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

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.

Concurrent Associations between Expressive Language Ability and Independence in Adolescents and Adults with Fragile X Syndrome

“…This study also addresses the call for psychometrically sound measures for evaluating treatment efficacy in studies of individuals with ID [66][67][68]. In particular, we have shown previously that ELS-derived measures are feasible, are subject to only minimal practice effects, have strong test-retest reliability, and have construct validity for individuals with FXS and other forms of ID [45,49]. The data from the present study show that differences on ELS-derived measures are associated with real-world functional competence in late adolescence and early adulthood, which is an association valued by treatment-regulating bodies, such as the U.S. Food and Drug Administration, when deciding on the utility of an outcome measure for establishing treatment efficacy.…”

“…The aim of the present study was to examine these concurrent relationships for older adolescents and young adults with FXS. In doing so, we assessed dimensions of spoken language likely to shape the capacity for independent functioning and did so using Expressive Language Sampling (ELS), which has recently been psychometrically validated for use in FXS [45][46][47] and other ID conditions [48,49].…”

Providing a parent-administered outcome measure in a bilingual family of a father and a mother of two adolescents with ASD: brief report

“…See previous publications for detailed information about the ELS-N task. 15,18 Note that all the procedures for examiner-delivered administration version (e.g., the ELS-N administration manual, the ELS-N scripts and the ELS-N fidelity scoring rubric (FSR)) are available online at https://ctscassist.ucdmc.ucdavis.edu/ ctscassist/surveys/?s=W9W99JLMNX;. The goal for parents was to administer the ELS-N as a trained examiner would, with the only exception being a modest adjustment of the fidelity standards during training as described in the following section.…”

“…[10][11][12] Naturalistic language sampling may provide a better alternative for assessing expressive language in ASD because it is less subject to floor effects, more likely to be sensitive to change over time, and more likely to yield results generalizable to everyday functioning. [13][14][15][16][17] Moreover, there are now Expressive Language Sampling (ELS) procedures that have been developed and shown to have strong psychometric properties for many school-age and older individuals with neurodevelopmental disorders 15,16,18 At the same time, however, there are limitations of current ELS procedures. First, many of these ELS procedures are designed to be administered only by trained research or clinical staff in in-person settings.…”

“…To begin addressing these limitations, we developed an inhome, parent-administered version of our validated ELS narration procedures (ELS-N 15,18 ;) in both English and Spanish, along with a training program for parents so that they achieve adequate fidelity in their administration, all through telehealthdelivered procedures. We have conducted a small-scale study examining the feasibility and preliminary psychometrics of this in-home version for Spanish-and English-speaking families who have children with ASD.…”