9.21 Vestibular Review Flashcards
Inhibited side resting rate reaches 0 at
180˚/s
What happens to the inhibited side when it reaches over 180˚/s?
unable to contribute information
potential causes for dizziness
- cardiovascular
- meds
- stroke
- epilepsy
- BPPV
Function of vestibular system
- balance
- equilibrium
- gaze stabilization
What is gaze stabilization?
ability to focus on an object while you’re moving your head
What are the sensory organs in the vestibular system?
hair cells
otoconia are composed of
calcium carbonate
Which organs (general) have otoconia?
gravity sensitive organs
The vestibular nerve uses this cranial nerve
CN VIII
What is the reflex we talked about?
VOR
If a pt has a peripheral vestibular problem, what are some of the vestibular symptoms that might be seen?
- dizziness
- nystagmus
- nausea
- imbalance
- difficulty with postural control
- unsteady
What is oscillopsia?
- objects in the visual field appear to oscillate
- perception that your environment/surroundings are moving when your head moves
medical causes of vestibular damage
- viral infection
- ototoxia (i.e. metal poison)
What are symptoms of CNS vestibular problems?
- disconjugate movements
- purely vertical nystagmus
- dysarthria
- numbness/tingling
- facial drooping
What is retinal slip?
- error signal
- blurred vision with head movement
Associated symptoms that go along with peripheral neuritis?
- oscillopsia
- hearing
- dizziness
Many pts with frequent inner ear infections will ℅ ________
aural fullness
CNS/VOR following injury
The CNS is able to modify the VOR after an injury
nystagmus slow phase represents:
vestibular input/stimulation
fast phase
correction of eye in orbit
Direction of nystagmus (from the peripheral system) is always:
- in the same direction
- regardless of where we gaze or position the eyeball
What happens if the pt gazes in the direction of the fast phase?
nystagmus increases
vertical nystagmus?
Peripheral nystagmus is not vertical
Is nystagmus different for each eye?
no, same in both eyes
Pts with this will avoid rapid movements to the affected side
unilateral vestibular loss
For pts with unilateral vestibular loss, can the other side give input? What is a limiting factor?
- yes
- only gives input up to a speed of 180˚/sec
- after that, they receive no more input from the unaffected side
What is needed to recalibrate the VOR?
- vision
- head movement
VOR recalibration: environment
- need different positions, light, etc.
- context dependent
What types of movements are beneficial for unilateral vestibular injury to help recalibrate the VOR?
small movements that begin to blur
