Responses In Infants Research Articles

Early parental vocal contact in neonatal units: rationale and clinical guidelines for implementation.

This paper aims to present clear and evidence-based proposals for the integration of Early Parental Vocal Contact into the clinical practices of neonatal units. In the first part, we present a comprehensive rationale exploring the ontogenesis of voice perception in both term and preterm newborns that establishes a foundational understanding. This knowledge serves as a crucial starting point for developing evidence-based auditory and multisensory interventions aimed at fostering the developmental trajectory of preterm infants. Drawing insights from neuroscience and brain development, our proposals underscore the significance of tailoring auditory environments within neonatal settings. Special attention is given to the unique needs of preterm infants, factoring in their gestational age and maturation levels. In the second part clinical guidelines for implementation are provided and healthcare professionals are supported to assist parents in modulating their vocal interactions, aligning them with the infant's responses. Furthermore, we provide practical suggestions for engaging in discussions with parents about the content, duration, and frequency of vocal interventions. Finally, we delve into the potential roles of caregivers, parents, and health professionals within this enriched parental vocal interactional environment. Our perspective is firmly grounded in an infant and family-centered developmental care philosophy, aiming to enhance the overall well-being and the neurodevelopment of preterm infants in neonatal units.

OBJECTIVE ASSESSMENT AND COMMUNICATION OF THE PHYSIOLOGIC STATUS OF THE SICK INFANT

The practice of midwifery involves the initial and ongoing assessment of newborn infants in terms of their maturity, transition to extrauterine life, completeness of resuscitation and ongoing health status. The universally familiar Apgar score is an essential tool for initial neonatal assessment for midwives as for other medical professionals.1 The score was developed by Virginia Apgar as an objective measure of the physiologic status of the infant after birth, and to quantify the progress through, and adequacy of, resuscitation and adaptation to extra-uterine life. While elements of the Apgar score are relevant for assessing and describing the status of the infant after 10 minutes of age, the score as a whole is not used routinely beyond this time. The Pediatric Assessment Triangle (PAT) is a newly developed tool for ongoing, objective assessment of an infant's (or child's) physical appearance.2,3 The PAT can be used to describe the presence of abnormal physiology, define whether an infant is in distress or actually experiencing system failure, and assess the infant's response to intervention by observing the resolution or progression of the clinical problem. The PAT has the potential to be a valuable tool for midwives, both for ongoing assessment, and as a means of describing the status of an infant to other health care professionals using objective terminology. The use of objective criteria and precise terminology can strengthen the impact and relevance of communication and contribute to logical decision-making about immediate care and long-term disposition. A consistent framework is also valuable when providing follow-up, particularly where a treatment or intervention has been suggested and it is important to communicate whether the infant has responded. The purpose of this paper is to describe the Pediatric Assessment Triangle, explain how it is applied and to suggest the use of this tool by midwives in practice.

Managing the “big black brain” in low resource setting: A case report of early outcome after hinge craniotomy

Background: The big black brain (BBB) phenomenon is described as an infant’s response to an acute subdural hematoma (SDH). It is characterized by hypodensity and swelling of the supratentorial compartment as a whole. Numerous factors may contribute to the formation of the BBB. Due to its high morbidity and mortality, the management of BBB is still debatable. In this report, we describe a 2-month-old boy who had bilateral hemispheric hypodensity and underwent hinge craniotomy. Case Description: The patient was referred to our hospital with decreased consciousness. The patient had a history of seizures and cardiopulmonary arrest. There is no history of trauma. The computed tomography revealed a subacute SDH on the left parietal and occipital lobe along with hypodensity in both hemispheres with preservation of posterior fossa, consistent with hemispheric hypodensity. We performed a hinge craniotomy for the emergency procedure and evacuated only the hemisphere with the bleeding side. The patient cried spontaneously 24 hours after the procedure and was discharged six days later. Conclusion: Early outcomes of hinge craniotomy as an alternative procedure for treating the BBB were positive. However, long-term outcomes, particularly the infant’s development, should be monitored.

EEG repetition and change detection responses in infancy predict adaptive functioning in preschool age: a longitudinal study

Neurodevelopmental disorders (NDDs) are mostly diagnosed around the age of 4–5 years, which is too late considering that the brain is most susceptive to interventions during the first two years of life. Currently, diagnosis of NDDs is based on observed behaviors and symptoms, but identification of objective biomarkers would allow for earlier screening. In this longitudinal study, we investigated the relationship between repetition and change detection responses measured using an EEG oddball task during the first year of life and at two years of age, and cognitive abilities and adaptive functioning during preschool years (4 years old). Identification of early biomarkers is challenging given that there is a lot of variability in developmental courses among young infants. Therefore, the second aim of this study is to assess whether brain growth is a factor of interindividual variability that influences repetition and change detection responses. To obtain variability in brain growth beyond the normative range, infants with macrocephaly were included in our sample. Thus, 43 normocephalic children and 20 macrocephalic children were tested. Cognitive abilities at preschool age were assessed with the WPPSI-IV and adaptive functioning was measured with the ABAS-II. Time–frequency analyses were conducted on the EEG data. Results indicated that repetition and change detection responses in the first year of life predict adaptive functioning at 4 years of age, independently of head circumference. Moreover, our findings suggested that brain growth explains variability in neural responses mostly in the first years of life, so that macrocephalic children did not display repetition suppression responses, while normocephalic children did. This longitudinal study demonstrates that the first year of life is an important period for the early screening of children at risk of developing NDDs.

Increasing the dose of ibuprofen with postnatal age to close a hemodynamically significant patent ductus arteriosus in very preterm infants.

Patent ductus arteriosus (PDA) is associated with neonatal morbidities in high-risk preterm infants. Early neonatal treatment by ibuprofen induces the ductus arteriosus (DA) closure in approximatively 60% of infants. Dose escalation of ibuprofen according to postnatal age has been suggested for improving the DA closure rate. The aim of this study was to assess the efficacy and tolerance of an increasing dose regimen of ibuprofen. This single-center retrospective cohort study involved infants hospitalized from 2014 to 2019 in our neonatal unit. Selection criteria were gestational age < 30weeks, birth weight < 1000g, and treatment by ibuprofen. Three dose levels were used and consisted of a daily intravenous injection of ibuprofen-tris-hydroxymethyl-aminomethane (ibuprofen-THAM) for three consecutive days: (i) 10 -5 -5mg/kg before the 70th h of life (H70) (dose level 1), (ii) 14 -7 -7mg/kg between H70 and H108 (dose level 2), (iii) 18 -9 -9mg/kg after H108 (dose level 3). The ibuprofen-induced DA closure was compared between ibuprofen schedules, and the Cox proportional-hazard regression was performed to identify factors associated with the ibuprofen efficacy. Tolerance was assessed through renal function, acidosis, and platelet count. One hundred forty-three infants met the inclusion criteria. The ibuprofen-induced DA closure was observed in 67 infants (46.8%). One course of ibuprofen at dose level 1 was more efficient in closing the DA than other schedules (dose level 1, one course (n = 70): 71%, dose level 2 or 3, one course (n = 20): 45%, two-course schedules (n = 53): 15%, p < 0.0001). Independent factors associated with ibuprofen-induced DA closure were a complete antenatal schedule of steroids (p = 0.001), a lower CRIB II score (p = 0.009), and a lower and earlier exposure to ibuprofen (p < 0.0001 and p = 0.002). No severe side effects were observed. Neonatal mortality and morbidities were similar regardless of the infant's response to ibuprofen. Conclusion: Increasing ibuprofen doses with postnatal age failed to reach an efficacy similar to earlier treatment. Although the infant response to ibuprofen was likely to depend on multiple factors, the optimal use of ibuprofen included its early initiation. What is Known: • Ibuprofen is the current first-line treatment for patent ductus arteriosus during the early neonatal period in very preterm infants. • However, the ibuprofen efficacy rapidly declined with postnatal age during the first week of life. A dose escalation of ibuprofen according to postnatal age has been suggested to improve the ibuprofen-induced ductus arteriosus closure. What is New: • The rapid drop of ibuprofen's ability to close hemodynamically significant patent ductus arteriosus persisted beyond the postnatal day 2 despite the dose adjustment arguing for an early initiation to optimize its efficacy. • The early selection of patients who will suffer from patent ductus arteriosus-related morbidities and who will positively respond to ibuprofen is an issue that could determine the future place of ibuprofen in the patent ductus arteriosus management.

Bidirectional associations between maternal controlling feeding and food responsiveness during infancy.

Parental controlling feeding styles and practices have been associated with greater food-approaching appetitive behaviors (i.e., food responsiveness) linked to childhood obesity. Recent longitudinal research suggests that this relationship may be reciprocal such that controlling feeding predicts child appetite and vice versa. However, to date no studies have considered these associations during infancy. The current study investigates prospective bidirectional associations between controlling feeding (restriction, pressure, and food to soothe) and infant food responsiveness. Mothers (N = 176) reported their controlling feeding and their infant's food responsiveness at infant age 2, 6, and 14 months. A 3-wave cross-lagged panel model was used to test the effect of controlling feeding at an earlier time point on infant food responsiveness at a later time point, and vice versa. Maternal controlling feeding and infant food responsiveness showed moderate stability across infancy. Net of covariates, we observed parent-driven prospective relations between pressuring feeding styles and food to soothe with infant food responsiveness. Pressuring to finish was a significant predictor of increases in food responsiveness from 2 to 6 months (p = 0.004) and pressuring with cereal was a significant predictor of increases in food responsiveness from 6 to 14 months (p = 0.02). Greater use of situational food to soothe was marginally associated with higher food responsiveness from 2 to 6 months (p = 0.07) and 6 to 14 months (p = 0.06). Prospective associations between restrictive feeding styles and infant food responsiveness were not observed. Findings point to pressuring feeding styles and food to soothe as potential early life intervention targets to prevent increases in food responsiveness in infancy. Longitudinal research with follow-up in the toddler and preschool years are needed to understand how these associations unfold over time and whether child-driven effects of food responsiveness become apparent as children get older.

A prospective study of the infant gut microbiome in relation to vaccine response.

The establishment of the gut microbiome plays a key symbiotic role in the developing immune system; however, its influence on vaccine response is yet uncertain. We prospectively investigated the composition and diversity of the early-life gut microbiome in relation to infant antibody response to two routinely administered vaccines. Eighty-three infants enrolled in the New Hampshire Birth Cohort Study were included in the analysis. We collected blood samples at 12 months of age and assayed the isolated serum to quantify total IgG and measured antibody to pneumococcal capsular polysaccharide and tetanus toxoid. Stool samples were collected from infants at 6 weeks of age and sequenced using 16S rRNA, and a subset of 61 samples were sequenced using shotgun metagenomics sequencing. We observed differences in beta diversity for 16S 6-week stool microbiota and pneumococcal and tetanus IgG antibody responses. Metagenomics analyses identified species and metabolic pathways in 6-week stool associated with tetanus antibody response, in particular, negative associations with the relative abundance of Aeriscardovia aeriphila species and positive associations with the relative abundance of species associated with CDP-diacylglycerol biosynthesis pathways. The early gut microbiome composition may influence an infant's vaccine response. Early intestinal microbiome acquisition plays a critical role in immune maturation and in both adaptive and innate immune response in infancy. We identified associations between early life microbiome composition and response to two routinely administered vaccines-pneumococcal capsular polysaccharide and tetanus toxoid-measured at approximately 1 year of age. Our findings highlight the potential impact of the gut microbiome on infant immune response that may open up opportunities for future interventions.

Hematological changes in neonatal mice with phlebotomy-induced anemia.

Anemia is a nearly universal diagnosis in preterm infants, caused by phlebotomy, and exacerbated by the underlying erythropoietic immaturity. Newborn infants are exposed to the unique stressor of fetal-to-neonatal transition, which requires significant adaptation ex utero. Accordingly, the preterm infant's response to anemia may alter the ability to confront underlying illness. This study utilized our preclinical mouse model of phlebotomy-induced anemia (PIA) to comprehensively investigate associated hematological changes. C57BL/6 mice were subjected to timed phlebotomy between postnatal days 2--10 to induce severe anemia. Complete blood counts were determined by the Sysmex XT-2000iV analyzer. Anemic pups showed a gradual reduction of RBC and hemoglobin (Hb) and increased reticulocyte (RET) counts and red cell distribution width (RDW), however, with reduced RET-Hb from postnatal day (P) of 4 onwards. Elevated levels of high fluorescent RET and immature reticulocyte fraction (IRF) were noted in anemic mouse pups, but low and medium fluorescent RET were reduced. Also, the reduction of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were noted in anemic pups. No changes were seen in lymphocytes, but monocytes and neutrophils were significantly elevated from P4-P6. PIA in mouse pups is associated with hematological changes that may be exacerbating factors in neonatal diseases. Anemia is common and often severe in premature infants. Investigation of hematological parameters in settings of preclinical anemia may be an index of therapeutic strategies. Preclinical model evaluating the effects of neonatal anemia on the remainder of complete blood count. Detailed time kinetic phlebotomy-induced anemic mice enable us to study the impact on developmental delays in erythropoiesis and possible strategic intervention. Hematological effects of severe anemia in mice might provide insight on how best to investigate anemia in preterm infants.

Exclusive breast-feeding, the early-life microbiome and immune response, and common childhood respiratory illnesses

The impact of breast-feeding on certain childhood respiratory illnesses remains controversial. We sought to examine the effect of exclusive breast-feeding on the early-life upper respiratory tract (URT) and gut microbiome, the URT immune response in infancy, and the risk of common pediatric respiratory diseases. We analyzed data from a birth cohort of healthy infants with prospective ascertainment of breast-feeding patterns and common pediatric pulmonary and atopic outcomes. In a subset of infants, we also characterized the URT and gut microbiome using 16S ribosomal RNA sequencing and measured 9 URT cytokines using magnetic bead-based assays. Of the 1949 infants enrolled, 1495 (76.71%) had 4-year data. In adjusted analyses, exclusive breast-feeding (1) had an inverse dose-response on the ⍺-diversity of the early-life URT and gut microbiome, (2) was positively associated with the URT levels of IFN-α, IFN-γ, and IL-17A in infancy, and (3) had a protective dose-response on the development of a lower respiratory tract infection in infancy, 4-year current asthma, and 4-year ever allergic rhinitis (odds ratio [95% CI] for each 4 weeks of exclusive breast-feeding, 0.95 [0.91-0.99], 0.95 [0.90-0.99], and 0.95 [0.92-0.99], respectively). In exploratory analyses, we also found that the protective association of exclusive breast-feeding on 4-year current asthma was mediated through its impact on the gut microbiome (P= .03). Our results support a protective causal role of exclusive breast-feeding in the risk of developing a lower respiratory tract infection in infancy and asthma and allergic rhinitis in childhood. They also shed light on potential mechanisms of these associations, including the effect of exclusive breast-feeding on the gut microbiome.

The prism of reactivity: Concordance between biobehavioral domains of infant stress reactivity

Across a range of challenging contexts, a complex system of stress responses within multiple domains (e.g., behavior, physiology) support, or thwart, an infant’s capacity to navigate an ever-changing world. As understanding of these individual stress response systems has improved, researchers have called for integrated examinations across multiple systems and domains. However, extant research has usually focused on reactivity within a single system and very few explore the associations between multiple domains of stress responding. Drawing on a diverse sample of 135 mother-infant dyads, the current study explored biobehavioral concordance across the Autonomic Nervous System (ANS; measured via both cardiac and salivary indicators), Hypothalamic-pituitary-adrenal (HPA; measured via salivary indicators) axis, observed behavior, and maternal reports of temperament. Correlation analysis generally revealed moderate negative associations between ANS and HPA axis, moderate negative associations between ANS and coded negative behavior, and small-to-moderate positive associations between ANS and coded object engagement and social behavior. Salivary biomarkers and maternal report of infant temperament showed less concordance across systems and domains than cardiac ANS indicators. These findings provide a foundational understanding of the associations between biobehavioral indicators of stress responses in infancy, a period of high developmental plasticity.

Mother's engagement with infant linked to infant's responding to threat

AbstractThe early development of threat perception in infancy might be dependent on caregiver context, but this link has not yet been studied in human infants. This study examined the emergence of the young infant's response to threat in the context of variations in caregiving behavior. Eighty infant‐caregiver dyads (39 female infants, all of western European descent) visited the laboratory when the infant was 5 months old. Each dyad completed a free‐play task, from which we coded for the mother's level of engagement: the amount of talking, close proximity, positive affect, and attention directed toward the infant. When the infant was 7 months old, they came back to the laboratory and we used functional near infrared spectroscopy and eye tracking to measure infants’ neural and attentional responses to threatening angry faces. In response to threat, infants of more‐engaged mothers showed increased brain responses in the left dorsolateral prefrontal cortex—a brain region associated with emotion regulation and cognitive control among adults—and reduced attentional avoidance. These results point to a role for caregiver behavioral context in the early development of brain systems involved in human threat responding.

Neural Correlates of Infant Face Processing and Later Emerging Autism Symptoms in Fragile X Syndrome.

Fragile X syndrome (FXS) is the leading known genetic cause of autism spectrum disorder (ASD) with 60–74% of males with FXS meeting diagnostic criteria for ASD. Infants with FXS have demonstrated atypical neural responses during face processing that are unique from both typically developing, low-risk infants and infants at high familial risk for ASD (i.e., infants siblings of children with ASD). In the current study, event-related potential (ERP) responses during face processing measured at 12 months of age were examined in relation to ASD symptoms measured at ~48 months of age in participants with FXS, as well as siblings of children with ASD and low-risk control participants. Results revealed that greater amplitude N290 responses in infancy were associated with more severe ASD symptoms in childhood in FXS and in siblings of children with ASD. This pattern of results was not observed for low-risk control participants. Reduced Nc amplitude was associated with more severe ASD symptoms in participants with FXS but was not observed in the other groups. This is the first study to examine ASD symptoms in childhood in relation to infant ERP responses in FXS. Results indicate that infant ERP responses may be predictive of later symptoms of ASD in FXS and the presence of both common and unique pathways to ASD in etiologically-distinct high-risk groups is supported (i.e., syndromic risk vs. familial risk).

Leber Congenital Amaurosis

Leber Congenital Amaurosis (LCA) is one of the most severe forms of hereditary retinal dystrophies described approximately 150 years ago and is a cause of vision loss early in childhood. Although LCA is characterized by wandering nystagmus, poor pupillary reflex (amaurotic pupils), and undetectable or severely abnormal ERG responses in infancy, there is a milder form called Severe Early Childhood Onset Retinal Dystrophy (SECORD) presenting after infancy usually before the age of five. LCA and SECORD describe a clinically and genetically diverse group of diseases. To date, there are 30 different genes determined to cause LCA/SECORD, and these genes are thought to account for approximately 70-80% of the disease spectrum. In recent years, with the initial successful results reported in treatment with gene therapy, LCA/SECORD has become the focus of new researches. This review summarizes the genetic and pathophysiological basis, different genetic types, and their clinical findings, diagnosis, differential diagnosis, and current developments in the treatment of LCA/SECORD.

Oxygen saturation (SpO2) targeting for newborn infants at delivery: Are we reaching for an impossible unknown?

For more than 200 years, pure oxygen was given ad libitum to newborn infants requiring resuscitation. Due to oxidative stress and injury concerns, a paradigm shift towards using “less” oxygen, including air (21% oxygen) instead of pure (100%) oxygen, occurred about twenty years ago. A decade later, clinicians were advised to adjust fractional inspired oxygen (FiO2) to target oxygen saturations (SpO2) that were derived from spontaneously breathing, healthy, mature infants. Whether these recommendations are achievable, beneficial, harmful or redundant is uncertain. The underlying pathology leading to resuscitation varies between infants and may considerably alter an infant's response to supplemental oxygen. In this review, we summarize available evidence for the use of SpO2 monitoring at delivery for newborn infants, elucidate existing knowledge and service gaps, and suggest future research recommendations that will lead to the safest clinical strategies for this standard and important practice.

Understanding Early-Life Adaptive Immunity to Guide Interventions for Pediatric Health.

Infants are capable of mounting adaptive immune responses, but their ability to develop long-lasting immunity is limited. Understanding the particularities of the neonatal adaptive immune system is therefore critical to guide the design of immune-based interventions, including vaccines, in early life. In this review, we present a thorough summary of T cell, B cell, and humoral immunity in early life and discuss infant adaptive immune responses to pathogens and vaccines. We focus on the differences between T and B cell responses in early life and adulthood, which hinder the generation of long-lasting adaptive immune responses in infancy. We discuss how knowledge of early life adaptive immunity can be applied when developing vaccine strategies for this unique period of immune development. In particular, we emphasize the use of novel vaccine adjuvants and optimization of infant vaccine schedules. We also propose integrating maternal and infant immunization strategies to ensure optimal neonatal protection through passive maternal antibody transfer while avoiding hindering infant vaccine responses. Our review highlights that the infant adaptive immune system is functionally distinct and uniquely regulated compared to later life and that these particularities should be considered when designing interventions to promote pediatric health.

Characteristics of Speech-Evoked Envelope Following Responses in Infancy.

Envelope following responses (EFRs) may be a useful tool for evaluating the audibility of speech sounds in infants. The present study aimed to evaluate the characteristics of speech-evoked EFRs in infants with normal hearing, relative to adults, and identify age-dependent changes in EFR characteristics during infancy. In 42 infants and 21 young adults, EFRs were elicited by the first (F1) and the second and higher formants (F2+) of the vowels /u/, /a/, and /i/, dominant in low and mid frequencies, respectively, and by amplitude-modulated fricatives /s/ and /∫/, dominant in high frequencies. In a subset of 20 infants, the in-ear stimulus level was adjusted to match that of an average adult ear (65 dB sound pressure level [SPL]). We found that (a) adult–infant differences in EFR amplitude, signal-to-noise ratio, and intertrial phase coherence were larger and spread across the frequency range when in-ear stimulus level was adjusted in infants, (b) adult–infant differences in EFR characteristics were the largest for low-frequency stimuli, (c) infants demonstrated adult-like phase coherence when they received a higher (i.e., unadjusted) stimulus level, and (d) EFR phase coherence and signal-to-noise ratio changed with age in the first year of life for a few F2+ vowel stimuli in a level-specific manner. Together, our findings reveal that development-related changes in EFRs during infancy likely vary by stimulus frequency, with low-frequency stimuli demonstrating the largest adult–infant differences. Consistent with previous research, our findings emphasize the significant role of stimulus level calibration methods while investigating developmental trends in EFRs.

Earlier Intervention for Medically Fragile Pediatric Inpatient Population

Earlier Intervention for Medically Fragile Pediatric Inpatient Population

Neonatal vaccination primes persistent HIV Env-specific antibodies that are augmented by a single booster immunization in late infancy

Abstract Breastmilk transmission of HIV remains unacceptably high. Vaccine approaches that prime robust virus-specific immune responses in infancy may prevent acquisition during the breastfeeding period. Moreover, vaccine responses that generate robust immunological memory that persists into adolescence could prevent sexual transmission later in life. The current study investigated the immunological benefit of late boosting following vaccination in infancy. Two groups of neonatal rhesus macaques were immunized with a clade C HIV Env protein adjuvanted with 3M-052 stable emulsion (SE) vaccine (Env Only) alone or together with a modified vaccinia Ankara (MVA) vector expressing HIV Env and SIV Gag (MVA/Env) at 0, 6, and 12 weeks of age. Env-specific B cells were present in blood yet absent from lymph nodes in the Env Only group by week 14. At week 32, 18 weeks following the last immunization, we could still detect Env-specific plasma IgG responses capable of autologous and heterologous HIV Env binding, Env-specific ADCC activity and CD4 blocking in both groups. A final booster immunization at week 32 enhanced avidity and function of Env-specific plasma IgG in both groups. These data confirmed previous work by our group that demonstrated HIV Env protein adjuvanted with the TLR7/8-based 3M-052-SE primed greater immune responses than Span85-Tween 80 Squalene. Our data from the Env Only vaccine regimen are consistent with the induction of Env-specific antibody responses in human infants. These results support the idea that early life vaccination is an effective means to induce persistent HIV Env-specific IgG responses that can be boosted in infancy and could be exploited to drive protective immunity against HIV acquisition prior to sexual debut.

A Study on Infant's Response to Disability: Using Zhuang Zi fable's ‘Ataeta story’

A Study on Infant's Response to Disability: Using Zhuang Zi fable's ‘Ataeta story’

An Animal Model for Mammalian Attachment: Infant Titi Monkey (Plecturocebus cupreus) Attachment Behavior Is Associated With Their Social Behavior as Adults.

Close social bonds are integral for good health and longevity in humans and non-human primates (NHPs), yet we have very little understanding of the neurobiological differences between healthy and unhealthy relationships. Our current understanding of social bonding is grounded in Bowlby’s theory of attachment. Work done with human infants and adult couples has suggested that attachment behavior developed in infancy remains stable through development into adulthood. Unfortunately, knowledge of the neurobiological correlates of attachment behavior has been limited due to a lack of animal models with both infant and adult attachments similar to humans. To address this, we measured behavioral responses to separation from their primary attachment figure in infant and adult titi monkeys (Plecturocebus cupreus). In Experiment 1, we tested for a linear relationship between the subject’s response to separation as an infant and their response to separation as an adult. We found greater decreases in infant locomotor behavior in the presence, as opposed to absence, of their primary attachment figure to be indicative of decreased anxiety-like behavior in the presence, as opposed to absence, of their adult pair mates during a novelty response task. In Experiment 2, we increased our sample size, accounted for adverse early experience, and tested a different outcome measure, adult affiliative behavior. We hypothesized that the level of intensity of an infant’s response to separation would explain affiliative behavior with their mate as an adult, but adverse early experience could change this relationship. When we compared infant response to separation to adult affiliative behavior during the first 6 months of their first adult pair bond, we observed a linear relationship for infants with typical early experience, but not for infants with adverse early experience. Infants with a greater change in locomotive behavior between the father and alone conditions were more affiliative with their first adult pair mate. These data support the use of titi monkeys as an appropriate animal model for further investigation of the neurobiology underlying attachment behavior.