Heart Rate Variability In Infants Research Articles

Exposure to prenatal stressors and infant autonomic nervous system regulation of stress.

The purpose of this study was to determine the relationship between fetal exposure to maternal prenatal stressors and infant parasympathetic (PNS) and sympathetic (SNS) nervous function at 3 timepoints across the first year of life. Autonomic nervous system impairments may mediate associations between gestational exposure to stressors and later infant health problems. Heart rate variability (HRV) provides a sensitive index of PNS and SNS function. However, no studies have assessed longitudinal associations between prenatal stressors and infant HRV measures of both PNS and SNS over the first year of life. During the third trimester of pregnancy, 233 women completed measures of life stressors and depression. At 1, 6 and 12 months of age, a stressor protocol was administered while infant electrocardiographic (ECG) data were collected from a baseline through a post-stressor period. HRV measures of PNS and SNS activity (HF, LF, LF/HF ratio) were generated from ECG data. We used multilevel regression to examine the aims, adjusting for maternal depression and neonatal morbidity. There were no associations between prenatal stressors and any baseline or reactivity HRV metric over the infant's first year of life. However, exposure to more stressors was associated with lower post-stressor LF HRV at both 6 (β = -.44, p = .001) and 12 (β = -.37, p = .005) months of age. Findings suggest potential alterations in development of the vagally mediated baroreflex function as a result of exposure to prenatal stressors, with implications for the infants' ability to generate a resilient recovery in response to stressors.

Perceived Parenting Stress Is Related to Cardiac Flexibility in Mothers: Data from the NorBaby Study.

Heart rate variability (HRV) is an indicator of autonomic nervous system activity, and high levels of stress and/or depressive symptoms may reduce HRV. Here, we assessed whether (a) parental stress affected HRV in mothers during the perinatal period and whether this is mediated by bonding and (b) whether antenatal maternal mental states, specifically repetitive negative thinking, depressive symptoms, and pregnancy-related anxiety, have an impact on infant HRV, and lastly, we investigated (c) the relationship between maternal HRV and infant HRV. Data are from the Northern Babies Longitudinal Study (NorBaby). In 111 parent-infant pairs, cardiac data were collected 6 months after birth. In the antenatal period, we used the Pregnancy-Related Anxiety Questionnaire-Revised, the Edinburgh Postnatal Depression Scale, and the Perseverative Thinking Questionnaire; in the postnatal period, we used the Parenting Stress Index and the Maternal Postnatal Attachment Scale. Higher levels of perceived parenting stress but not depressive symptoms were associated with lower HRV in mothers (τ = -0.146), and this relationship was not mediated by maternal bonding. Antenatal maternal mental states were not associated with infant HRV. There was no significant correlation between maternal HRV and infant HRV. Our observational data suggest that perceived stress reduces cardiac flexibility. Future studies should measure HRV and parenting stress repeatedly during the perinatal period.

Impact of low-level prenatal alcohol exposure and maternal stress on autonomic regulation.

Prenatal alcohol exposure (PAE) impacts the neurodevelopment of the fetus, including the infant's ability to self-regulate. Heart rate variability (HRV), that is, the beat-to-beat variability in heart rate, is a non-invasive measurement that can indicate autonomic nervous system (ANS) function/dysfunction. The study consisted of a subset of our ENRICH-2 cohort: 80 participants (32 PAE and 48 Controls) who had completed three visits during pregnancy. The participants completed a comprehensive assessment of PAE and other substances throughout pregnancy and assessments for stress, anxiety, and depression in the third trimester. At 24 h of age, infant HRV was assessed in the hospital during the clinically indicated heel lance; 3- to 5-min HRV epochs were obtained during baseline, heel lancing, and recovery episodes. Parameters of HRV differed in infants with PAE compared to Controls during the recovery phase of the heel lance (respiratory sinus arrhythmia (RSA) and high-frequency (HF), p < 0.05). Increased maternal stress was also strongly associated with abnormalities in RSA, HF, and low-frequency / high-frequency (LF/HF, p's < 0.05). Alterations in ANS regulation associated with PAE and maternal stress may reflect abnormal development of the hypothalamic-pituitary-adrenal axis and have long term implications for infant responsiveness and self-regulation. Previous studies have focused on effects of moderate to heavy prenatal alcohol exposure (PAE) on autonomic dysregulation, but little is known about the effects of lower levels of PAE on infant self-regulation and heart rate variability (HRV). Prenatal stress is another risk factor for autonomic dysregulation. Mild PAE impacts infant self-regulation, which can be assessed using HRV. However, the effect of prenatal stress is stronger than that of mild PAE or other mental health variables on autonomic dysregulation.

Methods for analyzing infant heart rate variability: A preliminary study.

Heart rate (HR) and heart rate variability (HRV) reflect autonomic development in infants. To better understand the autonomic response in infants, reliable HRV recordings are vital, yet no protocol exists. The purpose of this paper is to present reliability of a common procedure for analysis from two different file types. In the procedure, continuous electrocardiograph recordings of 5-10 min are obtained at rest in infants at 1 month of age by using a Hexoskin Shirt-Junior's (Carre Technologies Inc., Montreal, QC, Canada). Electrocardiograph (ECG; .wav) and R-R interval (RRi; .csv) files are extracted. The RRi of the ECG signal is generated by VivoSense (Great Lakes NeuroTechnologies, Independence, OH). Two MATLAB (The MathWorks, Inc., Natick, MA) scripts converted files for analysis with Kubios HRV Premium (Kubios Oy, Kuopio, Finland). A comparison was made between RRi and ECG files for HR and HRV parameters, and then tested with t tests and correlations via SPSS. There are significant differences in root mean squared successive differences between recording types, with only HR and low-frequency measures significantly correlated together. Recording with Hexoskin and analysis with MATLAB and Kubios enable infant HRV analysis. Differences in outcomes exist between procedures, and standard methodology for infant HR analysis is needed.

Bringing the laboratory into the home: A protocol for remote biobehavioral data collection in pregnant women with emotion dysregulation and their infants.

Pregnant women struggling with emotion dysregulation may be more likely to engage in a wide range of health risk behaviors. This protocol describes a study on intergenerational transmission of emotion dysregulation from the third trimester of pregnancy to 18 months postpartum. Biobehavioral markers of emotion dysregulation are typically measured in laboratory settings which was prohibited by many universities during the COVID-19 pandemic. We describe how markers of emotion dysregulation (e.g. maternal, fetal, and infant heart rate variability) are collected remotely. We detail how data collection can be augmented to reach diverse populations who may not otherwise participate in laboratory-based research.

Prolonged Video-EEG and Heart Rate Variability can Elucidate Autonomic Dysregulation in Infantile Apneic Seizures

BackgroundInfantile apneic seizures (IASs) are unexpected life-threatening events. We aimed to determine the utility of prolonged video-electroencephalography (vEEG) and heart rate variability (HRV) in IAS. MethodsThe study included seven infants with apneic seizures captured by vEEG, percutaneous oxygen saturation (SpO2), and electrocardiography (ECG). Interictal, preictal, and postictal HRV of patients and N2 sleep HRV of 10 age-matched controls were determined. ResultsWe analyzed seven vEEGs (duration = 17 to 87 hours) of seven patients aged three to 13 months (mean onset age of apneic event = 6.3 months). Fifteen apneic seizures (one to five per infant) were captured. The initial apneic seizure was captured at 7.5 to 76 hours (mean = 36.6 hours) after vEEG initiation. Ictal rhythmic delta/theta/fast waves were seen over temporal (five patients), central (one), and diffuse areas (one). Ictal SpO2 decreased between 1.5% and 90% (mean = 47.9%). Ictal decreased heart rate (HR) (six seizures) and ictal increased HR (14) was detected. Both decreased and increased HR was observed (five). The preictal low-frequency (LF)/high-frequency (HF) ratio was significantly higher than the interictal LF/HF ratio (P = 0.048). Preictal (P = 0.048), and postictal (P = 0.019) root mean square of successive differences (RMSSDs) of patients were lower than the sleep RMSSD of controls. These results indicated dominant sympathetic activity. RMSSD from interictal to preictal periods tended to be higher in IAS with decreased HR than in IAS with increased HR alone (P = 0.066). The postictal RMSSD showed tendency to be higher in IAS with decreased HR than in IAS with increased HR alone (P = 0.088). The decreased HR and increased RMSSD suggested not only sympathetic activity but also escalated parasympathetic activity in IAS. ConclusionsInfants with unexpected apneic events should be monitored with prolonged vEEG, SpO2, and ECG. Abnormal HRV in infants with apneic seizures might indicate additional autonomic dysregulation in IAS.

Machine learning model on heart rate variability metrics identifies asymptomatic toddlers exposed to zika virus during pregnancy

Objective. Although the Zika virus (ZIKV) seems to be prominently neurotropic, there are some reports of involvement of other organs, particularly the heart. Of special concern are those children exposed prenatally to ZIKV and born without microcephaly or other congenital anomalies. Electrocardiogram (ECG)—derived heart rate variability (HRV) metrics represent an attractive, low-cost, widely deployable tool for early identification of developmental functional alterations in exposed children born without such overt clinical symptoms. We hypothesized that HRV in such children would yield a biomarker of fetal ZIKV exposure. Our objective was to test this hypothesis in young children exposed to ZIKV during pregnancy. Approach. We investigated the HRV properties of 21 children aged 4–25 months from Brazil. The infants were divided into two groups, the ZIKV-exposed (n = 13) and controls (n = 8). Single-channel ECG was recorded in each child at ∼15 months of age and HRV was analyzed in 5 min segments to provide a comprehensive characterization of the degree of variability and complexity of the heart rate. Main results. Using a cubic support vector machine classifier we identified babies as Zika cases or controls with a negative predictive value of 92% and a positive predictive value of 86%. Our results show that a machine learning model derived from HRV metrics can help differentiate between ZIKV-affected, yet asymptomatic, and non-ZIKV-exposed babies. We identified the box count as the best HRV metric in this study allowing such differentiation, regardless of the presence of microcephaly. Significance. We show that it is feasible to measure HRV in infants and toddlers using a small non-invasive portable ECG device and that such an approach may uncover the memory of in utero exposure to ZIKV. We discuss putative mechanisms. This approach may be useful for future studies and low-cost screening tools involving this challenging to examine population.

Kangaroo father care: A pilot feasibility study of physiologic, biologic, and psychosocial measures to capture the effects of father-infant and mother-infant skin-to-skin contact in the Neonatal Intensive Care Unit.

Robust literature supports the positive effects of kangaroo mother care (KMC) on infant physiologic stability and parent-infant bonding in the Neonatal Intensive Care Unit (NICU). Comparatively little is known about kangaroo father care (KFC) in the NICU, and KFC implementation has been limited. Our pilot feasibility study objective was to examine KFC effects on premature infants and fathers as compared to KMC. Parents of preterm NICU infants independently completed a 90-min Kangaroo Care (KC) session on consecutive days. Infant heart rate variability (HRV) and apnea/periodicity measures were compared (pre-KC to KC; KFC to KMC). Additionally, we assessed the feasibility of administering three psychosocial questionnaires to fathers and mothers in the NICU and after discharge. Ten preterm infants completed 20 KC sessions (334/7 -374/7 weeks post-menstrual age). Results demonstrated similar infant physiologic responses between KMC and KFC, including significant differences in measures of HRV (p<.05) between KC and non-KC periods. Eighty-eight percentage of questionnaires administered were completed, supporting the utilization of these instruments in future research of this population. If confirmed, these preliminary results identify an opportunity to objectively assess KFC effects, supporting the development of empirically based KFC programs benefitting NICU families.

Maternal Pregnancy Diet Quality Is Directly Associated with Autonomic Nervous System Function in 6-Month-Old Offspring

Many pregnant women are consuming diets of poor overall quality. Although many studies have linked poor prenatal diet quality to an increased risk of specific diseases in offspring, it is not known if exposure to poor prenatal diet affects core neurophysiological regulatory systems in offspring known to lie upstream of multiple diseases. We aimed to examine the association between prenatal diet quality and autonomic nervous system (ANS) function in infants at 6 mo of age. Data from 400 women (aged >18 y, with uncomplicated pregnancies) and their infants participating in the Maternal-Infant Research on Environmental Chemicals-Infant Development cohort were used to investigate links between prenatal diet quality and infant ANS function at 6 mo of age. Prenatal diet quality was assessed using the Healthy Eating Index (2010), calculated from a validated FFQ completed by women during the first trimester. Infant ANS function was measured using 2 assessments of heart rate variability (HRV) including root mean square of successive differences (RMSSD) and SD of N-N intervals (SDNN). Associations were analyzed before and after adjustment for socioeconomic status, maternal depression symptoms, maternal cardiometabolic dysfunction, breastfeeding, and prenatal smoking. Poorer prenatal diet quality was associated with lower infant HRV assessed using RMSSD (B: 0.07; 95% CI: 0.01, 0.13; R2=0.013) and SDNN (B: 0.18; 95% CI: 0.02, 0.35; R2=0.011). These associations remained significant after adjustment for confounding variables [RMSSD: B: 0.09; 95% CI: 0.003, 0.18; squared semipartial correlation (sp2)=0.14 and SDNN B: 0.24; 95% CI: 0.0, 0.49; sp2=0.13]. In a large cohort study, poorer prenatal diet quality was associated with lower offspring HRV, a marker of decreased capacity of the ANS to respond adaptively to challenge. Therefore, poor prenatal diet may play a significant role in the programming of multiple organ systems and could increase general susceptibility to disease in offspring.

Social Stress-Related Epigenetic Changes Associated With Increased Heart Rate Variability in Infants.

Early life stress can result in persistent alterations of an individual’s stress regulation through epigenetic modifications. Epigenetic alteration of the NR3C1 gene is associated with changes in the stress response system during infancy as measured by cortisol reactivity. Although autonomic nervous system (ANS) reactivity is a key component of the stress response, we have a limited understanding of the effects of NR3C1 DNA methylation on ANS reactivity. To examine this relation, ANS stress responses of term, 4–5-month-old healthy infants were elicited using the face-to-face still-face paradigm, which involved five, 2-min episodes. Two of these episodes were the “still-face” in which the mother was non-responsive to her infant. EKG was acquired continuously and analyzed in 30 s-intervals. Cheek swabs were collected, and DNA was extracted from buccal cells. Respiratory sinus arrhythmia (RSA) was measured as heart rate variability (HRV). Mean HRV was calculated for each 30-s “face to face” episode. DNA methylation of NR3C1 was calculated using bisulfite pyrosequencing. Percent DNA methylation was computed for each of the 13 NR3C1 CpG sites. The relations between mean HRV for each “face to face” episode and percent DNA methylation was examined averaged over CpG sites 1–6 and 7–13 and at each individual CpG site. Higher HRV at baseline, first reunion, and second still-face was related to greater methylation of NR3C1 CpG sites 1–6. Higher HRV at the second reunion was related to greater methylation of NR3C1 CpG sites 12 and 13. These data provide evidence that increased methylation of NR3C1 at CpG sites 12 and 13 are associated with increased activation of parasympathetic pathways as represented by increased HRV.

Cardiac interaction between mother and infant: enhancement of heart rate variability

The vagal activity of infants is represented by heart rate variability (HRV) and associated with both growth and socioemotional development. The enhancement of an infant’s vagal tone activity might be beneficial for development. This study explored whether HRV in infants aged 3–8 months can be enhanced by influencing HRV in mothers (40 dyads). The power of the low frequency (LF) component of maternal HRV was facilitated using slow-paced breathing. We investigated whether the change in maternal HRV affected the LF component in infants held by their mothers. In older infants (N = 14, 6–8 months) the LF power showed an increase during maternal paced breathing, whereas a delayed increase occurred after termination of maternal paced breathing in younger infants (N = 16, 3–5 months). These results show that the effects of maternal cardiac activity on the infant’s HRV are age-dependent. This age-dependent reactivity of the infant’s HRV could be due to the development of the inner model in infants which regulates physiological functions, including cardiac activity. This finding might help develop efficient methods for enhancing vagal nerve activity in infants.

Heart rate and heart rate variability in infants during olfactory stimulation

Background: Various plant odours have been shown to decrease heart rate and increase parasympathetic nervous activity. However, ‘innate’ autonomic responses without the influences of experience, assumptions and prejudices of odours remains unclear.Aim: To clarify changes in heart rate and heart rate variability in infants while presenting different components of plant odours.Subjects and methods: The study participants included 17 infants aged 1–3.5 months. Each infant was exposed to the odours of α-pinene, D-limonene and air (as a control) for 2 minutes after a 2-minute resting period without any odours. The intervals of heartbeat (R-R intervals) were recorded during this process.Results: Heart rate significantly decreased in response to the odour of limonene. Frequency analysis of heart rate variability revealed that the power value at 0.2 Hz was significantly higher during the odour presentation of limonene compared to the baseline and that at 0.1 Hz and 0.4 Hz was significantly lower during α-pinene presentation.Conclusion: Autonomic responses to specific natural odours may be partly shaped innately, while underlying physiological mechanisms may be different between infants and adults.

Nocturnal heart rate variability in 1-year-old infants analyzed by using the Least Square Cosine Spectrum Method

BackgroundTo evaluate the dynamic nature of nocturnal heart rate variability, RR intervals recorded with a wearable heart rate sensor were analyzed using the Least Square Cosine Spectrum Method.MethodsSix 1-year-old infants participated in the study. A wearable heart rate sensor was placed on their chest to measure RR intervals and 3-axis acceleration. Heartbeat time series were analyzed for every 30 s using the Least Square Cosine Spectrum Method, and an original parameter to quantify the regularity of respiratory-related heart rate rhythm was extracted and referred to as “RA (RA-COSPEC: Respiratory Area obtained by COSPEC).” The RA value is higher when a cosine curve is fitted to the original data series.ResultsThe time sequential changes of RA showed cyclic changes with significant rhythm during the night. The mean cycle length of RA was 70 ± 15 min, which is shorter than young adult’s cycle in our previous study. At the threshold level of RA greater than 3, the HR was significantly decreased compared with the RA value less than 3.ConclusionsThe regularity of heart rate rhythm showed dynamic changes during the night in 1-year-old infants. Significant decrease of HR at the time of higher RA suggests the increase of parasympathetic activity. We suspect that the higher RA reflects the regular respiratory pattern during the night. This analysis system may be useful for quantitative assessment of regularity and dynamic changes of nocturnal heart rate variability in infants.

The influence of physical activity during pregnancy on maternal, fetal or infant heart rate variability: a systematic review.

BackgroundPhysical activity (PA) during pregnancy has been shown to be associated with several positive effects for mother, fetus, and offspring. Heart rate variability (HRV) is a noninvasive and surrogate marker to determine fetal overall health and the development of fetal autonomic nervous system. In addition, it has been shown to be significantly influenced by maternal behavior. However, the influence of maternal PA on HRV has not yet been systematically reviewed. Therefore, the aim of this systematic review was to assess the influence of regular maternal PA on maternal, fetal or infant HRV.MethodsA systematic literature search following a priori formulated criteria of studies that examined the influence of regular maternal PA (assessed for a minimum period of 6 weeks) on maternal, fetal or infant HRV was performed in the databases Pubmed and SPORTDiscus. Quality of each study was assessed using the standardized Quality Assessment Tool for Quantitative Studies (QATQS).ResultsNine articles were included into the present systematic review: two intervention studies, one prospective longitudinal study, and six post-hoc analysis of subsets of the longitudinal study. Of these articles four referred to maternal HRV, five to fetal HRV, and one to infant HRV. The overall global rating for the standardized quality assessment of the articles was moderate to weak. The articles regarding the influence of maternal PA on maternal HRV indicated contrary results. Five of five articles regarding the influence of maternal PA on fetal HRV showed increases of fetal HRV on most parameters depending on maternal PA. The article referring to infant HRV (measured one month postnatal) showed an increased HRV.ConclusionsBased on the current evidence available, our overall conclusion is that the hypothesis that maternal PA influences maternal HRV cannot be supported, but there is a trend that maternal PA might increase fetal and infant HRV (clinical conclusion). Therefore, we recommend that further, high quality studies addressing the influence of maternal PA on HRV should be performed (methodological conclusion).

An automated method for coding sleep states in human infants based on respiratory rate variability.

A novel quantitative method for coding epochs of active and quiet sleep in infants using respiration is reported. The approach uses the variance of the instantaneous breathing rate within brief epochs of sleep. Variances are normalized within subject by dividing by the 75th percentile variance across epochs. Then, a normalized variance active sleep threshold of 0.29 was determined to produce the highest concordance with a method based on visual inspection of respiratory variability (100% and 90% for quiet and active sleep, respectively). The method was independently validated by comparing to standard polysomnographic state coding (87% and 80% concordance for quiet and active sleep) as well as with behavioral state coding (92% and 78% for quiet and active sleep). Validity was also demonstrated by showing that sleep states identified by the method resulted in the expected state differences in infant heart rate variability and electrocortical activity.

Heart rate variability in infants with West syndrome

PurposeWest syndrome (WS) is a severe age-related acute epileptic encephalopathy of infancy characterized by infantile spasms, hypsarrhythmia and psychomotor delay. The aim of this study was to investigate if patients with WS had an altered autonomic output to the heart. MethodsIn 23 patients with WS the heart rate variability (HRV) was investigated by examining time- and frequency-domain parameters of HRV at the time of the diagnosis of hypsarrhythmia and compared to 22 age-matched controls. For the WS patients the same dataset was obtained and compared again at the end of the study period, when hypsarrhythmia was no longer present. ResultsCompared to controls, patients with WS during hypsarrhythmia had significantly lower SDNN (the standard deviation of the NN interval, i.e. the square root of variance) (19.2ms; p=0.007, Mann–Whitney's U-Test) and total power (242ms2; p=0.044, Mann–Whitney's U-Test) in the awake state, indicating an abnormal autonomic output to the heart. Comparing the initial to the final examination demonstrated a significant increase in the HRV parameters SDNN (31.3ms) and total power (757ms2; p=0.001 and p=0.013, Wilcoxon Signed Ranked Test). In addition, at the final examination the WS-patients no longer differed significantly from the controls. ConclusionOur data suggest that the initial reduction in HRV in patients at the time of onset of WS is transient and related to the presence of hypsarrhythmia.

Aerobic exercise during pregnancy influences infant heart rate variability at one month of age

BackgroundPreviously, we reported that regular maternal aerobic exercise during pregnancy was associated with lower fetal heart rate (HR) and higher heart rate variability (HRV) at 36weeks gestation. We now report the effect of maternal exercise on infant HR and HRV in subjects who remained active in the study at the one-month follow up visit. AimsWe aimed to determine whether differences in fetal cardiac autonomic control related to maternal physical activity were an in utero phenomenon or would persist 1month after birth. Study designMagnetocardiograms (MCGs) of infants born to regularly exercising (≥30min of aerobic activity, 3 times per week; N=16) and non-exercising (N=27) pregnant women were recorded using a fetal biomagnetometer. Normal R-peaks were marked to derive infant HR and HRV in time and frequency domains, including the root mean square of successive differences (RMSSD), the standard deviation of normal-to-normal interbeat intervals (SDNN), and power in the low frequency (LF) and high frequency (HF) bands. Group differences were examined with Student's t-tests. ResultsInfants born to exercising women had significantly higher RMSSD (P=0.010), LF power (P=0.002), and HF power (P=0.004) than those born to women who did not engage in regular physical activity while pregnant. ConclusionInfants born to women who participated in regular physical activity during pregnancy continued to have higher HRV in the infant period. This suggests that the developing cardiac autonomic nervous system is sensitive to the effects of maternal physical activity and is a target for fetal programming.

Infant physiological regulation and maternal risks as predictors of dyadic interaction trajectories in families with a preterm infant.

This longitudinal study examined predictors of rates of growth in dyadic interaction quality in children born preterm who did not experience significant neurological findings during neonatal intensive care unit (NICU) hospitalization. Multiple methods were used to collect data from 120 preterm infants (48% girls, 52% boys) and their mothers. Infant heart rate variability (HRV), gestational age, neonatal health, feeding route, and maternal socioeconomic (SES) risks were assessed at NICU discharge (mean of 36 weeks postconception). Mother-child interactions were observed at 4, 9, 16, and 24 months postterm and analyzed with hierarchical linear modeling. On average, children's quality of play, interest, and attention increased over time while their dysregulation and irritability decreased, whereas average maternal positive affect and involvement declined in quality (ps < .05), although there was individual variation in rates of change. Mothers of infants with higher postfeeding HRV (i.e., vagal regulation) exhibited less decrease in positive affect and involvement between 4 months and 24 months, compared with mothers of infants with lower HRV (p < .05). Although infants with higher postfeeding HRV showed less positive affect and communication at 4 months, they exhibited significantly greater increases in positive affect and social competence and decreases in dysregulation and irritability between 4 months and 24 months, compared with infants with lower HRV (ps < .05). Dyads experiencing more SES risks showed less optimal interactions at 4 months; this difference remained as children grew older (ps < .05). Results have implications for our understanding of social development in preterm infants.

Heart rate variability in infants with central coordination disturbance

Despite a remarkable medical progress in the field of Developmental Medicine and Child Neurology, early identification of infants at risk for permanent motor disabilities still presents challenge for both clinicians and researchers. As an indicator of cardiac autonomic control, it was shown that heart rate variability (HRV) might reflect not only sympathetic or parasympathetic activity but also functional integrity of the central nervous system (CNS). Furthermore a pattern of HRV was demonstrated to correlate with motor developmental outcome in high risk infants. The purpose of this study was to analyze the clinical usefulness as well as predictive value of time-domain HRV parameters in infants with central coordination disturbance. The study included 35 infants with central coordination disturbance and 37 healthy age and sex-matched controls. Time-domain HRV indices were analyzed from 24-h electrocardiography recordings. We found significantly lower values of SDNN, SDANN and RMSSD parameters in infants with central coordination disturbance compared to controls. Additionally, logistic regression analyses demonstrated independent predictive value of parameters SDNN and SDANN in infants who subsequently developed cerebral palsy (CP). By performing receiver operating characteristic (ROC) analyses, the optimal cut-off value of SDNN <= 48 ms predicted CP with a sensitivity of 68.7% (95% CI 41.4–88.9) and specificity of 84.2% (95 CI 60.4–96.4) while the optimal cut-off value of SDANN <= 41 ms predicted CP with a sensitivity of 87.5% (95% CI 61.6–98.1) and specificity of 57.9% (95 CI 33.5–79.7). We are in opinion that time domain HRV analysis could be helpful clinically as well as a prognostic tool in infants with central coordination disturbance.

Effects of nutritive and non-nutritive sucking on infant heart rate variability during the first 6 months of life

The effects of eating on heart rate variability (HRV) differ between adults and newborns. This may reflect the impact of suckling on the overall psychophysiological and autonomic nervous system maturation. The purpose of the present study was to explore whether the reactions of HRV during feeding change towards the adult pattern during the first 6 months of life. In addition, the effects of non-nutritive and nutritive sucking on heart rate (HR) and HRV were compared. The participants were 23 infants on whom recordings were performed as newborns and at 6, 12 and 24 weeks old. Nutritive sucking caused an increase in HR and a decline in HRV. The results were consistent with previous reports of a decrease in high frequency components of HRV during feeding in newborns, reflecting a decrease in parasympathetic activity. This response was apparent in all four ages studied, and remained similar throughout the 6-month period. However, age as an independent factor seemed to influence both HR and HRV. Pacifier sucking had no significant effects on HRV at any age. The results demonstrate the physical strain that sucking imposes on the baby, with a specific autonomic nervous system response involved. We consider this response an essential part of the overall psychophysiological maturation of infants.