Effects of early intervention on EEG power and coherence in previously institutionalized children in Romania

Abstract

Two groups of Romanian children were compared on spectral power and coherence in the electroencephalogram (EEG) in early childhood. One group consisted of previously institutionalized children who had been randomly assigned to a foster care intervention at a mean age of 23 months. The second group had been randomized to remain in institutional care. Because of a policy of noninterference, a number of these children also experienced placement into alternative family care environments. There were minimal group differences between the foster care and institutionalized groups in EEG power and coherence across all measured frequency bands at 42 months of age. However, age at foster care placement within the foster care group was correlated with certain measures of EEG power and coherence. Earlier age at foster care placement was associated with increased alpha power and decreased short-distance EEG coherence. Further analyses separating age at placement from duration of intervention suggest that this effect may be more robust for EEG coherence than EEG band power. Supplementary analyses examined whether the EEG measures mediated changes in intellectual abilities within the foster care children, but no clear evidence of mediation was observed.

Figure 1

Scatterplots showing 42-month EEG band power for absolute (µV²) and relative power (proportion) in the theta, alpha, and beta band against age of placement into foster care. The Pearson correlation coefficients for the relation between placement age and EEG power are also shown. The individual values for children in the institutionalized group (IG) are shown for reference.

Figure 2

Scatterplot showing the relation between mean EEG coherence between frontal and temporal electrode sites (averaged across hemisphere) and age at foster care placement within the foster care group (FCG).

Figure 3

Illustration of the early-placed and late-placed subgroups within the larger foster care group (FCG). Each horizontal line represents one participant within the FCG. Note: The chart shows the entire FCG (excluding children placed after 30 months of age), while the analyses in the text deal with only the children with complete EEG data.