Postural Control Flashcards

1
Q

Contributing factors to motor control

A

Task Factors
-stability= req when sitting or standing static
-mobility= req when moving BoS
-Task may be manipulated to increase demand
Eg: lifting load, accuracy for task, task certainty and complexity, body orientation

Environmental factors

  • Regulatory features= influence mvmt so must conform to those features eg uneven surfaces
  • Non-regulatory features= may affect mvmt performance but mvmt does not have to conform to them eg. Background noise

Individual Factors

  • Perception= discernment of sensory info+ high level interpretation
  • Cognition= attention, planning, problem solving, motivation, engagement, emotion
  • Action= how certain activity is accomplished
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2
Q

Define postural control

A

Control of body’s position for orientation and balance

  • Orientation=controlling relationship between body segments, task, environment
  • Balance= controlling CoM in relation to BoS
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3
Q

Describe Stationary BoS

A

Maintained control of orientation and balance when not moving
SUSTAIN= hold a posture eg sit or stand still
MAINTAIN= maintain control over stationary BoS when performing a movement eg Reaching
RETAIN= retain control when responding to perturbation
eg. push or sneeze

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4
Q

Describe Changing BoS

A

Maintained control of orientation and balance when
PROJECT= project body up and down from position eg hop or jump
PROPEL= propel body towards new position eg stand up, sit down
PROTECT= protect body in response to external perturbation eg. take a step to prevent falling

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5
Q

Strategies used in Postural Control

A
Neuromuscular Synergies
Adaptive Mechanism
Anticipatory Mechanisms
Individual Sensory system
Sensory strategies 
Musculoskeletal components 
internal representations
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6
Q

Describe NM Synergies

A

-set number of strategies used by CNS= prevent loss of balance by correcting displacement of COM+ to keep it within BoS in event unpredictable perturbation
E.g Ankle, hip and stepping strategies
-Combo of strategies used

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7
Q

Describe Adaptive mechanism

A
  • use feedback from sensory and motor system –> more variable corrective component than NM synergies
  • Used after both unexpected and expected perturbations
  • Development of direction specific patterns + fine tuning –> req to develop head control, sitting, standing
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8
Q

Describe Anticipatory Mechanism

A

-FF system of PC- pre tuning sensory and motor systems prior to mvmt
-based on predictions made by the CNS
-Diagram:
Anticipatory reaction= presents in FF manner, either before or simultaneously to prime mover
Adaptive reaction= presents after prime move, correction to disturbance
Time separating anticip+ reactionary at 50ms after onset of prime mover activity–> this is time req for sensory feedback + second motor output to be generated
-Development of anticipatory mech

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9
Q

Describe Individual sensory system

A

Tactile, visual, somatosensory, vestibular

-provides info to CNS of body’s position and mvmt

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10
Q

Describe Sensory strategies

A

-How info is organised + interpreted from individual sensory system contributes to PC
-Tactile= orients body to stim
Vestib= central reference for other systems
Prop= relative position of body parts, orient to support surface, joint pos sense, muscle length
VIsion= motivates to move, orient to visual surrounds by 6months

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11
Q

Describe development of sensors

A

Utero
-Tactile by 3wks
Newborn
-Tactile= primary sense after birth
-Vision= preterm infant can follow but not focus until term. Drives exploratory behaviour + mvmt
-Prop= present at/soon after birth
-Vestibular= drives head response initially (3-6 months), then vision takes over as system matures

2-3 years
-vision dominates, prop + vestibular contribute

4-6 years

  • very variable
  • tactile largely mature by 4y

7-8+ years

  • prop from feet
  • vision- less important unless leaning new skill
  • vestib mature by 6y
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12
Q

Describe Musculoskeletal components

A
  • PC affected by growth, body alignment, muscle and postural tone, muscle strength, joint ROM
  • Growth= changes in shape and height- head vs body size, limb length, trunk length, growth of organs, soft tissue (CoG infants=T12, adults L5)
  • Body alignment= flexor position initially, 3-6 months dev Cx curve, 8months dev Lx curve
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13
Q

Describe internal representations

A

Provide postural frame of reference–> related to sensory input to develop maps or internal rep of body schema

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14
Q

Deficits in PC shown in children with Neurological disorders

A
CP
Developmental co-ord disorder
Spina Bifida
Down Syndrome
Autism
Premature birth
Sensorineural Hearing loss
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15
Q

6 elements of postural control

A
Sensory orientaiton
Anticipatory postural adjustments 
Reactive postural responses
Stability limits/verticality
Stability in gait
Biomechanical constraints
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16
Q

Tests for Biomechanical constraints

A

MSK- components

  • BoS
  • COM alignment
  • Ankle strength with ROM
  • Hip/Trunk lateral strength
  • Sit on floor+ stand up
17
Q

Tests for Reactive Postural Responses

A

NM synergies, adaptive mech

  • in place response forward + bid
  • compensatory stepping correction- fwd, bad, lat
  • attempts to elicit responses of ankle+ hip strategies
18
Q

Test for Anticipatory postural adj

A

Anticipatory mech

  • sit to stand
  • rise to toes
  • Stand on one leg
  • alternate stair touch
  • standing arm raise
19
Q

Tests for Sensory orientation

A

Sensory strategies, individual sensory system

  • Sensory integration for balance ( modified CTSIB)
  • Incline - EC
20
Q

Tests for stability limits/verticality

A

Internal represent

  • sitting verticality and lateral lean (L and R)
  • Functional reach forward
  • Functional reach lateral
21
Q

Tests for stability in gait

A

All

  • Gait on level surface
  • Change in gait speed
  • Walk with horizontal head turns
  • Walk with pivot turns
  • step over obstacles
  • Timed up and go test
  • Timed up and go w/dual task
22
Q

Vertical head righting

A

Ability: orient head to gravity when trunk is displaced away from vertical orientation  no loss of head position when body moves underneath
- Uses sensory perception of movement (away from vertical), optical head righting, vestibular head righting

Typical Performance = Normal absence in newborns  emerges at 3mo  remains throughout life

Atypical= partial/full loss of head orientation, head movement causes increase or decrease in muscle tone

23
Q

Horizontal head righting

A

Ability: orient head to gravity when trunk is displaced away from vertical orientation  no loss of head position when body moves underneath

Typical performance = normal absence in newborns  emerges 4-5mo  remains throughout life

Atypical= loss of head orientation, abnormal tone

24
Q

Horizontal head right/landau

A

Ability: orient head, trunk, LL to gravity when positioned in prone suspension  via Cx, trunk, hip and knee ext, PF in prone

Typical = normal absence in newborns  emerges 4-5mo w/ Cx ext  rest occurs at 6mo and remains through life 
Atypical = partial/delayed response, abnormal tone
25
Q

Body on body righting

A

Ability: to “right” (segmental rotation) the trunk when LL or UL is moved diagonally across body  automatic postural adjust

Typical = normal absence in newborns, ‘en block’ follow  emerges 3-4mo, trunk rot follow movement of limb  integrated 3-5y and retained through life 
Atypical = no/partial response, asymmetry ( muscle length/strength,  segmental rotation at spine), hypertonia (cause en block)
26
Q

Placing Mechanism

A

Ability: Clear foot/hand + place on firm surface as protective mechanism to avoid tripping

  • Retract from tactile stim at dorsum of foot  DF foot + toe ext, hip knee flex  ext towards support surface  +ve support (eg. Foot caught on rug)
  • Withdrawwal from stim on dorsum of hand  sh + elbow fl, wrist + finger ext  ext towards support surface  +ve support
Typical = normal absence in newborns  emerges at 1-4mo with suspension test  integrated 8mo, response varies on situation 
Atypical = no reaction, delayed response, over-exaggerated/immature
27
Q

Supporting Reaction- LL

A

Ability: WB through LL + support self in standing and later walking  want  in ext tonus in WB LL so can push into erect standing
- Stim = proprioceptive input through palmar surface of feet or tactile stim of dorsum of foot

Typical = 1mo – sterotyped ext tonus  2-6mo no supporting period may occur  integrates from 6mo, child bounces up and down on toes, bilateral +ve (legs ext) or –ve (fl) support  10-12mo +ve support in one leg w/ -ve support in contralateral, allows for weight shifting 
Atypical = no/partial, exaggerated responses
28
Q

Supporting Reaction UL

A

Ability: Bear weight through palms of hands following placing reaction in 4 point or crawling  weight taken through base of hands + elbow ext occurs

Typical = emerges birth-2mo w/ finger fl when weight taken through hands  2-8mo sees palm of hand more contact with surface  6mo bilateral +ve (arm ext) or –ve (arms flexed)  10-12mo +ve support in one arm and –ve support in contra
Protective Reactions

29
Q

Protective Reaction

A
  • 3 things to determine if protective response successful
    o Has to be fast (may be difficult for spasticity)
    o Has to be accurate – direction they’re going
    o Has +ve support
  • Requires fast vestib reflexes and some visual  stimulates elbow ext, sh abd/er/ext, wr and finger ext
Typical = 6 mo forward response, 8mo sideways, 10mo backwards 
Atypical = no/partial, exaggerated, asymmetry, flexion of arms after 8mo, prolonged propping
30
Q

Parachute Reaction

A

Ability: Perform parachute/protective reaction in LL in downwards direction - driven by vestib input  lower leg ext of hip and knees, foot DF
- Involves same 3 principles as protective

Typical: normal absence in newborns  6-12mo LL protective reaction
Atypical: no/partial, asymmetry, exaggerated, flexion of arms or absence after 8mo

31
Q

Equilibrium Reaction

A

Ability: Move body against disturbing force to maintain position in space – vestibular input  trunk + limb mvmt counter disturbance to maintain balance, hip/knee/ankle strategies in standing

Typical:

  • 6-8mo = emerges in prone  LF of trunk against direction of tilt + abd and ext of limbs
  • 8-10mo = emerges in supine  same as above
  • 10mo = emerges in sitting  LF, F and E of trunk opposite to til. Arms to counterbalance
  • 18mo = emerges in standing  ankle, knee, hip corrections. Use trunk + arms to maintain position

Atypical: No/partial, asymmetry, lack of balance reaction, over reliance on righting/protective reactions