Lecture 21 Flashcards
What does galvanic mean?
- Constant Current
What is Galvanic Vestibular Stimulation used for?
- Detect vestibular deficiency
- Activate vestibular system artificially
What does Galvanic Vestibular Stimulation mean?
- Constant current of vestibular system using electrodes placed over mastoid process
What happens in a healthy individual when you place electrodes over the mastoid processes?
- the current messes with the vestibular system
What is located under the mastoid process?
- Cranial Nerve XIII
What does cathode stimulation do using galvanic vestibular stimulation?
- Increases firing of peripheral vestibular afferents
What does the anode do during galvanic vestibular stimulation?
- Decreases firing of peripheral vestibular afferents
What happens as a result of galvanic vestibular stimulation?
- Distinct sway towards the anode side
- More pronounced with eyes closed
- Causes roll of segments relative to each other
- Ocular torsion with eyes open
What happens when you remove the stimulus of a galvanic vestibular stimulation?
- Returns back to background discharge
What happens when you change the current of the electrical perturbations of a galvanic vestibular stimulation?
- more current: get more modulation
- creates artificial change to the vestibular firing rate
Why would you use Galvanic Vestibular Stimulation?
Test Vestibular System
- Creates temporary/distinct vestibular perturbation
- Magnitude and duration are easily controlled
- GVS results in predictable and well-documented postural response
What do you look for when testing the vestibular system using galvanic vestibular stimulation?
If working properly
- Sway toward anode side
- Ocular torsion with eyes open
If not working
- No response
When do we pay more attention to the vestibular system than the visual input?
- When the eyes are closed
What happens if the anode is on the right ear during galvanic vestibular stimulation?
- Sway to the right
What is the roll illusion of galvanic vestibular stimulation?
- Where the somatosensory system thinks the head is