How poverty shapes brain development of children in low-income countries

Charles Nelson, professor of Pediatrics at Harvard Medical School, is thrilled that he will be in Bangladesh in early December to follow-up on a study he is leading to understanding how poverty shapes the brain of children growing up in low-income countries. This study is unprecedented. 

The findings are likely to inform policy interventions to help kids meet their potential not just in Bangladesh but in other countries, including India, that face abject poverty. More than 200 million children in developing countries are at a risk of not meeting their developmental potential by five years of age. Existing evidence shows that most children who grow up poor tend to lag behind their “normal” counterparts in school. They earn lower income as adults, which then trap them in the cycle of poverty. India was ranked 100th behind Bangladesh (88) in the recently released Global Hunger Index of 119 countries.  

However, most of the research on how adversity and poverty affect children’s brain development has happened in developed countries. “But poverty in the US is nothing like it is in Bangladesh,” said Nelson. There is no baseline or template of how the brain of children growing up in poor settings look like during the first few years of life. “It’s important to develop that template,” said Nelson. “Because then you can design interventions to shift the baseline in a positive direction.” 

This study, which began two years ago, is unique because nobody has ever studied brain development of children so young—between two years and 36 months — in a poor country with this level of adversity, using three different brain imaging tools at the same time. 

Scanning the brain in its early years helps understand how negative experiences early in life affect the brain. So, there are sick malnourished children growing up in poor households with anaemic mothers going through domestic violence. “The combination is particularly toxic,” said Nelson. 

And, given the greater plasticity at that age, you can design interventions for better results, said Rashidul Haque, senior scientist at The International Centre for Diarrhoeal Disease Research, Bangladesh, who is collaborating with Nelson on this study.  

They recruited about 500 children living in slums of Mirpur area in Dhaka. Parents of most of these children do daily wage labour or work in a garment factory or in the transport sector and earn about $125 every month. They bring their children to a field office where researchers scan their brains using three different tools — Electroencephalography (EEG), functional near-infrared spectroscopy (fNIRS), and Magnetic Resonance Imaging (MRI). Children prefer EEG and fNIRS because they involve a headband of sensors that children easily wear whereas in MRI they have to go under a big machine, said Shahria Hafiz Kakon, medical officer, working with Haque. The study is funded by the Bill & Melinda Gates Foundation. 

The preliminary findings show that the kids have significantly reduced grey and white matter in their brain in comparison to the kids growing up in the United States. Think of grey matter as a CPU of the brain where computations are performed. White matter as the cables that connect things. 

Similarly, some networks like the one that supports aspects of vision — light, colour or motion perception—were weak in these kids. When tests like peek-a-boo were played to surprise the kids, the associated brain regions were much less active. The cognitive and language ability scores were also found to be dramatically reduced. For example, only nine per cent of the kids from the sample tested for cognitive ability scored above average. The researchers are in the process of quantifying their results and haven’t published their findings yet. The researchers are recruiting kids from affluent households in Dhaka to see how their brain differ from the brain of the kids in the slums.

Nelson said that poverty is known to diminish three crucial things in the brain — language, memory and cognition. The degree might vary based on severity of poverty. 

While the study will test specific interventions soon, the growing scientific evidence shows that nutrition alone is not enough in achieving other development outcomes like cognition and language. Policy interventions in developing countries focused on nutrition to reduce risks of early death in childhood. Nutrition is essential for survival and health. “Now, we are examining the quality of life and we want to ensure that children not only survive but thrive,” said Aisha Yousafzai, associate professor of Global Health at Harvard University. Yousafzai’s research in Pakistan showed that the children who received guided parental interaction in the early days of childhood had significantly better cognitive and language scores in comparison to kids who received only nutritional intervention, and also in comparison to the kids who received standard care. Yousafzai believes that it is time to combine other interventions with nutrition. 

Agrees, Nandini Chatterjee Singh, a professor at the National Brain Research Centre in Haryana. Based on her research on the positive impact of music on the brain of autistic children in India, Singh wants to explore whether music can have compensatory effects on the brain affected by poverty. “The impact of different stimuli on the brain development has opened up the possibility that completely different set of stimuli might act as a compensatory agent,” said Singh. She says that the findings of the Bangladesh study could guide similar studies in India. 

The kids whom Nelson’s team recruited in Bangladesh are between two and five years old now. Nelson is interested in doing follow-up studies, for as long as he can, especially as these kids transition into school, to track their performance. Nelson kept studying the brain of orphan kids in Romania till they were 16 years old, and found that the low IQ, poor executive functions, social awkwardness persisted in them. They now also have high rates of psychopathology issues. 

But right now, Nelson has one question in his mind about the children in Bangladesh: is the grey matter in their brain the same or has it deteriorated?