Infancy: Arousal States, Motor Development
Vocabulary
Sleep: A state that reduces energy expenditure in the brain, the brain undergoes metabolic housekeeping and increases its help. Aids in development of visual and sensorimotor systems. Information is consolidated
Crib: Used commonly in the US for sleeping infants
Co-sleeping: A process where parent and infant sleep in the same location or area, much more common outside of the US, common among immigrants to the US
Rapid eye movement sleep (REM): Displayed by small fidgeting movements, facial grimacing. Irregular breathing occurs, associated with dreaming, 8-9 hours a day for an infant (active sleep), heart rate and EEG data are irregular
Non-REM sleep: Sleep where the body is totally at rest, breathing is slow and regular, heart rate and EEG data are slow and regular, 8-9 hours a day as an infant
Sudden Infant Death Syndrome (SIDS): The unexpected and unexplained death of a sleeping infant, greatest risk from 2-4 months, not understood. One cause might be suffocation from a blanket or being face down with no way to remove the object or change position. Risk factors include exposure to smoking/drugs, prematurity and low birth weight, poor APGAR scores, abnormal sleep/wake cycles, and low arousal sensitivity. Infants with these tend to be lower in serotonin
APGAR score: Assessed almost immediately after birth for an infant, gives a general health indication (appearance, pulse, grimace)
ABCs of safe sleep: Alone on their back in a crib in an independent space. Includes an uncovered face, firm mattress
Drowsiness: An arousal state for an infact, around one hour a day
Alert Awake: An arousal state for an infant, the body is awake but inactive, eyes are open and attentive and there is breathing, from 2-3 hours a day
Active Awake: An arousal state for an infant, has movement, irregular breathing, and ‘stomach time’ is encouraged, 2-3 hours a day
Crying: A behavior displayed by infants, more when they are younger with a slight increase at 7-9 months, means of communication (to get attention for hunger/discomfort/pain/overstimulation)
Emotional contagion: The concept of emotional spreading, if one infant is crying, other nearby ones will likely cry
Colic: Excessive crying for no apparent reason
Reflex: An inborn automated response to a particular form of stimulation, for example blink and breathing
Moro Reflex: Happens in response to loss of support, infant will move arms left and right trying to ‘catch’ itself, disappears after 6 months
Rooting reflex: Happens when a baby turns their head in response to physical cheek stimulation, disappears after 3 weeks, helps infant find feeding sources, stronger when the infant is hungry
Sucking reflex: Happens when infants automatically adjust sucking pressure, voluntary after 4 months. Permits feedings
Palmar grasp reflex: Happens when an infant grasps their fingers into their palm when their palm is pressed, disappears after 3-4 months, prepares for voluntary grasping, promoting social interaction
Tonic neck reflex: Happens when an infants head turns to one side while lying down “fencing”, as a response of being set down, disappears after 4 months, prepares for voluntary reaching and early signs of hand-eye coordination
Stepping reflex: Happens when an infant is held upright, feet move back and forth as if walking, disappears at 2 months, tied to weight gain, prepares for voluntary walking
Swimming reflex: Infants will when put in water go face down, kick, and paddle. This disappears at 4-6 months, and helps the infant to survive if they should be dropped into water. Swimming isn’t encouraged at this age, as they breathe in the water and can’t hold their breath
Babinski reflex: Happens when infants toes fan our and curl as the foot twists in response to stroking of the sole, disappears at 8-12 months, function is unknown
Cephalocaudal: Growth in the ‘head to tail’ manner, head grows before arms, trunk, and legs
Proximodistal: Grows from the center of the body outward, control of the head and trunk before arms and legs
Gross motor development: The process of developing the skill to do actions associated with moving around the environment
Fine motor development: The process of developing the skill to do smaller actions associated with skills and interacting with the environment
Prereaching: Poorly coordinated swipes that an infant does, not reaching for an object and doesn’t seem motivated, might be a reflex. Happens from birth to 7 weeks
Reaching: Coordinated outstretching for an object, starts with two hands at 3-4 weeks and one hand at 7 months
Ulnar grasp: When fingers wrap around an object, done intentionally and not as a reflex, grip is adjusted to the object. Objects are moved from hand to hand, happens at 4 - 5 months
Pincer grasp: Used the thumb independently from the rest of the hand, emerges around 9 months and helps with eating
Milestones:
Head held erect when help upright, less bobbing around than there is at birth (3 weeks - 4 months, average 6 weeks)
Lift themself by their hands when on their belly (3 weeks - 4 months, average 2 months)
Roll from their side to on their back (3 weeks - 5 months, average 2 months)
Roll from the back to the side, takes longer than reverse as it is more coordinated and might require arm movements (2 to 7 months, average 4.5 months)
Ability to sit upright independently (5 - 9 months, average 7 months)
Crawling, wide range of time demonstrates how variable development can be, can be any kind of independent movement, can be multiple and develop over time. Once one is practiced and becomes efficient for the infant, it is usually more sticked to, tends to be standard crawling (5 - 11 months, average 7 months)
Standard: Arms/legs moving opposable
Army Crawl: Arm pull the lower body
Inchworm: Feet and legs scooch up and then the front of the body moves
Bear: Up on the hands and feet
Bum Shuffling: Sitting, scooching body up to meet meet
Spider: Belly up movement
Log roll: Rolling from side to side
Standing (average 8 months)
Walking alone, walking on knees does not count and neither does cruising, which is walking while holding objects like furniture for support (9-11 months, average 11.25 years)
To respond to an infant crying, it is important to be attentive. “Letting it out” isn’t real for infants, there is less crying with more parental physical contact. Crying is complex, decisions to deal with it are based on culture, suspected cause of the crying, and context
At 1 year, infants should be around 30 inches tall. Height increases 50% in the first year, and 75% over 2 years as compared to birth. Weight has doubled by 5 months, tripled by a year, and quadrupled at 2 years. Boys tend to be heavier/larger, black infants tend to be larger, Asian infants tend to be smaller
Infants develop first cephalocaudally, then proximodistally
More recent research shows there are interactions between different developmental systems that lead to complex systems of action and development, rather than a simple maturational process. Motor development timelines are unique for each child, on their own timeline. Factors include, CNS development, body movement capacities, child goals, and environmental influences
Cultural practices greatly influence motor development. For example, stretching happens to Nigerian infants by their caretakers, they also lift them up in a process known as suspension, associated with quicker adaption of skills. In Kenya, the Kipsigi are placed in shallow dug holes to encourage sitting, and bouncing while feet are on the ground, this is good for walking and upright development, but discourages crawling
Cultural practices can also delay development, such as the Zinacanteco infants in Mexico, where there is a lot of open flames, meaning babies are often swaddled or worn to keep them safe. There is also delay in the US with belly motor skills, due to over concerns about SIDS