A Retrospective Video Analysis of Canonical Babbling and Volubility in Infants with Fragile X Syndrome at 9-12 Months of Age.
Katie Belardi, Linda R Watson, Richard A Faldowski and 6 others
PMID 28247019WHAT IT FOUND
In home videos at 9 to 12 months, none of 10 infants later diagnosed with fragile X met the usual babbling stage, while 8 of 14 typical infants did.
They also vocalized less. This may help flag early language risk, but it does not diagnose.
Key findings
01At 9 to 12 months, 0 of 10 infants with fragile X met the canonical babbling criterion, while 8 of 14 infants with typical development did.
02The median canonical babbling ratio was .03 for infants with fragile X and .16 for infants with typical development.
03The median total volubility was 31.5 syllables for infants with fragile X and 54.0 syllables for infants with typical development.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study had only 10 infants with fragile X and 14 typical infants, and it was powered to detect a very large effect size of 1.06. The videos were home recordings, not controlled laboratory samples, and only 10 minutes of vocal behavior were examined. Six of the 14 typical infants did not meet the .15 canonical babbling criterion, so failure to meet the criterion was not specific to fragile X. The fragile X videos had fewer total events and marginally more physical restriction than the typical videos, and the fragile X group was older on average, though not significantly. Only one female was in the fragile X group, so sex differences could not be assessed. Infants with both fragile X and autism spectrum disorder were excluded, so the findings may not represent all infants with fragile X.
The easy way to misread this
Do not read an infant not meeting the babbling criterion at 9 to 12 months as proof of fragile X. Six of the 14 typical infants also did not meet the criterion, and the study had only 10 infants with fragile X.