Early motor and pre-linguistic verbal development in Prader-Willi syndrome - A case report.
In Prader-Willi syndrome, absent fidgety movements and missing canonical babble before six months are early warning signs.
01Research in Context
What this study did
Doctors filmed one baby with Prader-Willi syndrome every week from birth to six months.
They scored the baby’s general movements and counted any canonical babble sounds like “ba” or “ga.”
What they found
The baby never showed normal “fidgety” arm and leg waves.
No canonical babble appeared by six months.
Both signs point to early brain wiring problems before most parents notice delays.
How this fits with other research
de Campos et al. (2012) reviewed 18 papers and found every risk group shows its own movement style. The PWS case adds the missing genetic piece to that map.
Myers et al. (2018) tracked Down syndrome infants and saw that joint-attention, not babble, predicted later language. In PWS the babble is absent, so the red flag differs by syndrome.
Fusaroli et al. (2022) pooled autism voice data and found small pitch differences. The PWS infant had no canonical sounds at all, showing silence can be a louder alarm than odd sounds.
Why it matters
You can spot PWS risk in the first half-year. If you see flat, stiff movements and no repetitive babble by 3–4 months, refer for early intervention even before genetic tests return.
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02At a glance
03Original abstract
BACKGROUND: Prader-Willi syndrome (PWS) is a rare genetic disorder. Infants with PWS show a neurodevelopmental dysfunction which entails a delayed motor and language development, but studies on their spontaneous movements (i.e. general movements) or pre-linguistic speech-language development before 6 months of age are missing so far. AIM: To describe early motor and pre-linguistic verbal development in an infant with PWS. METHODS AND PROCEDURES: Prospective case report; in addition to the assessment of general movements and the concurrent movement repertoire, we report on early verbal forms, applying the Stark Assessment of Early Vocal Development-Revised. OUTCOMES AND RESULTS: General movements were abnormal on days 8 and 15. No fidgety movements were observed at 11 weeks; they only emerged at 17 weeks and lasted until at least 27 weeks post-term. The movement character was monotonous, and early motor milestones were only achieved with a delay. At 27 weeks the infant produced age-adequate types of vocalisations. However, none of the canonical-syllable vocalisations that typically emerge at that age were observed. Early vocalisations appeared monotonous and with a peculiarly harmonic structure. CONCLUSIONS AND IMPLICATIONS: Early motor and pre-linguistic verbal behaviours were monotonous in an infant with PWS throughout his first 6 months of life. This suggests that early signs of neurodevelopmental dysfunction (i.e. abnormal general movements) might already be diagnosed in infants with PWS during their first weeks of life, potentially enabling us to diagnose and intervene at an early stage.
Research in developmental disabilities, 2019 · doi:10.1016/j.ridd.2019.01.012