Vestibular Flashcards
What are the roles of the vestibular system?
stabilize visual image during head movement
provide sensory information for spatial orientation
maintain postural stabillity when stationary and during movement
what is postural control
control’s the body’s position in spce for stability and orientation between body segments and the environement
what is postural stability
maintenace of the COM over the BOS
what is postural orientation
ability to maintain relationship between body segments and between body and environment for a task
What are the sesory input systems
visual
vestibular
somatosensory
What are the motor output systems
VOR- vestibulo ocular reflex
VCR- vestibulo collic reflex
VSR- vestibulo spinal reflex
what plane is the utricle
horiontal
what plane is the saccule
vertical
the urticle and saccules form…
the otolith
what do the otoconia do?
provide shear forces for hair cell deflecion
What do the otoliths do?
linear motion detection
tonic discharge
push/pull relationship
What do the semicircular canals do?
angular motion detection
tonic discharge
push/pull relationship
What does the thalamus do to contribute to postural control?
assists in discrimination between self and movement and environmental movement
multisensory integration for postural control
What does the reticular formation do to contribute to postural control?
reticulospinal tract (RST) receives inpput from all vestibular nuclei
what does the cerebellum contribute to postural controol?
interacts with LVST, MVST, RST
afferent impulse travel directly from the end organ to the cerebellum
What is the vestibular cortex
junction of parietal and insular lobe
multisensory integration of vestibular information with somatosensation and vision
What does the posterior inferior cerebellar artery (PICA) supply
the inferior vestibular nuclsupplies the inferior portion of the cerebellum
What does the basilar artery supplu
supplies the pons and more superior vestibular nuclei
What is the vestibular ocular reflex (VOR)
stabilizes gaze during head movement
VOR is intact and mature by 1 y.o.
What is the vestibulo-spinal reflex (VSR)
coordinates the head and body movements to maintain head in upright position
LVST- adjusts limb movement for balance
MVST-cervial connections, branches to extrocular muscles
What is the vestibulocollic reflex (VCR)
head righting– stabilizes the head and neck
produces coordinated movements to track a moving target
What is a whiplash injury
common with flexion extension injury
20% experience dizziness
primary symptom is neck pain
Common findings of cervicogenic dizziness
occipital or bitemporal HA
nekc pain
head is not straight
decreased ROM
dizziness
sensation of fallin
difficulty reading
feeling tired
What is cervical vertigo
dizziness — an unpleasant and vague feeling involving spatial discomfort, unsteadiness, dullness
likely a proprioceptive cervical mechanism
What are the three balance systems
somatosensory
vestibular
visual
What are the ten vestibular functional classifications?
- vestibular/somatosensory integration at rest
- canal funciton
- gaze stability
- otolish function
- impaired postural control
- ooculomotor function
- cervicogenic dizziness
- visual motion hypersensitivity
- somatosensory hypersensitivity
- head position provoked dizziness
What is the testing for vestibular/somatosensory integration at rest?
sensation of motion at rest.
sensation of motion when eyes are closed and body is stable
due to an asymmetry of info from inner ear
What is an intervention for sensation of motion at rest
settling– mathcing the vestibulat/somatosensory inputs
What is the test for canal function
head motion provioked dizziness
asymmetry of information from inner ear canals or brain
What are interventions for canal function
habituation
rolling: eyes closed supine to prone
head turns/pitch eyes closed seated
standing spinning eyes closed
chair spins eyes closed
Testing for gaze stability
VOR
head impulse test (eyes require catch up saccade to re focus)
dynamic visual acuity = gold standard (postive= >3lines of visual acuity
gaze stability with head turns (postive= blurred vision during head motion)
What is otolith function
ability to utilize gravity sense to orient position
What are otolith function test and interventions
head righting
tilt board/rocker
lateral reaching
tandem stance or tandem gait
2x4
What is impaired postural control
vestibular referencing
somatosensory referencing
visual referencing
What is impaired vestibulat referenncing
condition 4 of mCTSIB:
foam eyes closed
What is impaired somatosensory referencing
feet together eyes closed
want to observe balance stratgeies
affects ankles or input through groun
condition 2 of MCTSIB
What are interventions for impaired somatosensory referencing
weighted extremitites with function mobility
perturbations through ankles for ankle strategy– balnce rocker board
uneven surfaces
What is somatosensory reliance test?
foam feet apart, eyes opne, hands at sides
if they are stiff, holding positiong
not able to be dynamic or lose balance they are reliant on somatosensory
What is an intervention for somatosensory reliance
balance training on compliant, narrow or perturbed surface with cuing to decrease MM co-contraction
2x4 to promote hip strategy
What is impaired visual referencing for postural control test and intervention
screen oculomotor for abnormalities
intervention –REFER
What is visual relaince for postural control testins
compare feet together eyes closed to eyes open feet together test= should be similar
figur 8 test– (abnormal = sway pattern that follows thumb, indicates patient demonstrated visual dependence)
What are visual reliance for postural control interventions?
balance tasks eyes closed
walking with head turns and pitch
figure 8’s
optokinetics
What are the tests for oculomotor function
saccades
smooth pursuit
convergence/divergence
possible visual impairment
sccreen for central dysfunction causing sx
treat with testing
What are the tests for cervicogenic dizziness
body rotation under stable head
laser= joint position error test— proprioception
motor control
