Expressive language development in adolescents with Down syndrome and fragile X syndrome: change over time and the role of family-related factors

Laura Del Hoyo Soriano,Sara T Kover,Angela John Thurman,Leonard Abbeduto,Danielle Harvey

doi:10.1186/s11689-020-09320-7

Laura Del Hoyo Soriano, Sara T Kover + Show 3 more

Open Access

https://doi.org/10.1186/s11689-020-09320-7

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Abstract

BackgroundIt is well known that individuals with Down syndrome (DS) or fragile X syndrome (FXS) demonstrate expressive language difficulties beginning early in childhood. It is less clear, however, whether expressive language skills change during the adolescent period in these individuals, and if any of these changes are syndrome specific. Studying this, as well as the role of maternal and family-related factors in expressive language development, may provide the foundation for efficacious interventions for adolescents with DS or FXS.MethodsIn this study, we examined expressive language trajectories, assessed through conversation and narration, in 57 adolescent males with intellectual disability (ID) (20 DS and 37 FXS) in relation to the diagnostic group (DS vs. FXS) and family-related factors (maternal IQ, maternal psychological distress, closeness in the mother–child relationship, family income, and maternal and paternal education) after adjusting for chronological age (CA) and nonverbal cognition.ResultsChanges over repeated annual assessments for males with DS or FXS were observed only during conversation, such as an increase in talkativeness, but a decrease in syntax complexity and lexical diversity. We found a diagnosis-related effect in the change over time in conversational talkativeness favoring those with FXS. Finally, a closer mother–child relationship predicted less decrease over time in lexical diversity during conversation, and participants of mothers who graduated college showed a greater increase in conversational talkativeness over time compared to those of mothers with a high school education.ConclusionsOur results suggest that, during the adolescent period for males with DS or FXS, there is an increase in the amount of talk produced in conversational contexts, but also a decrease in the quality of the language produced. In addition, our results indicate syndrome-specificity for aspects of expressive language development and reinforce the protective role of family-related factors.

Highlights

Down syndrome (DS) and fragile X syndrome (FXS) are the two most common genetic causes of intellectual disability (ID)
We focused on understanding the expressive language development of males with ID associated with DS or FXS, with an emphasis on both common and unique developmental patterns and mechanisms
We used naturalistic conversation and narration language sampling techniques in a longitudinal design and computed these diverse measures of expressive language performance in verbal individuals with ID associated with DS and with FXS

Summary

Introduction

Down syndrome (DS) and fragile X syndrome (FXS) are the two most common genetic causes of intellectual disability (ID). We focused on understanding the expressive language development of males with ID associated with DS or FXS, with an emphasis on both common and unique developmental patterns and mechanisms. It is well known that individuals with Down syndrome (DS) or fragile X syndrome (FXS) demonstrate expressive language difficulties beginning early in childhood. It is less clear, whether expressive language skills change during the adolescent period in these individuals, and if any of these changes are syndrome specific. As well as the role of maternal and family-related factors in expressive language development, may provide the foundation for efficacious interventions for adolescents with DS or FXS

Results

Discussion

Conclusion