Quantifying positional plagiocephaly: reliability and validity of anthropometric measurements

Area of Science:

• Pediatric medicine
• Biomedical engineering
• Clinical measurement

Background:

• Positional plagiocephaly treatment is debated due to the absence of reliable methods to measure its severity.
• Anthropometric measurements, specifically caliper measurements of cranial vault asymmetry (CVA), are proposed for quantifying plagiocephaly.
• Standardized and validated measurement tools are crucial for research on plagiocephaly's natural history and intervention effectiveness.

Purpose of the Study:

• To investigate the reliability and validity of anthropometric measurements (CVA) for assessing positional plagiocephaly.
• To evaluate the inter-rater and intrarater reliability of CVA measurements and assigned severity categories.
• To compare CVA measurements with visual analysis scores for correlation.

Main Methods:

• Two clinicians independently measured CVA using calipers on infants referred for plagiocephaly or torticollis.
• An observer recorded visual analysis scores during the same clinical visits.
• CVA scores were categorized into normal (<3 mm), mild/moderate (≤12 mm), and moderate/severe (>12 mm) severity levels.

Main Results:

• Intrarater reliability for CVA measurements was high (kappa = 0.98, 0.99).
• Inter-rater reliability for CVA measurements was poor (kappa = 0.42).
• Inter-rater reliability for severity categories was poor (kappa = 0.28) and showed no correlation with visual analysis (kappa = 0.31).

Conclusions:

• Current anthropometric CVA measurement methods demonstrate poor inter-rater reliability, limiting their clinical utility for positional plagiocephaly.
• A more stable and meaningful measurement system is required for reliable assessment of plagiocephaly severity and treatment efficacy.
• Further research is needed to develop validated tools for objective plagiocephaly assessment.