Development of Normal Postural Control Flashcards
what are the 4 movements problems infant is confronted with
- overcoming effects of gravity
- mastering head control
- controlling interactions between head, trunks and limbs
- control of task specific movements
- (ability to adapt motor plans to changing environments)
first movements in infancy are what
reflexive (primitive reflexes)
is an involuntary response to a sensory stimulus
reflex
monosynaptic spinal cord reflexes
DTRs
polysynaptic spinal reflexes
flexor withdrawal reflex - noxious stimulus
brainstem reflexes that produce changes in muscle tone and postures
tonic reflexes (tonic labrythine, ATNR, STNR)
midbrain and motor cortex reflexes that are automatic control of head and trunk against gravity, maintain and recover COG with BOS and persist into adulthood
right and equilibrium reflexes
initial movements in infancy are
random and unpurposeful
neonatal kicking involves ____ in which both lower limbs and pelvis move together, and unable to _____ one LE from the other
coupling, disassociate
maturation of the NS is noted when the infant can kick both legs and pelvis remains still or when _______ is observed
reciprocal kicking
how does motor develop occur in terms of proximal and distal and cephalic and caudal
proximal —> distal
cephalic —> caudal
where does motor control develop first and second
- First: head, upper trunk, and UE
- Second: lower trunk, abs, pelvis and LE
midline stability of the neck and trunk occurs before what other muscle stability
shoulder and pelvic
head to midline is followed by _____ to midline
limbs
grasp develops from _____ first then thumb/index finger
ulnar fingers
full-term infants are born in
physiological flexion
____ is the dominant tone in all positions in infancy, when at rest and with all passive and active movements
flexion
antigravity control develops in extensors _____ flexors in each posture
before
which develops first, fine or gross motor
gross motor
what is Rood’s sequence
mobility –> stability –> controlled mobility –> skill
- ability to initiate movement
- initially random moving towards purposeful
- suggests normal neuromuscular development
- adult mobility is the available ROM and has sufficient motor unit recruitment
mobility of roods sequence
- able to maintain static posture in WB antigravity positions
- tonic holding
- co-contraction
stability of roods sequence
isometric contraction of postural extensors
tonic holding
antagonist muscle contractions to provide midline or WB
co-contraction
- mobility superimposed on stability
- dynamic postural control
- ability to weight shift in a posture
- proximal segment moves over a fixed distal segment
- ex: quadruped rocking
- occurs accidentally at first
- thousands of practice repetitions
controlled mobility of roods sequence
- most mature movement
- possible after controlled mobility is mastered
- proximal segments stability while distal segments are free for movement
- allows for manipulation and exploration of environment
- ex: U/L reaching, creeping, crawling, walking
skill of roods sequence
WB on ____ extremities occurs before ____ extremities
flexed
extended
what are some examples of factors that can influence the developmental process
growth, maturation, and adaption
3 components of development of postural control
- tilting and equilibrium reactions
- protective extension responses
- righting reactions
maintaining ones center of mass/gravity within one’s base of support; most advanced and last to develop
tilting and equilibrium reactions
ability to compensate if balance is disturbed; predictable; rapid perturbation of COG outside BOS causes extension of extremities to prevent fall; elicited when head righting and tilting/equilibrium responses are unable to regain postural control
protective extension responses
orient the head in space and keep eyes and mouth horizontal; head maintained in upright position regardless of if body is tilted/rotated; head or body moves to maintain or regain alignment
righting reactions
what are the two types of righting reactions
neck on body (NOB) and body on body (BOB)
elicited when surface on which the child is sitting or standing is moved causing a shift in COM
tilting reaction
the perturbation is a force directed at the child’s body
equilibrium reaction
what are the 3 responses to attempt to bring COG back within BOS with tilting/equilibrium reactions
- lateral head and trunk righting occurs away from weight shift
- trunk rotation away from weight shift
- opposite limbs will abduct if stimulus is too great
relationship between postural alignment and movement
postural control
postural control implies what
- readiness to move
- ability to adapt or react to threats of balance
- ability to anticipate postural needs to support a motor plan
what are the 7 components of postural control system
- limits of stability
- sensory organization
- eye-head stabilization
- MSK system
- motor coordination
- predictive central set
- environmental adaptation
the maximum distance an individual can lean away from the BOS without changing BOS
limits of stability
limits of stability in adults (ant, post, lateral)
ant: 8
post: 4
lateral: 8
amount of sway depends on velocity of movement of COM at the limits of stability
sway referenced
application of ground reaction force at the body surface detects the amplitude of sway
center of pressure
integration of sensory inputs from visual, vestibular, and somatosensory systems provide NS with information about movement
sensory organization
very important for head control in infancy
vision
both map together starting at neck, then trunk to extremities and provides feedback and feedforward information
vestibular and proprioception
input from tactile and proprioception
somatosensation
what 3 components make up sensory organization
vision, vestibular, somatosensation
we use our eyes to provide visual information of where we are in space and to tell us if our environment is till or moving
vision
we use our feet to provide sensory cues about the surface, muscular system helps maintain upright posture, and joint proprioception provides us with info about joint position
somatosensory
inner ears provide info about where we are in space; helps most during movement; inner ear control info about eye and head coordination as well as balance strategies
vestibular system
what are the 3 functions of the vestibular system
- stabilization of visual images on fovea of retina during head movement to allow clear vision
- maintain postural stability especially during movement of head
- provides CNS with exact info used for spatial orientation of head in 3 dimensions
what are the names of the 3 semicircular canals (SCC)
anterior (superior)
horizontal (lateral)
posterior (inferior)
what are the 2 otolith organs
utricle and saccule
bony and high concentration of NA:K
perilymph
membranous and high concentration K:NA
endolymph
what are SCC filled with
endolymph
contains hair cells and gel matrix known as _____
ampulla
cupula
sense angular velocity in all 3 planes
SCC
is deflected with endolymph movement
cupula
____ toward side you move toward, and _____ the other side
excitatory
inhibitory
if you move your head to one side, does the fluid move to the same or opposite direction
opposite
SCC work with mixed pairs
- ant works with opposite post
- horizontals work together
sense linear acceleration
otolith organs
sense forward and reverse acceleration
utricle
senses up and down acceleration
saccule
consists of matrix attached to hair cells
maculae
what is the normal force of gravity of the vestibular system, which is why the vestibular system functions differently in space
1 G
what nerve is always firing for the vestibular system
vestibulocochlear (8)
information travels from hair cells (scarpa’s ganglion) down _____
8th CN
where are vestibular nuclei located and how many are their
pons
- 4 major
- 7 minor
VOR (sup/med)
vestibulo-occular reflex –> inner ear tells eyes where to move
VSR (lateral)
vestibulospinal –> balance reactions and postural reactions
what are the 2 branches of the vestibular branch of CN 8 and what do they communicate with
superior vestibular - communicates with lateral and ant SCC and utricle
inferior vestibular - communicates with post SCC and saccule
where does CN 8 exit and with what other structures
internal auditory canal
facial N and labyrinthine A
processing of vestibular sensory and extravestibular sensory input occur _____
simultaneously
4 major collections of cell bodies in the brainstem to manage incoming vestibular information and routes information to many different areas to process proprioceptive, visual, tactile, and auditory information needed for postural control and stable gaze
vestibular nuclear complex
what do vestibular nuclei have connections with
cerebellum, reticular activating system, and CN 3, 4, 6
receives information from maculae of utricle and projects to lateral vestibulospinal tract and indirectly influences LMN that innervate extensors through VSR
lateral vestibular nucleus
receives information from cristae ampullaris and projects to the medial vestibulospinal tract; indirectly influences LMN that stabilize head through vestibulocolic reflex (VCR)
medial vestibular nucleus
receives information from cristae ampullaris and projects to the MLF to coordinate movement of the eyes with head through VOR
superior vestibular nucleus
receives information from maculae in utricle and from cristae ampullaris and projects to cerebellum to influence balance and postural awareness through medial and lateral vestibulospinal tracts
inferior vestibular nucleus
is a major recipient of information in and out of the vestibular complex
cerebellum
information from vestibular complex is relayed to the ______ ______ (midline)
cerebellar vermis (AKA flocculonodular region)
primarily involved in adjusting and maintaining calibration of VOR and static and dynamic posture via VSR
cerebellum
vestibular nuclei also send projections to the _____ which is responsible for regulation of autonomic NS functions (N/V, HR, respiration)
reticular formation
what are the 2 descending extrapyramidal tracts
medial and lateral vestibulospinal tracts
information from vestibular system also integrates in ____ for spatial mapping
hiccocampus
pathology of the vestibular system is often seen in what
ocular movements
what muscles does the anterior SCC connect with to create up torsional movement
superior and inferior rectus
what muscles does the posterior SCC connect with to create down torsional movement
inferior rectus and superior oblique
what muscles does the horizontal SCC connect with
medial and lateral rectus muscles
maintains image stationary on retina (high speed) during head movement; only reflex working at high speed and prevents images from blurring
vestibulo-ocular reflex
1:1 eye velocity to head velocity with VOR
vestibular gain
equal but opposite head and eye relationships
vestibular phase
occurs when somatosensory, visual and vestibular systems work appropriately and seamlessly, normal postural control engages and balance occurs subconsciously
sensorimotor integration
is the process of the CNS continuously determining/adjusting the percent of input needed from each of the 3 systems to remain upright
sensory reweighting
our brain is the computer to process the information we receive from our different senses: vision, touch, and inner ear through a process known as
sensory integration
provide orientation of the head in space and is the stable visual image created even when the head is moving
eye-head stabilization
anticipatory stabilization of head in space before the body moves
head stabilization in space
what are 2 important sensory receptors in the head
eyes and vestibular
resistance from viscoelastic properties of the muscle is under the regulation of what structures
muscle spindles, golgi tendon organs, and descending motor tracts
ability to coordinate the activation of muscles in sequence to produce controlled motion (synergy of muscles)
motor coordination
postural readiness is dependent on input from sensation and cognition in anticipation of movement
predictive central set
anticipated movement before it occurs, you know how much muscle force is likely needed to lift a heavy bookbag from the floor vs table (feedforward)
positive predictive central set
sensory input that occurs after the movement takes place for comparison and error detection
feedback
posture and movement adaptation to changes in the environment based on sensory input
environmental adaptation
what are the 3 sway referenced postural strategies recruited to maintain upright balance
ankle, hip, and stepping strategies
- quiet static standing occurs as result of sway at ankles
- solid surface in contact with feet
- intact visual, somatosensory, and vestibular input
- muscle activity intends to bring person back to midline
- distal to proximal requirement
ankle strategy
in ankle strategy, backward sway is countered by what muscles
anterior tibialis, quads, abdominals
in ankle strategy, anterior sway is countered by what muscles
gastroc, hamstrings, trunk extensors
larger and faster perturbations or if the surface the person is standing on is smaller/narrower than the feet and is a rapid correction by the hips to restore equilibrium; muscles activated in proximal to distal sequence
hip strategy
if displacing the floor backward (perturbing someone in the back) the subject will stay forward with activation of what
hip activation of abdominals and then quadriceps
if displace the floor forward (pushing someone in the chest), subject will sway backward with
hip action of paraspinals then hamstrings
when ankle and hip strategies are not successful to restore balance; usually to expand BOS
stepping strategy
during the first 3 years of life, which system is dominant
visual
ankle sway is present as early as ____ but recovery is slower in kids than adults
18 months
somatosensory dependence emerges around age ___ and matures around age ____ and then predominates through adulthood
7
10
vestibular information is utilized but slowly matures until _____, least effective in kids
15
