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.     

Changes in rhythmic suckle feeding patterns in term infants in the first month of life

To quantify parameters of rhythmic suckle feeding in healthy term infants and to assess developmental changes during the first month of life, we recorded pharyngeal and nipple pressure in 16 infants at 1 to 4 days of age and again at 1 month. Over the first month of life in term infants, sucks and swallows become more rapid and increasingly organized into runs. Suck rate increased from 55/minute in the immediate postnatal period to 70/minute by the end of the first month (p<0.001). The percentage of sucks in runs of > or =3 increased from 72.7% (SD 12.8) to 87.9% (SD 9.1; p=0.001). Average length of suck runs also increased over the first month. Swallow rate increased slightly by the end of the first month, from about 46 to 50/minute (p=0.019), as did percentage of swallows in runs (76.8%, SD 14.9 versus 54.6%, SD 19.2; p=0.002). Efficiency of feeding, as measured by volume of nutrient per suck (0.17, SD 0.08 versus 0.30, SD 0.11 cc/suck; p=0.008) and per swallow (0.23, SD 0.11 versus 0.44, SD 0.19 cc/swallow; p=0.002), almost doubled over the first month. The rhythmic stability of swallow-swallow, suck-suck, and suck-swallow dyadic interval, quantified using the coefficient of variation of the interval, was similar at the two age points, indicating that rhythmic stability of suck and swallow, individually and interactively, appears to be established by term. Percentage of sucks and swallows in 1:1 ratios (dyads), decreased from 78.8% (SD 20.1) shortly after birth to 57.5% (SD 25.8) at 1 month of age (p=0.002), demonstrating that the predominant 1:1 ratio of suck to swallow is more variable at 1 month, with the addition of ratios of 2:1, 3:1, and so on, and suggesting that infants gain the ability to adjust feeding patterns to improve efficiency. Knowledge of normal development in term infants provides a gold standard against which rhythmic patterns in preterm and other high-risk infants can be measured, and may allow earlier identification of infants at risk of neurodevelopmental delay and feeding disorders.     

Ultrasound demonstration of tongue motions during suckle feeding

In this study the authors used ultrasound to demonstrate characteristic internal actions of the tongue during suckling. Its medial portion, into which the genioglossus is inserted, moves in relation to its lateral portions, into which the styloglossus and hyoglossus are inserted. A peristaltic wave of successive inferior and superior displacements moves posteriorly in the medial portion, compressing or 'milking' the nipple and propelling the expressed milk towards the pharynx. The lateral portions of the tongue enclose the nipple and the bolus and serve as reference for the displacements of the medial portion. These observations are related to anatomical studies of the tongue. The coordination pattern of suckle is compared with that of pharyngeal swallow. In instances where suckle and swallow are immediately sequential, the peristalsis which is common to both is continuous in the oral and pharyngeal portions of the food pathway.     

Stroke in newborn infants

The few days before and after birth are a time of special risk for stroke in both mother and infant, probably related to activation of coagulation mechanisms in this critical period. Arterial ischaemic stroke around the time of birth is recognised in about one in 4000 full-term infants, and may present with neurological and systemic signs in the newborn. Neonatal seizures are most commonly the clinical finding that triggers assessment. In other children, perinatal stroke is recognised only retrospectively, with emerging hemiparesis or seizures after the early months of life. Risk factors for perinatal stroke include hereditary or acquired thrombophilias and environmental factors. Perinatal stroke underlies an important share of congenital hemiplegic cerebral palsy, and probably some spastic quadriplegic cerebral palsy and seizure disorders. There is much to be learned about the natural history of perinatal stroke, and there are as yet no evidence-based strategies for prevention or treatment.     

Near-infrared spectroscopy in newborn infants.

Neonatal encephalopathy of early onset, plausibly related to hypoxia and ischemia remains one of the main problems in perinatal medicine. Efforts are necessary to find new non-invasive methods for assessing brain oxygenation. Near-infrared spectroscopy (NIRS) provides information on the concentrations of the oxygenated and reduced forms of hemoglobin, as well as the redox state of cytochrome aa3. Different important variables can be derived through hemoglobin measurement, such as cerebral blood volume and flow, and the responses of these to changes in pCO2. Changes in cytochrome aa3 may provide immediate information on intracellular oxygen utilization. Various studies have shown the feasibility of NIRS in preterm infants. Methodological and technical problems of this method are discussed.     

Brain vein disorders in newborn infants

The brain veins of infants are in a complex phase of remodelling in the perinatal period. Magnetic resonance venography and susceptibility‐weighted imaging, together with high‐resolution Doppler ultrasound, have provided new tools to aid study of venous developmental anatomy and disease. This review aims to provide a comprehensive background of vein development and perinatal venous lesions in preterm and term‐born infants, and to encourage further research in both the fetus and the newborn infant, with the aim of preventing or mitigating parenchymal injury related to diseases involving veins.     

Seizures in the newborn and young infants

The electro-clinical features of neonatal seizures were described. Although they were usually secondary to the underlying pathological process, there were a few cases of benign familial convulsions which seemed to be dominantly inherited. In the new born, clinical seizures occurred mainly in active-REM sleep in contrast to those in the older children and adults. Atypical seizures were also seen in young infants, although less frequently than in the newborn. There were a considerable number of epilepsies beginning in the first year of life associated with a favorable prognosis. Unclassified epilepsies manifesting as brief generalized motor seizures with normal interictal EEGs showed the most favorable outlook, while infantile spasms and other secondary generalized epilepsies had the worst outcome. Partial seizures were intermediate between the above two.     

Intravenous paraldehyde for seizure control in newborn infants

We studied 14 newborn infants with seizures after birth asphyxia or other causes. Paraldehyde was given as a 200 mg/kg IV bolus followed by an infusion of 16 mg/kg/h (10 cases), or as a 400 mg/kg bolus (4 cases). Serum concentrations of paraldehyde were higher in periods of adequate seizure control than in periods of little or no response. Paraldehyde serum concentrations above 10 mg/dl were associated with anticonvulsant effects and were achieved in most neonates with a 2-hour infusion of 200 mg/kg/h. If there is no effect, serum concentrations are probably below 10 mg/dl and an additional 200 mg/kg can be given safely over 1 hour.     

Processing acoustic change and novelty in newborn infants

Research on event-related potential (ERP) correlates of auditory deviance-detection in newborns provided inconsistent results; temporal and topographic ERP characteristics differed widely across studies and individual infants. Robust and reliable ERP responses were, however, obtained to sounds (termed 'novel' sounds), which cover a wide range of frequencies and widely differ from the context provided by a repeating sound [Kushnerenko et al. , (2002) NeuroReport , 13, 1843–1848]. The question we investigated here is whether this effect can be attributed to novelty per se or to acoustic characteristics of the 'novel' sounds, such as their wide frequency spectrum and high signal energy compared with the repeated tones. We also asked how sensitivity to these stimulus aspects changes with development. Twelve newborns and 11 adults were tested in four different oddball conditions, each including a 'standard' sound presented with the probability of 0.8 and two types of infrequent 'deviant' sounds (0.1 probability, each). Deviants were (i) 'novel' sounds (diverse environmental noises); (ii) white-noise segments, or harmonic tones of (iii) a higher pitch, or (iv) higher intensity. In newborns, white-noise deviants elicited the largest response in all latency ranges, whereas in adults, this phenomenon was not found. Thus, newborns appear to be especially sensitive to sounds having a wide frequency spectrum. On the other hand, the pattern of results found for the late discriminative ERP response indicates that newborns may also be able to detect novelty in acoustic stimulation, although with a longer latency than adults, as shown by the ERP response. Results are discussed in terms of developmental refinement of the initially broadly tuned neonate auditory system.     

Ultrasound measurement of the ventricular size in newborn infants

High resolution real-time ultrasound scans were obtained through the anterior fontanelle to measure the lateral ventricles of 540 neonates of various gestational ages. Coronal scans showed that the distance between the falx and the lateral wall of the body of the lateral ventricle (ventricular index) and the greatest axis of the lateral ventricle (ventricular axis) were correlated with increasing gestational age. Growth charts were constructed for neonates of various gestational ages, from 24 to 40 weeks. The greatest distance perpendicular to the ventricular axis was defined as the ventricular depth. The depth of normal lateral ventricles was 0.18 cm (range, 0.13-0.23 cm). Hopefully, the data concerning ventricular sizes obtained in this survey can be utilized for the early diagnosis and control of posthemorrhagic ventriculomegaly.     

Hemodynamic responses to speech and music in newborn infants

We used near‐infrared spectroscopy (NIRS) to study responses to speech and music on the auditory cortices of 13 healthy full‐term newborn infants during natural sleep. The purpose of the study was to investigate the lateralization of speech and music responses at this stage of development. NIRS data was recorded from eight positions on both hemispheres simultaneously with electroencephalography, electrooculography, electrocardiography, pulse oximetry, and inclinometry. In 11 subjects, statistically significant (P < 0.02) oxygenated (HbO₂) and total hemoglobin (HbT) responses were recorded. Both stimulus types elicited significant HbO₂ and HbT responses on both hemispheres in five subjects. Six of the 11 subjects had positive HbO₂ and HbT responses to both stimulus types, whereas one subject had negative responses. Mixed positive and negative responses were observed in four neonates. On both hemispheres, speech and music responses were significantly correlated (r = 0.64; P = 0.018 on the left hemisphere (LH) and r = 0.60; P = 0.029 on the right hemisphere (RH)). On the group level, the average response to the speech stimuli was statistically significantly greater than zero in the LH, whereas responses on the RH or to the music stimuli did not differ significantly from zero. This suggests a more coherent response to speech on the LH. However, significant differences in lateralization of the responses or mean response amplitudes of the two stimulus types were not observed on the group level. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.