Iron deficiency in infancy is associated with altered neural correlates of recognition memory at 10 years

Abstract

Objective: To determine the long-term effects of iron deficiency on the neural correlates of recognition memory.

Study design: Non-anemic control participants (n=93) and 116 otherwise healthy formerly iron-deficient anemic Chilean children were selected from a larger longitudinal study. Participants were identified at 6, 12, or 18 months as iron-deficient anemic or non-anemic and subsequently received oral iron treatment. This follow-up was conducted when participants were 10 years old. Behavioral measures and event-related potentials from 28 scalp electrodes were measured during an new/old word recognition memory task.

Results: The new/old effect of the FN400 amplitude, in which new words are associated with greater amplitude than old words, was present within the control group only. The control group also showed faster FN400 latency than the formerly iron-deficient anemic group and larger mean amplitude for the P300 component.

Conclusions: Although overall behavioral accuracy is comparable in groups, the results show that group differences in cognitive function have not been resolved 10 years after iron treatment. Long-lasting changes in myelination and energy metabolism, perhaps especially in the hippocampus, may account for these long-term effects on an important aspect of human cognitive development.

Copyright © 2012 Mosby, Inc. All rights reserved.

Figures

Figure 1

Topographic distribution of scalp potentials to new and old words for A, controls and B, FIDA at 344 milliseconds poststimulus. Grand averaged ERP waveforms for C, controls and D, FIDA over the left frontal electrode (F3). The x-axis represents latency in milliseconds (ms), and the y-axis represents amplitude in microvolts (μV). New Words Old Words

Figure 2

Mean latency to peak amplitude of the FN400 component, collapsed across condition. The x-axis represents ‘group’ and the y-axis represents latency in milliseconds (ms). Error bars represent +1 standard error of the mean. ■ Controls FIDA

Figure 3

Topographic distribution of scalp potentials collapsed across memory condition for A, controls and B, FIDA at 699 milliseconds poststimulus. C, Grand averaged ERP waveforms for the mean amplitude of the P300 component collapsed across condition. The x-axis represents latency in milliseconds (ms) and the y-axis represents amplitude in microvolts (μV). Controls FIDA