Neural sensitivity to social cues in preterm preschoolers: Reduced voice but not face processing

Preterm birth has been linked to atypical social development, with preterm individuals displaying atypical social gaze patterns of more frequent but shorter looks toward faces. We compared proportional looking times to the face and the eyes during face-to-face interactions in preterm (N = 45) and full-term (N = 29) five-year-olds, using a video-based eye-tracking set-up. Children participated in four interaction tasks, including silent looking at their mother, silent looking at a female stranger, and a positive and negative conversation with their mother. No group differences were found between preterm and full-term children in proportional dwell times to the face or the eyes, suggesting typical social orienting during face-to-face interactions. We observed a marginal effect of interaction partner, with children spending proportionately more time gazing at their mother’s face than at a stranger’s face. Typical social gaze may reflect a developmental catch-up in social orientation following initial delays in infancy. Alternatively, advances in neonatal medical care may have been successful in improving social functioning after preterm birth. These findings should be interpreted cautiously, given how context-dependent and individual gaze behavior is. Future longitudinal studies employing consistent methodological approaches are needed to investigate how social gaze develops over time following preterm birth.

Reciprocal gaze, the mutual exchange of eye contact, plays a key role in human communication and bonding, yet it is often experienced as challenging for individuals with autism. In recent years, administration of the neuropeptide oxytocin is increasingly considered a novel approach for supporting social experiences in children with autism, but insights regarding its effects on mutual gaze or pupil dynamics remain limited—particularly regarding how chronic, repeated dosing impacts these processes.This double-blind, randomized, placebo-controlled trial examined the effects of four weeks of chronic intranasal oxytocin administration on gaze behavior and pupil dynamics during live dyadic interactions in school-aged children with autism (aged 8-12 years, 15 oxytocin, 20 placebo).While the overall duration of fixations toward the face remained unchanged, oxytocin altered the distribution of gaze, resulting in a more balanced pattern of looking toward and away from the face of a live interaction partner, an effect observed only in the oxytocin group and not in the placebo group. In addition, the four-week oxytocin administration period induced a relative increase in pupil dilation, an index of sympathetic arousal and attentional engagement, with this heightened autonomic responsivity showing a moderate association with children’s self-reported feelings of secure attachment.Together, these findings indicate that repeated oxytocin administration may modulate gaze parameters in live social interactions in children with autism. While cautiously encouraging, future work will be needed to further delineate whether these changes meaningfully reflect ameliorated experience and comfort in social settings.

Background Nonverbal social cues are essential for social communication and play a fundamental role in social interactions. Given the socio-communicative challenges often observed in prematurely born individuals, it is important to explore whether they have specific difficulties in using and interpreting these cues during face-to-face interactions. This systematic review examines how preterm (PT) born individuals use and process nonverbal cues compared to full-term (FT) peers. Methods A systematic search across multiple medical and psychological databases was conducted. Only studies investigating the use of or the response to nonverbal cues in face-to-face interactions among PT individuals, compared to FT controls were included. Risk of bias was assessed using the JBI Critical Appraisal Checklist. Results Across the 26 included observational studies, consistent findings indicate that PT infants gaze less at faces in early infancy, exhibit more gaze aversion and show less gaze following behavior. Their ability to respond to joint attention appears delayed but improves over time, with possible catch-up by early childhood. Moderately PT infants exhibit more negative facial expressions during the still-face procedure, and PT infants generally smile less and cry more during social interactions. Gesture production, both deictic and representational, is initially delayed but appears to normalize by early childhood. While basic imitation skills are present at birth, the imitation of more complex gestures tends to be delayed. Conclusion Compared to FT peers, PT individuals exhibit notable difficulties in both using and responding to nonverbal social cues during face-to-face interactions. This review highlights the need for further research, particularly longitudinal studies employing standardized coding methods and stricter inclusion criteria, to better understand the long-term impact of prematurity on socio-communicative development. Registration This systematic review is registered in PROSPERO with following identification ID CRD42024592467.

Importance: Individuals exposed to perinatal risk factors are at increased risk for cardiovascular and neurodevelopmental disorders. Heart rate variability, an index of autonomic nervous system function, is widely used to assess long-term health risk in these populations, yet findings remain inconsistent. Objective: To quantify heart rate variability differences between individuals with perinatal risk factors (including preterm birth, intrauterine growth restriction, and low birth weight) and healthy full-term controls, and to examine sources of heterogeneity. Data sources: PubMed, EMBASE, Web of Science, Scopus, and APA PsycArticles were searched through April 2025, supplemented by ClinicalTrials.gov and reference screening. Study selection: Peer-reviewed studies reporting heart rate variability in perinatal risk populations versus healthy controls after hospital discharge. Of 7,781 screened articles, 27 met inclusion criteria. Data extraction and synthesis: This review followed PRISMA 2020 guidelines and was registered on PROSPERO (CRD42024527673). One reviewer extracted data using a standardized form, with verification by a second reviewer. A total of 176 effect sizes were extracted. Multilevel random-effects models accounted for dependency within studies. Main outcome(s) and measure(s): The primary outcome was heart rate variability difference between groups, expressed as Cohen's d. Results: Across 27 studies (1,890 participants) and 176 effect sizes, the overall effect was modest and marginally significant (d = -0.24; 95% CI: -0.50 to 0.02; p = 0.07), with substantial heterogeneity (Higgins I = 87.7%). Effect sizes differed significantly by perinatal condition (p < 0.001). Congenital heart disease (d = -1.07) and genetic syndromes (d = -1.02) showed large heart rate variability reductions, while growth-related conditions showed moderate effects (d = -0.44). Heart rate variability differences attenuated with age (Beta = +0.027 per year; p = 0.04), with strongest effects in early development (d = -0.85) and apparent normalization during adolescence. Conclusions and relevance: Autonomic consequences of perinatal adversity are condition-specific and developmentally dynamic. Structural and genetic conditions show pronounced deficits, while other conditions show substantial developmental heterogeneity. These findings underscore the importance of age- and condition-specific assessment and longitudinal follow-up. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research was funded by FWO research grants G0C9521N, G054526N, G0B0318N and S003524N, KU Leuven grant KA/20/080, and a grant of UZ Leuven Child Hospital Fund. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study is a systematic review and meta-analysis of previously published research. The data used in this study were obtained from openly available, peer-reviewed articles and public databases (e.g., PubMed, EMBASE,...). Since all data were retrieved from published aggregate results and no individual-level participant data were used, this work did not require new institutional review board (IRB) approval or additional participant consent. The study protocol was prospectively registered in PROSPERO (registration number: CRD42024527673). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.

Background: Efficient processing of emotional socio-communicative cues is fundamental to human social interaction. Anxiety is associated with altered emotion processing, including heightened vigilance and negative attentional and interpretation biases that may compromise social functioning. Maternal anxiety may further shape offspring socio-emotional development, increasing vulnerability to psychopathology. However, the neural mechanisms underlying intergenerational associations between anxiety and emotion processing remain poorly understood. Methods: We examined self-reported anxiety and implicit neural emotion discrimination in mothers (N=46) and their prematurely born 5-year-old children (N=57). Using frequency-tagging EEG, we assessed neural sensitivity to emotional faces and voices. Associations between maternal anxiety and mothers’ own emotion processing, as well as children’s neural responses were examined, alongside links between child anxiety and neural sensitivity. In visual and auditory oddball paradigms, neutral faces or voices were presented at base rates with periodic expressive stimuli. Neural responses at the oddball frequency indexed implicit emotion discrimination, enabling objective measurement of emotional sensitivity. Results: Across modalities, mothers showed higher responses to fearful versus happy stimuli, indicating an implicit threat bias. Higher maternal anxiety predicted reduced neural sensitivity to fearful versus happy faces and voices, suggesting a negative interpretation bias and attenuated differentiation of emotional cues. In children, higher child anxiety was related to reduced right-hemispheric engagement during emotional face processing, while higher maternal anxiety predicted reduced sensitivity to emotional voices. Conclusion: These findings demonstrate that (subclinical) anxiety is associated with altered implicit emotion processing in both mothers and their children, highlighting potential neural mechanisms underlying intergenerational transmission of socio-emotional vulnerability.

Background/Objectives. Human voices convey critical socio-affective information, including emotional states. Although autism has frequently been associated with difficulties in processing vocal emotional cues, findings remain inconsistent, particularly in adults. This study investigated neural and behavioral sensitivity to vocal emotion expressions in autistic adults using an objective auditory frequency-tagging EEG paradigm. Methods. Twenty-five autistic adult men and 25 age- and IQ-matched non-autistic men completed an auditory frequency-tagging EEG task and an auditory and multimodal emotion-recognition assessment. During EEG recording, neutral vocal utterances were presented at 4 Hz, with emotional utterances (fear, anger, happiness, or sadness) inserted every third stimulus, generating an oddball frequency of 1.333 Hz indexing vocal emotion discrimination. Results. No significant group differences were observed in neural or behavioral measures of emotion processing. Robust oddball EEG responses were present in both groups, indicating automatic discrimination of emotional from neutral vocalizations. Fearful and angry vocalizations elicited the strongest neural responses. On the behavioral task, autistic and non-autistic participants showed comparable performance in the auditory modality as well as in the visual and audiovisual modalities, with auditory emotion recognition being the most challenging condition for both groups. Conclusions. These findings provide converging neural and behavioral evidence for intact vocal emotion processing in autistic adult men and are consistent with the view that socio-affective processing differences may attenuate across development. Auditory frequency-tagging EEG shows promise as a sensitive tool for studying individual differences in socio-affective processing.

Bidirectional temporal contingency in infant-caregiver interaction is believed to be instrumental in shaping the development of turn-taking and speech. Likewise, caregivers are known to modulate their voices in a distinctive register when speaking to infants. Yet, less is known about whether these modulations are features of caregivers' timely responses to infant vocalisations, and whether such features support infant participation in turn-taking bouts. We analysed 231 daylong home recordings of 111 mother-infant dyads (4-34 months). Mother and infant vocalisations were automatically identified and infant vocalisations classified as cries or non-cries. Contingent responses were vocalisations which followed the vocal offset of the preceding speaker within 2 s, allowing overlapping responses. Features of infant-directed speech (pitch, pitch variability, intensity, voice quality, duration and speech rate) were extracted from maternal vocalisations. Furthermore, alignment in pitch, intensity and voice quality of mother responses to infant vocalisations was calculated. Maternal responses were also automatically classified as single words, questions, declaratives, or imperatives. Mothers' contingent responses showed a simplified and acoustically salient profile compared to non-contingent speech: they were shorter and slower, with higher pitch variability, intensity and voice quality, and they were more likely to be single words and questions. Contingent responses that were shorter, slower and clearer (higher intensity and voice quality) were more often followed by infant vocalisation. These findings suggest that beyond temporal contingency, caregivers' brevity, acoustic clarity and question-asking may also support the turn-taking exchanges through which early communicative competence develops.

Efficient voice recognition is vital for social communication, but evidence on voice identity processing difficulties in autism spectrum disorder (ASD) is mixed. This review clarifies current knowledge and future research needs. A systematic review of 22 studies examined unfamiliar voice discrimination, voice familiarity recognition, identification, neural correlates, gender/age perception, and self-voice recognition. ASD individuals show intact gender/age inference but impaired unfamiliar voice discrimination, likely due to low-level acoustic encoding issues. Voice familiarity recognition and identification are impaired in children but improve with age. Aside from perceptual functioning, high-level cognitive encoding difficulties are implied, suggestive for both apperceptive and associative phonagnosia. Neuroimaging showed altered brain responses in voice-sensitive areas associated with both perceptual processing and reward or salience.

Atypical oxytocinergic functioning and altered microbiome compositions have both been implicated in autism, with growing evidence of interactions between these systems. However, how exogenous oxytocin influences the oral microbiome remains largely unexplored. This exploratory study examined for the first time how oral microbiome alterations link to oxytocinergic signalling in school-aged autistic (n = 80) and non-autistic children (n = 40). Additionally, we investigated the effect of four-weeks of intranasal oxytocin administration in autistic children on oral microbiome compositions immediately post-treatment (T1) and at four-weeks follow-up (T2). At baseline, lower endogenous salivary oxytocin levels were linked to greater microbial evenness and diversity, with twelve genera showing significant associations with oxytocin levels. In autistic children, four weeks of oxytocin administration was associated with significant increases in the abundances of Centipeda immediately post-treatment (T0-T1), alongside decreases in Moraxella (T0-T1), and subsequent reductions in Rothia observed at the four-week follow-up (T1-T2). Particularly, the genus Moraxella emerged as relevant, as lower baseline abundance was associated with higher endogenous oxytocin levels, and a stronger oxytocin-induced downregulation of its abundance correlated with greater increases in endogenous oxytocin levels, accompanied by hypomethylation of the oxytocin receptor gene. All results persisted after adjusting for nutrition and dental care. This exploratory study provides initial evidence for a role of the oxytocinergic system in shaping the oral microbiome in autistic children. These results may facilitate the integration of oral microbiome profiling into autism diagnostic criteria and stimulate future studies on the use of oxytocin as a therapeutic option targeting oral microbiome alterations.

Anxiety-related disorders are prevalent and can severely impact daily functioning, making the study of their underlying mechanisms a priority. Symptom provocation is an experimental approach enabling researchers to elicit and examine specific symptoms under controlled conditions in people affected by these disorders. This article provides an overview of symptom provocation techniques, their implementation, and their role in advancing research on anxiety-related disorders (including anxiety disorders, obsessive-compulsive disorder, and post-traumatic stress disorder). We outline key considerations for conducting high-quality symptom provocation studies, addressing study design and objectives, ethical considerations, experimenter training, study logistics, data validity, and opportunities for technological integration and collaboration. We provide guiding principles for obtaining more rigorous, reliable, and clinically meaningful findings to advance the current understanding of anxiety-related disorders.

Premature birth increases risk for socio-emotional difficulties and altered autonomic regulation, yet because physiological regulation supports development, dysregulation may have lasting consequences. We evaluated social functioning and physiological regulation in 70 preterm children aged 5.5 years compared to 32 matched full-term controls (Total sample: 59 boys, 43 girls; 98% White). Heart rate and heart rate variability (HRV) were recorded during rest and structured social interactions with the mother and a stranger, including eye contact, conversations, and triadic play. Preterm children demonstrated significantly greater social difficulties and internalizing problems than full-term peers. Across conditions, they exhibited consistently elevated heart rate, whereas HRV patterns were comparable between groups. Specifically, RMSSD-HRV varied by interaction partner (stable with mother, fluctuating with stranger), while HF-HRV reflected general condition effects independent of partner familiarity. Conversation tasks elicited the strongest autonomic activation, with pronounced vagal withdrawal during negative exchanges. In conclusion, preterm children show persistent cardiac hyperarousal and social-behavioral difficulties, yet maintain context-dependent autonomic regulation similar to full-term peers. The distinct sensitivity of HRV indices suggests preserved regulatory mechanisms, indicating that prematurity's physiological signature may reflect heightened baseline arousal rather than impaired regulation.

Purpose: Speech perception is a fundamental part of everyday communication that relies on more than simple identification of words and sentences. Attention and listening engagement both contribute to speech perception, while representing distinct aspects of the listening experience. Attention is typically associated with cognitive focus, whereas listening engagement additionally involves cognitive and affective immersion in sound. Despite their importance, these states remain difficult to disentangle, behaviorally and physiologically. Both have been linked to interpersonal synchronization (the synchronization of biobehavioral signals across individuals), raising questions about what this synchronization actually reflects. Method: In this study, we disentangled attention and listening engagement by independently manipulating both factors within a single experiment. Thirty participants listened to two simultaneously presented streams of meaningful speech and were instructed to focus on only one. Both attended and unattended stimuli were designed to be either engaging or non-engaging. Neural activity was recorded using EEG, while physiological responses were measured using heart rate and electrodermal activity. Results: Interpersonal synchronization was computed from neural and bodily signals, alongside a self-report measure of listening engagement and auditory attention decoding (AAD), a neural measure of selective attention. Interpersonal synchronization of all three modalities significantly predicted listening engagement, whereas neural interpersonal synchronization was the only measure that significantly predicted attention. These findings suggest that attention is primarily driven by cognitive processes represented in the brain, while listening engagement additionally involves affective processes that are more strongly reflected in bodily responses. Conclusions: Overall, this study demonstrates that different forms of interpersonal synchronization reflect distinct dimensions of the listening experience and supports interpersonal synchronization as a potential objective marker of listening engagement.

Background: Accurate emotion processing is crucial for social development. Preterm birth is associated with neurodevelopmental alterations and increased vulnerability to subtle socio-emotional difficulties, often described within the preterm behavioral phenotype. Previous studies have reported impaired emotion recognition in preterm populations, but have largely relied on behavioral tasks and primarily focused on facial expressions. Because explicit emotion recognition is still developing in early childhood, objective neural markers of implicit emotion discrimination may be particularly informative for early detection. Methods: We administered a series of frequency-tagging electroencephalography (EEG) paradigms to investigate neural sensitivity to brief changes in emotional expressions in a cohort of five-year-old preterm children (N = 66), and age-matched full-term peers (N = 32). Frequency-tagging EEG utilizes fast periodic stimulation to elicit synchronized brain responses measurable in the frequency domain. Neural sensitivity to changes in emotional expressions was examined in both the visual and auditory modality, using oddball paradigms with neutral faces or voices presented at base frequency and emotional expressions (either fearful or happy) presented as periodic oddballs. Linear mixed models were used to investigate the effects of group, emotion, and prematurity severity. Results: All children showed implicit neural discrimination between neutral and emotional expressions. Compared to full-term peers, children born very preterm (≤32 weeks of gestation) showed reduced neural sensitivity to both facial and vocal emotion expression changes. Children born moderate-to-late preterm (33-36 weeks of gestation) also showed reduced neural sensitivity, but only for vocal expressions. Across modalities, reduced neural sensitivity to happy emotional expressions was associated with higher parent-reported social difficulties. Conclusions: Five-year-old children born preterm show reduced neural sensitivity to brief changes in facial and vocal emotional expressions compared with full-term peers. Strikingly, the impact of prematurity severity differed between the visual and auditory modalities, indicating differential maturation of higher-level visual and auditory processing following preterm birth. These findings contribute to a more detailed understanding of socio-emotional development after preterm birth and highlight the importance of early, modality-sensitive monitoring of socio-emotional development across the entire preterm population.

Background Preterm birth is a life-changing event, followed by hospitalization in the Neonatal Intensive Care Unit. During this critical period of biological immaturity, preterm infants encounter atypical sensory stimulation and (painful and stressful) medical interventions. Such early environmental factors can alter the development of the hypothalamic-pituitary-adrenal (HPA) axis and the oxytocinergic system, potentially leading to long-term effects on neurodevelopment. The research on these physiological markers in preterm individuals remains inconclusive, partly due to variability in study designs, sample collection, and participant selection. Studies later in life, during childhood or adulthood, are particularly scarce. Methods Oxytocin and cortisol levels, and DNA methylation of the oxytocin receptor gene (OXTR) and the glucocorticoid receptor gene (NR3C1) were assessed in 39 preterm and 38 full-term school-aged children. Salivary samples were collected at two timepoints: one sample after awakening, and two samples at the end of the study visit. Results Preterm children had lower morning oxytocin levels but similar afternoon oxytocin levels compared to full-term children. Both groups showed elevated cortisol levels in the morning compared to the afternoon. Preterm children exhibited a steeper decline in cortisol, with lower afternoon cortisol levels compared to full-term children. DNA methylation of NR3C1 was lower in preterm children, whereas no group differences were observed for OXTR. Conclusion These findings suggest differences in salivary measures of the HPA axis and oxytocinergic system in preterm school-aged children compared to full-term children, highlighting the importance of further research into the long-term impact of preterm birth and early life stressors.

Autistic children often experience behavioral difficulties alongside nutritional and gastro-intestinal (GI) problems, including gut dysbiosis. Recent research has highlighted important interactions between the oxytocinergic system and gut microbiome compositions, however, insights into how exogenous administration of oxytocin may influence GI health remain largely unexplored.Here, we first examined whether nutrition, GI symptoms and microbiome compositions vary in autistic versus non-autistic children, and how alterations link to clinical-behavioral difficulties and oxytocinergic signaling. Next, we examined the effect of a four-week intranasal oxytocin administration regimen on GI health/dysbiosis in autistic children enrolled in a randomized placebo-controlled trial.Compared to non-autistic children, autistic children consumed more soft drinks, and fewer vegetables and experienced abdominal pain more frequently over the past three months. Notably, epigenetic variations in the oxytocin receptor gene (OXTR) were associated with stool consistency, indicating that children with looser stools exhibited lower OXTR methylation levels, indicative of increased receptor expression. Additionally, a higher abundance of Romboutsia was associated with OXTR hypo-methylation and more anxiety-like behavior. In autistic children, the four-week oxytocin regimen had no effect on bacterial diversity but did modify stool consistency, leading to less dense stools with an overall more normal stool consistency, and an increased abundance of the potentially anti-inflammatory genus Fusicatenibacter.To conclude, this study provides novel insights into the role of the oxytocinergic system in GI symptoms and gut microbiome compositions in autistic children, and preliminary evidence suggesting a modulatory effect of exogenously administered oxytocin on these parameters.

Improved survival of very preterm (<32 weeks of gestation) infants has highlighted neurodevelopmental and socio-emotional challenges. As altered gaze behavior and autonomic functioning may contribute to these difficulties, we investigated this in thirty-nine very preterm and thirty-eight full-term 8-to-12-year-old children. We assessed gaze behavior during a semi-structured conversation. Autonomic functioning was evaluated through heart rate variability and skin conductance responses at rest and during an eye contact paradigm. Preterms exhibited shorter but more frequent gazes toward their conversation partner than full-terms. Moreover, both at rest and during the eye contact paradigm, they demonstrated higher heart rate variability. No group differences in skin conductance responses were observed at rest, but during the eye contact paradigm, preterms displayed more pronounced skin conductance responses regardless of condition. Very preterm children exhibited reduced sustained social attention and heightened autonomic activity. Nevertheless, reported subjective experiences were similar among both groups, suggesting that heightened arousal reflects general physiological reactivity rather than perceived stress. This underscores the importance of potential interventions targeting attentional control to improve socio-emotional outcomes in very preterm children.

BackgroundChildren born preterm face increased risks of neurodevelopmental difficulties, comprised within the "preterm behavioral phenotype". This study examined behavioral and socio-emotional development in preterm preschoolers using a multi-informant approach to characterize behavioral profiles, mental health outcomes, and their associations with gestational age, birth weight, and early medical experiences.Methods102 five-year-old children (70 preterm, 32 full-term) were assessed using standardized measures, including parent and teacher questionnaires (Child Behavior Checklist, Teacher Report Form, Social Responsiveness Scale, ADHD Questionnaire) and direct clinical observation (Autism Diagnostic Observation Schedule-2). Analyses examined group differences and associations with gestational age, birth weight and neonatal intensive care unit (NICU) parameters, including early procedural pain, respiratory support and kangaroo care.ResultsPreterm children demonstrated a predominantly subclinical phenotype, characterized by elevated difficulties across domains. Marked informant discrepancies emerged: parents reported more internalizing symptoms, attention deficits, social-communication difficulties, and autism-related traits in the preterm group, whereas teacher ratings showed stronger associations with gestational age, birth weight, and early medical procedures. Early NICU experiences were linked to later outcomes: greater exposure to skin-breaking procedures predicted higher reported behavioral problems, whereas more kangaroo care was associated with fewer reported social difficulties.ConclusionsPreterm preschoolers display subtle yet meaningful socio-emotional vulnerabilities that manifest below clinical thresholds, but still warrant continued surveillance. Divergence between parent and teacher perspectives underscores the importance of multi-informant assessment across contexts. Associations between early procedural pain and later socio-emotional outcomes identify a modifiable risk factor, emphasizing the importance of optimized neonatal pain management and minimizing medical intensity.

Premature birth increases risk for socio-emotional difficulties and altered autonomic regulation, yet because physiological regulation supports development, dysregulation may have lasting consequences. We evaluated social functioning and physiological regulation in 70 preterm children aged 5.5 years compared to 32 matched full-term controls (total sample: 59 boys, 43 girls; 98% White). Heart rate and heart rate variability (HRV) were recorded during rest and structured social interactions with the mother and a stranger, including eye contact, conversations, and triadic play. Preterm children demonstrated significantly greater social difficulties and internalizing problems than full-term peers. Across conditions, the preterm children exhibited consistently elevated heart rate, whereas HRV patterns were comparable with the full-term group. Across both groups, RMSSD-HRV varied by interaction partner (stable with mother, fluctuating with stranger), while HF-HRV reflected general condition effects independent of partner familiarity. In both groups, conversation tasks elicited the strongest autonomic activation, with the lowest parasympathetic indices during negative interactions. In conclusion, preterm children show persistent cardiac hyperarousal and social-behavioral difficulties yet maintain context-dependent autonomic regulation similar to full-term peers. The distinct sensitivity of HRV indices suggests preserved regulatory mechanisms, indicating that prematurity's physiological signature may reflect heightened baseline arousal rather than impaired regulation.