EM

Cognitive Tests and Major Cognitive Outcomes

Cognitive Tests

  • A variety of standardized cognitive tests were used to assess outcomes in multiple cognitive domains.
  • These cognitive domains included:
    • Learning abilities
    • Verbal reasoning
    • Intellectual functioning
    • Information processing speed
    • Vocabulary
    • Word reasoning
    • Speed and accuracy of discrimination
    • Fine and gross motor skills
    • Coding
    • Symbol search
    • Working memory
  • Specific tests:
    • Wechsler Pre-school and Primary Scale of Intelligence (WPPSI) was administered in half of the studies [55 56 57 60 61 63 ].
    • 9-Hole Peg Test (9-HPT) was administered in two experimental studies [56 B.57 ].
    • Mullen Scale of Early Learning (MSEL) was administered in two studies [59, 62 B].
  • Table 2 provides details on:
    • Cognitive tests used in each trial
    • Cognitive domains assessed
    • Effects on cognitive outcomes of preschool-aged children

Major Cognitive Outcomes

Single Nutrient Supplementation

  • Five RCTs measured the effect of supplement-based interventions on children's cognition.
  • Three trials found no significant impact on cognition with:
    • B vitamin supplementation [55]
    • Iodized salt supplementation [59]
    • Guava supplementation [62]
  • Guava Supplementation Details:
    • Guava is rich in vitamins, minerals, and lycopene (a carotenoid phytonutrient with antioxidant effects) [67].
    • It was used to facilitate nonheme iron absorption [68].
    • Guava supplementation improved iron status but had no significant effect on cognitive function [68 B].
  • Trials that found significant results:
    • Iron intervention [58]:
      • For children with iron deficiency anemia, iron supplementation increased accuracy and the speed of discrimination on the continuous performance task.
      • For children with adequate iron status at baseline, iron supplementation did not affect performance on the continuous processing task.
    • DHA supplementation intervention [59]:
      • No significant differences in cognitive function scores between the intervention and placebo groups.
      • Higher blood DHA levels were significantly associated with higher scores on the Peabody Picture Vocabulary Test (measures listening comprehension and vocabulary).

Multiple-Micronutrient Supplementation

  • Three RCTs measured the impact of multiple-micronutrient food fortification on children's cognitive development.
  • 11-week intervention [64]:
    • Consisted of eight grams of a point of use multiple micronutrient powder added to maize-meal porridge at breakfast for children 36-79 months of age.
    • Children in the intervention group significantly increased their scores on the simultaneous scale and the non-verbal index of the Kaufman Assessment Battery for Children compared to the control group.
  • Longer trial with somewhat younger children [65]:
    • The cognitive benefits of a point of use multiple micronutrient powder were dependent upon whether the child was attending a low-quality or a high-quality preschool.
    • The quality of preschools was assessed.