Early Childhood Development

1. Early Childhood Development SHH 278 December 3, 2007

2. Core Concepts • Human development is shaped by a dynamic and continuous interaction between biology and experience (transactional model). • Culture influences every aspect of human development • Self-regulation is cornerstone of development and cuts across all domains

3. Core Concepts, contin. • Children are active participants in their own development • Human relationships are building blocks • The broad range of individual differences makes the distinction between normal variation, transient delays and permanent impairment difficult

4. Core Concepts, contin. • Individual pathways of development are characterized by continuities and discontinuities • Human development is shaped by an interplay between vulnerability and resilience • The timing of experience can matter, but the developing child is plastic

5. Core Concepts, contin. • The course of development in early childhood can be altered by effective interventions (coming event).

6. Phases of Brain Development (Last trimester-first year) • Neurulation and neurogenesis • Migration • Neuronal differentiation and pathfinding • Synaptogenesis • Maturation and pruning • Gliagenesis or myelination

8. The Messengers • Information is carried across synapses and along nerves by chemicals. • Receptors on neurons are specific to the chemical • The number of receptors may reflect experience • Neural growth factors may also reflect experience, and affect structure of the brain • These messengers are also affected by events elsewhere in the body

10. Negative Effects on Developing Brain • Effects depend on timing of exposure • Much of development occurs very early before the pregnancy may be recognized • Some substances may be more toxic to the fetus than the infant (blood-brain barrier)

11. Sources of Damage • Single gene conditions • Altered brain structure • Build up of natural metabolites • Multigenic conditions • Chromosomal abnormalities • Prenatal infection (TORCHeS) • Prenatal heavy metal exposure (Pb, Hg, Al)

12. Sources, contin. • Substance Use • Alcohol • Tobacco • Cocaine • Other environmental exposure (PCBs) • Chronic stress • Nutrient Deficiencies (Fe-deficiency in infancy) • Post-natal infection

13. Domains of Development • Attention (Selectivity, persistence, inhibitory control) • Language • Everyday Cognition (schemata, scripts) • Intelligence • Reading and Spelling • Theory of mind (understanding others, beliefs, deceptions, read expressions)

14. Domains, contin. • Morality/Character development • Gender • Attachment • Emotional Development • Peer Relations • Sleeping and Feeding (state regulation) • Physical growth/development

15. Environmental Influences on Development • Characteristics of the individual (temperament, physical appearance) • Family (structure, relationships, stress and change in families, sibship and birth order) • School (climate, organization) • Culture/Community (social class, neighborhood, media)

16. Pathways for Environmental Effects on Neurodevelopment • Parental Processes

17. Pathways for Environmental Effects on Neurodevelopment • Parental Processes • Parental physical and emotional health • Provision of stimulating experiences in the home • Parental sensitivity • Parental harshness

18. Disruptions of Parental Processes • Maternal depression • Child maltreatment and neglect • Parental loss • Lack of resources (education, income, inadequate day care, substance use

19. Pathways for Environmental Effects on Neurodevelopment • Parental Processes • Neighborhood Processes

20. Neighborhood Processes • Resources for Parents • Relationships • Norms or Collective Efficacy • Evidence is limited • Observational studies show minor effects • Moving to Opportunity

21. Pathways for Environmental Effects on Neurodevelopment • Parental Processes • Neighborhood Processes • Child Care Processes

22. Disruptions of Care Processes • Poor quality care • Emergence of negative development

23. Consideration of Physical Growth and Health • Physical growth • Height • Weight for Height • Acute illness • Resilience • Vulnerability

24. Physical Health, contin. • Chronic illness • Drug side effects • Absenteeism • Limitations in daily activities • Effects of symptoms (chronic otitis)

25. Case Study • Low Birth Weight

26. Mean Total IQ by Birthweight n=179 n=280 n=132 n=97 >2500 gr 1501-2500 gr 1001-1500 gr <=1000 gr

27. Risk of Behavioral Problems Score >14 by BWTOdds Ratio & Confidence Intervals * <=1000 gr 1001-1500 gr 1501-2500 gr >2500 gr * * * 0.0 1.00 2.00 3.00

28. What is LBW? What does it signify?

29. Low Birth Weight • Shortened gestation-true risk for fetal immaturity • Low weight for given duration of gestation • IUGR-intrauterine growth restriction • Obstetric diagnosis based on serial ultrasound • SGA-Small for gestational age • Pediatric diagnosis from fetal growth charts • Combines pathological lbw with constitutionally small

30. What is being measured • Risk for infant mortality (and morbidity) • “Too small; too soon” • Birth weight • Duration of pregnancy • Early definition • Yllpo: in 1930s-“risk” = <=2500 grams • Based on inflection point in bwt distribution, not much empiricism

32. Evolution of definitions • WHO 1948 • Immature=<=2500 grams • Premature= <37 completed weeks of gestation • WHO 1961 • Low birth weight= <=2500 grams • Premature=<37 weeks

33. Further Definitions • Birth weight • Low birth weight= <2500 grams (5.5 lbs) • Very low birth weight = <1500 grams (3.3 lbs.) • Extremely low birth weight = <1000 grams (2.2 lbs) • Confounds duration of pregnancy with adequacy of weight gain

34. Target Construct for Measurement • “Fetal maturity” • Fetal development is sufficient for extra-uterine life • Variations in organ maturity even for a given gestational age • 38-42 weeks optimal for this transition for most infants • Gestational age is preferred measure

35. More Definitions • Extreme prematurity <28 weeks • Moderately preterm 30 or 32-36 wks • Late premature 36 weeks • Term 37-41 completed weeks

36. Measures, contin. • Duration of gestation <37 weeks • Last menstrual period (LMP) • Ultrasound before 20 weeks • Biophysical profile • Fetal lung maturity • Physiologic severity measures • Postnatal physical examination

37. Biological Factors influencing birth weight • Constitutional low weight • Duration of gestation • Congenital malformations • Toxic exposures (smoking) • Defects of placentation • Complications of pregnancy • Multiple gestation

38. Percentage of Preterm Births-US Births

39. Demographic Factors Increasing the Risk of Prematurity • Maternal age at the extremes of reproductive span • Race/ethnicity • Poverty • Multiple births

40. Why is Prematurity/Low Birth Weight a Problem? • Mortality

41. Significance of Cut Points • “Risk factors” • Cut points should be biologically meaningful • Do cut points in birth weight/gestational age have meaning for mortality?

42. Infant mortality by birth weight

43. Infant Mortality by Gestational Age

44. Mortality by Gestational Age, 1986/87-1996/96 Hack, 1991; Lemons, 2001

45. Significance of Birth Weight Cut Points • Traditional cut-points do not signal biological break points • Effects of changes in birth weight • A unit increase in birth weight does not equally affect mortality at different gestational ages • Even for given gestational age/birth weight, other factors may influence outcome

46. Intrauterine events • Complications of pregnancy, especially those associated with IUGR constitute fetal stressors • Response to stress • Accelerated maturation • Fetal programming

47. Why is Prematurity/Low Birth Weight a Problem? • Mortality • Morbidity

48. Neurodevelopmental Morbidity related to prematurity • What? • How?

49. Survival With Major Morbidity Lemons, et al, 2001

50. Type of Specific Conditions Reported by Birth Weight Asthma Neuro-Seq Sens-Neur L.D. Int CNS Cond