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

Abstract

Background: 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, 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. Methods: In 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 motherchild relationship, family income, and maternal and paternal education) after adjusting for chronological age (CA) and nonverbal cognition. Results: Changes 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. Conclusions: Our 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.

Molecular convergence between Down syndrome and fragile X syndrome identified using human pluripotent stem cell models

“…In most cases FXS is driven by a tri-nucleotide repeat expansion in the 5 0 UTR of the fragile X messenger ribonucleoprotein 1 (FMR1) gene, which leads to epigenetic silencing and complete loss of the encoded RNA binding protein FMRP (Bagni et al, 2012;Darnell et al, 2011;Dictenberg et al, 2008). While both DS and FXS are characterized by broad phenotypic variability, patients with DS and FXS share intellectual disability and deficits in expressive communication, as well as increased rates of autism, seizure disorders, and mental health disorders compared with the general population (Capone et al, 2006;Del Hoyo Soriano et al, 2020;Finestack et al, 2009;Jensen and Bulova, 2014;Martin et al, 2009;Tranfaglia, 2012). Other phenotypes diverge; unlike patients with FXS, patients with DS are at increased risk for childhood leukemias and DS is one of the most common genetic causes of early-onset Alzheimer's disease (Mateos et al, 2015;Tcw and Goate, 2017).…”

Using Telehealth-Delivered Procedures to Collect a Parent-Implemented Expressive Language Sampling Narrative Task in Monolingual and Bilingual Families With Autism Spectrum Disorder: A Pilot Study

“…(19,20). In addition, the ELS-N procedures can distinguish between language profiles on specific neurodevelopmental populations (21) and capture change over time (22). For all these reasons, the ELS-N task has been proposed as a potential outcome measure for clinical trials involving individuals with intellectual and developmental disabilities (23)(24)(25) and has been used in several clinical trials for these populations (e.g., Protocol Neu-2566-FXS-001; A Safety Study of NNZ-2566 in Patients With Fragile X Syndrome, 2013-2017).…”

The association between expressive language skills and adaptive behavior in individuals with Down syndrome

“…More specifically, when compared either to individuals with typical development (TD) or with other neurodevelopmental disabilities (NDDs) of similar mental ages (MAs), individuals with DS demonstrate, as a group, relative strengths in the areas of nonverbal communication, gross motor skills, visual motor integration, and visual imitation 4,5 . In contrast, auditory short-term memory, episodic memory, aspects of visuospatial construction and executive function, and language are areas that are particularly challenging for individuals with DS [6][7][8][9][10][11][12] .Language skills constitute one of the most impaired aspects of the cognitive profile of individuals with DS. Research has also shown, however, that within the area of language some aspects are generally more affected than others among those with DS 9 .…”

“…Indeed, there is considerable research documenting that multiple areas of expressive language lag behind MA expectations [13][14][15] . For example, individuals with DS score less well on measures of vocabulary and syntax when compared to younger TD peers 10,[16][17][18][19] and similarlyaged peers with other developmental disabilities, both matched on MA 17,20,21 . There is also evidence suggesting that expressive syntax skills are more impaired than are expressive vocabulary skills in individuals with DS 22 as expressive syntax appears to lag relative to both nonverbal cognition and vocabulary level-expectations [13][14][15]23,24 .…”

“…For example, individuals with DS score less well on measures of vocabulary and syntax when compared to younger TD peers 10,[16][17][18][19] and similarlyaged peers with other developmental disabilities, both matched on MA 17,20,21 . There is also evidence suggesting that expressive syntax skills are more impaired than are expressive vocabulary skills in individuals with DS 22 as expressive syntax appears to lag relative to both nonverbal cognition and vocabulary level-expectations [13][14][15]23,24 . Therefore, severity of impairment also varies across different areas of expressive language in DS.…”