Early Motor Development Flashcards
What is the role of cognitive development on the development of movement? (how infants move: first thing to consider)
recall the maturational perspective on development: brainstem/spinal cord - primitive reflexes
mid-brain:righting reactions
cerebral cortex:equilibrium reactions
as the brain develops, the maturational perspective suggests that the CNS was _
the sole constraint to guide early motor behaviour
- imlries unindirectional control
is the maturational perspective correct about the CNS being the sole constraint to guide early motor behaviour? (first thing to consider)
no
- recent evidence suggests that movement also affects brain development (interaction is key)
- this helps to explain movements that had not really been considered by earlier researchers: those appear randomly or spontaneously
ex. if you place an infant on their back, what movements will likely occur?
are (infant movements) these type of movements reflexive?
no
- they occur in the absence of any apparent stimululs (or for any apparent reason)
- they are spontaneous (stereotypie) movements
define spontaneous movements
infant movements that occur without any apparent stimulation
ex. supine kicking, spontaneous movements
What did Thelen et al study?
1985-1995
- studied supine kicking movements by analyzing position and timing of limb segments
describe supine kicking (Thelen and colleagues)
- movements are not random
- they are rhythmic and coordinated
- ankle, knee and hip joints move cooperatively (not independently)
supine kicking patterns are not as random as we thought - they appear to be _
early precursors of walking
break down supine kicking into 6 steps
- from extended position flexion begins
- hip and knee flexing ankle dorsiflexing
- hip knee and ankle fully flexed; pause
- extension begins with knee extension
- hip and knee extending, ankle plantarflexing (toe pointing)
- end of extension phase: between-kick interval
*if you pretend they are standing, resembles walking
flexion>pause>extension>between kick interval
why are infants less efficient at walking movements* (not in notes)
infants tend to co-contract their muscles vs adults who only contract what they need and are more efficient
- infants more variable
what patterns appear to be early precursors of grasping?
- spontaneous arm movements (pre-grasp reaching)
- again, high degree of coordination of elbow, wrist and finger joints
note: the fingers do not extend independently
What is related to being tired?
head banging*
why dp stereotypies exist?
- newborn musculature is underdeveloped
- lack of ability to produce interntional, goal-directed movements
what is the original theory for spontaneous movements
movements are extraneous, with no purpose
what is the current theory for spontaneous movements
- movements are “building blocks,” which are similar to, and serve as a function for some voluntary movements
- the developing brain results in the generation of these movements (maturational)
- the movements in turn shapethe development of the brain (ecological)
(infantile) reflexive movements occur quickly after _
the onset of stimuli
describe infantile reflexes
- they involve single muscle or specific group of muscles (not the whole body)
- they cannot be extinguished at any one time
- persistence may indicate neurological problems
describe infantile reflexes (cont’d)
- they are involuntary stereotyped movement responses to a particular stimulus
- dominant movement from during the last 4 months of prenatal life (iex. begin to develop in utero) and the first 4 months after birth
- occur subcortically (below the level of the higher brain centers)
why do infantile reflexes occur?
- built-in response, facilitates survival
- allows interaction with the environment
- reflexive movements result in sensory consequences, stimulate development
- during later portion of reflexive period, reflexes are modulated ‘building blocks’ for future movement
what are the general types of infantial reflexes?
- primitive
- postural
- locomotor
what is the purpose of primitive infantial reflexes?
survival and protection
what is the purpose of postural infantial reflexes?
reaction to gravity
what is the purpose of locomotor infantial reflexes?
resemble voluntary locomotion
what 7 primitive reflexes did we talk about in class?
- asymmetric tonic neck reflex
- symmetric tonic neck reflex
- doll-eye reflex
- palmar grasping
- moro reflex
- sucking reflex
- babinski reflex
describe the asymmetric tonic neck reflex
- infant starts in supine position
stimulus: turn head to one side
response: same-side arm and leg extend - facilitates bilateral body awareness
- facilitates hand-eye coordination
- also called ‘bow and arrow’ or ‘fencer’s’ position
describe the symmetric tonic neck reflex
infant starts sitting
stimulus: tip forward
response: neck and arms flex, legs extend (tip back, neck and arms extend, legs flex)
- facilitates equilibrium (vestibular development)
- persistence may impede many motor skills and cause spinal flexion deformities
*may act as warningsigns if they continues to have these past a certain age
describe the doll-eye reflex
infant starts in vertical position
stimulus: movement to supine and back to vertical
response: eyes open and close
- facilitates vestibular development
- triggers of sleep and alertness
describe palmar grasping
stimulus: touch palm with finger or object
response: hand closes tightly around object
describe the moro reflex
infant starts in vertical position
stimulus: suddenly but gently lower baby’s head
response: arms and legs extend rapidly
- may signify CNS dysfunction if lacking
- may signify sensory motor problem if persists
- may delay sitting and head control if persists
- may indicate injury to one side of brain if asymmetrical
describe the sucking reflex
stimulus: touch face above or below lips
response: sucking motion begins
describe the babinski reflex
infant starts in any position
stimulus: stroke sole of the foot from heel to toe
response: toes fan out
*if maintained, can indicate damage to corticospinal tract
postural reflexes (postural reactions) facilitate_
posture maintenance in changing environment
describe postural reflexes
- maintain head in an upright position(breathing)
- aid in development of mobility (eg. righting and rolling)
- help to develop equilibrium while in motion (eg. parachute)
- postural reflexes typically appear after 2 months
- they are typically sequential (ie. righting must occur before rolling)
- initially similar to primitive reflexes, then incorporated into general repertoire of movements
name the 3 postural reflexes we talked about in class
- derotative righting reflex
- labytinthine righting reflex
- parachute reflex
describe the derotative righting reflex
- infant starts in supine position
stimulus: turn head to one side, or turn legs and pelvis to other side
response: body follows head in rotations, or trunk and head follow in rotation - facilitates equilibrium reactions
describe the labyrinthine righting reflex
- infant starts in a supportive upright position
stimulus: tilt infant
reponse: head moves to stay upright - necessary for bringing the body into an upright position and to orient in relation to gravity
describe the parachute reflex
infant starts upright
stimulus: lower infant toward the ground rapidly
response: legs extend (4 months)
- tilt forward: arms extend (7 months)
- tilt sideways: arms extend (6 months)
- tilt backwards: arms extend (9 months)
describe locomotor reflexes
- locomotor reflexes facilitate voluntary gait
- they typically appear much earlier than the voluntary movement
- they are rhythmic movements that begin to show classic elements of coordinated movement
- crawling, stepping, swimming
name the 2 locomotor reflexes we talked about in class
- stepping reflex
- swimming reflex
decribe the stepping reflex
starting position: held upright
stimulus: infant upright with feet touching surface
response: legs lift and descend
- precursor to later voluntary walking
- disappears after approximately 5-months (unless you hold the child upright in water, then it reappears)
describe the swimming reflex
starting position: prone in water
stimulus: place infant in or over water
response: swimming!
- not the oscillation movements (like a tadpole
what is the purpose of reflexes?
some have clear reasons to emerge, others are less obvious
- the roles have been described in 3 different ways: structural, functional, applied
describe the structural role of reflexes
reflexes are a byproduct of the developing neurological system (hardwiring)
describbe the functional role of reflexes
reflexes serve specific functions related to survival (breathe, eat, etc.)
decribe the applied roles of reflexes
reflexes foreshadow volitional goal-directed movements
our current though is that infantile reflexes serve as _
building blocks to voluntary movement
describe the relationship between reflexes and voluntary movement
early researchers (eg. McGraw) believed that voluntary movement was not possible until reflexes had been inhibited (motor interference)
researchers are seeing that other factors than just the nervous system are involved in motor development
