Vestibular System Flashcards
Describe the vestibulo-ocular reflex (VOR)
What are the tests in the VNG battery?
How are vertical eye movements recorded?
How are horizontal eye movements recorded?
How is nystagmus recorded?
What is the role of the vestibular system in balance maintenance?
T/F: The maculae contain otoconia
True
T/F: Type I hair cells are only in the cristae
False - both the maculae and cristae
T/F: The crista contain cupola
True
T/F: Supporting cells are in the maculae and cristae
True
T/F: the cristae respond to gravity
False - maculae responds to gravity
T/F: the maculae responds to head tilts (being in tilted position, not tilting motion)
True
T/F: the maculae responds to head turns
False - crista responds to head turns
When the __________ canal is excited, the _____________ canal is inhibited
right anterior
left posterior
Eye movements are innervated by which cranial nerves?
CN III
CN IV
CN VI
CN V
Where is CN III located?
midbrain
Where is CN VI located?
pons
Where is CN VIII located?
Pons, Medulla
What information is integrated for balance?
- Vestibular system
- Visual input
- Somatosensory receptors
- Hearing
What is the purpose of VOR?
Maintain a gaze on a fixed target while the head moves. The eyes move in the opposite direction of the head movement.
If one’s right vestibular organ stops working, when the person tries to stand straight, what will happen?
Lean or fall to the right
If one’s right vestibular organ stops working, what will you observe re: eye movements?
Left beating nystagmus
Eyes will pull to the right since the slow phase moves toward the vestibular system that is weak/affected
How is eye position graphed?
jagged lines
How is eye velocity graphed?
dots
T/F: Eye velocity is calculated for the fast phase
False - eye velocity is calculated for the SLOW PHASE
Describe an optokinetic test
A series of dots or the entire visual field moving across the front of the testee
Describe a saccade test
A dot jumps randomly. Testee needs to follow with their eyes.
Descrive a gaze test
Dot stays still; testee stares at it
Describe spontaneous nystagmus test
Vision is denied
Describe smooth pursuit test
Dot moves back and forth
Describe a positionAL test
Static
Examines effect of gravity on specific head orientation
Nonlocalizing finding on its own
Describe a positionING test
Dynamic
Examines effect of a specific head movement
Identifies BPPV
Which direction should you expect with right warm irrigation?
Right beating nystagmus
Which direction should you expect left warm irrigation?
Left beating nystagmus
Which direction should you expect right cool irrigation?
Left beating nystagmus
Which direction would you expect left cool irrigation?
Right beating nystagmus
Provide two examples of symptoms (sensations) that a patient with a peripheral pathology is most likely to present
- Vertigo after head position changes
2.
Provide two examples of symptoms (sensations) that a patient with a central pathology is most likely to present
- Abnormal smooth pursuit (jagged eye movements; not smooth)
- Nystagmus remains when trying to fixate on an object (cannot suppress nystagmus)
Name two tests of VOR functions
- Rotational chair
2.
