Summary: Measuring and monitoring the circumference of a preterm baby’s head could help to predict intelligence later in life and identify potential neurocognitive problems. Researchers report faster head growth is linked to higher IQ scores at age 26.
Source: University of Warwick.
Regular measurements of head circumference of very preterm and full-term babies from an early age add valuable information when screening for long-term neurocognitive risk according to researchers from the University of Warwick and University of Tennessee, Knoxville.
Very Preterm (VP) and Very Low Birth Weight (VLBW) infants have smaller heads at birth, and therefore smaller brains, but measuring their head growth helps monitor risks to their brain growth and future IQ.
Regular early head circumference assessments add valuable information when screening for long-term neurocognitive risk – according to new research by an international research collaboration, including the University of Warwick, UK and the University of Tennessee Knoxville, US.
The researchers found that a method as simple and cost effective as frequently measuring head size adds valuable information when screening for long-term neurocognitive risk.
The research published in Journal of the International Neuropsychological Society examined the development of children who are born very preterm and/or very low birth weight who tend to have a lower head circumference at birth, and if their heads don’t grow sufficiently their IQ development might be impaired.
203 VP/VLBW (under 32 weeks gestational age and/or under 1500g) and 198 term born children (between 37 and 41 weeks gestation) were followed in Germany born in 1985-6 into adulthood.
Co-researchers Dr Dieter Wolke and Dr Julia Jaekel measured the head circumference at birth, 5 months, 20 months and 4 years of age. Intelligence was assessed with standardised tests in childhood – 6 and 8 years, and at 26 years.
They found that VP and VLBW infants had smaller heads at birth, but between birth and 20 months their heads grew relatively faster than that of term born children because they had to catch up.
Professor Dieter Wolke, from the Department of Psychology and Warwick Medical School at the University of Warwick is a senior author in the report, ‘Head growth and intelligence from birth to adulthood in very preterm and term born individuals.’ He comments:
“Measuring head circumference and thus head growth in early childhood is a proxy measure of brain volume growth in early childhood. It is simple and cheap to do and as shown in our research, slow head growth is a specific warning sign for potential neurocognitive problems.”
Dr Julia Jaekel, the first author from the University of Tennessee said:
“Those who showed faster head growth, whether preterm or term born, had higher intelligence scores at 26 years. Catch-up head growth was particularly beneficial for intelligence scores in VP and VLBW children. It was a better predictor than how early or at what birth weight infants were born.”
This research shows that head growth is a proxy measure of brain volume growth and is linked with long-term cognitive development. Monitoring the development of head growth, in particular in VP and VLBW infants, assists in the assessment of neurocognitive risks later in life.
The next step for researchers is to investigate how to assist with head growth and thus brain development in VP and VLBW children. Some of these targets for improvement are nutrition and eating, neuro-protective treatments, and appropriate cognitive and emotional stimulation as brain food.
Source: Alice Scott – University of Warwick
Publisher: Organized by NeuroscienceNews.com.
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Original Research: Abstract for “Head Growth and Intelligence from Birth to Adulthood in Very Preterm and Term Born Individuals” by Julia Jaekel, Christian Sorg, Josef Baeuml, Peter Bartmann, and Dieter Wolke in Journal of the International Neuropsychological Society. Published November 14 2018.
Head Growth and Intelligence from Birth to Adulthood in Very Preterm and Term Born Individuals
Objectives: The aim of this study was to investigate the effects of infant and toddler head growth on intelligence scores from early childhood to adulthood in very preterm (<32 weeks gestational age; VP) and/or very low birth weight (<1500 g; VLBW) and term born individuals.
Methods: 203 VP/VLBW and 198 term comparisons were studied from birth to adulthood as part of the prospective geographically defined Bavarian Longitudinal Study (BLS). Head circumference was assessed at birth; 5, 20 months; and 4 years of age. Intelligence was assessed with standardized tests in childhood (6 and 8 years: K-ABC) and at 26 years (Wechsler Adult Intelligence Scale, WAIS). Structural equation modeling (SEM) was used to model the effect of head growth on IQ.
Results: On average, VP/VLBW had lower head circumference at birth (27.61 cm vs. 35.11 cm, mean difference 7.49, 95% confidence interval [7.09–7.90]) and lower adult intelligence scores (88.98 vs. 102.54, mean difference 13.56 [10.59–16.53]) than term born comparison individuals. Head circumference at birth (e.g., total effect β=.48; p<.001 for adult IQ) and head growth in childhood predicted intelligence development from age 6 to 26 years in both VP/VLBW and term born individuals (70% of variance in adult IQ explained by full model). Effects of gestation and birth weight on intelligence were fully mediated by head circumference and growth.
Conclusions: This longitudinal investigation from birth to adulthood indicates head growth as a proxy of brain development and intelligence. Repeated early head circumference assessment adds valuable information when screening for long-term neurocognitive risk.