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Tran NN, Chwa JS, Brady KM, Borzage M, Brecht ML, Woon JX, Miner A, Merkel CA, Friedlich P, Peterson BS, Wood JC. Cerebrovascular responses to a 90° tilt in healthy neonates. Pediatr Res 2024; 95:1851-1859. [PMID: 38280952 PMCID: PMC11245387 DOI: 10.1038/s41390-024-03046-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/30/2023] [Accepted: 01/07/2024] [Indexed: 01/29/2024]
Abstract
BACKGROUND Tilts can induce alterations in cerebral hemodynamics in healthy neonates, but prior studies have only examined systemic parameters or used small tilt angles (<90°). The healthy neonatal population, however, are commonly subjected to large tilt angles (≥90°). We sought to characterize the cerebrovascular response to a 90° tilt in healthy term neonates. METHODS We performed a secondary descriptive analysis on 44 healthy term neonates. We measured cerebral oxygen saturation (rcSO2), oxygen saturation (SpO2), heart rate (HR), breathing rate (BR), and cerebral fractional tissue oxygen extraction (cFTOE) over three consecutive 90° tilts. These parameters were measured for 2-min while neonates were in a supine (0°) position and 2-min while tilted to a sitting (90°) position. We measured oscillometric mean blood pressure (MBP) at the start of each tilt. RESULTS rcSO2 and BR decreased significantly in the sitting position, whereas cFTOE, SpO2, and MBP increased significantly in the sitting position. We detected a significant position-by-time interaction for all physiological parameters. CONCLUSION A 90° tilt induces a decline in rcSO2 and an increase in cFTOE in healthy term neonates. Understanding the normal cerebrovascular response to a 90° tilt in healthy neonates will help clinicians to recognize abnormal responses in high-risk infant populations. IMPACT Healthy term neonates (≤14 days old) had decreased cerebral oxygen saturation (~1.1%) and increased cerebral oxygen extraction (~0.01) following a 90° tilt. We detected a significant position-by-time interaction with all physiological parameters measured, suggesting the effect of position varied across consecutive tilts. No prior study has characterized the cerebral oxygen saturation response to a 90° tilt in healthy term neonates.
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Affiliation(s)
- Nhu N Tran
- Institute for the Developing Mind, The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA, USA.
- Fetal and Neonatal Institute, Division of Neonatology, Children's Hospital Los Angeles, Los Angeles, CA, USA.
- Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
| | - Jason S Chwa
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Kenneth M Brady
- Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Matthew Borzage
- Fetal and Neonatal Institute, Division of Neonatology, Children's Hospital Los Angeles, Los Angeles, CA, USA
- Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Mary-Lynn Brecht
- School of Nursing, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jessica X Woon
- Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA, USA
| | - Anna Miner
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Carlin A Merkel
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Philippe Friedlich
- Fetal and Neonatal Institute, Division of Neonatology, Children's Hospital Los Angeles, Los Angeles, CA, USA
- Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Bradley S Peterson
- Institute for the Developing Mind, The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA, USA
- Department of Psychiatry, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - John C Wood
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Division of Cardiology, Children's Hospital Los Angeles, Los Angeles, CA, USA
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Effects of tilt on cerebral hemodynamics measured by NeoDoppler in healthy neonates. Pediatr Res 2021; 90:888-895. [PMID: 33504967 PMCID: PMC8566239 DOI: 10.1038/s41390-020-01354-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 12/20/2020] [Accepted: 12/28/2020] [Indexed: 01/30/2023]
Abstract
BACKGROUND Today, there are conflicting descriptions of how neonates respond to tilt. Examining physiologic responses of cerebral blood flow velocities (BFVs) in challenging situations like a tilt requires equipment that can cope with positional changes. We aimed to characterize how healthy term neonates respond to mild cerebral hemodynamic stress induced by a 90° tilt test using the recently developed NeoDoppler ultrasound system. METHODS A small ultrasound probe was fixated to the neonatal fontanel by a cap, and measured cerebral BFV in healthy neonates during and after a 90° head-up tilt test, five min in total, at their first and second day of life. Unsupervised k-means cluster analysis was used to characterize common responses. RESULTS Fifty-six ultrasound recordings from 36 healthy term neonates were analyzed. We identified five distinct, immediate responses that were related to specific outcomes in BFV, heart rate, and pulsatility index the next two min. Among 20 neonates with two recordings, 13 presented with different responses in the two tests. CONCLUSIONS Instant changes in cerebral BFV were detected during the head-up tilt tests, and the cluster analysis identified five different hemodynamic responses. Continuous recordings revealed that the differences between groups persisted two min after tilt. IMPACT NeoDoppler is a pulsed-wave Doppler ultrasound system with a probe fixated to the neonatal fontanel by a cap that can measure continuous cerebral blood flow velocity. Healthy neonates present with a range of normal immediate cerebral hemodynamic responses to a 90° head-up tilt, categorized in five groups by cluster analysis. This paper adds new knowledge about connection between immediate responses and prolonged responses to tilt. We demonstrate that the NeoDoppler ultrasound system can detect minute changes in cerebral blood flow velocity during a 90° head-up tilt.
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Gabbay U, Carmi D, Birk E, Dagan D, Shatz A, Kidron D. The Sudden Infant Death Syndrome mechanism of death may be a non-septic hyper-dynamic shock. Med Hypotheses 2018; 122:35-40. [PMID: 30593418 DOI: 10.1016/j.mehy.2018.10.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/15/2018] [Accepted: 10/20/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND Sudden Infant Death Syndrome (SIDS) mechanisms of death remains obscured. SIDS' Triple Risk Model assumed coexistence of individual subtle vulnerability, critical developmental period and stressors. Prone sleeping is a major risk factor but provide no clues regarding the mechanism of death. The leading assumed mechanisms of death are either an acute respiratory crisis or arrhythmias but neither one is supported with evidence, hence both are eventually speculations. Postmortem findings do exist but are inconclusive to identify the mechanism of death. WHAT DOES THE PROPOSED HYPOTHESIS BASED ON?: 1. The stressors (suggested by the triple risk model) share a unified compensatory physiological response of decrease in systemic vascular resistant (SVR) to facilitate a compensatory increase in cardiac output (CO). 2. The cardiovascular/cardiorespiratory control of the vulnerable infant during a critical developmental period may be impaired. 3. A severe decrease in SVR is associated with hyper-dynamic state, high output failure and distributive shock. THE HYPOTHESIS Infant who is exposed to one or more stressors responds normally by decrease in SVR which increases CO. In normal circumstances once the needs are met both SVR and CO are stabilized on a new steady state. The incompetent cardiovascular control of the vulnerable infant fails to stabilize SVR which decreases in an uncontrolled manner. Accordingly CO increases above the needs to hyper-dynamic state, high output heart failure and hyper-dynamic shock. CONCLUSIONS The proposed hypothesis provides an appropriate alternative to either respiratory crises or arrhythmia though both speculations cannot be entirely excluded.
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Affiliation(s)
- Uri Gabbay
- Quality Unit, Rabin Medical Center, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Doron Carmi
- Shoham Pediatric Clinic, Southern District, Clalit Health Services, Shoham, Israel
| | - Einat Birk
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Pediatric Cardiology Unit, Schneider Children's Medical Center, Petach Tikva, Israel
| | - David Dagan
- Surgeon General's Headquarters, Israel Defense Forces, Ramat Gan, Israel
| | - Anat Shatz
- ENT, Shaare Zedek Medical Center, Jerusalem, Israel; Atid, the Israeli Society for the Study and Prevention of SIDS, Jerusalem, Israel
| | - Debora Kidron
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Pathology Department, Meir Medical Center, Kfar Saba, Israel
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Myers MM, Elliott AJ, Odendaal HJ, Burd L, Angal J, Groenewald C, Nugent JD, Yang JS, Isler JR, Dukes KA, Robinson F, Fifer WP. Cardiorespiratory physiology in the safe passage study: protocol, methods and normative values in unexposed infants. Acta Paediatr 2017; 106:1260-1272. [PMID: 28419567 DOI: 10.1111/apa.13873] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/03/2017] [Accepted: 04/10/2017] [Indexed: 11/27/2022]
Abstract
AIM The Safe Passage Study, conducted by the Prenatal Alcohol in SIDS and Stillbirth Network, is investigating contributions of prenatal alcohol exposure to foetal and infant demise. This current report presents physiological data from full-term infants with no prenatal exposure to alcohol or maternal smoking. METHODS Data are from 666 infants from the Northern Plains (North and South Dakota) and South Africa. A standardised protocol assessed cardiorespiratory function during baseline and head-up tilts shortly after birth and at one month of age. RESULTS Analyses revealed significant increases in heart rate and decreases in BP from the newborn to one-month time period as well as diminished heart rate responses to head-up tilt in one-month-old infants. CONCLUSION The Safe Passage Study was successful in characterising physiology in a large number of infants at sites known to have elevated risks for SIDS. Results demonstrate that even with low prenatal adverse exposures, there are significant changes in cardiorespiratory function as infants enter the window of increased risk for SIDS.
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Affiliation(s)
- Michael M. Myers
- Department of Psychiatry; Columbia University Medical Center; New York NY USA
- Department of Pediatrics; Columbia University Medical Center; New York NY USA
- Division of Developmental Neuroscience; New York State Psychiatric Institute; New York NY USA
| | - Amy J. Elliott
- Community and Population Health Sciences; Sanford Research; Sioux Falls SD USA
- Department of Pediatrics; Sanford School of Medicine; University of South Dakota; Sioux Falls SD USA
| | - Hein J. Odendaal
- Department of Obstetrics and Gynecology; Faculty of Medicine and Health Science; Stellenbosch University; Cape Town Western Cape South Africa
| | - Larry Burd
- University of North Dakota Medical School; Grand Forks ND USA
| | - Jyoti Angal
- Community and Population Health Sciences; Sanford Research; Sioux Falls SD USA
- Department of Pediatrics; Sanford School of Medicine; University of South Dakota; Sioux Falls SD USA
| | - Coen Groenewald
- Department of Obstetrics and Gynecology; Faculty of Medicine and Health Science; Stellenbosch University; Cape Town Western Cape South Africa
| | - James David Nugent
- Division of Developmental Neuroscience; New York State Psychiatric Institute; New York NY USA
| | - Joel S. Yang
- Division of Developmental Neuroscience; New York State Psychiatric Institute; New York NY USA
| | - Joseph R. Isler
- Department of Pediatrics; Columbia University Medical Center; New York NY USA
| | | | | | - William P. Fifer
- Department of Psychiatry; Columbia University Medical Center; New York NY USA
- Department of Pediatrics; Columbia University Medical Center; New York NY USA
- Division of Developmental Neuroscience; New York State Psychiatric Institute; New York NY USA
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Calton M, Dickson P, Harper RM, Goldowitz D, Mittleman G. Impaired hypercarbic and hypoxic responses from developmental loss of cerebellar Purkinje neurons: implications for sudden infant death syndrome. THE CEREBELLUM 2015; 13:739-50. [PMID: 25132500 DOI: 10.1007/s12311-014-0592-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Impaired responsivity to hypercapnia or hypoxia is commonly considered a mechanism of failure in sudden infant death syndrome (SIDS). The search for deficient brain structures mediating flawed chemosensitivity typically focuses on medullary regions; however, a network that includes Purkinje cells of the cerebellar cortex and its associated cerebellar nuclei also helps mediate responses to carbon dioxide (CO2) and oxygen (O2) challenges and assists integration of cardiovascular and respiratory interactions. Although cerebellar nuclei contributions to chemoreceptor challenges in adult models are well described, Purkinje cell roles in developing models are unclear. We used a model of developmental cerebellar Purkinje cell loss to determine if such loss influenced compensatory ventilatory responses to hypercapnic and hypoxic challenges. Twenty-four Lurcher mutant mice and wild-type controls were sequentially exposed to 2% increases in CO2 (0-8%) or 2% reductions in O2 (21-13%) over 4 min, with return to room air (21% O2/79% N2/0% CO2) between each exposure. Whole body plethysmography was used to continuously monitor tidal volume (TV) and breath frequency (f). Increased f to hypercapnia was significantly lower in mutants, slower to initiate, and markedly lower in compensatory periods, except for very high (8%) CO2 levels. The magnitude of TV changes to increasing CO2 appeared smaller in mutants but only approached significance. Smaller but significant differences emerged in response to hypoxia, with mutants showing smaller TV when initially exposed to reduced O2 and lower f following exposure to 17% O2. Since cerebellar neuropathology appears in SIDS victims, developmental cerebellar neuropathology may contribute to SIDS vulnerability.
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Affiliation(s)
- M Calton
- Department of Psychology, The University of Memphis, 400 Innovation Drive, Memphis, TN, 38152, USA
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WITCOMBE NICOLEB, YIALLOUROU STEPHANIER, WALKER ADRIANM, HORNE ROSEMARYSC. Delayed blood pressure recovery after head-up tilting during sleep in preterm infants. J Sleep Res 2010; 19:93-102. [DOI: 10.1111/j.1365-2869.2009.00793.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
Current evidence suggests that multiple neural mechanisms contribute to the fatal lethal event in SIDS. The processes may develop from a range of otherwise seemingly-innocuous circumstances, such as unintended external airway obstruction or accidental extreme flexion of the head of an already-compromised structure of the infant upper airway. The fatal event may occur in a sleep state which can suppress muscle tone essential to restore airway patency or exert muscle action to overcome a profound loss of blood pressure. Neural processes that could overcome those transient events with reflexive compensation appear to be impaired in SIDS infants. The evidence ranges from subtle physiological signs that appear very early in life, to autopsy findings of altered neurotransmitter, including serotonergic, systems that have extensive roles in breathing, cardiovascular regulation, and thermal control. Determination of the fundamental basis of SIDS is critical to provide biologic plausibility to SIDS risk reduction messages and to develop specific prevention strategies.
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Affiliation(s)
- Ronald M Harper
- Department of Neurobiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
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Akkurt D, Akay YM, Akay M. Nicotine and elevated body temperature reduce the complexity of the genioglossus and diaphragm EMG signals in rats during early maturation. J Neural Eng 2009; 6:056004. [DOI: 10.1088/1741-2560/6/5/056004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Fifer WP, Fingers ST, Youngman M, Gomez-Gribben E, Myers MM. Effects of alcohol and smoking during pregnancy on infant autonomic control. Dev Psychobiol 2009; 51:234-42. [PMID: 19253344 DOI: 10.1002/dev.20366] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Prenatal exposure to smoking and alcohol increases the risk for Sudden Infant Death Syndrome (SIDS). Physiological changes associated with these exposures are not well studied. Full-term infants were tested within the first 3 days of life. We hypothesized that maternal alcohol consumption and/or smoking during pregnancy would alter autonomic nervous system function. Newborns whose mothers smoked during pregnancy had lower beat-to-beat heart rate variability in quiet sleep. Infants whose mothers consumed alcohol had lower global heart rate variability, but only in active sleep. Unexposed infants demonstrated increases in heart rate with head-up tilt and decreases in heart rate with head-down tilt, but smoking and alcohol-exposed infants showed no significant responses. These results indicate that autonomic function is altered by prenatal exposure to alcohol and smoking. Such markers may provide early identification of infants at greatest risk for SIDS.
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Affiliation(s)
- William P Fifer
- Department of Psychiatry, Columbia University College of Physicians & Surgeons, New York, NY, USA.
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Pivik RT, Dykman RA, Jing H, Gilchrist JM, Badger TM. Early infant diet and the omega 3 fatty acid DHA: effects on resting cardiovascular activity and behavioral development during the first half-year of life. Dev Neuropsychol 2009; 34:139-58. [PMID: 19267292 DOI: 10.1080/87565640802646726] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This investigation evaluated variations in resting heart rate (HR) measures during the first half year of life in healthy, full-term infants who were either breast-fed (BF), or fed formula with (milk-based: MF; soy-based: SF) or without (soy-based: SF(-)) commercially supplemented DHA (decosahexaenoic acid). In infants fed the DHA-deficient diet, higher HR and lower values for heart rate variability measures were observed, indicating decreased parasympathetic tone in this group. These effects, appearing at 4 months and continuing for the remainder of the study period, are consistent with suggestions that the 3-5-month postnatal interval may be an important period in the development of cardiovascular regulation. The absence of these effects in SF infants receiving the DHA-supplemented formula suggests that neither soy protein nor the associated phytochemicals in soy formula contribute to these effects to any appreciable extent. In general, the results do not indicate differences in any of the study variables attributable to soy formula per se.
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Affiliation(s)
- R T Pivik
- Arkansas Children's Nutrition Center, Little Rock, Arkansas 72202, USA.
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Grieve PG, Stark RI, Isler JR, Housman SL, Fifer WP, Myers MM. Electrocortical functional connectivity in infancy: response to body tilt. Pediatr Neurol 2007; 37:91-8. [PMID: 17675023 DOI: 10.1016/j.pediatrneurol.2007.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Revised: 01/18/2007] [Accepted: 04/18/2007] [Indexed: 11/30/2022]
Abstract
To test the hypothesis that infant cortical regions activated by a head-up tilt also exhibit increased functional electrocortical connectivity, prone sleeping newborn and 2- to 4-month-old infants were tilted head-up to 30 degrees. Electroencephalogram (EEG) data were collected with 128 electrodes and coherence calculated to quantify electrocortical synchrony. Local coherence, defined as the average of coherence measurements between the EEG at each electrode site and neighboring sites (approximately 1 cm electrode spacing), was found in activated cortical regions that had previously shown increased high-frequency power with tilt. Long-distance coherence was computed between the regions. Newborn infants had significant increases in local coherence in the activated left frontal, right frontal-temporal, and occipital cortical regions; long-distance coherence increased between the right frontal-temporal and occipital regions. In contrast, infants at 2 to 4 months old, the age of maximum risk for sudden infant death syndrome, had no significant changes in coherence. Newborn and 2- to 4-month-old infants thus have different electrocortical responses to a classic cardiovascular challenge.
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Affiliation(s)
- Philip G Grieve
- Department of Pediatrics, Columbia University, and New York State Psychiatric Institute, New York, NY 10032, USA.
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Ludington-Hoe SM, Johnson MW, Morgan K, Lewis T, Gutman J, Wilson PD, Scher MS. Neurophysiologic assessment of neonatal sleep organization: preliminary results of a randomized, controlled trial of skin contact with preterm infants. Pediatrics 2006; 117:e909-23. [PMID: 16651294 DOI: 10.1542/peds.2004-1422] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Sleep is important to brain organization, but few strategies to promote sleep among premature infants have been tested. Behaviorally based measures of sleep have shown increased quiet sleep (QS) and decreased active sleep (AS) during skin-to-skin contact (SSC) with the mother, but these results have not been confirmed with objective electroencephalographic/polysomnographic measures of sleep organization. Important differences exist between behavioral and electroencephalographic/polysomnographic definitions of sleep state. METHODS Data for the first 28 relatively healthy, preterm subjects of an ongoing randomized trial of one 2- to 3-hour session of SSC or incubator care between feedings are reported here. Infants were positioned prone, inclined, and nested in an incubator during the 2- to 3-hour pretest period, were fed, and then went into the test period of SSC or incubator care. Infants were left largely undisturbed throughout testing. A mixed-model regression analysis compared the test-pretest differences in outcome measures within and between groups. RESULTS Results showed that arousals were significantly lower in the SSC group, compared with the control group, for the entire study period and for test-pretest matched segments of QS and AS. Rapid eye movement was significantly lower for the SSC group for the study period and AS segments. Indeterminate sleep was significantly lower for the SSC group when confounding environmental variables were included in the regression analysis. When 4 subjects who experienced excessive ambient light levels during SSC were removed from analysis, QS increased during SSC. CONCLUSIONS The patterns demonstrated by the SSC group are analogous to more-mature sleep organization. SSC may be used as an intervention to improve sleep organization in this population of preterm infants.
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Affiliation(s)
- Susan M Ludington-Hoe
- School of Nursing, Case Western Reserve University, Cleveland, Ohio 44106-4904, USA.
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Myers MM, Gomez-Gribben E, Smith KS, Tseng A, Fifer WP. Developmental changes in infant heart rate responses to head-up tilting. Acta Paediatr 2006; 95:77-81. [PMID: 16373301 DOI: 10.1080/08035250500325074] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
AIM Newborn infants produce significant heart rate responses to both head-up and head-down tilting: heart rate increases with head-up tilting and decreases with head-down tilting. However, previously we found that, at 2-4 mo of age, heart rate increases were no longer significant following slow head-up tilting. This study was designed to determine if 2-4-mo-old infants have significant increases in heart rate when tilted rapidly. METHODS Fifty-four infants were tested as newborns or at 2-4 mo of age. Heart rate was measured while infants were tilted to a 30 degrees head-up angle either slowly over a period of 30 s or rapidly in 5 s. RESULTS Newborns exhibited increases in heart rate using both tilt speeds; however, at 2-4 mo of age, heart rate did not change significantly using either speed of tilting. CONCLUSION There are significant early developmental changes in cardiac responses to hypotensive challenge. Newborns react like adults, mounting sustained increases in heart rate in response to head-up tilting, but at 2-4 mo of age sustained heart rate responses are no longer significant. Tilt tests may provide a standardized method for assessing autonomic competence during the period of maximum vulnerability to sudden infant death syndrome.
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Affiliation(s)
- Michael M Myers
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, USA.
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Niblock MM, Luce CJ, Belliveau RA, Paterson DS, Kelly ML, Sleeper LA, Filiano JJ, Kinney HC. Comparative anatomical assessment of the piglet as a model for the developing human medullary serotonergic system. ACTA ACUST UNITED AC 2005; 50:169-83. [PMID: 16043226 DOI: 10.1016/j.brainresrev.2005.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 05/10/2005] [Accepted: 05/13/2005] [Indexed: 10/25/2022]
Abstract
Because the piglet is frequently used as a model for developmental disorders of the medullary serotonergic (5-HT) system in the human infant, this review compares the topography and developmental profile of selected 5-HT markers between humans in the first year of life and piglets in the first 60 days of life. The distribution of tryptophan hydroxylase-immunoreactive 5-HT neurons in the human infant medulla is very similar, but not identical, to that in the piglet. One notable difference is the presence of compact clusters of 5-HT neurons at the ventral surface of the piglet medulla. While it lacks these distinctive clusters, the human infant medulla contains potentially homologous 5-HT neurons scattered along the ventral surface embedded in the arcuate nucleus. Each species shows evidence of age-related changes in the 5-HT system, but the changes are different in nature; in the human infant, statistically significant age-related changes are observed in the proportional distribution of medullary 5-HT cells, while in the piglet, statistically significant age-related changes are observed in the levels of 5-HT receptor binding in certain medullary nuclei. Analyses of 5-HT receptor binding profiles in selected nuclei in the two species suggest that the equivalent postnatal ages for 5-HT development in piglets and human infants are, respectively, 4 days and 1 month, 12 days and 4 months, 30 days and 6 months, and 60 days and 12 months. Collectively, when certain species differences are considered, these data support the use of the piglet as a model for the human infant medullary 5-HT system.
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Affiliation(s)
- Mary M Niblock
- Department of Physiology, Dartmouth Medical School, 1 Medical Center Drive, Lebanon, NH 03756, USA.
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Grieve PG, Myers MM, Stark RI, Housman S, Fifer WP. Topographic localization of electrocortical activation in newborn and two- to four-month-old infants in response to head-up tilting. Acta Paediatr 2005; 94:1756-63. [PMID: 16421036 DOI: 10.1111/j.1651-2227.2005.tb01850.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS (1) To confirm that head-up tilting causes sustained increases in the heart rate (HR) of newborn infants but not during the period of maximum vulnerability to SIDS at 2-4 mo of age, and (2) to determine whether electrocortical activation (changes in high-frequency EEG power) also shows topographic and age-dependent effects of tilting. METHODS HR and electrocortical activity were recorded in 15 newborn and 12 2- to 4-mo-old infants during head-up tilting. Infants were tilted, three times, to a 30 degrees head-up position. Electrocortical activity was acquired using a 128-lead EEG system. Changes in HR and high-frequency (12-50 Hz) power in the electrocortical signal were computed from the flat to the head-up position. RESULTS Newborn infants had significant increases in HR and robust increases in high-frequency power in the left frontal, right frontal-temporal, and occipital regions following head-up tilt. At 2 to 4 mo of age, HR did not change significantly and tilt-related increases in high-frequency power were smaller. CONCLUSION The patterns of HR change and electrocortical activation with tilting of newborn infants are different from infants at the age of highest risk for SIDS.
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Affiliation(s)
- Philip G Grieve
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
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Myers MM, Shair HN, Cohen M. Blood pressure responses to feeding in infancy: spin-offs of serendipity. Dev Psychobiol 2005; 47:268-77. [PMID: 16252294 DOI: 10.1002/dev.20095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This article summarizes results from a program of research that has focused on understanding the characteristics of, and factors that shape, acute cardiovascular responses to feeding in infants. The work developed from behavioral observations in rats suggesting a linkage between variations in maternal behavior and adult blood pressure. However, the hypothesis that specific types of interactions, in particular those associated with feeding, might alter cardiovascular function was greatly influenced by a serendipitous observation made by Myron Hofer several years earlier. Myron discovered that nutrient availability is a key regulator of cardiovascular function in newborn rats. Our spin-off studies established that, in newborn rats and human infants, ingestion of nutrient is associated with robust increases in heart rate and blood pressure.
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Affiliation(s)
- Michael M Myers
- New York State Psychiatric Institute, Department of Developmental Psychobiology, Columbia University College of Physicians and Surgeons, New, New York, USA.
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Dietrich KN, Eskenazi B, Schantz S, Yolton K, Rauh VA, Johnson CB, Alkon A, Canfield RL, Pessah IN, Berman RF. Principles and practices of neurodevelopmental assessment in children: lessons learned from the Centers for Children's Environmental Health and Disease Prevention Research. ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:1437-46. [PMID: 16203260 PMCID: PMC1281293 DOI: 10.1289/ehp.7672] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Principles and practices of pediatric neurotoxicology are reviewed here with the purpose of guiding the design and execution of the planned National Children's Study. The developing human central nervous system is the target organ most vulnerable to environmental chemicals. An investigation of the effects of environmental exposures on child development is a complex endeavor that requires consideration of numerous critical factors pertinent to a study's concept, design, and execution. These include the timing of neurodevelopmental assessment, matters of biologic plausibility, site, child and population factors, data quality assurance and control, the selection of appropriate domains and measures of neurobehavior, and data safety and monitoring. Here we summarize instruments for the assessment of the neonate, infant, and child that are being employed in the Centers for Children's Environmental Health and Disease Prevention Research, sponsored by the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency, discuss neural and neurobiologic measures of development, and consider the promises of gene-environment studies. The vulnerability of the human central nervous system to environmental chemicals has been well established, but the contribution these exposures may make to problems such as attention deficit disorder, conduct problems, pervasive developmental disorder, or autism spectrum disorder remain uncertain. Large-scale studies such as the National Children's Study may provide some important clues. The human neurodevelopmental phenotype will be most clearly represented in models that include environmental chemical exposures, the social milieu, and complex human genetic characteristics that we are just beginning to understand.
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Affiliation(s)
- Kim N Dietrich
- University of Cincinnati College of Medicine, Division of Epidemiology and Biostatistics, Department of Environmental Health, and the Cincinnati Children's Environmental Health Center, Cincinnati, Ohio, USA
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Kinney HC, Myers MM, Belliveau RA, Randall LL, Trachtenberg FL, Fingers ST, Youngman M, Habbe D, Fifer WP. Subtle Autonomic and Respiratory Dysfunction in Sudden Infant Death Syndrome Associated With Serotonergic Brainstem Abnormalities: A Case Report. J Neuropathol Exp Neurol 2005; 64:689-94. [PMID: 16106217 DOI: 10.1097/01.jnen.0000174334.27708.43] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Sudden infant death syndrome (SIDS) is characterized by a sleep-related death in a seemingly healthy infant. Previously, we reported abnormalities in the serotonergic (5-HT) system of the medulla in SIDS cases in 2 independent datasets, including in the Northern Plains American Indians. The medullary 5-HT system is composed of 5-HT neurons in the raphé, extra-raphé, and arcuate nucleus at the ventral surface. This system is thought to modulate respiratory and autonomic function, and thus abnormalities within it could potentially lead to imbalances in sympathetic and parasympathetic tone. We report the case of a full-term American Indian boy who died of SIDS at 2 postnatal weeks, and who had subtle respiratory and autonomic dysfunction measured prospectively on the second postnatal day. Cardiorespiratory assessment of heart rate variability suggested that the ratio of parasympathetic to sympathetic tone was higher than normal in active sleep and lower than normal in quiet sleep in this case. At autopsy, arcuate nucleus hypoplasia and 5-HT receptor-binding abnormalities in the arcuate nucleus and other components of the medullary 5-HT system were found. This case suggests that medullary 5-HT system abnormalities may be able to be identified by such physiological tests before death. Replication of these findings in a large population may lead to the development of predictive cardiorespiratory assessment tools for future screening to identify infants with medullary 5-HT abnormalities and SIDS risk.
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Affiliation(s)
- Hannah C Kinney
- Department of Pathology, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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Raz A, Lieber B, Soliman F, Buhle J, Posner J, Peterson BS, Posner MI. Ecological nuances in functional magnetic resonance imaging (fMRI): psychological stressors, posture, and hydrostatics. Neuroimage 2005; 25:1-7. [PMID: 15734338 DOI: 10.1016/j.neuroimage.2004.11.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 11/09/2004] [Accepted: 11/10/2004] [Indexed: 11/22/2022] Open
Abstract
Brain imaging techniques such as functional magnetic resonance imaging (fMRI) have forged an impressive link between psychology and neuroscience. Whereas most experiments in cognitive psychology require participants to perform while sitting upright in front of display devices, fMRI obliges participants to perform cognitive tasks while lying supine and motionless inside a narrow bore. In addition to introducing psychological and physical stressors, such as loud thumps and head restraints, fMRI procedures also alter brain hydrostatics. The ecological factors associated with current fMRI technology, such as supine posture, may skew cognitive processing and influence hemodynamic and electrophysiological measurements, especially in extreme age groups and pathological populations. Recognizing the central role of fMRI in unraveling the neural mechanisms of cognition, we outline ways to address these limitations.
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Affiliation(s)
- Amir Raz
- MRI Unit, Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York State Psychiatric Institute, 1051 Riverside Drive, Box 74, New York, NY 10032, USA.
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Abstract
Recent evidence suggests sudden infant death syndrome (SIDS) infants have a diminished capacity to respond to autonomic challenges during a vulnerable developmental period. We speculate that a dysfunction or altered trajectory in the development of the autonomic nervous system may be detected in utero and also may play a role in the pathogenesis of unexplained late stillbirth. Some fetuses, as well as infants, may be more vulnerable than others to autonomic challenges during periods of autonomic instability. Investigation of potential shared underlying mechanisms in both SIDS and unexplained stillbirth will require expanded epidemiological investigation of genetic and environmental correlates along with a systematic study of developmental physiology and neuropathology. As with SIDS, there are likely important interactions between genetic susceptibility and environmental exposures occurring during gestation, which lead to infants who have altered trajectories or deficits in autonomic function and who need to be identified before they enter the periods of greatest risk.
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Affiliation(s)
- William P Fifer
- Department Psychiatry, Columbia University, and Psychiatric Institute New York, 10032, USA.
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