Language Development From Early Childhood to Adolescence in Youths With Fragile X Syndrome.
Nancy C Brady, Kandace Fleming, Shelley L Bredin-Oja and 2 others
PMID 33002370WHAT IT FOUND
For adolescents with Fragile X Syndrome, maternal commenting is linked to growth in vocabulary but not sentence length.
While vocabulary continues to expand, syntax remains flat. Therapists should support responsive interaction for vocabulary gains but use direct instruction to target complex grammar.
Key findings
01Maternal commenting rates were positively associated with growth in receptive vocabulary (PPVT-4) and the rate of different words used by the child, but did not predict changes in mean length of utterance (MLU) or expressive vocabulary (EVT-2).
02Language growth trajectories differed by measure: receptive vocabulary and rate of different words showed continued growth into adolescence, whereas mean length of utterance (MLU) showed no significant change from age 10, indicating persistent syntax deficits.
03Nonverbal IQ was a significant predictor for all language outcomes, with higher IQ associated with higher baseline scores and steeper growth trajectories for vocabulary measures.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The sample size for girls was small (11), preventing separate statistical modeling for sex differences, though descriptive trends suggested girls had higher standardized test scores. Data collection spanned a long period with gaps between childhood and adolescent visits (mean 76.91 months), which may affect the continuity of trajectory modeling. Language samples were limited to a single context (snack preparation) to maintain consistency over time, which may restrict the range of vocabulary and syntax observed compared to more diverse contexts. The study did not examine pragmatic language skills or grammaticality in detail, focusing instead on length and vocabulary measures.
Declared interests
The study was supported by National Institute of Child Health and Human Development Grants. No conflicts of interest are reported in the provided text.
The easy way to misread this
Do not assume that increasing maternal responsivity will improve sentence length or grammatical complexity. The study found that while commenting predicted vocabulary growth, it had no association with mean length of utterance (MLU), suggesting syntax requires different, more direct intervention strategies.