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Physical Development in Toddlers and Infants. Chapter 4. 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
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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: <10th percentile of birth weight for gestational age
Physical Development in Toddlers and Infants • Infant Mortality: • USA is 28th 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
Infant Mortality • Factors related to infant mortality • Low birth weight • Prematurity • Congenital abnormalities • SIDS • Pregnancy complications • Respiratory distress
Infant Mortality • Reducing Infant Mortality • Modifying lifestyles • Smoking • Substance abuse • Nutrition • Prenatal care • Contraception—young maternal age linked with predictors of infant mortality
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
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
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
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
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 • OccipitalLobe-associated with visual processing • Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech
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
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
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
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
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
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
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
Sensory Systems • Auditory Sense • Adults and older children use code-switching when interacting with infants • Higher frequency • Sing-song rhythm • Rhyming
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
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
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
Reflexes—Hardwired Systems • Postural Reflexes • Parachute reflex • Locomotor reflexes • Stepping • Crawling • swimming
Motor Development • Gross Motor—large muscle groups • Neck • Torso • Arms • Legs • Fine Motor—smaller muscle groups • Finger & Thumb • Refined grasping reflex (pincher motions)
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
Toilet Training • Key Elements • Voluntary muscle control • Awareness of the need • Access to toilet • Caregiver coach & praise • Motive to control bladder and intestine
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