The goal of this observational study is to learn about typical neurodevelopment in children aged 6 months to 5 years who live in Bahir Dar, Ethiopia. The main aims of the study are:

Aim 1: To characterize typical neurodevelopment as measured by i) brain volume using low-field MRI and ii) scores on behavioral assessments of early child neurodevelopment.

Aim 2: To characterize typical pre-academic school skills in early childhood as measured by tasks of visual processing, reasoning, verbal expression and school readiness.

Aim 3: To identify factors influencing child development in a community in Bahir Dar, Amhara region of Ethiopia, as measured by validated measures of maternal mental health, home environment, and childhood adversity.

Participants will complete one low-field MRI scan at enrollment, have a hemoglobin blood test, and undergo age-appropriate neurodevelopmental assessments and surveys that may include:

• WHO Global Scales for Early Development (GSED) [ages 6 - 36 months]
• Tasks of visual reasoning and verbal expression [ages 48-60 months]
• Executive Functions test using the tablet-based NIH Toolbox [ages 48-60 months]
• School Readiness questionnaire assessing knowledge of literacy, numeracy, early reading, crystallized knowledge, memory, and self-regulation [ages 48-60 months]
• Maternal report of child's motor, cognitive and socioemotional skillsChild Anthropometrics assessment

Additional assessments of the participant's family and environment will include

• Medical History questionnaire
• Family socioeconomic status
• Maternal Mental Health
• Recent Life Events and hardship
• Home Environment and Parenting UNICEF's MICs Family Care Indicators)
• Food security and feeding practices

More than 170 million children worldwide under 5 years of age fail to meet their developmental potential. Reduced or impaired neurodevelopment in early life can impact lifelong patterns of cognitive and behavioral development, beginning with early and pre-academic skills that are vital to academic success, achievement, and predictive of later income, health access, and socioeconomic standing. Improved early neurodevelopment, on the other hand, can spark an intergenerational cascade of improved family and child health outcomes.

Infant and early childhood neurodevelopment can be impacted by a diverse array of environmental factors beginning from the earliest stages of fetal development. Premature birth, low birth weight, poor maternal health, maternal stress, inadequate maternal and infant nutrition, reduced breastfeeding, exposure to disease, environmental neurotoxicants, and environmental adversity can all shape developing brain systems and impact emerging brain cognitive and behavioral functions. However, there is a gap in our understanding of neurodevelopmental patterns in children across LMIC settings where many neurodevelopmentally impactful adversities are magnified. Increased knowledge of risk and protective factors associated with neurodevelopmental characteristics in children can support the identification of the global and regional factors that drive poor neurodevelopmental outcomes in children and help to inform interventions to improve child outcomes.

The Bahir Dar Child Development (BCD) study will characterize patterns of neurodevelopment in a community sample of children in Bahir Dar, Amhara, Ethiopia using a cross-sectional design covering children aged 6 - 60 months. Neuroimaging data collected using a low-field portable MRI scanner will be coupled with neurocognitive assessments and a broad assessment of child and family medical history, nutritional status, socioeconomic standing, and other social determinants of health. These data will be harmonized and integrated with similar data collected from other regions and countries to provide a global map of development and identify important targetable factors that will improve neurodevelopmental outcomes.

Inclusion Criteria:

• Children living in Bahir Dar town with parents who are willing and able to travel to Felege Hiwot Regional Hospital clinic for study visits
• Healthy child without active clinical symptoms/complaints
• Child within specified age ranges for each cohort/group (+/- 2 months)

Exclusion Criteria:

• Child born with a severe congenital birth defect or hypoxic ischemic encephalopathy (birth asphyxia) per maternal report
• Severe developmental or behavioral disorder per maternal report
• Severe illness/clinical signs or symptoms of illness based on maternal and child report (including vomiting, headache, or seizures)
• Plans to move out of catchment area in less than 1 year

Children will be identified at rural health centers, outpatient vaccination clinics or campaigns, and other health facilities around Bahir Dar, Amhara, Ethiopia.