Single-Word Speech Intelligibility in Children and Adults With Down Syndrome Purpose A single-word identification test was used to study speech production in children and adults with Down syndrome (DS) to determine the developmental pattern of speech intelligibility with an emphasis on vowels. Method Speech recordings were collected from 62 participants with DS aged 4–40 years and 25 typically ... Research Article
Newly Published
Research Article  |   December 06, 2017
Single-Word Speech Intelligibility in Children and Adults With Down Syndrome
 
Author Affiliations & Notes
  • Alyssa Wild
    433 Waisman Center, University of Wisconsin-Madison
  • Houri K. Vorperian
    433 Waisman Center, University of Wisconsin-Madison
  • Ray D. Kent
    433 Waisman Center, University of Wisconsin-Madison
  • Daniel M. Bolt
    Department of Educational Psychology, University of Wisconsin-Madison
  • Diane Austin
    433 Waisman Center, University of Wisconsin-Madison
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication.×
  • Correspondence to Houri K. Vorperian: vorperian@waisman.wisc.edu
  • Editor-in-Chief: Krista Wilkinson
    Editor-in-Chief: Krista Wilkinson×
  • Editor: Rebecca McCauley
    Editor: Rebecca McCauley×
Article Information
Speech, Voice & Prosodic Disorders / Special Populations / Genetic & Congenital Disorders / Newly Published / Research Article
Research Article   |   December 06, 2017
Single-Word Speech Intelligibility in Children and Adults With Down Syndrome
American Journal of Speech-Language Pathology, Newly Published. doi:10.1044/2017_AJSLP-17-0002
History: Received January 6, 2017 , Revised September 29, 2017 , Accepted October 11, 2017
 
American Journal of Speech-Language Pathology, Newly Published. doi:10.1044/2017_AJSLP-17-0002
History: Received January 6, 2017; Revised September 29, 2017; Accepted October 11, 2017

Purpose A single-word identification test was used to study speech production in children and adults with Down syndrome (DS) to determine the developmental pattern of speech intelligibility with an emphasis on vowels.

Method Speech recordings were collected from 62 participants with DS aged 4–40 years and 25 typically developing participants aged 4–7 years. Panels of 5 adult lay listeners transcribed the speech recordings orthographically, and their responses were scored in comparison with the speakers' target words.

Results Speech intelligibility in persons with DS improved with age, especially between the ages of 4 and 16 years. Whereas consonants contribute to intelligibility, vowels also played an important role in reduced intelligibility with an apparent developmental difference in low versus high vowels, where the vowels /æ/ and/ɑ/ developed at a later age than /i/ and /u/. Interspeaker variability was large, with male individuals being generally less intelligible than female individuals and some adult men having very low intelligibility.

Conclusion Results show age-related patterns in speech intelligibility in persons with DS and identify the contribution of dimensions of vowel production to intelligibility. The methods used clarify the phonetic basis of reduced intelligibility, with implications for assessment and treatment.

Acknowledgments
This work was supported by Research Grant R01 DC006282 to Houri K. Vorperian from the National Institute on Deafness and Other Communication Disorders. This study was also supported in part by core grants P30 HD03352 and U54 HD090256 to the Waisman Center from the National Institute of Child Health and Human Development. Special thanks to Allison Carolan, Ekaterini Derdemezis, Allison Petska, Daniel Reilly, Peggy Rosin, and Emily Reinicke for assistance with experimental design, task setup, and data collection; Robert Olson for software programming; Carlyn Burris, Erin Douglas, Julie Eichhorn, Ellie Fisher, Katie Lester, Erin Nelson, and Katelyn K. Tillman for data collection; Elaine Romenesko and Lela Murchison for data analysis and data collection; Gabriel Jardim for assistance with figure edits; and Abigail Lamers and Courtney Wagner for assistance with references. Portions of this research were presented in 2015 at the American Speech-Language-Hearing Association Convention in Denver, CO.
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