How Early Adversity Relates to Brain Activity Years Later
A follow-up study on Romanian orphans.
Posted Jun 02, 2019
As of January 2019, the federal government has reported that nearly 3,000 children were forcibly separated from their parents migrating across the US border with Mexico and put into detention shelters or foster care. Much of what scientists know about how brain development in children is impaired by adverse early life experience comes from studies on Romanian orphans who suffered severe neglect under the Communist Romanian dictator Nicolae Ceausescu.
The latest research by scientists tracking the neurological development of these children, published in the journal Developmental Science online in advance of print, shows that disruptions in caregiving produce detrimental effects on a child’s brain function, evident by EEG (electroencephalogram) analysis after children reached teen age (16-17 years old). The new data show that improvements in brain electrical activity seen after orphans were removed from orphanages and placed into foster home care were reversed when foster care was interrupted.
This latest report is a continuation of a long-term, longitudinal study of the Romanian orphans by Charles Nelson of Boston Children’s Hospital, Nathan Fox of the University of Maryland, College Park, Charles Zeanah of Tulane University, and co-authors Ranjan Debnath and Alva Tang at the University of Maryland. This research studied the effects of parental care on the development of the brain using a randomized experimental design, much as in drug studies. Orphans were assigned randomly into two groups that either remained institutionalized or were placed in foster home care. One hundred thirty-six young children, between 6 and 31 months of age, from orphanages in Bucharest, Romania, participated in the study. Sixty-eight of the children were randomly assigned to foster care homes and 68 children were assigned to continue in institutional care. The randomized, longitudinal study design (meaning the same children were followed over time) provides the most rigorous experimental approach possible, but it has raised difficult ethical issues.
The study has previously reported that EEG analysis of the orphan’s brainwaves indicates that their brain electrical activity deviates significantly from neurotypical children. Other research has documented developmental delays and psychological and neuroanatomical impairments in these children. The orphans have low alpha and beta brainwave power and higher theta brainwave power than matched controls (normally reared children of the same age). These are different frequency bands of brainwave oscillations, increasing in oscillation frequency from theta (4-7 Hz) to alpha (8-13 Hz) to beta waves (14-25 Hz).
This altered EEG signature has been associated with ADHD, learning disorders, disruptive behavior disorders, and psychosocial risk factors. However, orphans who were placed in foster home care showed normal EEGs when assessed 12 years later, while those who remained in institutions still had these abnormal features in their EEG.
This follow-up study confirmed that placing the orphans in foster care restored the EEG to normal, adding that this improvement persists into the teenage brain. But it also uncovered that disruptions in foster care, including changing foster care homes or reunification with their biological families, reversed the benefits.
A higher number of disruptions in foster care was associated with increased theta power and decreased alpha power, a pattern of brain activity often observed in children living in impoverished environments. The authors conclude that disruptions in a stable family environment adversely influence brain electrical activity in children, with effects that can persist in the teen brain.
The authors characterize these differences in EEG power as an indication of an immature stage of brain development, and with strong supporting evidence. It should be noted, however, that differences in EEG power and brain function are correlative. Many normal variants of EEG activity are seen, including low alpha wave power, which are in part genetically determined.
Secondly, the power of EEG measured with scalp electrodes is affected by differences in skull density, which might be influenced by adverse conditions. Brainwaves penetrate the skull to different extents depending on their frequency of oscillation.
Finally, characterizing these differences in brainwave features as being detrimental also rests on correlation. Precisely how alpha wave power, for example, influences the detrimental consequences of adverse childhood experience is not certain. An alternative interpretation could be that changes in brain function underlying these differences in EEG are adaptive to the different environments the children experience. For example, heightened vigilance may be a beneficial adaptation to a novel, stressful, or unstable environment and such alterations in the child’s brain could have effects on their EEG.
Nevertheless, these changes in electrical activity in the teen brain correlate with the disruption of a normal family environment that can be reversed by returning the child to a wholesome family environment, provided it is a stable one.
There is no question, however, that instability in a child’s home environment produced by removing children from their parents does affect brain development and electrical activity in ways that can persist into the teenage years. Neuroscientists have learned a great deal from studying the tragic plight of the Romanian orphans—lessons that may connect with the experiences of other young children separated from their parents.