Early predictors of language outcomes in Down syndrome: A mini-review

Clarifying the developmental association between gesture and later vocabulary for autistic children

Gestures serve as both a communication and a word-learning tool, with typically developing children consistently showing that early gestures are positively associated with later vocabulary skills. However, many autistic children experience delays and challenges in both gesture and vocabulary skills, and studies also show mixed gesture-vocabulary associations; thus, it is unclear whether gestures in autistic children support emerging vocabulary skills. To address previous conflicting findings, the current conceptual replication study uses linear models with a large sample (N = 451) of 12- to 24-month-old English-raised infants to investigate whether gestures are associated with expressive and receptive vocabulary. Using the infant-sibling design, gesture-vocabulary associations and group moderation were investigated in three groups: infant-siblings of autistic children who later meet the criteria for autism themselves (HL-ASD, n = 73), infant-siblings who did not meet criteria for autism (HL-Neg, n = 238), and a control group without a family history of autism (LL-Neg, n = 140). Both LL-Neg and HL-ASD groups showed positive associations between 12-month gestures and 18-month receptive vocabulary; however, only the LL-Neg group showed a positive association between 12-month gestures and 18-month expressive vocabulary. For 12-month gestures and 24-month receptive and expressive vocabulary, the LL-Neg and HL-Neg groups showed positive association, whereas the HL-ASD group did not. Similarly, the LL-Neg and HL-Neg groups showed positive associations between 18-month gestures and 24-month vocabulary, but the HL-ASD did not. Overall, the LL-Neg group showed significant gesture-vocabulary associations across all tested models, while the HL-ASD only showed one significant positive association.

[Inequalities in time to diagnosis of Down Syndrome in Bolivia]

Down Syndrome is the most common genetic condition and a leading cause of intellectual disability. Individuals in rural areas, particularly those with disabilities, often face disparities in healthcare access. Analyzing clinical records of patients diagnosed with Down Syndrome between 2013 and 2022 by the Institute of Genetics at the Universidad Mayor de San Andrés in La Paz, Bolivia, this study examined the time to diagnosis for 250 patients with Down Syndrome. The findings revealed that patients from rural areas with Down Syndrome take an average of five months to receive a diagnosis, compared to two months in urban areas (p<0.001). No significant differences were found in the time to diagnosis based on gender. However, a higher proportion of males from rural areas was observed (p=0.03). The results suggest that individuals in rural areas face challenges in receiving a timely diagnosis. On the other hand, women may not be brought to cities for proper diagnosis and treatment due to gender biases in certain communities. The importance of improving access to early diagnosis and treatment in rural areas is emphasized.

Cross-Sectional Analysis of Caregiver-Reported Expressive Language Profiles and Associated Covariates in Individuals with Down Syndrome

OBJECTIVE

To describe the distribution of expressive language abilities of individuals with Down syndrome (DS) in a clinical sample and characterize demographic, environmental, and medical factors associated with varying expressive language profiles.

METHODS

Cross-sectional analysis was completed on a sample of 345 individuals with DS between the ages of 4 and 22 years who were enrolled into a longitudinal clinical database between March 2018 and August 2021. Expressive language-related items on a standardized caregiver-reported questionnaire assessing domains of functioning in neurodevelopmental disorders were used to conduct latent variable modeling and determine caregiver-reported expressive language (CREL) classes across the sample. Linear regression was used to explore associations between CREL classes and predictor variables.

RESULTS

Latent variable modeling revealed 3 distinct classes of CREL abilities representing higher, middle, and lower CREL. Individuals in the lower CREL class were more likely to be female, to use sign language or visual communication systems, have reduced pronunciation, attend private or residential school, and to be in a substantially separate classroom. Membership was not predicted by complex medical histories or co-occurring neurodevelopmental diagnoses.

CONCLUSION

Caregiver-reported expressive language abilities in a cohort of individuals with DS were variable, with most of the individuals belonging to higher or middle CREL classes, relative to one another. Additional studies are indicated to understand factors that predict higher expressive language ability and explore how to direct services to individuals who are at risk of more profound language delays.