Neurodevelopmental Effects of Early Deprivation in Post

University of Wisconsin

Harvard Medical School / Children’s Hospital Boston

University of Wisconsin

University of Wisconsin

University of Minnesota

University of Minnesota

University of Minnesota

University of Minnesota

University of Minnesota

The neurodevelopmental sequelae of early deprivation were examined by testing (N = 132) 8 and 9 year old children who had endured prolonged versus brief institutionalized rearing or rearing in the natal family. Behavioral tasks included measures that permit inferences about underlying neural circuitry. Children raised in institutionalized settings showed neuropsychological deficits on tests of visual memory and attention, as well as visually mediated learning and inhibitory control. Yet, these children performed at developmentally appropriate levels on similar tests where auditory processing was also involved and on tests assessing executive processes such as rule acquisition and planning. These findings suggest that specific aspects brain-behavioral circuitry may be particularly vulnerable to post-natal experience.

Over the past decade, increased attention has been devoted to the development of children who have spent some or all of their lives in institutional care (Johnson, 2001). The increase in adoption of institutionalized children has heightened concerns about long-term effects of early deprivation. While the deprivation experienced by children in institutional settings is often impossible to accurately quantify, the environments many of these children endure fall below the quality needed to sustain normal physical and behavioral development. As evidence, institutionalized infants/toddlers lose about 1 month of linear growth for every 2–3 months in institutional care (Johnson, 2001) with behavioral development exhibiting similar dramatic delays retardation (Gunnar, 2001). When institutionalized children are placed in families, marked improvements in physical, social, and cognitive functioning is typically observed, yet many of the children maintain persistent behavioral problems (Ames, 1997; Hodges & Tizard, 1989; Rutter, 1998; Verhulst et al., 1990; Verhulst et al., 1992). The developmental difficulties experienced by many of these children raise questions about the effects of early deprivation including factors such as failure to provide adequate nutrition, medical care, stimulation, and the lack of consistent and supportive caregiving relationships. Although early research emphasized the significance of maternal deprivation, Rutter (1981) rightly noted that many other types of stimulation needed for normal development are also deficient in these environments.

The critical questions that emerge from the plight of these children concern which aspects of inadequate stimulation result in cascading developmental effects, which developmental processes are most affected by inadequate early care, and specification about how the transfer to more normative caregiving can foster growth and recovery following institutionalization. Institutionalized children have experienced highly species atypical deprivation; in many countries the institutional conditions are quite poor: children may be confined to cots, fed gruel through propped up bottles, lack toys or stimulation, and receive very little linguistic stimulation and/or one-to-one interaction with caregivers (Nelson, 2007; Rutter et al., 1998). Even in institutions where basic physical needs were met, lack of individualized care and attention remain prominent. At adoption, children generally move into middle- to upper-middle class families, who are generally highly stable and well educated (Hellerstedt et al., 2007). In short, adoption marks a dramatic termination of deprivation, allowing an examination of the impact of early deprivation/neglect on subsequent development. Adoption into a supportive home can provide a profound natural intervention in the life of a child exposed to significant early adversity (van Ijzendoorn et al., 2005). As a result, internationally-adopted children provide a natural experiment on the impact of different degrees and duration of care on subsequent biobehavioral development. Despite occasional significant adjustment problems of the children, there are very few adoption disruptions for families who adopt internationally (e.g., Brumble, 2007). Furthermore, all studies of children adopted or fostered from institutions have shown that, varying with duration of institutionalization, once out of the institution children begin to show remarkable rebounds in physical and cognitive development (Kreppner et al., 2007; Maclean, 2003). Both the capacity of children to rebound after early institutional care and limitations on recovery imposed by longer periods of institutionalization was recently demonstrated experimentally in a study involving random assignment to high quality foster care for children who began their lives in Romanian institutions (Nelson et al., 2007). Studying post-institutionalized children several years after adoption allows examination of long-term impacts of early experience on children’s development.

The present study is specifically motivated by the convergence of behavioral studies of post-institutionalized children and experimental studies of deprivation on the nonhuman primates (see review by Sanchez & Pollak, 2008). In terms of domains where children do not appear to catch-up in the immediate years following adoption, Beckett et al. (2007) reported that children adopted after prolonged period of institutional care from Romania had significantly lower scholastic attainment scores than those adopted early (before 6 months) either within the United Kingdom (UK) or from Romania. A separate research team also concluded that although adopted children showed age-expected development in some domains, adoptions after 12 months of age were associated with problems in school achievement (van Ijzendoorn & Juffer, 2006). Another recent report indicated that children residing within Romanian orphanages had poorly developed language abilities (Windsor et al., 2007). One recent study focused specifically on language and cognitive outcomes at 6 and 11 years of age with a large sample of institutionally-reared Romanian children adopted into UK families. This study noted few negative effects of deprivation if institutionalization ended before the age of 6 months. Even for the children over 18 months, the presence of even very minimal language skills (the child’s ability to imitate speech sounds) at the time of arrival was a strong positive prognostic factor for school-aged cognitive outcomes. Importantly, variations in adoptive parent characteristics were unrelated to differences in the adopted children’s cognitive outcomes (Croft, Beckett, et al., 2007). Studies of institutionally-reared children yield consistent evidence that early deprivation can have long-term consequences for cognitive functioning and school readiness. Yet, most extant research has employed gross measures of functioning such as checklists, questionnaires, school records, and global DQ and IQ tests. While such global measures provide some suggestion of which neural systems may have been affected, they are not specific enough to test hypotheses about the development of neural systems. Our goal was to more directly examine brain-behavior processes in systems believed to underlie children’s scholastic performance, such as aspects of attention, inhibitory control, working memory, and learning.

These domains are of interest not only because of the persistent difficulties observed in previously neglected children, but because nonhuman primate studies suggest that the prefrontal cortex (PFC) and its associated systems are particularly relevant to understanding cognitive functions and may be especially vulnerable to early experience (e.g. Sanchez et al., 2003). The PFC develops over a protracted period, well into adolescence (Huttenlocker, 1990; Sowell et al., 1999). While the timing of development in different regions has not been fully determined, there is evidence that neuronal organization in the dorsolateral prefrontal cortex (Brodman areas 9 and 10) changes dramatically until 5–7 years of age (Blinkov & Glezer, 1968), and slows thereafter. A similar protracted period has been observed for the neurotransmitter systems mediating prefrontal activity. Bourgeois (2001) has plotted the overproduction and pruning of synapses in the rhesus monkey against that of the human, taking into consideration differences in age compression (i.e., the rate at which each species develops), and has reported remarkable similarity across species. Collectively, these data, coupled with the postmortem data, point to a protracted period of PFC development. Presumably this may allow experience-dependent fine-tuning of attention, learning, emotion, and memory systems (e.g., Black, Jones, Nelson & Greenough, 1998).

Although it is critical to understand whether and how postnatal deprivation/neglect influences brain development in human children, the human neuroscience evidence is sparse. Two studies conducted by Chugani and colleagues reported that post-institutionalized (PI) children from Romania showed significantly decreased metabolism bilaterally in the orbital frontal gyrus, the infralimbic prefrontal cortex, the medial temporal structures (amygdala and head of hippocampus), the lateral temporal cortex, and the brain stem as compared to normal adults and children with chronic epilepsy. Diffusion tensor imaging also suggested that the PI children had reduced white matter tracts between the anterior temporal and frontal lobes (Chugani,Behen, Muzik, Juhasz, Nagy, &Chugani2001; Eluvathingal et al., 2006). These brain imaging findings are consistent with recent work from the Bucharest Early Intervention Project (BEIP; see Zeanah et al., 2003). For example, this group has reported that children reared in institutions show dramatic reductions in brain activity as revealed by the electroencephalogram and the event-related potential (see Marshall et al., 2004; Parker et al., 2005a,b). Importantly, children placed in high-quality foster care before the age of two years show improvement in their EEG (Marshall et al., in press); ERP amplitude also improves with placement in foster care, although it is not time- or sensitive-period dependent (Moulson et al., in press).

The present study sought to determine which domains of cognitive development may be particularly affected by institutional neglect/deprivation using children adopted internationally from orphanages or other institutions. These post-institutionalized children were (a) adopted over age 12 months, (b) spent at least 75%of their lives prior to adoption in institutional care, and (c) resided in their adoptive families for a minimum of 3 years at the time of testing. We compared these children to two different groups. Our first comparison group consisted of children who were adopted before 8 months predominantly from foster care overseas, having little or no institutional care history. This group helps to control for prenatal factors and heritable factors associated with a child becoming orphaned or abandoned. Our second comparison group consists of non-adopted children who were reared in their families of origin. As noted by Rutter et al. (1997), even when using "normed" neuropsychological evaluations, and especially when using non-standardized tests, it is critical to include non-adopted children who have grown up in families of similar economic and educational histories to the families of adopted children. Furthermore, for domains that yielded differences between the post-institutionalized children and both other groups, we examined whether duration of institutional care correlated with the children’s performance. Thus, the strategy employed here is to identify as “institutional deprivation effects” those cognitive functions for which the post-institutionalized group differs from the two comparison groups and, further, where the duration of institutional care is associated with the outcome within the post-institutionalized group. Here, we focus on basic cognitive/learning processes that might underlie school-based learning problems.

The participants were 132 children ages 8 years, 0 months to 9 years, 11 months. Three groups were examined (see Table 1 for details). A post-institutionalized (PI) group whose selection criteria was adopted 12 months of age or older (range 12 to 78 mos, M = 23.4 mos, Sd = 12.9) having spent at least 75% of their preadoption lives in institutional care. Over 50% of this group had no experience other than institutional care prior to adoption (M = 22.1 mos in institutional care, Sd=12.4). Children in the PI group were adopted from Asia (n = 19), Latin America (n = 1), Russia/Eastern Europe (n=27) and Africa (n=1). An early adopted predominantly from foster care (EA) group whose selection criteria was adoption at 8 months or earlier (range 2 to 8 mos, M=5.2 mos, Sd=1.7 mos) having spent 2 months or less in institutional care. Nearly 83% of this group had spent all of their preadoption lives in foster care overseas. Those with institutional experience had been adopted before 3 months of age. Children in the EA group were adopted from Asia (67%) and Latin America (33%). The EA group permitted comparison with children who had experienced loss of birth families and adoption into another culture. Finally, the third group was children born and raised in their birth families in the United States (non-adopted, NA). The children were recruited and tested at two sites, the University of Wisconsin (n=58) and the University of Minnesota (n=74). As shown in Table 1, there were no differences between the three groups in terms of the numbers of boys versus girls, child’s age, or parent education. As expected, children in the PI group had lower IQ scores than those children in the two (EA and NA) comparison groups, F (2,131) = 16.13, p < .001. On average, adoptive parents had higher family incomes than those from control families, F (2,131) = 3.99, p = .02.

Sample Characteristics

The internationally-adopted children were drawn from the Minnesota and the Wisconsin International Adoption Project Registries–registries of families created through international adoption that expressed interest in being contacted about research participation. The non-adopted children were recruited in Wisconsin through fliers and advertisements and in Minnesota from the Institute of Child Development Participant Pool, a registry of children whose parents indicated interest in being contacted about research opportunities in response to a mailing soon after their children were born.

Within 6 months of the present study, the children were all screened to determine if they met the study’s group assignment (described above) and exclusion criteria. Criteria for group assignment were determined through phone interview and parent questionnaire. Children then participated in an extensive developmental profile, parts of which determined exclusion criteria. Children were excluded if their IQs were below the normal range (

Descriptive Data on Domains Exhibiting Significant Group Differences