Sensory Strategies for Balance

What is the ability to maintain orientation of one’s body parts in respect to other body parts & gravity?

postural control

what is the condition where forces acting on body are balanced such that the COM is w/in stability limits, the boundaries of BOS?

balance

what is the response to external forces acting on the body, displacing the COM or moving the BOS?

Reactive Postural Control

What is the anticipation of internally generated, destabilizing forces imposed on the body’s own movements?

proactive (anticipatory) Postural Control

What is the modification of postural responses to changing task & environmental demands?

Adaptive Postural Control

In standing, the COM is located about how high body height above the BOS?

⅔ (S2)

Consider normal sagittal plane postural alignment. Select the response that correctly reflects the position of the line of gravity

Slightly anterior to ankle & knee joints, thru midline of trunk

The maximum distance an individual is willing or able to lean in any direction w/o LOB or changing BOS is called?

Limits of stability

What is the small postural shifts we make in order to keep balance?

postural sway

What is the path that COP will take when standing still, feet not moving, BOS not changing?

sway envelope

What is the ability to maintain posture w/ minimal movement?

steadiness

What sensory systems provide input to the CNS?

Vision

Vestibular

Somatosensory

What integrates information & initiates action, goal directed conscious & unconscious actions?

CNS

Sensory strategies for balance: Visual system provides information to detect

relative orientation from body segments, Orientation of body in space, & Perception of mvmts

Sensory strategies for balance: Visual system has 2 functional systems. Which visual sub-system involves sensory motor vision; info about entire visual field, gives general awareness? (is what makes you not trip)

ambient vision/implicit vision

Sensory strategies for balance: somatosensory system provides inputs of

Cutaneous & pressure sensations

Muscle & joint proprioception

Sensory strategies for balance: somatosensory system provides information of relative orientation & mvmt of

body in relation to support surface

Where on the body is cutaneous sensation as well as proprioception important for maintaining upright balance?

feet, ankles, hip

Sensory strategies for balance: vestibular system provides orientation of

head in respect to gravity

Acceleration/deceleration of head

Gaze stabilization (vestibular ocular reflex (VOR): maintains stable gaze when head is moving)

Regulation of postural tone & muscle activation: vestibulospinal reflex

Sensory strategies for balance: system coordination during Quiet stance our somatosensory system has its greatest weight (most important) because it is 

quickest to respond to a perturbation

System coordination when there is an impaired somatosensory there is an increased weight on

visual system

if an individual has Impaired Somatosensory AND Visual then the

Vestibular system becomes critical

conflict from any other balance systems is solved by the decision maker system aka

vestibular system

What are the sensory strategies for balance for a complex patient w/ neurologic diagnoses?

Sensory inputs are redundant

CNS flexibility: can be trained to recalibrate how uses sensory info, task & context dependent, CNS weights timing/accuracy

Multi-system impairment WILL impact postural control/balance

Role of cognition/attention: in order to use this info, you’ll need to attend & interpret info to plan effective responses

What is an outcome measure that could be used for a pt w/ balance issues?

Romberg (20-30s)

What type of sensory loss is most commonly associated w/ positive Romberg test?

somatosensory (proprioception impairment)

Sensory strategies for balance: Visual system has 2 functional systems. Which system has the central retina responsible for majority of it providing info about fine details of what we need to be seeing & understanding visually? (visual acuity)

focal vision/cognitive vision/explicit vision

A Snellen chart score of 20/50 or worse has impact on ones balance. What kind of vision is assessed here?

visual acuity