Expressive language sampling as a source of outcome measures for treatment studies in fragile X syndrome: feasibility, practice effects, test-retest reliability, and construct validity
Abstract Background The evaluation of treatment efficacy for individuals with fragile X syndrome (FXS) or intellectual disability (ID) more generally has been hampered by the lack of adequate outcome measures. We evaluated expressive language sampling (ELS) as a procedure for generating outcome meas...
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2020-03-01
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Series: | Journal of Neurodevelopmental Disorders |
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Online Access: | http://link.springer.com/article/10.1186/s11689-020-09313-6 |
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Article |
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DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Leonard Abbeduto Elizabeth Berry-Kravis Audra Sterling Stephanie Sherman Jamie O. Edgin Andrea McDuffie Anne Hoffmann Debra Hamilton Michael Nelson Jeannie Aschkenasy Angela John Thurman |
spellingShingle |
Leonard Abbeduto Elizabeth Berry-Kravis Audra Sterling Stephanie Sherman Jamie O. Edgin Andrea McDuffie Anne Hoffmann Debra Hamilton Michael Nelson Jeannie Aschkenasy Angela John Thurman Expressive language sampling as a source of outcome measures for treatment studies in fragile X syndrome: feasibility, practice effects, test-retest reliability, and construct validity Journal of Neurodevelopmental Disorders Outcome measures Clinical trials treatment Expressive language Fragile X syndrome Psychometrics |
author_facet |
Leonard Abbeduto Elizabeth Berry-Kravis Audra Sterling Stephanie Sherman Jamie O. Edgin Andrea McDuffie Anne Hoffmann Debra Hamilton Michael Nelson Jeannie Aschkenasy Angela John Thurman |
author_sort |
Leonard Abbeduto |
title |
Expressive language sampling as a source of outcome measures for treatment studies in fragile X syndrome: feasibility, practice effects, test-retest reliability, and construct validity |
title_short |
Expressive language sampling as a source of outcome measures for treatment studies in fragile X syndrome: feasibility, practice effects, test-retest reliability, and construct validity |
title_full |
Expressive language sampling as a source of outcome measures for treatment studies in fragile X syndrome: feasibility, practice effects, test-retest reliability, and construct validity |
title_fullStr |
Expressive language sampling as a source of outcome measures for treatment studies in fragile X syndrome: feasibility, practice effects, test-retest reliability, and construct validity |
title_full_unstemmed |
Expressive language sampling as a source of outcome measures for treatment studies in fragile X syndrome: feasibility, practice effects, test-retest reliability, and construct validity |
title_sort |
expressive language sampling as a source of outcome measures for treatment studies in fragile x syndrome: feasibility, practice effects, test-retest reliability, and construct validity |
publisher |
BMC |
series |
Journal of Neurodevelopmental Disorders |
issn |
1866-1947 1866-1955 |
publishDate |
2020-03-01 |
description |
Abstract Background The evaluation of treatment efficacy for individuals with fragile X syndrome (FXS) or intellectual disability (ID) more generally has been hampered by the lack of adequate outcome measures. We evaluated expressive language sampling (ELS) as a procedure for generating outcome measures for treatment research in FXS. We addressed: (a) feasibility, (b) practice effects over two administrations, (c) test-retest reliability over the repeated administrations, and (d) construct validity. We addressed these issues for the full sample as well as for subgroups defined by age, IQ, and ASD status. Methods Participants were 106 individuals with FXS between ages 6 and 23 years who had IQs within the range of intellectual disability (IQ < 70). ELS procedures for collecting samples in conversation and narration were followed and analyzed separately. Five measures were derived from transcripts segmented into C-units (i.e., an independent clause and its modifiers): number of C-units per minute (talkativeness), number of different word roots (vocabulary), C-unit length in morphemes (syntax), percentage of C-units containing dysfluency (utterance planning), and percentage of C-units that were fully or partly unintelligible (articulatory quality). ELS procedures were administered twice at 4-week intervals for each participant. Standardized tests and informant reports were administered and provided measures for evaluating construct validity of ELS measures. Results We found low rates of noncompliance, suggesting the task can be completed meaningfully by most individuals with FXS, although noncompliance was higher for younger, lower IQ, and more autistic participants. Minimal practice effects and strong test-retest reliability over the 4-week interval were observed for the full sample and across the range of ages, IQs, and autism symptom severity. Evidence of convergent construct validity was observed for the measures of vocabulary, syntax, and unintelligibility for the full sample and across the range of IQ and autism symptom severity, but not for participants under age 12. Conversation and narration yielded largely similar results in all analyses. Conclusions The findings suggest that the ELS procedures are feasible and yield measures with adequate psychometric properties for a majority of 6 to 23 years with FXS who have ID. The procedures work equally well regardless of level of ID or degree of ASD severity. The procedures, however, are more challenging and have somewhat less adequate psychometric properties for individuals with FXS under age 12. |
topic |
Outcome measures Clinical trials treatment Expressive language Fragile X syndrome Psychometrics |
url |
http://link.springer.com/article/10.1186/s11689-020-09313-6 |
work_keys_str_mv |
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doaj-568cea0ff36648b89d50b89940503a152020-11-25T00:47:16ZengBMCJournal of Neurodevelopmental Disorders1866-19471866-19552020-03-0112112310.1186/s11689-020-09313-6Expressive language sampling as a source of outcome measures for treatment studies in fragile X syndrome: feasibility, practice effects, test-retest reliability, and construct validityLeonard Abbeduto0Elizabeth Berry-Kravis1Audra Sterling2Stephanie Sherman3Jamie O. Edgin4Andrea McDuffie5Anne Hoffmann6Debra Hamilton7Michael Nelson8Jeannie Aschkenasy9Angela John Thurman10UC Davis MIND Institute and Department of Psychiatry and Behavioral Sciences, University of CaliforniaDepartments of Pediatrics, Neurological Sciences and Biochemistry, Rush University Medical CenterWaisman Center and Department of Communication Sciences and Disorders, University of Wisconsin-MadisonDepartment of Human Genetics, Emory UniversityDepartment of Psychology, University of ArizonaUC Davis MIND Institute and Department of Psychiatry and Behavioral Sciences, University of CaliforniaDepartments of Pediatrics, Neurological Sciences and Biochemistry, Rush University Medical CenterDepartment of Human Genetics, Emory UniversityDepartments of Pediatrics, Neurological Sciences and Biochemistry, Rush University Medical CenterDepartments of Pediatrics, Neurological Sciences and Biochemistry, Rush University Medical CenterUC Davis MIND Institute and Department of Psychiatry and Behavioral Sciences, University of CaliforniaAbstract Background The evaluation of treatment efficacy for individuals with fragile X syndrome (FXS) or intellectual disability (ID) more generally has been hampered by the lack of adequate outcome measures. We evaluated expressive language sampling (ELS) as a procedure for generating outcome measures for treatment research in FXS. We addressed: (a) feasibility, (b) practice effects over two administrations, (c) test-retest reliability over the repeated administrations, and (d) construct validity. We addressed these issues for the full sample as well as for subgroups defined by age, IQ, and ASD status. Methods Participants were 106 individuals with FXS between ages 6 and 23 years who had IQs within the range of intellectual disability (IQ < 70). ELS procedures for collecting samples in conversation and narration were followed and analyzed separately. Five measures were derived from transcripts segmented into C-units (i.e., an independent clause and its modifiers): number of C-units per minute (talkativeness), number of different word roots (vocabulary), C-unit length in morphemes (syntax), percentage of C-units containing dysfluency (utterance planning), and percentage of C-units that were fully or partly unintelligible (articulatory quality). ELS procedures were administered twice at 4-week intervals for each participant. Standardized tests and informant reports were administered and provided measures for evaluating construct validity of ELS measures. Results We found low rates of noncompliance, suggesting the task can be completed meaningfully by most individuals with FXS, although noncompliance was higher for younger, lower IQ, and more autistic participants. Minimal practice effects and strong test-retest reliability over the 4-week interval were observed for the full sample and across the range of ages, IQs, and autism symptom severity. Evidence of convergent construct validity was observed for the measures of vocabulary, syntax, and unintelligibility for the full sample and across the range of IQ and autism symptom severity, but not for participants under age 12. Conversation and narration yielded largely similar results in all analyses. Conclusions The findings suggest that the ELS procedures are feasible and yield measures with adequate psychometric properties for a majority of 6 to 23 years with FXS who have ID. The procedures work equally well regardless of level of ID or degree of ASD severity. The procedures, however, are more challenging and have somewhat less adequate psychometric properties for individuals with FXS under age 12.http://link.springer.com/article/10.1186/s11689-020-09313-6Outcome measuresClinical trialstreatmentExpressive languageFragile X syndromePsychometrics |