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
what are the determinants of balance in the NM system?
- postural movement strategies
- coordination
- sensory integrity and processing
- perceptual function: verticality
what are the determinants of balance with cognitive/mental function?
- arousal
- attention
- executive function
- multi-task ability
what are the determinants of balance for behavioral factors?
- past experience
- fear of falling
- self-efficacy
- balance confidence
what are postural movement strategies?
- movement of the muscles and joints in a coordinated manner to maintain posture and balance during voluntary movement and when perturbed
- the CNS quickly moves between patterns depending on the demands of the activity or environment
what are the contracts that makeup postural movement strategies?
- biomechanics contraints
- anticipatory postural adjustments
- corrective responses/fixed support (hip/ankle strategies)
- protective responses (change in support strategy –> stepping strategy, reaching or grasping)
what is sensory processing?
- integrity: how well the body’s sensory systems work
- processing: organization, selection, and integration of sensory information to maintain postural control as the task or environment change
what are the sensory systems that are involved in sensory processing?
- vision
- vestibular: provides the CNS with info about the position and movement of the head with respect to gravity and inertial forces
- somatosensation: touch, temp, proprioception, pain
how can sensory systems be tested?
- our body can compensate for loss of a system
- sensory organization test (SOT): examined with dynamic posturography
- clinical test of sensory interaction and balance (CTSIB): foam and dome test
what is perceptual function/verticality?
- ability to orient the body in relation to the line of gravity
what is executive function?
- complex cognitive skills including insight, judgement, memory, problem solving, and attention
- these skills are necessary for planning, initiation, sequencing, and monitoring of goal-directed behavior
what are examples of executive function?
- difficulty processing information (flight canceled, busy gym, road closed)
- planning and preparing (going on a trip, preparing for an exam)
what is multitask capacity?
- able to successfully participate in more than one task (dual task or multiple task)
what are examples of multitask capacity?
- stop walking and talking test
- TUG cognitive
- impaired cognition is affecting the ability to physically move
what is balance confidence?
confidence in being able to maintain balance while performing activities
what is falls self-efficacy?
persons perception about their abilities to deal with a fall
what is fear of falling?
worry or concern regardless of their h/o falls
what is activity avoidance?
limiting an activity, despite capability, that can result on an increased risk of falls and decrease QOL
what is the floor affect?
scoring near the bottom
what is the ceiling effect?
- scoring near the top
- unable to capture the pts functional status where they are and hard to measure change
what does a grade of 4 (normal) look like for static balance?
maintain steady balance w/o handout support
what does a grade of 4 (normal) look like for dynamic balance?
accepts maximal challenge and can shift weight easily within a full range in all directions
what does a grade of 3 (good) look like for static balance?
able to maintain balance without handheld support with limited postural sway
what does a grade of 3 (good) look like for dynamic balance?
accepts moderate challenge
what does a grade of 2 (fair) look like for static balance?
maintains balance with handheld support, may require minimal assistance
what does a grade of 2 (fair) look like for dynamic balance?
ablate accept minimal challenge, maintains balance while turning head/trunk
what does a grade of 1 (poor) look like for static balance?
requires handheld support and moderate-maximal assistance to maintain the position
what does a grade of 1 (poor) look like for dynamic balance?
unable to accept challenge or move without loss of balance
what does a grade of 0 look like for functional balance?
unable to maintain balance
what are the 6 sensory conditions for the Sensory Organization Test (SOT) or the Clinical Test of Sensory Interaction and Balance (CTSIB)?
- EO firm surface (EOSS)
- EC firm surface (ECSS)
- EO w/ sway referenced visual surround or dome (VCSS)
- EO on sway referenced support surface or foam (EOMS)
- EC on sway referenced support surface or foam (ECMS)
- EO on sway referenced support surface and visual surround or dome (VCMS)
what kind of information can the SOT/CTSIB produce?
- doesn’t diagnose specifically what is wrong
- tells what sensory system the person is relying on
- allows for conclusion of a possible deficit in one or more areas
what can be concluded if a pt has an increased saw or falls on conditions 2, 3, 5, and 6?
they are dependent upon their vision for balance
what can be concluded if a pt has an increased saw or falls on conditions 4, 5, and 6?
they are dependent upon the surface/somatosensory system for balance
what can be concluded if a pt has an increased saw or falls on conditions 5 and 6?
- they have vestibular loss (inability to rely on vision or somatosensory)
- *can only rely on vestibular, only aspect here that can be “diagnosed”
what can be concluded if a pt has an increased saw or falls on conditions 3, 4, 5, and 6?
they have a sensory selection problem (multiple systems involved)
what does the Function in Sitting Test (FIST) examine?
sensory, motor, proactive, reactive, and steady state balance
what does the FIST involve?
- pt performs 14 items
- nudging, timed sitting doe 30s EO/EC, moving head side to side, picking up an object behind them and on the floor, reaching, scooting
how is the FIST scored and what is the MDC?
- scores 0-4 where 0 is complete assistance and 4 is independence
- total out of 56
- MDIC = 6-7
– want at least a 6 pt change
what does the Activities Specific Balance Confidence (ABC) Scale examine?
pts confidence in their balance
what does the ABC Scale involve?
- 16 item self report survey
- pt rates confidence in different activities 0-100% where 0 is none and 100 is complete confidence
- includes picking up something from floor/above head, getting in/out of car, walk across large parking lot or crowded mall, stepping on/off escalator, walking on icy sidewalks
in which populations may the ABC Scale not be the best measure and why?
pts with brain or spinal cord injury b/c they are not aware of their own challenges or may not have movement at certain segments
what is the cut-off score for older adults for the ABC Scale?
<67% = risk for falls
what are the general levels of physical functioning for older adults when scoring the ABC Scale?
- <80% = high level of physical functioning
- 50-80% = moderate level of physical functioning
- <50% = low level of physical functioning
what are the values of MDC for PD and acute/chronic stroke for the ABC Scale?
- PD = 13%
- acute and chronic stroke = 14%
what does the Berg Balance Scale (BBS) examine and what control strategies for balance?
- examines static and dynamic balance
- specifically anticipatory and steady state (not reactive)
what does the BBS involve?
- 14 items rated 0-4 when 0 is unable to perform and 4 is independent
- out of 56 points
- includes sit to stand and transfers, standing with EO, standing in Romberg/tandem/SLS, reaching forward, picking up object from floor, turn 360 degrees, alternating foot taps on a step
- no gait, can’t use an assistive device
which scale is the gold standard for balance?
Berg Balance Scale
what is the cutoff score for older adults?
- <49 for older adults
- under 40 = almost 100% risk for falls
- optimal cut-off score is determined by knowing whether or not the person has a hx of fall in last 6 mo
does a 1 point job indicate an increased fall risk by much on BBS?
- it varies
- a 1 point drop on the scale can increase fall risk anywhere from 3-8% depending on where the baseline score is
what is the significance for BBS for pts with PD?
- <52
- not good for SCI
- limited utility for middle stage PD to predict falls
– reactive postural control may be lost and this test doesn’t look at reactive; not a foos picture of their balance (–> ceiling effect)
what is the MDC for the BBS for pts with acute stroke, chronic stroke, older adults in nursing home, and PD?
- acute stroke = 6.9
- chronic stroke = 4.13
- older adults in nursing home = 10.4
- PD = 5
what does the Fullerton Advanced Balance (FAB) Scale measure?
advanced balance for higher functioning pts
what does the Fullerton/FAB involve?
- 10 items score from 0-4
- 40 points total
- includes stepping on and over a 6 in bench, tandem walk, SLS, stand on foam, two-footed jump, walk with head turns, reactive postural control (posterior)
what control strategies for balance does the Fullerton/FAB measure?
steady state, anticipatory, reactive
what is the cut-off score for the Fullerton/FAB?
<25 = high risk for falls in older adults
what does the mini BESTest involve?
- 14 items, 0-2 scale when 0 is severe impairment and 2 is no impairment
- includes anticipatory (sit to stand, rise on toes, SLS) and reactive (forward, backward, lateral) postural control, sensory orientation (standing, standing on foam and incline with EC), dynamic gait (walk with head turns, TUG dual task, pivot turns, obstacles, change in gait speed)
what is the cut-off score and MDC for the mini BESTest?
- cut-off score for falls = 24 points
- MDC = 4 for older adults
what control strategies for balance does the mini BESTest measure?
steady state, anticipatory, reactive
what does the Timed Up and Go test examine?
-how a pt stands up from a chair, walks 3 meters, turn, walks back to the chair, and sits
- can use assistive device
what is the cut-off score for the TUG?
> 13.5 sec = higher risk for falls
what is the MDC for TUG in CVA and PD?
- CVA= 2.9 sec
- PD = 4.85 sec
what is involved in the TUG Manual dual task?
- hold a glass of water
- grasp it from a table, carry it, place back down, sit
what is involved in the TUG Cognitive dual task?
- also part of mini BESTest
- count backwards by 3s from a number between 20-100 OR repeat every other letter of the alphabet
what control strategies for balance does the TUG measure?
anticipatory
what are the cut-off scores for the TUG dual tasks?
- older adults (TUG Cog): >15 sec
- PD (TUG Cog): >10% difference in speed between typical
- PD (TUG Man): >4.5 sec difference between typical
