Spoken language outcome measures for treatment studies in Down syndrome: feasibility, practice effects, test-retest reliability, and construct validity of variables generated from expressive language sampling

• Type of Material: Article
• Authors: Angela John Thurman, University of California Davis; Jamie O. Edgin, University of Arizona; Stephanie Sherman, Emory University; Audra Sterling, University of Wisconsin Madison; Andrea McDuffie, University of California Davis; Elizabeth Berry-Kravis, Rush University; Debra Hamilton, Emory University; Leonard Abbeduto, University of California Davis
• Language: English
• Date: 2021-04-08
• Publisher: BMC
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s). 2021
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1186/s11689-021-09361-6
• Title of Journal or Parent Work: Journal of Neurodevelopmental Disorders
• Volume: 13
• Issue: 1
• Start Page: 13
• End Page: 13
• Grant/Funding Information: This research was supported by the following grant from the National Institutes of Health, R01HD074346, P50HD103526, and UL1TR000002.
• Keywords: Psychometrics; Down syndrome; Neurosciences; Expressive language; Outcome measures; Neurosciences & Neurology; Clinical trials; Life Sciences & Biomedicine; Treatment; Clinical Neurology; Expressive language sampling; Science & Technology
• Research Categories: Chemistry, Biochemistry; Biology, Neuroscience; Psychology, Psychobiology; Biology, Genetics

Abstract

Background The purpose of this study was to evaluate expressive language sampling (ELS) as a procedure for generating spoken language outcome measures for treatment research in Down syndrome (DS). We addressed (a) feasibility, (b) practice effects across two short-term administrations, (c) test-retest reliability across two short-term administrations, (d) convergent and discriminant construct validity, and (e) considered comparisons across the conversation and narration contexts. Method Participants were 107 individuals with DS between 6 and 23 years of age who presented with intellectual disability (IQ < 70). The utility of ELS procedures designed to collect samples of spoken language in conversation and narration were evaluated separately. Variables of talkativeness, vocabulary, syntax, utterance planning, and articulation quality, derived from transcripts segmented into C-units (i.e., an independent clause and its modifiers), were considered. A 4-week interval was used to assess practice effects and test-retest reliability. Standardized direct assessments and informant report measures were collected to evaluate construct validity of the ELS variables. Results Low rates of noncompliance were observed; youth who were under 12 years of age, had phrase-level speech or less, and had a 4-year-old developmental level or less were at particular risk for experiencing difficulty completing the ELS procedures. Minimal practice effects and strong test-retest reliability across the 4-week test-retest interval was observed. The vocabulary, syntax, and speech intelligibility variables demonstrated strong convergent and discriminant validity. Although significant correlations were found between the variables derived from both the conversation and narration contexts, some differences were noted. Conclusion The ELS procedures considered were feasible and yielded variables with adequate psychometric properties for most individuals with DS between 6 and 23 years old. That said, studies of outcome measures appropriate for individuals with DS with more limited spoken language skills are needed. Context differences were observed in ELS variables suggest that comprehensive evaluation of expressive language is likely best obtained when utilizing both contexts.