Applying Dutch and US versions of the BSID-II in Dutch children born preterm leads to different outcomes

Area of Science:

• Developmental Psychology
• Pediatric Neurodevelopment
• Psychometrics

Background:

• Accurate assessment of infant development is crucial for early intervention.
• The Bayley Scales of Infant Development-2nd edition (BSID-II) is a widely used tool for evaluating developmental outcomes.
• Cross-cultural application of standardized tests requires careful consideration of normative data.

Purpose of the Study:

• To compare developmental outcomes in preterm infants using Dutch versus US test procedures and norms of the BSID-II.
• To identify potential discrepancies in developmental scores attributed to differing normative data.
• To evaluate the clinical relevance of observed Dutch-US differences in BSID-II scores.

Main Methods:

• Administered the BSID-II to 376 preterm infants at corrected ages of 6, 12, 24, and 36 months.
• Calculated raw scores using both US and Dutch test procedures.
• Compared raw scores, Mental Developmental Index (MDI), and Psychomotor Developmental Index (PDI) using Dutch versus US normative data.

Main Results:

• Small but statistically significant differences were found between Dutch and US raw scores.
• Large, clinically relevant differences were observed in MDI and PDI scores, especially at 6 and 12 months.
• Differences suggest potential bias in Dutch normative data or a slower developmental pace in Dutch children.

Conclusions:

• Applying international developmental tests with local standardization may yield clinically significant discrepancies.
• The study highlights challenges in using tests developed in one country for another, even with local norms.
• Potential bias in normative data necessitates careful interpretation of developmental assessments across different populations.