Explicit memory performance in infants of diabetic mothers at 1 year of age

Abstract

The aim of the present research was to investigate the impact of abnormal fetal environment on explicit memory performance. Based on animal models, it was hypothesized that infants of diabetic mothers (IDMs) experience perturbations in memory performance due to exposure to multiple neurologic risk factors including: chronic hypoxia, hyperglycemia/reactive hypoglycemia, and iron deficiency. Memory performance, as measured by the elicited/deferred imitation paradigm, was compared between 13 IDMs (7 female, 6 male; mean age 365 days, SD 11) and 16 typically developing children (7 female, 9 male; mean age 379 days, SD 9). The IDM group was characterized by shorter gestational age (mean 38 weeks, SD 2), greater standardized birth weight scores (mean 3797 grams, SD 947), and lower iron stores (mean ferritin concentration 87 μg/L, SD 68) in comparison with the control group (mean gestational age: 40 weeks, SD 1; mean birth weight: 3639 grams, SD 348; mean newborn ferritin concentration 140 μg/L, SD 46). After statistically controlling for both gestational age and global cognitive abilities, IDMs demonstrated a deficit in the ability to recall multi-step event sequences when a delay was imposed. These findings underscore the importance of the prenatal environment on subsequent mnemonic behavior and suggest a connection between metabolic abnormalities during the prenatal period, development of memory circuitry, and behavioral mnemonic performance.Infants of diabetic mothers (IDMs) comprise a compelling group in which to examine associations between fetal risk factors and subsequent memory performance. The adverse environment associated with the diabetic pregnancy consists of multiple neurologic risk factors including: 1) chronic hypoxia (Widness et al., 1981), 2) hyperglycemia/reactive hypoglycemia, and 3) iron deficiency (Petry et al., 1992), which, on the basis of animal models, have been shown to act selectively on regions of the fetal brain that are involved in explicit memory (e.g., the hippocampus, Barks et al., 1995;de Ungria, et al., 2000). Based on the known Several studies have demonstrated that neurobehavioral outcomes in human children who were born to diabetic mothers are inversely correlated with the quality of metabolic regulation during pregnancy (e.g., Rizzo et al., 1997). However, these investigations have typically examined global cognitive development in children well downstream from the proposed insult, and are not necessarily related to specific risk factors or areas of injury. The purpose of the present research was to further characterize outcomes related to development in an abnormal prenatal environment by examining the relation between IDM's abnormal prenatal environment and behavioral explicit memory performance using the elicited imitation paradigm. Risk FactorsPrenatal hypoxia and hyperglycemia/reactive hypoglycemia have been associated with both poor behavioral and neurologic outcomes. Specifically, prenatal hypoxia is linked with motor and cognitive deficits in humans (e.g., Low et...

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