Postural Control Flashcards
what is the definition of postural control?
the ability to control the body’s position in space with respect to gravity, support surfaces, visual surround and internal references
what is the definition of stability?
ability to control the COM in relation to the BOS under static and dynamic conditions
what is the definition of orientation?
relationship between the body’s segments, the body, and the environment
what are the 3 aspects that can control posture (includes sitting and standing)?
task, individual, environment
what are the 6 constructs that can affect balance?
- biomechanics constraints
- stability limits/verticality
- anticipatory postural adjustments
- postural responses
- sensory orientation
- stability in gait
- *can also include task complexity, environmental demands, cognition, perception/Pusher’s syndrome, confidence/balance self-efficacy
how can we identify balance deficits?
- observe movement patterns –> task analysis
- include task progressions or regressions to detect balance deficits
- include balance outcome measures
which core tasks can demonstrate a deficit in steady state postural control without any variations?
sitting, standing
which core tasks demonstrate a deficit in anticipatory postural control without any variations?
sit to stand, walk and turn, step up/step down, reach/grasp/manipulate
which core tasks demonstrate a deficit in anticipatory postural control with variations?
sitting, standing
which core tasks can demonstrate a deficit in reactive postural control when perturbed?
sitting, standing, walk and turn
which core tasks can demonstrate a deficit in reactive postural control with a spontaneous LOB just by completion of the task?
sitting, sit to stand, standing, walk and turn, step up/step down, reach/grasp/manipulate
what are the 3 control strategies for balance?
- steady state postural control (SSPC)
- anticipatory postural control (APC)
- reactive postural control (RPC)
what are the determinants of balance for deficits in SSPC?
- postural movement strategies
- sensory processing
- balance confidence
- verticality
what are the determinants of balance for deficits in APC?
- postural movement strategies
- sensory processing
- balance confidence
- executive function/multitask ability
what are the determinants of balance for deficits in RPC?
- postural movement strategies
- sensory processing
how is SSPC evaluated?
- limits of stability and narrowing BOS can be evaluated
- static sitting balance can also be evaluated w/ eyes closed and on foam
what is SSPC?
seeing how someone can control their COM within their BOS under predictable, static conditions
what is APC?
- how postural muscle activity anticipates the voluntary movement, ensuring stability of the body during task performance
- unconscious muscle activity to counterbalance a movement
is APC a feedback or feedforward mechanism? how?
- feedforward
- ability to generate postural adjustments prior to voluntary movement to counter an upcoming postural disturbance or realigning the body’s COM prior to changing the VOS
what are some other tasks that evaluate APC?
sit to stand, rise to toes, stand on one leg, take one step forward, reach
how is APC evaluated in sitting?
- dynamic sitting balance
- ability to move from and return to a neutral alignment while performing a functional task
- reaching forward, head turns, actively crossing a leg
what is RPC?
- ability to respond to sensory input that signals a need for a response to maintain postural control
- response is unanticipated (can be generated internally or externally)
is RPC a feedback or feedforward mechanism? how?
- feedback
- 3 ways:
– ankle strategy
– hip strategy
– stepping strategy
when does an ankle strategy typically occur?
in response to a small perturbation on a firm surface
how does an ankle strategy work?
onset of muscle activation distally first at gastrocs/TA followed by hamstrings/quads then paraspinals/abdominals
what is the order of ankle strategy response when getting pushed from behind or the floor came beneath you from A to P?
- results in forward sway
- gastrocs –> hamstrings –> paraspinals
what is the order of ankle strategy response when getting pushed from the front or the floor came beneath you from P to A?
- results in backward sway
- anterior tib –> quads –> abs
when does a hip strategy typically occur?
in response to a larger/faster perturbation with a compliant or small support surface
how does a hip strategy work (motion size, activation order)?
- produces large motion
- proximal to distal activation
what is the order of hip strategy response when getting pushed from behind or the floor came beneath you from A to P?
- results in forward sway
- abdominals –> quads
what is the order of hip strategy response when getting pushed from in front or the floor came beneath you from P to A?
- results in backward sway
- paraspinals –> hamstrings
what muscles are activated with a lateral sway?
hip abductors
when does a stepping strategy typically occur?
due to larger, faster perturbation that can’t be corrected by ankle or hip strategy
how is a stepping strategy tested?
- having the pt lean into your hands until their COM moves to the edge of the BOS
- tested forward, backward, lateral
what is considered a normal grading for the stepping strategy?
recovers independently, single large step
what is considered an impaired grading for the stepping strategy?
more than one step
what is considered an absent grading for the stepping strategy?
no step or would fall without assistance
what is the response for a slow perturbation for reactive balance in sitting?
- righting reaction
- when reaching above the shoulder level on the same side:
– trunk elongates on WB side
– trunk shortens on NWB side
– head aligns w/ gravity
what is the response for a fast perturbation for reactive balance in sitting?
- protective extension
- results in a reach, abduction of limbs toward downward side
what are underlying determinants of balance?
body systems that contribute to producing and maintaining body orientation and stability during tasks and activities
what body function or structure (impairments) can cause the balance limitation?
- MSK system
- NM system
- cognitive/mental function
- behavioral factors
what are the determinants of balance in the MSK system?
- ROM: at the joint
- flexibility: muscle extensibility
- muscle performance: strength, power, endurance
- alignment/posture: biomechanics relationship of body segments to each other and the BOS