Download Infant Physical Development2016

Physical Growth and Development
OT 500
Spring 2016
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Cephalocaudal Development
◦ Upper part of the head to the lower parts of the body
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Proximodistal Development
◦ Trunk outward – from body’s central axis toward periphery
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Differentiation
◦ Tendency of behavior to become more specific and distinct
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Weight doubles at about 5 months;
triples by first birthday
Height increase by 50% in first year
Infants grow 4 to 6 inches in second
year; and gain 4 to 7 pounds
Growth for the most part appears
continuous but actually it occurs in
spurts
Figure 5.1
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Children’s heads are proportionately larger than adults’
◦ Cephalocaudal development
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Changes in proportion of arms and legs
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Growth impairment during infancy and early childhood
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Causes may be organic or non-organic
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Biologically based or non-biologically based
◦ Marasmus; Condition related to FTT; Diet low in essential
nutrition
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Linked to physical, cognitive, behavioral, and emotional
problems
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Deficiencies in caregiver-child interaction may play a role
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Canalization – catch up growth once FTT is resolved
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Infants require breast milk or iron fortified formula
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Solid foods may be introduced about 4 to 6 months
◦ Iron-enriched cereal, strained fruits, vegetables, and meats
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Whole cow’s milk delayed until 9 to 12 months
◦ Teething biscuits in later part of first year
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Choice to breastfeed is influenced by
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Domestic and occupational arrangements
Attitudes regarding benefits for bonding and infant health
Fear of pain, unease with breastfeeding, and public breastfeeding
Community and familial support; Level of education
Colostrum early form of breast milk
Advantages of breast milk
◦ Conforms to digestion process, possesses needed nutrients with a
high level of nutrients into low volume
◦ Contains mother’s antibodies; Protects against childhood
lymphoma
◦ Helps protect against infant diarrhea; Is less likely than formula to
cause allergies
◦ Helps prevent obesity later in life
◦ Maternal health benefits
◦ Human newborns prefer it; It’s free
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Disadvantages of breast milk
◦ HIV, alcohol, drugs, and environmental hazards may be
transmitted through breast milk
◦ Mother must be adequately nourished
◦ Physical demands on mother
 Lack of social support
 Return to work – pumping can be too demanding
 Stress and mastitis
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What about mothers who smoke?
◦ No harmful effects on infants have been noted
◦ Can reduce milk supply
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Neurons are the basic unit of nervous system; they
receive and transmit messages; formation of
neurons is complete at birth
Neurons vary according to function and location; As
child matures, neuronal axons grow in length,
Dendrites and Axon terminals proliferate so that
connections or networks become more complex
Myelin makes messages more efficient; myelination
occurs with maturation through childhood;
Inhibition of myelination results in disease such as
multiple sclerosis
Figure 5.3
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The brain is the command center of organisms
Brain of neonate weighs less than one pound; By
the child’s first birthday, the brain triples in weight,
reaching nearly 70% of adult weight
Brain Structures include the
◦ Medulla : heartbeat, respiration
◦ Cerebellum: Maintains balance, control motor
behavior, coordinate eye movements with body
sensations
◦ Cerebrum: Allows human learning, thought,
memory, language
Figure 5.4
Figure 5.5
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Growth Spurts in Brain Development
◦ Prenatal - during 4th and 5th months
 Proliferation of neurons
◦ 25th week prenatal through end of second year after birth
 Proliferation of dendrites and axon terminals
Figure 5.6
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At birth, brain areas well myelinated include
◦ Heartbeat and respiration
◦ Sleeping and arousal
◦ Reflex activity
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Intentional physical activity coincides with myelination
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Myelination of sensory areas
◦ Hearing – begins about 6th month of pregnancy and continues
to age 4
◦ Vision – begins shortly before full term but develops rapidly
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Brain development is affected by maturation (nature) and
sensory stimulation and motor activity (nurture)
◦ Rats in enriched environment
 More synapses per neuron
◦ Human infants have more neural connections than adults
 If activated by experience, connection survives
 If not activated, connection does not survive
◦ Adequate nutrition is necessary
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Follows cephalocaudal and proximo-distal patterns
Develop postural control , balance and stability; further development of
the musculoskeletal system
Many infant motor primitive reflex patterns are “Integrated”; replaced by
higher level, voluntary controlled movements; Develop automatic
reactions like righting, equilibrium, and protective reactions
Gross motor skills develop; coordination, muscle strength, endurance,
and agility;
Fine motor skills including reaching and grasping, hand use, dexterity,
visual- motor coordination, bilateral coordination
MAJOR MOTOR MILESTONES:
 Rolling over supine to prone, 3-4 months
 Rolling over prone to supine 4-6 months
 Sits up 5-7 months; Belly crawls 5-7 months
 Crawls on hands and knees 7-9 months
 Pulls to stands and cruises holding onto something 9-11 months
 Walks 10-14 months
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Newborns track objects with eyes but do not reach for
them
Grasp reflex (dominates until about 3rd month)
◦ Grasp but do not release intentionally
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Voluntary grasping about 3 months
◦ Ulnar grasp, then radial grasp; gross fisted grasp patterns
◦ Pincer grasp with thumb opposition around 9-13 months
◦ Able to transfer toys from one hand to the other around 4-6
months
◦ Voluntary release with some control around 10-14 months;
can stack 2 one inch block around 15 months
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Visual – motor coordination developing; copy simple
horizontal and vertical lines 2-2.5 years of age
Figure 5.7
◦ Walk backwards
◦ Run
◦ Kick a ball
◦ Jump (clearing both feet together)
◦ Jump down from a raised surface
◦ Catch a large ball
◦ Move a push riding toy
◦ Climb up stairs; Climb down stairs
◦ Ride/Pedal a trike
◦ Climb in and out crib
◦ Climb into a car seat
Figure 5.8
Figure 5.9
Figure 5.10
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Maturation (nature)
◦ Myelination and differentiation is needed for certain voluntary
motor activities
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Experience (nurture)
◦ Experimentation to achieve milestones
◦ Slight effect in training to accelerate motor skills
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Reaction range
◦ Limits for the expression of inherited traits
Figure 5.11
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Neonates are nearsighted
◦ Greatest gains in visual acuity between birth and 6 months
◦ By about 3 to 5 years of age, approximate adult levels
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Neonates have poor peripheral vision
◦ Perceive stimuli within 30 degree angle
◦ By 7 weeks increases to 45 degrees
◦ By 6 months of age, equal to adult (90 degrees)
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Neonates attend longer to stripes than blobs
◦ By 8 to 12 weeks, prefer curved lines over straight
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Infants prefer faces
◦ Discriminate maternal and stranger faces
◦ Prefer attractive faces
◦ Pay most attention to edges
◦ Depth Perception: Develops around 6 months (onset of
crawling) Research using the Visual Cliff; Gibson and Walk
(1960) show infants will not go off the deep end!
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Perceptual constancy – perception of object remains stable
although sensations may differ under various conditions
Size constancy – perception of object’s size remains stable
although retinal size may differ due to distance; abilty
documented in early infancy
Shape constancy – perception of object’s shape remains
stable although shape on retina may change due to
looking at objects from various perspectives; ability seen
as early as 4-5 months of age.
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Neonates can orient toward direction of a sound
◦ 18 months locate sounds as well as adults
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Infants exposed to moderate noise levels as background
habituate to it and are less likely to waken due to noise
By 1 month, infants perceive differences between similar
speech sounds
By 3½ months discriminate caregivers’ voices
Infants perceive most speech sounds present in world
languages
◦ By 10 to 12 months, lose capacity to discriminate sounds not
found in native language
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Infants recognize that objects experienced by one sense
are the same as those experienced by another
◦ Looked longer at novel items than those previously handled
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Neonates’ role in perceptual development is largely passive
early on
Later, a child’s role in perception becomes more active as
they gain some control over what they look at, where they
go; start to develop interests and preferences so that their
attention becomes selective, and irrelevant information ignored
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Some in-born ways of responding to sensory stimuli; may be
some sensitive periods for vision
Nature and nurture equally important in perceptual development