Vestibular: Postural Control Exam Flashcards
What are the biomechanical factors that contribute to stability and orientation?
Degrees of freedom
Strength
Limits of stability
What are the movt strategies that contribute to stability and orientation?
Reactive
Anticipatory
Voluntary
What are the orientations in space the contribute to stability and orientation?
Perception
Gravity
Surfaces
Vision
Verticality
What are the sensory strategies that contribute to stability and orientation?
Sensory integration
Sensory reweighting
What are the controls of dynamics that contribute to stability and orientation?
Gait and proactive responses
What are the cognitive processes that contribute to stability and orientation?
Attention and learning
What test can we use to determine which type of balance problem a pt presents with?
The miniBEST test
What is the go to test for balance and vestibular pts?
The miniBEST test
What are the 6 specific domains of postural control?
Dynamic gait (including sensory and motor)
Sensory organization and weighting
COG position and voluntary control (limits of stability)
Postural responses (strategies, APAs, RPRs)
Dual tasking (cognitive interference)
MSK, cardio considerations
What is the DGI?
A dynamic gait screen with 4 items to assess balance
What are the 4 items on the DGI?
Horizontal head turns
Vertical head turns
Gait on level surfaces
Changes in gait speed
What is the max score of the DGI?
12
A score of less than 10/12 on the DGI indicates what?
Fall risk
Is the to allowed to use an AD with the FGA?
Yes
What is the FGA?
A modification of the DGI with improved reliability and decreased ceiling effect
What is the cutoff scores for the FGA?
Greater than or equal to 22/30 predicts falls in older adults
What are the tests done with the computerized dynamic posturography?
Sensory organization test (SOT)
Motor control test (MCT)
Adaptation test (ADT)
Limits of stability (LOS)
COG position/control
What is the SOT (sensory organization test)?
A 6 condition test with high specificity for what part of the system is contribution to imbalance
What is condition one of the SOT?
EO
Firm surface
When would we expect a pt to have issues with condition one of the SOT?
If they have a central lesion like a cerebellar issue
If they are making it up
What is condition two of the SOT?
EC
Firm surface
What is condition three of the SOT?
Firm surface
Moving environment with head in computer thingy creating unsteady vision
What is condition four of the SOT?
Unstable surface
EO
What is condition five of the SOT?
Unstable surface
EC
What is condition six of the SOT?
Unstable surface
Moving visual input in computer thingy to create unstable vision
What are the accurate systems in condition one of the SOT?
Vestibular
Vision
Somatosensory
What are the inaccurate systems in condition one of the SOT?
None
What are the accurate systems in condition two of the SOT?
Vestibular
Somatosensory
What are the inaccurate systems in condition two of the SOT?
Vision
What systems are accurate in condition three of the SOT?
Vestibular
Somatosensory
What systems are inaccurate in condition three of the SOT?
Vision
What systems are accurate in condition four of the SOT?
Vestibular
Visual
What systems are inaccurate in condition four of the SOT?
Somatosensory
What systems are accurate in condition five of the SOT?
Vestibular
What systems are inaccurate in condition five of the SOT?
Somatosensory
Vision
What systems are accurate in condition six of the SOT?
Vestibular
What systems are inaccurate in condition six of the SOT?
Vision
Somatosensory
What is the difference between condition five and six of the SOT?
Condition five takes away vision and therefore unreliable
Condition six makes vision unstable and therefore unreliable
Both make vision unreliable to test the vestibular system but are treated differently
T/f: you have to the stress the system to make it work
True
You have to manipulate _____ input to change motor output
Sensory
T/f: decreased strength and ROM can decrease the sway envelope available and make balance worse
True
With a polyneuropathy, what are the two possible outcomes of putting the pt in condition two of the SOT (firm surface, EC)?
They could have a lot of sway bc they already have impaired somatosensation and now you are taking away their visual system, so they have to relay in their vestibular system
OR
they could have no sway bc they have adapted to their changed somatosensation
What should we document about sway?
The direction and timing of it
How can we determine a pts COG?
Using a posturographic measurement (big tech stuff)
Using observation in the clinic
What are stability limits (limits of stability = LOS)?
The boundaries within which the body can maintain stability w/o changing the BOS
What mechanical factors limit normal COG position and LOS?
COG position and control
BOS
ROM
strength
What internal factors limit normal COG position and LOS?
Perception
Other than mechanical and internal factors, what can limit normal COG position and LOS?
Accurate interpretation
Pain
Experience with anxiety or fear
What is the only way to evaluate postural strategies?
Careful observation in the clinic
What questions should we be considering about a pts postural response strategies?
Is the pt choosing the appropriate strategy for the surface situation
Is the pt choosing the appropriate strategy for their stability and sway?
When an individual is unstable on an unstable or narrow surface, what street should be used?
Hip strategy
When an individual is stable and on a stable or broad surface, what strategy should be used?
Ankle strategy
If the individual is stable on a stable or broad surface and they are using a hip strategy, is this an appropriate strategy choice?
Nope, they should be using ankle strategies
If an individual is unstable on an unstable or narrow surface and they are using ankle strategies, if this apprise for the situation?
No, they should be using hip strategies
When should the make strategy be used?
When the surface is firm
When the sway/demand is little
Slow sway
When should the hip strategies be used?
On unstable surfaces
On narrow BOS
When perturbations and sway are too much
How can we test dual tasking?
TUGc (not explaining this one bc I think we all got this one)
How can we measure postural response strategies?
The miniBEST test
What inertial measurement options we should quantify?
Postural control/balance
Gait
TUG
How can we quantify COG sway area, mean sway, sway acceleration, and sway “jerk”?
With wearable sensors
How can we quantify gait?
With gait velocity
What component impairments may be present with imbalances?
Biomechanical alignment and control
Sensory system fxn, weighting, or integration
Motor system fxn or movt strategies
Cognitive or perceptual processes
Interaction with other systems
Integration into dynamic gait and fxn
What is electronystagmography (ENG)?
Use of electrodes placed to recorder and measure each eye muscle response
What is videonystagmography (VNG)?
Use of video/video infrared recording to observe, record, and measure eye muscle responses
What do ENG and VNG do?
Record eye movt in response to a stim delivered to each vestibular apparatus
What is caloric testing?
Using cold or warm water/air irrigated into the external auditory canal to induce nystagmus
What does a cold stim do in caloric testing?
Eyes move in horizontal nystagmus away from the side of the stim
What does a warm stim do in caloric testing?
Eyes move toward the side of the stim
What does absent or reduced reactive eye movt suggest in caloric testing?
It suggests a vestibular weakness of the horizontal SCC of the side being stimulated
If there is <25% difference bw the two ears with caloric testing, is this considered normal?
Yes
Increased responses of more than 25% in caloric testing usually signifies what?
Cerebellar disease
What is a normal response to caloric testing?
Equal intensity of the nystagmus response in both ears
If someone has a unilateral vestibular lesion, what would we see with caloric testing?
Decreased intensity of response in one ear
If someone has a bilateral vestibular lesion, what would we see on caloric testing?
No response or a very weak response in both ears
What is the stimulus in the rotational chair test?
Movt
What is the rotational chair test?
The pt is rotated in a chair in the dark with EO and ENG/VNG recording to stimulate both SCCs simultaneously in a pair where one is inhibited and the other excited
What is the rotational chair test used to measure?
The phase and gain (ratio) of head:eye movt
If the rotational chair test shows us decreased gain, what does this indicate?
Decreased vestibular sensitivity
Does a decreased gain in the rotational chair test usually indicate a unilateral or bilateral loss of vestibular fxn?
BL loss of vestibular fxn
If there is an abnormally large (increase) gain in the rotational chair test, what is this usually suggestive of?
Central dysfxn
What are the indications to use the rotational chair test?
Those in whom BL is suspected
Pediatrics
Those who can’t have or tolerate calorics
Those in which aphyisologic is suspected
What is the vestibular autorotation test (VAT)?
A test for VOR gains and phases that is performed in room light
The subject wears an accelerometer device on their head and is asked to focus on a stationary target and move their head at speeds greater than 2Hz and records the head and eye velocities
What is calculated by the VAT?
VOR gains (eye velocity amplitude/head velocity amplitude) and phases
What are VEMPs (vestibular evoked myogenic potentials)?
High intensity sounds that stimulate the vestibular system in the absence of head movt to provide a method for evaluating the otolithic organs separate from the SCC
What are the anatomical difference bw the utricle and saccule?
The utricle supplies the ipsi sup rectus and med rectus and the contralateral inf oblique and inf rectus via the sup vestibular nerve
The saccule supplies the ipsi SCM muscle via the inf vestibular nerve
What are the fxnal differences bw the utricle and saccule?
The utricle is principally related to eye movt
The saccule plays a major role in control of postural adjustments
What is the c-VEMP?
A series of clicks are used stimulate each ear to stimulate the saccule and inhibit the SCM on the same side
The firing rate of the ipsi SCM is recorded using EMG (surface)
C-VEMP results are abnormal if….
One side is 2x larger than the others
Low amplitude
Absent
Abnormal results of the c-VEMP would indicate what otolithic organ?
Saccule
What is the o-VEMP?
Series of clicks used to stimulate each ear and stimulate the utricle that inhibits the contralateral inferior oblique
Firing rate of the CL inf oblique is recoded using EMG (surface)
O-VEMP results are abnormal if…
Low in amplitude
Absent
An abnormal result on the o-VEMP would indicate which otolithic organ?
The utricle
