Reflex In Infants Research Articles

Mo1188 Volume Dependent Recruitment of Aerodigestive Reflexes in Infants With Severe Bronchopulmonary Dysplasia (SBPD) Across Maturation

Mo1188 Volume Dependent Recruitment of Aerodigestive Reflexes in Infants With Severe Bronchopulmonary Dysplasia (SBPD) Across Maturation

Goniometer Measurements of Oral Labial Angle and Evaluation of Oral Motor Reflexes in Preterm Infants: Comparison to Findings in Term Infants.

To date, no study has evaluated changes in oral labial angle as preterm infants mature. The main purpose of this study was to document goniometer measurements of the labial angle of the mouth in preterm infants, to assess changes with development, to compare to findings in healthy term infants, and also evaluate oral motor reflexes in these groups. Seventy-eight preterm infants and 45 healthy term infants were recruited for the prospective study. Labial angle was assessed via goniometer, and oral motor reflexes and the volume of milk ingested were evaluated. There was significant difference between term and preterm infants' labial angles (P < .01). The distribution of preterm infants' angles were similar to term infants' by 36 to 40 weeks' postmenstrual age. Goniometer measurements of the oral labial angle may reveal oral motor performance in preterm infants and may be relevant for feeding skills assessment in this group of infants.

Hypersensitive pupillary light reflex in infants at risk for autism.

BackgroundPost mortem brain tissue data and animal modeling work indicate cholinergic disruptions in autism. Moreover, the cholinergic system plays a key role in the early neurodevelopmental processes believed to be derailed early in life in individuals with the disorder. Yet, there is no data from human infants supporting a developmentally important role of this neurotransmitter system. Because the pupillary light reflex depends largely on cholinergic synaptic transmission, we assessed this reflex in a sample of infants at risk for autism as well as infants at low (average) risk.MethodsTen-month-old infants with an older sibling with autism (n = 29, 16 females), and thus a genetic predisposition to developing the disorder themselves, were presented with white flashes on a computer monitor, and pupillary responses were captured using eye tracking. A control group matched on age and developmental level (n = 15, seven females) was also tested.ResultsThe siblings of children with autism had a faster and stronger pupillary light reflex compared to control infants. Baseline pupil diameter was equal in the two groups, ruling out tonic autonomic imbalance as an explanation for these differences.ConclusionsThis study establishes that infant siblings of children with autism have hypersensitive pupillary light reflexes, a result which supports the view that altered sensory processing in infancy is associated with elevated autism risk. Moreover, the study indicates that individual differences in autism susceptibility are linked to differences in the cholinergic system during an early developmental period.

Postnatal Temporal, Spatial and Modality Tuning of Nociceptive Cutaneous Flexion Reflexes in Human Infants

Cutaneous flexion reflexes are amongst the first behavioural responses to develop and are essential for the protection and survival of the newborn organism. Despite this, there has been no detailed, quantitative study of their maturation in human neonates. Here we use surface electromyographic (EMG) recording of biceps femoris activity in preterm (<37 weeks gestation, GA) and term (≥37 weeks GA) human infants, less than 14 days old, in response to tactile, punctate and clinically required skin-breaking lance stimulation of the heel. We show that all infants display a robust and long duration flexion reflex (>4 seconds) to a single noxious skin lance which decreases significantly with gestational age. This reflex is not restricted to the stimulated limb: heel lance evokes equal ipsilateral and contralateral reflexes in preterm and term infants. We further show that infant flexion withdrawal reflexes are not always nociceptive specific: in 29% of preterm infants, tactile stimulation evokes EMG activity that is indistinguishable from noxious stimulation. In 40% of term infants, tactile responses are also present but significantly smaller than nociceptive reflexes. Infant flexion reflexes are also evoked by application of calibrated punctate von Frey hairs (vFh), 0.8–17.2 g, to the heel. Von Frey hair thresholds increase significantly with gestational age and the magnitude of vFh evoked reflexes are significantly greater in preterm than term infants. Furthermore flexion reflexes in both groups are sensitized by repeated vFh stimulation. Thus human infant flexion reflexes differ in temporal, modality and spatial characteristics from those in adults. Reflex magnitude and tactile sensitivity decreases and nociceptive specificity and spatial organisation increases with gestational age. Strong, relatively non-specific, reflex sensitivity in early life may be important for driving postnatal activity dependent maturation of targeted spinal cord sensory circuits.

Reversal of Acute Complex Regional Pain Syndrome Using the Practical Application of Neurodiagnostic Evaluation Process: A Case Study

In 2005, a patient in my practice developed complex regional pain syndrome type 1 (CRPS 1) after bunion surgery. The condition was properly diagnosed within 4 weeks with a diagnostic technique that I routinely use to diagnose chronic musculoskeletal pain, and it was successfully treated. The tests, which are based on primitive and postural reflexes in infants, were adapted to reflect normal and abnormal motor behaviors in adults after provocation of reflexes of the autonomic nervous system (afferent C fibers in peripheral nerves). Approximately 60 days after my patient's operation, the tests indicated a positive reflex at the posterior tibial nerve in the operated foot. Surgery to remove an accessory ossicle from the talus adjacent to this nerve resolved the CRPS 1 within 2 weeks. Since CRPS 1 is a dysfunctional state of the autonomic regulatory control of pain, it was postulated that a test based on autonomic nerve function could isolate the source of CRPS 1. The Practical Application of Neurodiagnostic Evaluation process was shown to be diagnostic for the cause of acute CRPS 1 and to allow its reversal. Further evaluation of the test for diagnosis and treatment of CRPS is needed.

The Babkin Reflex in Infants: Clinical Significance and Neural Mechanism

There have been very few studies concerning the Babkin reflex-opening of the mouth and flexion of the arms in response to stimulation of the palms. We attempted to clarify the clinical significance and neural mechanism of the reflex through systematic review. Searches were conducted on Medline, Embase, and Google Scholar from their inception through August 2012. In normal term infants, the Babkin reflex can be elicited from the time of birth, becomes increasingly suppressed with age, and disappears in the great majority by the end of the fifth month of age. A marked response in the fourth or fifth month of age and persistence of the reflex beyond the fifth month of age are generally regarded as abnormal. On the other hand, because there are some normal infants showing no response during the neonatal period or early infancy, the absence of the response during these periods is not necessarily an abnormal finding. Infants with these abnormal findings should be carefully observed for the appearance of neurological abnormalities including cerebral palsy and mental retardation. It is most likely that the Babkin reflex is mediated by the reticular formation of the brainstem, which receives inputs from the nonprimary motor cortices. On the basis of the hand-mouth reflex, more adaptive movement develops as control of the nonprimary motor cortices over the reflex mechanism in the reticular formation increases. Soon it evolves into the voluntary eye-hand-mouth coordination necessary for food intake as the control of the prefrontal cortex over the nonprimary motor cortices becomes predominant.

Low Vitamin B12 Intake during Pregnancy and Lactation and Low Breastmilk Vitamin B12 Content in Rural Kenyan Women Consuming Predominantly Maize Diets

Vitamin B12 deficiency during pregnancy and lactation may negatively affect fetal growth, brain development, pregnancy outcome, and breastmilk vitamin B12 content. To examine associations between pregnant and lactating women's vitamin B12 intake and pregnancy outcomes, breastmilk vitamin B12 concentration, and growth and development of breastfed infants from birth to 6 months. One hundred thirty-eight Kenyan women were followed during pregnancy, with 98 followed through 6 months of lactation and providing 294 randomly collected breastmilk samples. Maternal hematologic analyses were performed for erythrocyte morphology, erythrocyte size, and serum vitamin B12 concentration. Women's and infants'food intake was assessed. Breastmilk vitamin B12 was measured by a competitive binding isotope dilution technique. Infant anthropometric data and the Brazelton Neonatal Behavioral Assessment Scale (BNBAS) were assessed within 3 days after birth. The Infant Bayley Motor Scale was assessed at 6 months. Statistical analyses included simple regression and correlation analyses in relation to vitamin B12 status and gestational age. Intrauterine growth restriction and stillbirths were correlated with maternal macrocytic anemia and hypersegmented polymorphonuclear nuclei. Postpartum maternal vitamin B12 intake influenced breastmilk vitamin B12 levels 1 to 6 months postpartum. No associations were found between vitamin B12 intake during pregnancy or vitamin B12 levels in breastmilk and infant length, weight, or head circumference at birth or 6 months. Vitamin B12 intake during pregnancy was correlated with improved scores on infants' BNBAS reflex subscale (R = -0.19, p = .05) with adjustment for gestational age. Bayley Motor Scale results at 6 months were not significantly associated with breastmilk or supplemental feeding vitamin B12 content. Vitamin B12 deficiency may adversely affect pregnancy outcome, infant reflexes at birth, and breastmilk vitamin B12 content.

The Grasp Reflex and Moro Reflex in Infants: Hierarchy of Primitive Reflex Responses

The plantar grasp reflex is of great clinical significance, especially in terms of the detection of spasticity. The palmar grasp reflex also has diagnostic significance. This grasp reflex of the hands and feet is mediated by a spinal reflex mechanism, which appears to be under the regulatory control of nonprimary motor areas through the spinal interneurons. This reflex in human infants can be regarded as a rudiment of phylogenetic function. The absence of the Moro reflex during the neonatal period and early infancy is highly diagnostic, indicating a variety of compromised conditions. The center of the reflex is probably in the lower region of the pons to the medulla. The phylogenetic meaning of the reflex remains unclear. However, the hierarchical interrelation among these primitive reflexes seems to be essential for the arboreal life of monkey newborns, and the possible role of the Moro reflex in these newborns was discussed in relation to the interrelationship.

GSTM1 Modifies the Effect of Maternal Exposure to Environmental Tobacco Smoke on Neonatal Primitive Reflexes

The aim of this study was to examine whether infant metabolic gene polymorphisms modify the effect of maternal environmental tobacco smoke (ETS) on neonatal neurobehavior. We conducted a birth cohort study of 87 nonsmoking women who delivered single births of normal birth weight. We enrolled the women before delivery, interviewed them using a structured questionnaire, and collected umbilical cord blood. Umbilical cord cotinine, a blood indicator of prenatal ETS exposure, was analyzed. The Neonatal Neurobehavioral Examination-Chinese Version (NNE-C) was administrated within 5 days after delivery to examine neonatal neurobehavior. Four infant metabolic genes, CYP1A1 MspI, CYP1A1 Ile462Val, GSTT1, and GSTM1, were identified. Maternal ETS exposure during pregnancy was not related to neonatal neurobehavior when infant genetic polymorphisms were not considered. However, maternal ETS exposure did cause adverse effects in neonates with the absent type of GSTM1. Adverse effects were seen on the total NNE-C (β = -2.55; p = .02) and on primitive reflexes (β = -1.70; p = .004), especially in grasp reflexes (β = -.36; p = .011) and tonic neck reflexes (β = -.36; p = .049). In addition, there was a significant interaction between maternal ETS exposure and infant GSTM1 genotype on neonate grasp reflexes (p for interaction = .019). These data indicate that weaker responses in neonatal primitive reflexes in infants with the absent type GSTM1 were related to maternal ETS exposure during pregnancy.

乳児踵骨反射の潜時, 反射持続時間, 反応持続期間について

乳児踵骨反射の潜時, 反射持続時間, 反応持続期間について

Prenatal exposure to bisphenol A and phthalates and infant neurobehavior

Objective To examine the association of prenatal exposure to bisphenol A and select common phthalates with infant neurobehavior measured at 5 weeks. Methods We compared the concentration of maternal urinary metabolites of bisphenol A and phthalates at two distinct time points in pregnancy (16w, 26w) with scores on the NICU Network Neurobehavioral Scale (NNNS) at 5 weeks of age in a cohort of 350 mother/infant pairs. Results Prenatal exposure to BPA was not significantly associated with neurobehavioral outcomes at 5 weeks. Significant associations between prenatal exposure to measured phthalates and infant neurobehavioral outcomes differed by type of phthalate and were only seen with exposure measured at 26 weeks. Higher total di-butyl phthalate (DBP) metabolites at 26w were associated with improved behavioral organization evidenced by decreased arousal (p = .04), increased self-regulation (p = .052), and decreased handling (p = .02). In males, higher total di-2-ethylhexyl phthalate (DEHP) metabolites at 26w were associated with more nonoptimal reflexes (p = .02). Conclusion The association between prenatal phthalate exposure and infant neurobehavior differed by type of phthalate and was evident only with exposure measured at 26w. Prenatal exposure to DBP was associated with improved behavioral organization in 5-week-old infants. Prenatal exposure to DEHP was associated with nonoptimal reflexes in male infants. There was no evidence of an association between prenatal BPA exposure and infant neurobehavior.

Effect of Abrupt Esophageal Provocation on Sensory-Motor Characteristics of Esophageal Body and Upper Esophageal Sphincter (UES) Contractile Reflexes in Infants With Gastroesophageal Reflux Disease (GERD)

Effect of Abrupt Esophageal Provocation on Sensory-Motor Characteristics of Esophageal Body and Upper Esophageal Sphincter (UES) Contractile Reflexes in Infants With Gastroesophageal Reflux Disease (GERD)

Neural Mechanism and Clinical Significance of the Plantar Grasp Reflex in Infants

The plantar grasp reflex can be elicited in all normal infants from 25 weeks of postconceptional age until the end of 6 months of corrected age according to the expected birth date. This reflex in human infants can be regarded as a rudiment of responses that were once essential for ape infants in arboreal life. The spinal center for this reflex is probably located at the L(5)-S(2) levels, which, however, are controlled by higher brain structures. Nonprimary motor areas may exert regulatory control of the spinal reflex mechanism through interneurons. In infants, this reflex can be elicited as the result of insufficient control of the spinal mechanism by the immature brain. In adults, lesions in nonprimary motor areas may cause a release of inhibitory control by spinal interneurons, leading to a reappearance of the reflex. The plantar grasp reflex in infants is of high clinical significance. A negative or diminished reflex during early infancy is often a sensitive indicator of spasticity. Infants with athetoid type cerebral palsy exhibit an extremely strong retention of the reflex, and infants with mental retardation also exhibit a tendency toward prolonged retention of the reflex.

Suppression of the Oculocephalic Reflex (Doll’s Eyes Phenomenon) in Normal Full-Term Babies

Purpose: To determine the precise age of suppression of the oculocephalic reflex in infants and its relationship to specific clinical characteristics.Methods: The oculocephalic reflex was prospectively tested in 325 healthy full-term babies aged 1 to 32 weeks attending an orthopedic outpatient clinic. Two ophthalmologists raised the baby’s head 30 degrees above horizontal and rapidly rotated it in the horizontal and vertical planes while watching the conjugate eye movement. Suppression of the reflex, by observer agreement, was analyzed in relation to gestational age, postpartum age, postconceptional age, birth weight, and current weight. The data were fitted to a logistic regression model to determine the probability of suppression of the reflex according to the clinical variables.Results: The oculocephalic reflex was suppressed in 75% of babies by the age of 11.5 weeks and in more than 95% of babies aged 20 weeks. Although postpartum age had a greater influence than gestational age, both were significantly correlated with suppression of the reflex (p = 0.01and p = 0.04, respectively; two-sided t-test). Postpartum age was the best single variable explaining absence of the reflex. On logistic regression with cross-validation, the model including postpartum age and current weight yielded the best results; both these factors were highly correlated with suppression of the reflex (r = 0.74).Conclusions: The oculocephalic reflex is suppressed in the vast majority of normal infants by age 11.5 weeks. The disappearance of the reflex occurs gradually and longitudinally and is part of the normal maturation of the visual system.

778 Maturation of Volume Dependent Recruitment of Upper Esophageal Sphincter Contractile Reflex (UESCR) in Awake and Sleeping Premature Infants

778 Maturation of Volume Dependent Recruitment of Upper Esophageal Sphincter Contractile Reflex (UESCR) in Awake and Sleeping Premature Infants

T2071 Pilot Study On the Effect of Glutamate On Gastric Emptying and Gustofacial Reflexes in Healthy Infants

T2071 Pilot Study On the Effect of Glutamate On Gastric Emptying and Gustofacial Reflexes in Healthy Infants

Neonatal Apnea: What's New?

Apnea of prematurity (AOP) remains a major clinical problem in present day neonatology that warrants frequent evaluations and imposes challenges in therapeutic strategies. Although the pathogenesis of AOP is poorly understood, it is probably a manifestation of physiologic immaturity of breathing control rather than a pathologic disorder. Immature breathing responses to hypoxia, hypercapnia and exaggerated inhibitory pulmonary reflexes in preterm infants might also contribute to the occurrence or severity of AOP. Recent data suggest a role for genetic predisposition. Although typically resolve with maturation, the role of bradycardia and desaturation episodes associated with AOP in the development of sleep disorder breathing and neurodevelopmental delay needs further clarification. Pharmacological treatment with methylxanthines and CPAP remain the mainstay for treatment of AOP. However, recent studies have implicated central inhibitory neuromodulators including prostaglandins, GABA and adenosine in its pathogenesis, the fact that might provide future specific targets for treatment. This review will summarize new insights involving these issues as well as others involving the pathogenesis, treatment strategies and consequences of apnea in premature infants.

How to assess an infant's reflexes

How to assess an infant's reflexes

Esophageal swallowing reflexes in preterms

Gastro-esophageal reflux disease is frequent at all ages and multiple medications are used to treat symptoms. Most preterm infants will have swallowing problems as they develop feeding skills and will have reflux that may or may not be “symptomatic.” The frequency of diagnosis of symptomatic reflux varies widely between physicians and neonatal units. Similarly, the use of drug therapy that is unvalidated for efficacy or safety varies widely in this patient population. Jadcheria, Hoffman, and Shaker report an elegant study of the mechano- and chemo-sensitive stimuli of persistalsis and upper esophageal sphincter reflexes in preterm infants. With more studies like this, we may learn the physiologic basis for reflux in the preterm, which would be desirable to better direct drug therapies.

The amplitude of the Achilles tendon reflex in infants is related to body position

In this study, we investigated whether the Achilles tendon reflex (ATR) in healthy infants is modulated by changes in body position (prone vs. supine). The amplitude of the ATR was compared at postnatal day 1, months 2, 3 and 6, while infants were placed in prone and supine position. The ATR was considered “positive” when at least 1 of 20 tendon taps evoked a visible contraction of the ankle plantar flexor muscles. At 6 months, the amplitude and latency of the ATR were evaluated by electromyographic (EMG) recordings of the (lateral and medial) gastrocnemius muscle, with the infant in prone and supine position. At postnatal day 1, the clinical ATR response was more frequently present in prone than supine position (14/16 or 88% vs. 4/16 or 25%, respectively, p < 0.01). From 2 months onwards, the frequencies of positive ATRs were no longer significantly different between prone (14/14 or 100%) and supine position (10/14 or 67%). However, based on the EMG recordings at 6 months, the ATR amplitude was higher in prone compared to supine position ( n = 8, median 5.5 mV, range 4.7–6.6 mV; and median 3.8 mV, range 2.3–5.6 mV, p < 0.05). We conclude that the ATR response in healthy infants is more pronounced in prone than in supine position, either when clinically (visually) assessed during routine tendon tapping or when neurophysiologically assessed during surface EMG recording.