Calorics Flashcards
What is the goal of calorics?
Discover the degree where the vestibular system is responsive and how symmetric the responses are between L/R ears.
Which vestibular structures does calorics test?
- Lateral semicircular canals
- Superior nerve branch pathway alone
What does calorics not assess?
- The vertical canal
- Otolithic Function
What does caloric test provide?
Low frequency ear specific information due to the cupula deflecting
What kind of vestibular test is calorics? And what is the labyrinth sensitive to?
Peripheral vestibular test
Sensitive to temperature change
What does warm stimulation cause?
Excitation of the SCCs
What does cold stimulation cause?
Inhibition to SCCs
For caloric testing, why are patients placed in a dark room?
To eliminate fixation to accentuate peripheral vestibular nystagmus
For caloric testing, what does the change in temperature in the EAC cause?
Change in temperature in the EAC is sent to the horizontal canal since it’s closest to the TM of the EAC
For calorics, what is the flow of irrigation?
1st ear canal is irrigated —> Promontory —> Distal portion of H-SCC
For calorics, how should the pt be positioned?
- Reclined
- Head inclines at 30 d/s
For calorics, what are the temperatures for water?
It needs to be 7 d/s above or below 37 d/s (body temperature)
• Warm = 44 d/s
• Cold = 30 d/s
For calorics, what are the air temperatures?
It needs to be 13 d/s above or below 37 d/s (body temperature)
• Warm = 50 d/s
• Cold = 24 d/s
What does warm/cold air or water cause for calorics?
It causes a temperature gradient across the H-SCCs
Due to the flow of gravity, what happens to the endolymph in relation to temperature?
Gravity causes the endolymph to flow from the cooler area in the ear canal, to where the endolymph is more dense and then it’ll flow into the warmer area of the canal that is less dense.
