Relationship Between Perinatal and Neonatal Indices and Intelligence Quotient in Very Low Birth Weight Infants at the Age of 6 or 8 Years

Background

The majority of children born with very low birth weight (VLBW; < 1500 g) enter mainstream schools. They experience significant neurodevelopmental disabilities during childhood. The specific aims of our study were to evaluate the neonatal outcomes of VLBW infants and whether they would influence intelligence quotient (IQ), cognitive function and learning disabilities at the age of 6 or 8 years.

Methods

We enrolled VLBW neonates who weighed less than 1500 g and who were delivered at Shin-Kong Wu Ho-Su Memorial Hospital in 1996 and 1999. The psychological assessments were applied with the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) for age 6 and Wechsler Intelligence Scale for Children-Third Edition (WISC-III) for age 8. We recorded their demographic data, ventilation duration by days, length of stay, use of surfactant, respiratory distress syndrome (RDS), and other complications.

Results

According to whether the full scale intelligence quotient (FSIQ) was above or below the average score (FSIQ = 90), we divided VLBW children into two groups (< 90, n = 17; ≥ 90, n = 21). The children with lower gestational age had lower FSIQ (p = 0.013). The higher FSIQ group (≥ 90) showed more prenatal steroid use (5/17, 29.4% vs. 14/21, 66.7%; p = 0.049). There were more boys in the lower FSIQ group (< 90, 13/17, 76.5% vs. ≥90, 7/21, 33.3%; p = 0.011). The average IQ scores were 78.11 ± 9.05 and 102.57 ± 8.89 in the FSIQ < 90 and FSIQ < 90 groups, respectively. The groups were similar in ventilation duration by days, use of surfactant, frequency of sepsis, RDS, bronchopulmonary dysplasia, patent ductus arteriosus, intraventricular hemorrhage and retinopathy of prematurity.

Conclusion

Conclusion: In our study, the children with lower gestational age had lower FSIQ. There was no significant association between small for gestational age and IQ performance. The neonatal outcomes of VLBW infants did have less impact on IQ performance later in life.

KEY WORDS:  full scale intelligence quotient , very low birth weight , Wechsler Intelligence Scale for Children-Third Edition , Wechsler Preschool and Primary Scale of Intelligence

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