Year: 2020

First study to use automated eye tracking to measure developmental outcomes of a nutrition trial

Eye tracking image

A paper just published in the Journal of Nutrition reports the first study to use automated eye tracking to measure infant developmental outcomes of a nutrition randomized trial. Effects of early nutrition on infant neurobehavioral development are typically measured using assessment of behavioral milestones, such as crawling and saying words. These assessments may not be highly sensitive to individual differences between children because there is a wide range of variability in the age children attain these milestones that is normal. Children’s scores on these types of measures during the first two years after birth are not strongly correlated with children’s later cognitive abilities.

Woman holding child for eye tracking

Measures of infant looking behavior may be more sensitive than measures based on milestone attainment. Infants’ eye gazes provide meaningful information about their cognitive processing. For example, an infant’s novelty preference, demonstrated by looking longer at a new picture compared to a previously seen picture, shows that the infant remembers the previously seen picture. Automated eye trackers detect the gaze focal point using an infrared light source and a set of cameras that capture the light reflected from the cornea. Recent advances have made this technology more feasible for use in low- and middle-income country settings. In this study, we used automated eye tracking to assess infant cognition in Malawi, in combination with commonly-used developmental assessments based on acquisition of behavioral milestones.

Eye tracking tool

The trial was designed to test whether feeding children eggs during the complementary feeding period improves growth and development and was funded by the Bill & Melinda Gates Foundation. The trial was led by Dr. Christine Stewart at the UC Davis Institute for Global Nutrition and Dr. Kenneth Maleta at the University of Malawi College of Medicine, with the developmental outcomes led by Dr. Elizabeth Prado at the UC Davis Institute for Global Nutrition in collaboration with Dr. Lisa Oakes at the UC Davis Center for Mind and Brain.

Mazira Project Logo

Eggs are nutrient-rich foods, which have been found to promote child growth in Ecuador. We enrolled 660 children age 6-9 months in rural Malawi and randomly assigned half of the children to the intervention group, who received seven eggs per week for the study child and seven eggs per week for the household, and half of the children to the control group, who did not receive eggs. After six months, we did not find any differences between the group who received eggs and the control group in attention, memory, language, motor, or personal-social skills, except a smaller percentage of children who received eggs had delayed fine motor skills, such as picking up small objects with their fingers. This study highlights that positive effects of egg interventions may be found in some contexts but not others, which should be considered when deciding whether to invest in programs to promote child egg consumption. Although we did not find effects of the intervention on the eye-tracking measures, we successfully obtained usable data from 60% of targeted children at age 6-9 months and 72% of targeted children at age 12-15 months. These success rates were obtained in the context of a full day of data collection and project activities for the participants, with as many as 25 participants assessed on any given day. This suggests that automated eye tracking is a new promising method to evaluate early child development in nutrition research in low- and middle-income countries.

Prado and Adu-Afarwuah launch new project examining long-term neural effects of early nutrition in Ghana

Dr. Prado and Dr. Adu-Afarwuah seated with collaborators

On February 27, 2020, Dr. Elizabeth Prado and Dr. Seth Adu-Afarwuah launched a new project in Ghana funded by $2,600,000 from the US National Institutes of Health. The project will be the first long-term follow-up in Africa of a randomized controlled trial in which the intervention group received a fortified food during most of the first 1000 days, from early pregnancy through 18 months of age.

Nutrients such as vitamins, minerals, and fatty acids are the building blocks for children’s healthy brain development. Much of the brain’s structure is laid during pregnancy and early childhood, when the brain and nervous system are developing very rapidly. Many pregnant women and young children do not eat sufficient nutrient-dense foods that contain these essential nutrients. If these nutrients are not available during critical periods when the brain is developing rapidly, there could be long-term effects on the structure and function of the brain and nervous system.

This new project will follow up children at 8-12 years of age whose mothers participated in a randomized controlled trial of nutritional supplementation when they were pregnant 10 years ago. The Packets of nutritional supplementsoriginal trial, the International Lipid-Based Nutrient Supplements (iLiNS) DYAD (mother-child dyad) trial, was led by Dr. Kay Dewey at UC Davis and Dr. Anna Lartey at the University of Ghana and was funded by the Bill & Melinda Gates Foundation. Pregnant women and children in the intervention group received lipid-based nutrient supplements (LNS), made from peanut paste, vegetable oil, and milk powder, with added vitamins and minerals. While small-quantity LNS provides only a small amount of calories per day (~118 kcal), it is packed with the vitamins, minerals, and fatty acids that are needed for children’s growth and development. In the control groups, women received a daily micronutrient capsule, similar to a pre-natal multi-vitamin, and the children did not receive any supplement.

When the children were 4-6 years of age, we found that children in the LNS group had fewer social-emotional difficulties compared to the control groups, especially those from home environments with low nurturing care and learning opportunities. The aims of the new project are to see whether we find the same pattern when the children are 8-12 years of age and to understand the neural mechanisms of protective effects of early nutrition on the development of social-emotional difficulties among children in Ghana. This will be the first randomized controlled trial to assess long-term Sagittal cross section of braineffects of early nutritional supplementation on nervous system development through combining methods to assess neurophysiology in both the central and autonomic nervous systems, including structural magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI) and measures of autonomic nervous system (ANS) activity, including electrocardiogram and impedance cardiography. Co-investigators are Dr. Paul Hastings and Dr. Amanda Guyer at UC Davis, Dr. Adom Manu and Dr. Benjamin Amponsah at the University of Ghana, and Dr. Brietta Oaks at the University of Rhode Island.

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