Caloric test intent to induce horizontal nystagmus. Nystagmus is characterised by the slow movement of the eyes to one direction followed by fast saccade towards the opposite direction. The direction of nystagmus is usually determined by the direction of this fast saccade (and not by the direction from the initial slow movement). When cold water is inserted into the left ear, the eyes will move slowly to the left, but followed by a fast saccade movement to the right. The reason for COWS is hence because the direction to where the eyes quickly move to (in this case towards the right) to correct for the initial left movement determined the final direction of the nystagmus. Hence Cold - Opposite
Thank you, can you do more? A lot of resources/professors just tell us what the test indicates but doesn't explain the circuit like this. This helps a lot.
Agreed. There's not so much a misconception as a discordance with what people are talking about. COWS is referring to direction of nystagmus, which is opposite to the slow phase drift. Cold inhibits the canal, and causes a drift towards the tested ear and a fast phase saccade (nystagmus) away - or towards the opposite side (CO), whereas warmth causes a stimulation, subsequent slow phase away from the tested ear, but a corrective saccade (nystagmus) back to the same ear (WS). Hence COWS. The author was just referring to the slow phase rather than the saccade, so as long as you have the connection of COWS = nystagmus (or WOCS = slow) , then either way is a correct way to conceptualise it.
Thanks a lot this cleared my confusion. In harrison they have not elaborated it properly made me even more confused. COWS is for nystagmus CSWO for eye movement.
what I want know is; how temp water is able to influence endolymph given it only reaches the ear drum & is separated by ossicles. is it the surrounding external canal that warms up & heats the surrounding tissue that heats it?
This video is really helpful thank you so much. Can you make a video on what will happen if there is a lesion on the Vestibular nuclei or Vestibular nerve.
This video is awesome, great explanation. I have one question tho. Cold water sinks and warm water rises, I didnt really get how that affects the movement of endolymph. Can you elaborate please? Does that mean that cold water makes endolymph more dense and dense doesnt move as fast as warm endolymph? even if so, why does it make a change if we dont actually move, because endolymph doesnt move unless acceleration occurs right? How will warm endolymph start to move with no change in heads position. Im sorry if this is a stupid question, Im not good with physics xD
A whole year since your comment but i hope it'll still be useful, by introducing cold or warm water into the external ear canal, we decrease the temperature of the otherwise less warm or less cold (depends on the chosen water temperature) endolymph, which in turn creates a convective current, pushing colder layers of endolymph down or bringing hotter layers of endolymph up, thus creating enough motion to either hyperpolarize or depolarize hair cells by compressing or stretching tip-links of kinocilium.
So the initial movement which is CSWO wasnt a Nystagmus, but the second corrective movement is a Nystagmus with COWS mnemonic, and it moves with fast saccadic movement ?
So this is testing the Vestibular Ocular Reflex, and CSWO refers to this, while COWS refers to the nystagmus? How does this relate to the terms "left-beating" and "right-beating nystagmus"?
anyone had this test done and have vertigo for days after? mine isnt severe but ive got a rotating sensation, floor moving, fatigue..... its been 4 days im so scared its permanent
Can you explain why a physician does this rather than a nurse? Is it simply because a nurse cannot diagnose brain death? Or can you cause harm by doing this on someone? I’m guessing it is the former and not the latter.
Nurses can diagnose brain death. Usually, it's under the supervision of a physician. The diagnosis of brain death can be done by others than just a doctor but the law varies on where you are. This is more of a legal thing.
Shvan Jalal cows basically stands for the nystagmus, the fast component, which means when I use cold water to normal person the eyes will deviate to the side of irrigation , now right after deviation it will go back to midline (NYSTAGMUS) , that’s why they say cold linked with opposite , the opposite is nystagmus , not the initial eye movement keep in mind . So cows for normal person for the NYSTAGMUS
Dear,I understood it ,thank u for repetition, but My question was that (If the COWS is using for testing the normal person to see what happen in nystagmus patient ) or ( COWS is using for nystagmus patient ) ,, I think it must use for normal person 🌹
Shvan Jalal we don’t use cows generally to a normal person but , a person is comatose then this maneuver is performed to see cranial nerve 3-6 , if patient cranial nerves are damaged then it would be CSWO for the nystagmus.
That indicates brainstem lesion as there is a impairment of cranial nerve 3-6 , used for extraoccular muscles. If person is comatose , and this maneuver is showing CSWO for the NYSTAGMUS then you suspect lesion in brainstem :)
![Caloric test [Essential medicine]](http://i.ytimg.com/vi/6F1sSfGnTXk/mqdefault.jpg)
![Caloric test [Essential medicine]](/img/tr.png)
Caloric test intent to induce horizontal nystagmus. Nystagmus is characterised by the slow movement of the eyes to one direction followed by fast saccade towards the opposite direction. The direction of nystagmus is usually determined by the direction of this fast saccade (and not by the direction from the initial slow movement). When cold water is inserted into the left ear, the eyes will move slowly to the left, but followed by a fast saccade movement to the right. The reason for COWS is hence because the direction to where the eyes quickly move to (in this case towards the right) to correct for the initial left movement determined the final direction of the nystagmus. Hence Cold - Opposite
Can you tell me which will be the diseased vestibular system in this case?? Will it be the right vestibular system??
Thank you! Helped me put all the pieces together
So finalllyyy after watching thousands of videos on the same concept! This one helped. A BIG THANKSS!
My neuro exam is in a few days, and your explanation FINALLY made this concept make sense. THANK YOU!
Thank you, can you do more? A lot of resources/professors just tell us what the test indicates but doesn't explain the circuit like this. This helps a lot.
sure thing
Thank you for explaining everything so clearly. And special thanks to explaining the acronym (which made no sense to me until you explained it)
this just made me understand the whole concept of the caloric test!!!! TY sir! ur a life saver
Happy to help!
Finally, FINALLY understood this concept. Thanks so much
So what I understood from this video is: initially->CSWO, when the test is done->🐄. COWS.
Thanks for correcting the misconception.
Doctor H there is no misconception. Cold opposite or warm same refers to the nystagmus, not the direction of gaze
Agreed. There's not so much a misconception as a discordance with what people are talking about.
COWS is referring to direction of nystagmus, which is opposite to the slow phase drift.
Cold inhibits the canal, and causes a drift towards the tested ear and a fast phase saccade (nystagmus) away - or towards the opposite side (CO), whereas warmth causes a stimulation, subsequent slow phase away from the tested ear, but a corrective saccade (nystagmus) back to the same ear (WS). Hence COWS.
The author was just referring to the slow phase rather than the saccade, so as long as you have the connection of COWS = nystagmus (or WOCS = slow) , then either way is a correct way to conceptualise it.
Thank you for this clear explanation, I've been reading and searching it everywhere and finally understood it here. So, thanks
Thanks a lot this cleared my confusion. In harrison they have not elaborated it properly made me even more confused. COWS is for nystagmus CSWO for eye movement.
You make it so easy to understand. Thank you so much!
Excellent explanation! thanks !
Thank you sir for this really convincing explanation of such an intricate mechanism
Great Explanation !
Best explanation 🙏🏻🙏🏻🙏🏻
Thanx
thankyou sir for making this concept crystal clear.
very clear explanation that made me finally understand the whole COWS thing!
Amazing explanation 👍🏼
Perfectly explained 🌺
great job explaining it so simply. Thank you!
happy to help :)
thank you so much!! you explained the concept so clearly :D
Thanks...very....useful...👍🏻
CSWO Is normally initial eye movement. Vestibular ocular reflex?
And COWS is for nystagmus?
Yes. CSWO for SACCADIC MOVEMENT ie the initial eye movements and COWS is for the nystagmus that follows it.
Yes
Your explanation was really clear and helpful, thank you
what I want know is; how temp water is able to influence endolymph given it only reaches the ear drum & is separated by ossicles. is it the surrounding external canal that warms up & heats the surrounding tissue that heats it?
Great 😎
Thanks bro. You are a life saver!👊
no problem bro !
This video is really helpful thank you so much. Can you make a video on what will happen if there is a lesion on the Vestibular nuclei or Vestibular nerve.
thank you, this helps so much~!
What a great video!! thank you
Very nice explanation! Is it possible to receive the source or reference of the images used?
not sure where I put the file. Screenshot and reverse google image search is your best bet.
Great video
Thanks! Easily understood
Awesome
thank you!! perfect explanation
thanks a ton. this really helped out.
something difficult made so easy to understand!
Thank u that hepled me a lot.u made my day
Thank u very much❤️❤️❤️
wow this was so great thank you seriously
This video is awesome, great explanation. I have one question tho. Cold water sinks and warm water rises, I didnt really get how that affects the movement of endolymph. Can you elaborate please? Does that mean that cold water makes endolymph more dense and dense doesnt move as fast as warm endolymph? even if so, why does it make a change if we dont actually move, because endolymph doesnt move unless acceleration occurs right? How will warm endolymph start to move with no change in heads position. Im sorry if this is a stupid question, Im not good with physics xD
A whole year since your comment but i hope it'll still be useful, by introducing cold or warm water into the external ear canal, we decrease the temperature of the otherwise less warm or less cold (depends on the chosen water temperature) endolymph, which in turn creates a convective current, pushing colder layers of endolymph down or bringing hotter layers of endolymph up, thus creating enough motion to either hyperpolarize or depolarize hair cells by compressing or stretching tip-links of kinocilium.
Great work (y)
So the initial movement which is CSWO wasnt a Nystagmus, but the second corrective movement is a Nystagmus with COWS mnemonic, and it moves with fast saccadic movement ?
yup
Thank you very much:)
skip to 5:10 for explanation
Thank you very much
Perfect.
beautiful!
So this is testing the Vestibular Ocular Reflex, and CSWO refers to this, while COWS refers to the nystagmus?
How does this relate to the terms "left-beating" and "right-beating nystagmus"?
left and right beating just refers to the initial deviation the nystagmus is the corrective movement.
Thanks a lot :)🙏🏾
Thank u!🙏
I love you man
please tell me .. COWS is right for normal person ( without nystagmus) or for a patient who suffers with nystagmus ???
COWS refers to the nystagmus not the eye movement seen in the test.
The direction of nystagmus is defined by the fast component. Thus COWS hold true.
that's what I said in the video
THANK YOU!
Seems you're going to get the same results as with a well performed head impulse test.
anyone had this test done and have vertigo for days after? mine isnt severe but ive got a rotating sensation, floor moving, fatigue..... its been 4 days im so scared its permanent
So this test would not be appropriate or necessary for a conscious patient, correct?
yes
Wait what.. why?
You don't need subscribe only , you have to be paid , thanks a punch
oh i finally get this
Can you explain why a physician does this rather than a nurse? Is it simply because a nurse cannot diagnose brain death? Or can you cause harm by doing this on someone?
I’m guessing it is the former and not the latter.
Nurses can diagnose brain death. Usually, it's under the supervision of a physician. The diagnosis of brain death can be done by others than just a doctor but the law varies on where you are. This is more of a legal thing.
thx so clear now
Thanks brother
Nimesh Parmar can you tell me the COWS is right for normal person of for a patient with nystagmus ?
Shvan Jalal cows basically stands for the nystagmus, the fast component, which means when I use cold water to normal person the eyes will deviate to the side of irrigation , now right after deviation it will go back to midline (NYSTAGMUS) , that’s why they say cold linked with opposite , the opposite is nystagmus , not the initial eye movement keep in mind . So cows for normal person for the NYSTAGMUS
Dear,I understood it ,thank u for repetition, but My question was that (If the COWS is using for testing the normal person to see what happen in nystagmus patient ) or ( COWS is using for nystagmus patient ) ,, I think it must use for normal person 🌹
Shvan Jalal we don’t use cows generally to a normal person but , a person is comatose then this maneuver is performed to see cranial nerve 3-6 , if patient cranial nerves are damaged then it would be CSWO for the nystagmus.
That indicates brainstem lesion as there is a impairment of cranial nerve 3-6 , used for extraoccular muscles. If person is comatose , and this maneuver is showing CSWO for the NYSTAGMUS then you suspect lesion in brainstem :)
How water reaches inner ear , i mean there is a tympanic membrane in between? Can someone explain plz
the water does not reach the inner ear it just heats or cools the fluid already there
Cows is too confusing
Thanks for explanations
yup there are plenty of silly terms in medicine that make no sense
Cold opposite, warm same refers to the direction of nystagmus.
Thanksssssss
your weeeeelcome
thanks
Thank u sir
Treatment also apprise
Hi after this test i have pain in my ear 7days untill now ?
see your doctor
G.O.A.T
hey guy. thank you....freaking COWS.
np friend
One of the worst feelings in the world
Thank you very much