Language Samples From Children Who Use Speech-Generating Devices: Making Sense of Small Samples and Utterance Length Purpose Mean length of utterance in morphemes (MLUm) is underreported in people who use augmentative and alternative communication (AAC). MLUm is difficult to measure in people who use AAC because of 2 challenges described in literature: the challenge of small language samples (difficulty collecting representative samples) and the challenge of ... Research Article
Research Article  |   August 15, 2017
Language Samples From Children Who Use Speech-Generating Devices: Making Sense of Small Samples and Utterance Length
 
Author Affiliations & Notes
  • Thomas Kovacs
    Department of Communication Science and Disorders, University of Pittsburgh, PA
  • Katya Hill
    Department of Communication Science and Disorders, University of Pittsburgh, PA
  • 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 Thomas Kovacs: TRK30@Pitt.edu
  • Editor: Krista Wilkinson
    Editor: Krista Wilkinson×
  • Associate Editor: Kathryn Drager
    Associate Editor: Kathryn Drager×
Article Information
Augmentative & Alternative Communication / Language Disorders / Research Articles
Research Article   |   August 15, 2017
Language Samples From Children Who Use Speech-Generating Devices: Making Sense of Small Samples and Utterance Length
American Journal of Speech-Language Pathology, August 2017, Vol. 26, 939-950. doi:10.1044/2017_AJSLP-16-0114
History: Received June 18, 2016 , Revised December 19, 2016 , Accepted March 17, 2017
 
American Journal of Speech-Language Pathology, August 2017, Vol. 26, 939-950. doi:10.1044/2017_AJSLP-16-0114
History: Received June 18, 2016; Revised December 19, 2016; Accepted March 17, 2017

Purpose Mean length of utterance in morphemes (MLUm) is underreported in people who use augmentative and alternative communication (AAC). MLUm is difficult to measure in people who use AAC because of 2 challenges described in literature: the challenge of small language samples (difficulty collecting representative samples) and the challenge of transcribing short utterances (difficulty transcribing 1-morpheme utterances). We tested solutions to both challenges in a corpus of language samples from children who use speech-generating devices.

Method The first challenge was addressed by adjusting the length of the sampling window to obtain representative language samples. The second challenge was addressed by using mean syntactic length (MSL) as an alternative to MLUm.

Results A 24-hour sample window consistently failed to yield representative samples. An extended 1-month sample window consistently yielded representative samples. A significant positive prediction of MLUm by MSL was found in a normative sample. Observed measures of MSL were used to predict MLUm in representative language samples from children who use AAC.

Conclusions Valid measures of utterance length in people who use AAC can be obtained using extended sampling windows and MSL. Research is needed to characterize the strengths and limitations of both solutions.

Acknowledgments
The authors wish to thank Sean, Roger, and their family for contributing the data to the AAC database for this analysis. This study was derived from the first author's PhD predissertation project in the Department of Communication Science and Disorders at the University of Pittsburgh. The authors would like to thank Mike Dickey, Connie Tompkins, and Helen Stickney for their guidance and feedback. This study was approved by the Institutional Review Board at the University of Pittsburgh, IRB protocol number PRO1001053. Parental consent and child participant assent were obtained. Portions of this research were presented in 2015 at the Clinical AAC Research Conference in Charlottesville, VA, and the American Speech-Language-Hearing Association Convention in Denver, CO.
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