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Follow-up of the babies in the INTERGROWTH-21st project


Text prepared by Sandy Savini

Neurodevelopmental follow-up of babies from the original INTERGROWTH-21st study and its extension, INTERBIO-21st, are currently ongoing.

The INTERGROWTH-21st Project Neurodevelopment Package

Following the construction of the new international fetal and newborn growth standards, the INTERGROWTH-21st Consortium has expanded their interest to the neurodevelopment of the infants participating in the project. The aim was to improve the current understanding of neurodevelopment trajectories by including an assessment at 24 months on the international sample of children from the INTERGROWTH-21st Project. The objectives of the neurodevelopment assessment were to:

  1. Profile neurodevelopment outcomes in all key dimensions in geographically and culturally diverse populations
  2. Profile neurodevelopment in children born at term, between ≥34+0 and <37+0 weeks, and between 26+0 and 33+6 weeks
  3. Examine the associations between intra-uterine growth trajectories and neurodevelopment

When designing the methodology of the study, the main problem encountered was the lack of an appropriate tool to assess multiple domains of neurodevelopment. As a result, the INTERGROWTH-21st Project team decided to develop and test a novel, mixed methodology, global approach for the assessment of neurodevelopment in young children which would be quick and easy to administer by non-specialist research staff in both high and low resource settings.

After a review of existing psychometric tools to assess neurodevelopment at 24 months, and consultation with child development experts and authors of child psychometric measures, the INTERGROWTH-21st Neurodevelopment Package was created. This package measures multiple dimensions of neurodevelopment at 24 months by using a combination of psychological, clinical and electrophysiological tests. These include tests of visual acuity and contrast sensitivity (the Cardiff tests); a measure of cognition, language, motor skills, behaviour, attention and emotional reactivity (the INTER-NDA); a test of cortical auditory processing (by measuring auditory ERPs to a novelty odd-ball paradigm); and a measure of sleep patterns and daytime physical activity (actigraphy and sleep questionnaire adapted from the Brief Infant Sleep Questionnaire). The package takes between 35 to 45 minutes to administer, and has been implemented in five study sites (Brazil, India, Italy, Kenya and the UK) where more than 500 children have been assessed to date.

The INTERGROWTH-21st Project Neurodevelopment Package Standardisation

As with all parts of the INTERGROWTH-21st Project, to achieve uniformity in such a large multicentre study, it is important for all study sites to follow the same standardised assessment procedures to ensure maximal validity of the resulting indicators of neurodevelopment.

For this to be achieved a standardisation protocol was created to determine each individual neurodevelopment assessor’s adherence to the Neurodevelopment Manuals. The standardisation protocols implemented at each study site worldwide will ensure that the neurodevelopment data collected are of the highest quality to construct an international neurodevelopment profile of 24 month old children.

The standardisation of the Neurodevelopmental follow-up of the INTERGROWTH-21st Project is currently ongoing. The protocol will be released in August 2014. Please continue to check this website for the latest updates. 

The INTERBIO-21st Study

Information about INTERBIO-21st is available here.