1. Physical Development in Toddlers and Infants Chapter 4

2. Physical Development in Toddlers and Infants The beginnings—a rough start – Prematurity: <37 weeks gestation – Low birth weight: <5.5 pounds – Very low birth weight: < 3.5 pounds – Small for gestational age: <10 th percentile of birth weight for gestational age

3. Physical Development in Toddlers and Infants Infant Mortality: – USA is 28 th in the world in infant mortality in 1998 – USA overall infant mortality rate is 6.9/1000 births 14.1/1000 for African American babies

4. Infant Mortality – Factors related to infant mortality Low birth weight Prematurity Congenital abnormalities SIDS Pregnancy complications Respiratory distress

5. Infant Mortality Reducing Infant Mortality – Modifying lifestyles Smoking Substance abuse Nutrition Prenatal care Contraception—young maternal age linked with predictors of infant mortality

6. Infant Mortality Sudden Infant Death Syndrome – Risk Factors Infant sleep position Soft sleep surfaces Loose bedding Overheating Smoking Bed sharing/positional suffocation Low birth weight or preterm infants

7. Growth of Body Cephalocaudal—head to toe; top to bottom Proximodistal—center to extremeties Newborn weight around 7+ 1 Newborns lose some weight Rate of growth is most rapid in the initial few months of life

8. Feeding and Nutrition CDC, WHO, Academy of Pediatrics: Human milk is preferred over all other for infants with no contraindications for breast mild (e.g. PKU) Breast feeding in regions with water quality problems or sanitation problems can reduce the incidence of infant mortality through dehydration and diarrhea Potential for reinforcing bond between caregiver and infant

9. Feeding and Nutrition Risks for Breastfeeding – Maternal nutrition – HIV/AIDS can be passed to nursing infants – Cultural taboos—e.g. recent court case in Florida

10. Structure of the Brain and Nervous System Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli Occipital Lobe- associated with visual processing Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech

12. Brain Development At approximately 20 weeks gestation: – Brain has near the same number of neurons as full term infant – Development of neurons slows and development of synapses or connections among neurons (synaptogenesis) – At approximately 30-31 weeks cerebral cortex begins forming convolutions or folds – At birth the neonate’s brain has the appearance of the adult brain

13. Brain Development Establishment of myelin sheath (myelination) continues far into childhood and adolescence Myelin sheath insulates the axon and increases speed and efficiency of synaptic impulse Development of motor function occurs as myelin sheath develops in the motor areas of the brain

14. Brain Development Pruning occurs as unused neurons die Pruning begins during fetal development and continues across the lifespan Leads to diversion of nutrients to regions more used

15. Method of Habituation to Study Sensation and Perception Infants’ heart rates and rates and intensity of sucking change with novel stimulation Steps in habituation studies – Baseline data are collected with neutral stimulus – Introduction of novel stimulus – Change in response from baseline is recorded – Over repeated presentation of stimulus systems return to baseline – Neutral stimulus is reintroduced – Original novel stimulus is reintroduced

16. Sensory Systems Vision: – At birth vision is blurry Focal length 8-15 inches Tends to focus at the center of the visual field – Across development infants prefer Patterned objects to solid color objects Bright colors rather than pastels (3-6 months) Faces rather than other objects – Facial preference: initially at hairline, then eyes, then expression thus focal attention shifts

17. Sensory Systems Vision: Depth Perception—Visual Cliff – Infants as young as 1-2 months react to perceptual differences – Mechanisms: Binocular vision and parallax Relative size of objects at different distances Relative motion – Interactions between neurological maturation and experience

18. Sensory Systems Auditory Sense – Fetus reacts to loud noises as early as a few weeks before birth – Neonates sensitive to different sounds – React to human voice differentially – Early on (late neonatal period) infants can distinguish caregivers’ voices from others

19. Sensory Systems Auditory Sense – Adults and older children use code-switching when interacting with infants Higher frequency Sing-song rhythm Rhyming

20. Sensory Systems Smell – Breast fed infants recognize smell of mothers over other females (pads in armpits or breast pads) – Preference for breast milk regardless of whether the infant is breast fed Taste – Discriminate between sweet and sour tastes

21. Infant Cross-Modal Perception Synchrony—the co-occurance of two or more stimuli Cross-Modal—two sensations in different modalities (visual & auditory) Newborns can detect cross-modal synchrony – Bouncing ball with sound – Facial movement with speech Implications for language learning

22. Reflexes—Hardwired Systems Indicators of neurological and motor development Primitive Reflexes – Rooting and Sucking Reflexes – Grasping – Looming (depth perception) – Babinski Checked to determine neurological maturation

23. Reflexes—Hardwired Systems Postural Reflexes – Parachute reflex – Locomotor reflexes Stepping Crawling swimming

24. Motor Development Gross Motor—large muscle groups – Neck – Torso – Arms – Legs Fine Motor—smaller muscle groups – Finger & Thumb – Refined grasping reflex (pincher motions)

25. Motor Development Bases for Motor Development – Neurological Development – Caregiver interactions and encouragement – Opportunities for exercise & practice – Maturation of Cognitive System Cultural Differences – Wide variability in practices associated with differences in ages of onset but generally, across cultures, children tend to thrive with competent caregiving

26. Toilet Training Key Elements – Voluntary muscle control – Awareness of the need – Access to toilet – Caregiver coach & praise – Motive to control bladder and intestine

27. Toilet Training Readiness Signals – Indications that infant/toddler needs changing – Interest in toilet – Asks for more mature underwear Child-set pace for toilet training seems to be most adaptive strategy