Gastric electrical activity and gastric emptying in term and preterm newborns

The aims of this study were to evaluate the gastric electrical activity and gastric emptying in preterm and term newborns and to assess the development of gastric motility by comparing newborns of different gestational ages. The cutaneous electrogastrography and the ultrasonographic study of the gastric emptying were performed before and after milk formula in three groups of infants: 12 preterm newborns with a gestational age of 28-32 weeks, 11 preterm newborns with a gestational age of 32-36 weeks, and 10 full-term newborns with a gestational age of 36-40 weeks. All recording sessions were performed 1 week after infants had reached full enteral feeding. The percentage of normal slow waves was similar in the three groups but it was not predominant compared to tachygastria in the earliest premature infants (59.3% (12.7-92.3) vs. 29.6% (3.7-78.8); P < 0.05). In addition, a progressive increase in the normal slow wave percentage (59.3% (17.4-87.4), 60.9% (38.1-89.7), 77.8% (66.4-84.8); P < 0.05) was observed as gestation advanced. As regards gastric emptying parameters, the antral area was greater and T(1/2) was longer in the preterm newborns of 28-32 weeks than preterm newborns of 32-36 weeks and full-term newborns (fasting antral area: 0.96 cm2 (0.6-1.5), 0.63 cm2 (0.4-1.2), 0.55 cm2 (0.1-0.9) respectively, P < 0.05; T(1/2): 83.4 min (76.0-108.5), 70 min (57.5-89.5) and 71.8 min (54.9-81.2), respectively P < 0.05). The comparisons of gastric emptying curves made among the three groups showed a reduced antral dilatation in preterm newborns of 28-32 weeks compared to full-term newborns at 30 and 60 min after a meal. In conclusion, although enteral feeding is important for the development process of gastrointestinal motility, gastric electrical activity and gastric emptying show an intrinsic maturation depending on the gestational age.     

Brain maturation in the first 3 months of life,measured by electroencephalogram: A comparison between preterm and term-born infants

ObjectivePreterm infants are at risk for altered brain maturation resulting in neurodevelopmental impairments. Topographical analysis of high-density electroencephalogram during sleep matches underlying brain maturation. Using such an EEG mapping approach could identify preterm infants at risk early in life.Methods20 preterm (gestational age < 32 weeks) and 20 term-born infants (gestational age > 37 weeks) were recorded by 18-channel daytime sleep-EEG at term age (GA 40 weeks for preterm and 2–3 days after birth for term infants) and 3 months (corrected age for preterm infants).ResultsPreterm infant’s power spectrum at term age is immature, leveling off with term infants at 3 months of age. Topographical distribution of maximal power density however, reveals qualitative differences between the groups until 3 months of age. Preterm infants exhibit more temporal than central activation at term age and more occipital than central activation at 3 months of age. Moreover, being less mature at term age predicts being less mature at 3 months of age.ConclusionTopographical analysis of sleep EEG reveals changes in brain maturation between term and preterm infants early in life.SignificanceIn future, automated analysis tools using topographical power distribution could help identify preterm infants at risk early in life.     

Variability and stereotypy of spontaneous motility as a predictor of neurological development of preterm infants

Observations of the variability stereotypy ratio of spontaneous motility in a group of 47 preterm infants showed that stereotyped motor activity was related to the neurological diagnosis at term age. A minority of the neurologically deviant infants at term recovered during infancy. The presence of absence of intra-uterine growth retardation and an accumulation of obnoxious antenatal, perinatal and postnatal events seemed to affect outcome, particularly in the presence of extensive and permanent ultrasound findings. A normal neurological condition at term indicates a high probability of normal development.     

Utilization of surface electromyography during the feeding of term and preterm infants: a literature review

Aim  To evaluate studies that have used surface electromyography (sEMG) during feeding for term and preterm infants.
Method  Studies published between 1996 and 2009 were identified through databases (MEDLINE, EMBASE, CINAHL, LILACS, and SciELO) and divided into groups: term infants, preterm infants, and other situations with infants aged from 0 to 12 months.
Results  Five studies were found for suckling in term infants, two evaluating muscular activity during feeding in preterm infants, and one dealing with other situations. Some studies revealed striking differences in activity of the masseter muscle between breastfed and bottle-fed term infants (action diminished in bottle-fed infants). For preterm infants, authors evaluated sucking and sucking bursts and pointed out an effective means of evaluating muscle behaviour during feeding. There is evidence of a similarity in activity between cup feeding and breastfeeding.
Interpretation  Studies found in this literature review show the importance of using sEMG as a method of feeding assessment for term and preterm infants. For term infants, the masseter muscle presented greater muscular activity during breastfeeding and reduced activity during bottle-feeding. It was not possible to make comparisons between studies of preterm infants because of differences in methodological design.     

Characteristic motor patterns of phase II and behaviour of phase III in the fed state

The motor pattern of the phase II of the migration motor complex (MMC) is poorly characterized and it remains to be determined whether it differs from the fed motor-pattern. Furthermore, discrepancy exists on the disruption of ongoing MMCs by feeding, and finally, the understanding of the behaviour of phase Ills during enteral nutrition is incomplete. Therefore, canine intestinal motility was studied after meal and during enteral infusion of nutrients (elemental diet, glucose, maltose, amino acids) or of hypertonic saline (300–1520 mosmol kg^?1). Motility of the proximal, mid- and distal jejunum was recorded with strain-gauge transducers. The motor patterns of the interdigestive phase II, after feeding and during enteral nutrition were analysed by a computer. Additionally, the disruption of the MMC by food and by enteral infusion of nutrients or hypertonic saline was investigated. The inter digestive phase II consisted of three different contractile patterns, clustered contractions, a mixed contractile pattern and non-migrating bursts of propagated contractions (NBPCs). NBPCs differed significantly from the phase III activity in several motility parameters and by the lack of aboral migration. Only small differences existed between the motor patterns of phase II and of the fed state, whereas the motor pattern induced by enteral infusion of an elemental diet differed significantly from that of phase II. Ongoing MMCs of the proximal jejunum often continued to migrate to the mid- and distal jejunum. During enteral infusion of nutrients or of hypertonic saline, phase Ills recurred. The migration of ongoing phase Ills and the recurrence of subsequent phase Ills decreased with increasing caloric or osmotic loads. The following conclusions were reached, (a) The phase II of the MMC is a complex motor-pattern. NBPCs represent a new contractile pattern, (b) The MMC is a characteristic feature of the empty gut. After meal and during enteral nutrition, phase Ills are usually suppressed but they can recur during the digestive period.     

Gastric emptying patterns of a liquid meal in newborn infants measured by epigastric impedance

Epigastric impedance was used to measure the gastric emptying patterns of a liquid non-caloric meal (5 mL water kg⁻¹) in 30 healthy newborn infants. Twenty-six mature infants were examined in the first eight days of life, and four preterm infants were examined within 6 weeks after birth. The recordings consisted of two components: the emptying signal (the DC component), and a phasic 3 cycles per minutes (CPM) signal (the AC component). In some of the infants the phasic 3 CPM signal was also seen during the fasting state.
For mature infants the median half emptying time (T₅₀) was 6.9 min. For a second meal given within one hour after the first meal the half emptying time was 5.5 min ( P  < 0.01). In preterm infants the emptying times were not significantly different from mature infants.
Day-to-day variation was low with a coefficient of variation of 17% in nine infants.
A periodic change of the impedance signal, the phasic 3 CPM signal, was observed after a meal in 24 of the infants. The median frequency was 3.0 CPM in 20 mature and 2.9 CPM in four preterm infants. In nine infants a phasic 3 CPM signal was also observed during the fasting state, with a median frequency of 2.9 CPM.
Measurement of gastric emptying pattern with epigastric impedance is a simple investigation for the evaluation of gastric emptying time and phasic activity in mature and preterm infants. However, the method is sensitive to spontaneous movements of the children, resulting in non-valid measurements in around one fourth of the infants.     

Development of pharyngo‐esophageal physiology during swallowing in the preterm infant

Background Poor feeding is a common cause of prolonged hospitalization of preterm infants. Pharyngeal and upper esophageal sphincter (UES) function of preterm infants has been technically difficult to assess and is therefore poorly characterized. The aim of this study was to assess the development of pharyngeal motility, UES function, and their coordination during nutritive swallowing in preterm infants. Methods Development of swallowing was assessed in 18 preterm infants. High resolution manometry was performed at first oral feeding attempt (31–32 week) and then weekly for 4 weeks. Pharyngeal and UES pressure changes were characterized in 980 swallows. Key Results During swallowing, we observed an age‐related increase in peak pharyngeal pressure at the laryngeal inlet (1 cm above UES) but an age‐related decrease in the time required for the UES to fully relax to nadir. Analysis of the timing of proximal pharyngeal contractile peak and UES nadir showed that the UES was not fully relaxed when bolus propulsive forces were at their peak in the youngest infants. Conclusions & Inferences Results show developmental changes in infant swallow physiology that can be clearly linked to the effectiveness of nutritive swallowing. Most preterm infants demonstrated poor pharyngeal pressures at the laryngeal inlet coupled with poor coordination of pharyngeal propulsion with UES relaxation. These pressure patterns were less efficient than those demonstrated by older infants who were more adept at feeding. These observations may explain why infants under 34 weeks are physiologically unable to feed effectively and experience frequent choking and fatigue during feeding.     

Stress and Gastrointestinal Motility in Humans: A Review of the Literature

Clinical observations and uncontrolled single case experiments have suggested an effect of psychological stress on gastrointestinal motility. These observations encouraged a large number of experimental studies focusing on the influence of psychological stress on gastrointestinal motility. These controlled studies have shown that different kinds of stressors increase esophageal motor activity and induce secondary (nonpropulsive) esophageal contractions. Cold pressor test and transcutaneous electrical stimulation inhibited gastric emptying, auditory feedback and performance tasks inhibited the occurrence of interdigestive migrating motor complexes, and a noise stressor increased intestinal transit time. Furthermore, psychological stress (psychological stress interview, frustrating cognitive tasks, and anger) and physical stress (cold pressor test) stimulated large-bowel contractions and electrical spiking activity. The present studies give some evidence that patients with functional motility disorders respond differently to stressors as compared to healthy controls. In spite of these findings with short-acting stressors, there is no proof that stress has an effect on the manifestation of functional motility disorders. Nevertheless, this does not allow the conclusion that stress does not play any role in the manifestation of motility-related gastrointestinal disorders. In particular, there are no studies on the action of chronic stress on gastrointestinal motility. Thus further research is needed to elucidate the influence of stress, especially of chronic stress, on gastrointestinal motility.     

A COMPARISON OF NEUROBEHAVIORAL PERFORMANCE OF HEALTHY TERM AND LOW-RISK PRETERM INFANTS AT TERM

The neurobehavioral performance of a group of low-risk preterm and healthy term infants was assessed at term using the standardized Einstein Neonatal Neurobehavioral Assessment Scale. There was greater similarity than dissimilarity between the two groups; however, preterm infants demonstrated less consistent following to face and voice, and less sustained rooting and grasp reflexes. Preterm infants were more likely to have a more sustained asymmetric tonic neck reflex, a greater popliteal angle and evidence of tremor. These results support the view that processing capability appears to mature on an intrinsically programmed time- and environment-independent pathway, with environmental exposure challenging this adaptive capacity and modifying performance--predominantly with respect to reflexive elements.     

A Review of Functional Near-Infrared Spectroscopy Studies of Motor and Cognitive Function in Preterm Infants

Preterm infants are vulnerable to brain injuries,and have a greater chance of experiencing neurodevelopmental disorders throughout development. Early screening for motor and cognitive functions is critical to assessing the developmental trajectory in preterm infants, especially those who may have motor or cognitive deficits. The brain imaging technology functional near-infrared spectroscopy(fNIRS) is a portable and low-cost method of assessing cerebral hemodynamics, making it suitable for large-scale use even in remote and underdeveloped areas. In this article, we review peer-reviewed, scientific f NIRS studies of motor performance, speech perception, and facial recognition in preterm infants. f NIRS provides a link between hemodynamic activity and the development of brain functions in preterm infants. Research using fNIRS has shown different patterns of hemoglobin change during some behavioral tasks in early infancy. fNIRS helps to promote our understanding of the developmental mechanisms of brain function in preterm infants when performing motor or cognitive tasks in a less-restricted environment.     

Deficits in neural encoding of speech in preterm infants

Preterm children show developmental cognitive and language deficits that can be subtle and sometimes undetectable until later in life. Studies of brain development in children who are born preterm have largely focused on vascular and gross anatomical characteristics rather than pathophysiological processes that may contribute to these developmental deficits. Neural encoding of speech as reflected in EEG recordings is predictive of future language development and could provide insights into those pathophysiological processes. We recorded EEG from 45 preterm (≤ 34 weeks of gestation) and 45 term (≥ 38 weeks) Chinese-learning infants 0–12 months of (corrected) age during natural sleep. Each child listened to three speech stimuli that differed in lexically meaningful pitch (2 native and 1 non-native speech categories). EEG measures associated with synchronization and gross power of the frequency following response (FFR) were examined. ANCOVAs revealed no main effect of stimulus nativeness but main effects of age, consistent with earlier studies. A main effect of prematurity also emerged, with synchronization measures showing stronger group differences than power. By detailing differences in FFR measures related to synchronization and power, this study brings us closer to identifying the pathophysiological pathway to often subtle language problems experienced by preterm children.     

The Rectal Motor Complex

To identify patterns of motility in the rectum of humans during the day while awake and at night during sleep, and to correlate the patterns with interdigestive duodenal motor complexes and sleep cycles, intraluminal rectal pressure was recorded in 12 healthy subjects (five female, seven male; mean age, 28 years) using a flexible, noncompliant, silastic catheter and an Arndorfer system with a single perfused rectal port 6 cm above the anorectal junction, duodenal motility was recorded via a perfused oroduodenal tube, and sleep stages were determined electroencephalographically. Discrete bursts of rectal motor waves, called rectal motor complexes (RMCs), were identified on 72 occasions in 11 of the 12 subjects during 157 hours of recording. The RMCs were found in daytime during fasting or after feeding (0.2 ± 0.1 RMCs/hour), but were more easily and frequently identified at night during sleep (0.8 RMCs/hour, p < .01). The complexes had a distinct onset, a mean duration ± SEM of 9.5 ± 1.0 minutes, and a distinct decline. Within each complex, the waves had a mean frequency of 3.8 ± 0.3 per minute and a mean amplitude of 19 ± 2.7 mm Hg. Complex-to-complex intervals at night averaged 74 ± 15 minutes. No clear-cut temporal association was present between the complexes and phase III of interdigestive duodenal motor complex or the REM stage of sleep.     

Spontaneous movements in the supine position of healthy term infants and preterm infants with or without periventricular leukomalacia

Aim: The individual motor elements presumed to be essential for motor development were determined from spontaneous movements involving the entire body of normal term and preterm infants. Then, diagnostic items for motor abnormality in infants with periventricular leukomalacia (PVL) were investigated. Methods: Video recordings of 24 healthy term infants, 21 normal preterm infants (8 males, 13 females; median gestational age 30 weeks; median birth weight 1216 g) and 14 preterm infants with PVL (6 males, 8 females; median gestational age 30 weeks; median birth weight 1360 g) were analyzed. Results: In healthy term infants, predominant shoulder rotation was noticed until 1 month of age. After 2 months of age, isolated movements of the shoulder, elbow, hip, knee, and ankle frequently emerged. In preterm infants with PVL at the corrected age of 2 months, startle response and predominant shoulder rotation were more frequently seen and isolated neck, shoulder, elbow, hip, knee, and ankle movements were less frequently seen than in the normal preterm infants (Fisher’s exact test, p < 0.025). Interpretation: At 2 months of age, isolated movements evolve, and their failure to occur is suggested to be a useful sign for the diagnosis of cerebral motor disorders.     

The patterns of small bowel motility: physiology and implications in organic disease and functional disorders

The physiology and pathophysiology of small bowel motility are reviewed with particular focus on the motility patterns and periods that are detected by intraluminal manometry. Motility patterns are groups of phasic pressure waves resulting from contractions of the circular muscle layer of the small bowel that are organized by the enteric nervous system. Phase III of the migrating motor complex, the hallmark of the fasting motility period, thus reflects enteric neuromuscular function. Response to meal challenge also involves the CNS, reflexes beyond the gut and endocrine responses. Although specific disease diagnosis cannot be made by motility studies of the small bowel, the functional integrity is revealed. The normal occurrence of the essential patterns and periods of motility and the absence of distinctly abnormal patterns evidence preserved function, whereas the opposite indicates clinically significant dysmotility. Certain motility patterns are occasionally seen both in health and disease, and increased prevalence indicates a moderate dysfunction of yet unclear significance. Bacterial overgrowth with Gram-negative bacilli is the consequence of severe small bowel dysmotility, and a diagnosis that can be predicted by a motility study. Testing can be useful in the clinical management of paediatric and adult patients also by predicting the prognosis and response to enteral nutrition and medical therapy. Further studies are, however, needed to take full advantage of motility testing in clinical practise.     

Role of vision on early motor development: lessons from the blind

For a better understanding of the contribution vision makes to the development of other sensory systems and to movement and posture, we studied effects of early blindness by examining video recordings of 14 totally blind infants. Infants were born at term or preterm and showed no evidence of brain damage. During preterm and term periods no noticeable changes in motor activity were observed. Around 2 months postterm all infants showed clear delay in head control and abnormal, exaggerated type of 'fidgety movements'. Later, postural control was characterized by a prolonged period of ataxic features. Results indicate a lack of normal calibration exerted by vision on proprioceptive and vestibular systems. Early visuomotor coordination such as coordinated eye-head scanning and head orientating were present but disappeared after several weeks.     

Reproducibility of antroduodenal motility during prolonged ambulatory recording

Ambulatory recording of antroduodenal manometry is a novel technique with several advantages over standard stationary manometry recording. Although the feasibility of this technique in clinical practice has been demonstrated, reproducibility of antroduodenal motility recorded by means of ambulatory manometry has not been investigated. To test whether antroduodenal motility recorded by ambulatory manometry is reproducible, we performed two 24-h ambulatory antroduodenal manometry recordings in 18 healthy subjects according to an identical protocol with a 1-week interval. Motility was recorded with a five-channel solid-state catheter. Postprandial motility was recorded after consumption of two test meals and interdigestive motility was recorded nocturnally. Postprandial antroduodenal motor characteristics were identical between the separate recordings. The number and duration of nocturnal cycles of the interdigestive migrating motor complex were also in the same range. Phase III characteristics in general were not different between the two recordings. Only minor alterations were observed in the duration of phase III motor fronts with duodenal onset and in the number of interdigestive cycles concluded by duodenal onset phase III. Parameters obtained by qualitative analysis were comparable between the two recordings. The antroduodenal motility pattern, when measured by ambulatory recording with solid state catheters under standardized conditions, is very reproducible.     

Deglutition apnoea as indicator of maturation of suckle feeding in bottle-fed preterm infants

The maturation of deglutition apnoea time was investigated in 42 bottle-fed preterm infants, 28 to 37 weeks gestation, and in 29 normal term infants as a comparison group. Deglutition apnoea times reduced as infants matured, as did the number and length of episodes of multiple-swallow deglutition apnoea. The maturation appears related to developmental age (gestation) rather than feeding experience (postnatal age). Prolonged (>4 seconds) episodes of deglutition apnoea remained significantly more frequent in preterm infants reaching term postconceptual age compared to term infants. However, multiple-swallow deglutition apnoeas also occurred in the term comparison group, showing that maturation of this aspect is not complete at term gestation. The establishment of normal data for maturation should be valuable in assessing infants with feeding difficulties as well as for evaluation of neurological maturity and functioning of ventilatory control during feeding.     

Study of motor function development at 8 and 12 months of age in preterm and at term children

OBJECTIVE: To compare the development of motor function in children born preterm with those born at term, at 8 and 12 months of age. To investigate the relation of motor function quality at the age of 8 months with motor ability at 12 months. METHOD: Thirty-two children participated in this study: 16 were born preterm (risk group) and 16 were born at term (control group). The spontaneous movements of the children were assessed at 8 months and their mobility skills and independence were assessed at 12 months (corrected ages for the preterm group), using standardized developmental tests (AIMS and PEDI, respectively). Data were analysed using independent t-tests (between-group comparison) and Pearson correlation coefficients (within-group comparison). RESULTS: There was no significant difference in motor function, between those born preterm with those born at term, either at 8 or at 12 months of age. In the control group, there was significant association (r=0.67; p=0.004) between movement at 8 months and mobility skills at 12 months. In the risk group, there was significant relationship between skills and independence in mobility, at 12 months corrected age (r=0.80; p=0.0001). CONCLUSION: Preterm born children, without other disorders and with age correction, might show a similar motor development as those born at term. The path for the acquisition of motor abilities in preterm born children appears to differ among those infants.     

Extrauterine environment influences spontaneous low-frequency oscillations in the preterm brain

Low-frequency oscillations in cerebral blood flow that are suggestive of resting-state brain activity have recently been reported, but no study on the development of resting-state brain activity in preterm infants has been performed. The objective of this study was to measure the cerebral blood flow oscillations, which are assumed to represent brain function in the resting state, in preterm and term infants of the same postconceptional age. The subjects were 9 preterm infants who had reached full term (gestational age (GA): 23–34 weeks, postconceptional age: 37–46 weeks) and 10 term infants (GA: 37–40 weeks, postconceptional age: 37–41 weeks). Their changes in concentration of oxyhemoglobin ([oxyHb]) and deoxyhemoglobin ([deoxyHb]) were measured in the parieto-temporal region during quiet sleep using multi-channel near-infrared spectroscopy, and the power spectral densities (PSD) of the oscillations in the concentrations of these molecules were analyzed and compared. The preterm infants displayed a higher proportion of 0.06–0.10 Hz low frequency oscillations of [oxyHb] and [deoxyHb] than the term infants, and the gestational age and the proportion of low frequency oscillations were inversely correlated. These findings suggest that resting-state cerebral blood flow oscillations differ between preterm and term infants, and that the development of circulatory regulation and nerve activity in preterm infants are influenced by the extrauterine environment.     

Motor development from 4 to 8 months corrected age in infants born at or less than 29 weeks' gestation

Aim  Clinically, preterm infants show motor delay and atypical postures compared with their peers born at term. A longitudinal cohort study was designed to describe the motor development of very preterm infants from 4 to 18 months corrected age (CA). The study was also designed to investigate how the atypical postures observed in early infancy in the preterm infants might be related to their later motor development. Here we report the findings in early motor skills from 4 to 8 months CA.
Method  Early motor skills were assessed in 62 preterm infants (32 males, 30 females, mean gestation 26.94wks, SD 1.11) and 53 term infants (32 males, 21 females, mean gestation 39.55wks, SD 1.17) using the Alberta Infant Motor Scale (AIMS).
Results  The preterm infants demonstrated different motor behaviours from their term peers, with an uneven progression of motor skills in different positions from 4 to 8 months CA. At 8 months CA, 90%of the term infants were able to sit without arm support, but only 56%of the preterm infants could maintain sitting very briefly without arm support.
Interpretation  This uneven progression may have been due to an imbalance between the active flexor and extensor strength and hence inadequate postural control in these positions. The AIMS has also been shown to be a valid assessment tool to demonstrate unique characteristics in movement quality in the preterm population.