Sensory Integration and Postural Control Flashcards
What are the three basic elements of motor control?
stability
mobility
manipulation
What underlies all the elements of motor control?
postural control
Define postural control:
controlling body’s position in space for the dual purpose of ORIENTATION and STABILITY
Define orientation:
posture
starting position for a task
Define stability:
stable base for performing all tasks
controlling COM over BOS
What are the three determinants of postural control?
person
task
environment
What elements of the individual will contribute to postural control capabilities?
many… but mostly the individual’s sensory systems and sensory strategies
What is the purpose of sensory systems?
answer the question “where am I?”
body parts relative to each other, to environment, and to gravity
Somatosensory reacts at which speed?
fastest! (80-100 ms latency)
Vision reacts at which speed?
slower than somatosensory (200ms)
Which system is most sensitive to balance disturbance?
somatosensory
–> favored on fixed, level support surfaces (LESS EFFECTIVE on moving or tilted surfaced)
Which system reports information about position and motion of head with respect to surrounding objects?
vision
The somatosensory system measures:
body position and motion relative to support surface
**feet and ankle inputs are most important in quiet stance
Vision provides a reference for ____.
verticality
______ system is not always an accurate source of information about self-motion.
vision
What are the receptors of the vestibular system?
semi-circular canals
otoliths
_______ system measures position and motion of the head with respect to gravity and inertial forces.
vestibular system
Which system CAN’T detect the source of head movement?
vestibular system
The vestibular system acts as umpire with there is conflict about which conditions?
surface/vision
What motor outputs is the vestibular system responsible for generating?
VOR
VSR
What are the three phases of sensory integration for postural control?
- PROCESS inputs from periphery
- WEIGHT inputs based on relevance to task and environment
- SELECT sensory strategy
What is sensory strategy selection based on?
availability of inputs
accuracy
value to the task at hand
With a stable surface, what are the relative contributions of each of the systems?
70% SS
20% Vestibular
10% Visual
With an unstable surface, what are the relative contributions of each of the systems?
60% Vestibular
30% Visual
10% SS
What does posturography testing measure?
SWAY
quantifies standing balance in response to changes in sensory inputs
Posturography condition 1
*all systems available
Posturography condition 2
vision eliminated (eyes closed) *vestibular and SS still available
Posturography condition 3
vision inaccurate (sway reference visual surround) *challenges system to detect visual error and relies on vestibular to act as umpire
Posturography condition 4
SS inaccurate (sway reference platform) *vestibular and vision are available
Posturography condition 5
SS inaccurate and vision eliminated (sway reference platform and eyes closed)
*relies mostly on vestibular
Posturography condition 6
SS inaccurate, vision inaccurate (sway reference platform and visual surround)
*relies solely on vestibular
CTSIB stands for?
clinical test for sensory interaction in balance
Describe the 3 posturography motor strategies:
- sway (ankle strategy)
- hip strategy
- step or change in support (fall)
Posturography sensory strategies answer these 2 questions:
What systems are hypofxning?
What systems are more heavily weighted?
CTSIB is used to determine:
how sensory information is used to maintain vertical orientation (clinical use of the 6 conditions used for posturography)
How do you measure body sway for CTSIB?
measure body sway in identical posture for 30 seconds in each condition (feet together, hands on hips)
How do you make SS inaccurate for conditions 4, 5, and 6 with CTSIB?
foam!
Which conditions are eliminated in the modified CTSIB?
3 and 6
Describe the modified CTSIB protocol:
- eyes open standing on firm surface (all systems available)
- eyes closed standing on firm surface (rely on SS and vestibular)
- eyes open standing on foam (rely on vestibular and vision)
- eyes closed standing on foam (rely on vestibular)
What kind of motor response does the SC generate in postural control?
generates very short latency stretch responses and not effective against postural perturbations by themselves
Longer loop responses for postural control are mediated by the _____.
cortex
Integration of sensory inputs and generation of automatic, postural responses from:
vestibular nuclei
reticular formation
Brainstem response latency for postural control compared to SC response latency?
Brainstem longer than SC
Longer loop responses for postural control work to adapt and fine tune postural responses with ______.
experience
Longer loop responses for postural control preselect responses given features of the ______.
task or environment
Longer loop cortex mediated responses for postural control are responsible for longer latency responses such as:
stepping, change in support
