Adapting cognitive tests for infants in rural Gambia
Infants in rural Gambia scored lower on cognitive tests compared to US norms, with performance dropping progressively throughout early infancy.
Source
Adaptation of the Mullen Scales of Early Learning for use among infants aged 5- to 24-months in rural Gambia
What they did
Researchers adapted the Mullen Scales of Early Learning for local language and culture to test 171 infants in rural Gambia, though 21 participants did not complete testing. The testing took place in a region where approximately 80% of the population speaks Mandinka as their primary language. They measured cognitive development across multiple age groups and assessed its relationship with physical growth indicators while adjusting protocols between phases to reduce parental reporting.
What they found
While the youngest infants performed similarly to US norms, older age groups scored progressively lower, showing a significant decline in cognitive performance over time. Early visual reception abilities dropped first, while language declines emerged later in older infants. Additionally, both height-for-age and weight-for-height z-scores significantly predicted overall cognitive scores, indicating a link between physical growth faltering and slower cognitive development.
The limits
What it doesn't show
Because this study is observational, it cannot prove that malnutrition or growth faltering directly causes cognitive delays. The lack of a local control group or native Gambian reference norms means we cannot determine if the low scores reflect true developmental delays or simply cultural biases in Western-designed tasks. Furthermore, the researchers could not fully separate true age-related cognitive declines from the possibility that the testing tool becomes less culturally appropriate as infants grow older and require more complex instructions.
Key terms
- Mullen Scales of Early Learning
- A standardized assessment tool used to measure cognitive, motor, and language development in infants and preschool-aged children.
- Growth faltering
- A deceleration in physical growth rate, often used as an indicator of undernutrition or chronic infection in pediatric populations.
- Z-score
- A statistical measurement that describes a value's relationship to the mean of a group of values, measured in terms of standard deviations.
- Stunting
- A condition of impaired physical growth, defined by a height-for-age z-score below a critical threshold relative to reference norms.
- Wasting
- A sign of acute malnutrition characterized by a rapid loss of weight, defined by a weight-for-height z-score below a critical threshold.
Flashcards
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Quiz yourself
Which of the five Mullen Scales of Early Learning (MSEL) subscales is excluded from the calculation of the global cognitive t-score (Cog T)?
Common questions
Why did the researchers need to adapt the cognitive scale for Gambian infants?
Standardized cognitive tests like the MSEL are originally developed and normalized in Western, English-speaking countries. To prevent cultural bias, the researchers translated instructions and substituted unfamiliar items.
How did physical growth relate to cognitive performance in this study?
The study found that infants with better physical growth metrics—specifically height-for-age and weight-for-height—had higher cognitive scores, suggesting physical health and cognitive development are linked.
What were the differences in cognitive performance between boys and girls?
Unlike some Western studies where girls often score higher in early language development, this study found that boys generally outperformed girls on several subscales.
How did the researchers reduce the influence of parent reports on the scores?
Between the two phases of the study, the researchers provided administrators with additional training to minimize reliance on parent reports, which successfully reduced the percentage of items completed via parent report.
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