9.19 Vestibular (Big Concepts) Flashcards
Example of partial redundancy of the balance system
co-planar pairing
How do the paired SCC act together?
push - pull
Orientation of canals: wall
Stand at 45˚ to corner, chin slightly tucked:
- wall you’re facing = anterior canal
- wall behind = posterior canal
- floor = horizontal canal
What is the coplanar pair to the right posterior canal?
L anterior canal
What is the coplanar pair to the left anterior canal
R posterior canal
Quick head turn to R:
Fluid in R horizontal SCC
moves toward midline
Quick head turn to R:
Firing rates on R and L sides
R: firing rate goes up
L: firing rate goes down
Quick head turn to R:
eye movements
Eyes move left (equal and opposite direction)
Sustained spinning to R: endolymph movement
moves relatively toward midline (to L)
phases of peripheral nystagmus
- slow phase
- fast phase
Which phase is the VOR?
slow phase
fast pase is this type of movement
corrective
nystagmus aka
uncontrolled VOR
What is nystagmus?
- rhythmic, uncontrolled eye movement
- slow phase followed by a fast phase in the opposite direction
vascular supply of the peripheral system
NO collaterals to the peripheral system
only takes 5-15 seconds to cause damage
What are characteristics of a peripheral vestibular lesion?
- presence of nystagmus in the absence of visual fixation COMBINED WITH
- absence of nystagmus in the presence of visual fixation
Most common cause of dizziness in general population
cardiovascular
Most common PT presentation of dizziness
BPPV
Most common type of BPPV
posterior canal
2 causes of BPPV
- cupulolithiasis
- canalithiasis
cupulolithiasis
otoconia adhered to cupulae
canalithiasis
free floating otoconia in SSC
How does a pt present with complete bilateral vestibular loss?
- NO dizziness
- DO have a lot of instability
How to try to narrow down symptoms to diagnose?
- timing of symptoms
- circumstances which trigger symptoms
- associated symptoms
