:217–228.
  13. Kent R, Weismer G, Kent J, Rosenbek J: Toward phonetic intelligibility testing in dysarthria. J Speech Hear Disord 1989;54:482–499.
  14. Yorkston K, Beukelman D, Tice R: Sentence Intelligibility Test for Windows. Lincoln, Communication Disorders Software. Distributed by the Institute for Rehabilitation Science and Engineering, Lincoln, 1996.
  15. Hustad KC, Beukelman DR: Listener comprehension of severely dysarthric speech: effects of linguistic cues and stimulus cohesion. J Speech Lang Hear Res 2002;45:545–558.
  16. Hustad KC, Jones T, Daily S: Implementing speech supplementation strategies: effects on intelligibility and speech rate of individuals with chronic severe dysarthria. J Speech Lang Hear Res 2003;46:462–474.
  17. Hustad KC, Cahill MA: Effects of presentation mode and repeated familiarization on intellligibility of dysarthric speech. Am J Speech Lang Pathol 2003;12:1–11.

    External Resources

  18. Kirk R: Experimental Design: Procedures for the Behavioral Sciences, ed 3. Pacific Grove, Brooks/Cole, 1995.

 goto top of outline Author Contacts

Katherine Hustad
475 Waisman Center
1500 Highland Avenue
Madison, WI 53705 (USA)
Tel. +1 608 265 9977, Fax +1 608 263 7710, E-Mail kchustad@wisc.edu


 goto top of outline Article Information

Portions of these data were presented at the American Speech- Language and Hearing Association Annual Convention, Chicago, Ill. (November, 2003).

Number of Print Pages : 12
Number of Figures : 6, Number of Tables : 5, Number of References : 18


 goto top of outline Publication Details

Folia Phoniatrica et Logopaedica (International Journal of Phoniatrics, Speech Therapy and Communication Pathology)

Vol. 59, No. 6, Year 2007 (Cover Date: October 2007)

Journal Editor: Schutte, H.K. (Groningen)
ISSN: 1021–7762 (print), 1421–9972 (Online)

For additional information: http://www.karger.com/FPL


Copyright / Drug Dosage / Disclaimer

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.