NRSG 200 - Infant and Development

Neurogenesis

the creation of new neurons that begins in the embryo’s neural tube

When does the majority of nervous system development occur?

First year

Glial (microglial) cells

provide support and protection for neurons

Myelination

glial cells produce and coat the axons of neurons with myelin

Function of myelinated neurons

Myelinated neurons transmit neural impulses more quickly than unmyelinated neurons

Nodes of Ranvier

unmyelinated areas of myelinated neurons

Synaptogenesis

a  process in which neurons form synapses

Transient exuberance

the brain makes more connections than it needs in preparation to receive all conceivable kinds of stimulation

Synaptic pruning

the loss of unused neural connections by microglia in the brain

What has been linked with impaired synaptic pruning?

Brain disorders like shizophrenia

Cerebral cortex function

concerned with high level processes like consciousness, thought, emotion, reasoning, language, and memory

Cerebral cortex structure

• composed of a right and left hemisphere

• has multiple regions (lobes): frontal, parietal, temporal, and occipital

Left brain function

associated with language and positive emotions

Right brain function

associated with spatial awareness and negative emotions

Fontanelles

soft spots in the skull that close within the early months of life

2 main fontanelles

1. Anterior fontanelle

2. Posterior fontanelle

When does the anterior fontanelle close?

9-18 months

When does the posterior fontanelle close?

1-2 months

Cephalocaudal development

Body grows from head downwards

Proximodistal development

Body grows from the center outwards

Newborn weight first few days and few weeks after birth

• Normal to lose up to 10% of birth weight in the first week

• Should be back up to birthweight by 2 weeks old

Infant weight and growth by 6 months and 12 months

• Double birthweight by 6 months

• Triple birthweight by 12 months

Toddler height and growth (by age 2)

Height is approximately 75% taller than at birth

How are weight, length, and head circumference measured before the age of 2?

Growth curves

Normal growth curve percentiles

5th-85th percentiles

How are weight, length, and head circumference measured for pre-term infants?

Pre-term adjusted growth curves

What does a <5th percentile head circumference indicate?

Microcephaly

3 potential causes of microcephaly

1. Genetic conditions

2. Teratogens

3. Premature closing of fontanel

What does a >95th percentile head circumference indicate?

Macrocephaly

2 potential causes of macrocephaly

1. Tumor

2. Hydrocephalus

What does a <5th percentile weight indicate?

Failure to thrive

4 potential causes of failure to thrive

1. Inadequate nutrition

2. Medical condition

3. Neglect/abuse

4. Lack of parenting knowledge

When should preterm infants catch up to normal growth?

2 years old

Corrected gestational age

the age at which the child would be if he/she was born at term

Main risk for pre-term infants (size and growth related)

Failure to thrive

American Academy of Pediatrics (AAP) breastfeeding recommendation

• Breastfeed exclusively for 6 months

• Introduce soft food at 6 months, breastfeed until 12 months of life

World Health Organization (WHO) breastfeeding recommendation

Breastfeed through 2 years of life

4 benefits of breastfeeding for infant

1. Easier to digest than formula

2. Provides antibodies to boost infant’s immune system

3. Improves neurodevelopmental outcomes

4. Reduces the risk of allergies, obesity, childhood cancer, and SIDS

2 benefits of breastfeeding for mother

1. Decreased rates of diabetes, cardiovascular disease, breast and ovarian cancer

2. Facilitates mother-infant bonding

Formula recommendations (if mother cannot exclusively breastfeed)

non-breast-fed infants should be fed an iron-rich formula exclusively for at least the first 4 months of life

Introduction of soft foods

• Start with iron-fortified baby cereal mixed with breast milk or formula

• Progress to pureed vegetables and fruits before pureed meats

How often do newborns wake to eat?

Every 2-3 hours

Until what age should nighttime feedings continue?

5-6 months

When should infants begin to show signs of day-night sleep rhythms?

8 weeks

What % of the world’s children under 5 are moderately to severely underweight?

25%

About _____% of American households experience food insecurity

15

Food insecurity

Lack of consistent access to food

2 consequences of malnutrition

• Impaired learning, concentration, and language

• Stunted growth

3 most common nutrients missing from infant and toddler diets

1. Iron

2. Zinc

3. Calcium

APP recommends that what level is checked at 1 year, 18 months, and 2 year well visits, and why?

Hemoglobin levels, due to importance of iron for brain development

Marasmus

a wasting disease in which the body’s fat and muscle are depleted

Cause of marasmus

results from a diet that is chronically insufficient in all nutrients

Kwashikor

wasting disease found in children who experience a deficiency in protein

4 Kwashikor symptoms

1. Lethargy

2. Wrinkled skin

3. Bloating and swelling of the stomach, face, legs, and arms

4. Hair becomes thin, brittle, and colorless

Palmar and plantar grasp

grasp fingers/toes around objects that touch the palm of the soles of the feet

Palmar and plantar grasp timeline

Present at birth until 4 months of age

Rooting reflex

turns head and tongue toward stimulus when cheek is touched

Sucking reflex

sucks on object placed in mouth

Moro reflex

startle response in reaction to noise or position of head, where arms spread out quickly

Moro reflex timeline

present at birth until 5-7 months of age

Babinski reflex

fanning and curling the toes in response to stroking the bottom of foot

Babinski reflex timeline

present from birth-12 months

What does persistence of the Babinski reflex indicate?

Neurological problems

Stepping reflex

makes stepping movements as if walking when held upright with feet touching a flat surface

Parachute reflex

infant will extend arms when suspended and leaning baby forward

Parachute reflex timeline

appears around 6 months of age

Gross motor ability

the ability to control large movements of the body

Fine motor ability

the ability to control small movements, such as reaching and grasping

3 factors that shape motor development

• Central nervous system development

• Child’s goals

• Environmental supports/practice

2-month motor development milestones

1. Lift head

2. Grasps rattle

4-month motor development milestones

• Rolls from stomach to back

• Reaches for objects

6-month motor development milestones

• Sits without support

• Hand-to-hand transfer

9-month motor development milestones

• Pulls to stand

• Pincer grasp (between thumb and first finger)

• Cruises (stage in between crawling and walking, “shuffling”)

12-month motor development milestones

• Stands alone

• Walks

15-month motor development milestones

• Scribbles

18-month motor development milestones

• Walk up steps

• Eats with a spoon

• Drinks from a cup

2-year motor development milestones

• Kick and throw a ball

• Run

• Jump

Depth perception

the ability to perceive distance

Do newborns have depth perception?

Newborns have some depth perception

Visual cliff study setup

Infants are prompted to crawl to their parents over a “cliff” that is actually covered with clear plexiglass

Visual cliff study participants

36 infants, 6-14 months

Visual cliff study results

All infants refused to cross the “cliff”

Visual cliff study conclusion

crawling influences how infants perceive depth

Newborn imitation

may be inborn, demonstrated by social communication

Mirror neurons

specialized cells in motor areas of cerebral cortex

Deferred imitation

the ability to repeat an act performed some time ago

What age infants display deferred imitation?

6-12 months, time in which imitation is deferred increases throughout infancy

Piaget’s Cognitive Developmental Theory

children are active explorers who learn by interacting with the world, building their own understanding of everyday phenomena, and applying it to adapt to the world around them

Schemas

concepts, ideas, and ways of interacting with the world

According to Piaget, cognitive development is the result of which two phenomena?

1. Assimilation

2. Accommodation

Assimilation

integrating a new experience into a preexisting schema

Accommodation

changing a schema by adapting and modifying it considering the new information

Object permanence

when an infant or toddler is aware of an object when that object is no longer in its view

How do infants/toddlers demonstrate object permanence?

shown by the extended gaze on an object when it is hidden

Violation-of-Expectation

• a task in which a stimulus appears to violate physical laws

• If the infant looks longer at the unexpected event, it suggests that he or she is surprised by it, is aware of physical properties of objects, and can mentally represent them

A-not-B Error

occurs when infants uncover a toy hidden behind a barrier, yet when they observe the toy moved from Place A to Place B, they look for the toy in the first place it was hidden

Information Processing Model

cognition is a set of interrelated components that permit people to process information

How is information dealt with according to the information processing model?

information is taken in, manipulated, stored, and retrieved

3 mental stores of the brain

1. Sensory memory

2. Working (short-term) memory

3. Long-term memory

Sensory memory

• Holds incoming sensory information in its original form

• Information fades from sensory memory quickly if it is not processed