icarus
Forum Senior
Topics: 27
Posts: 149
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I Have a question regarding the cold/warm water test ( to check for the integrity of the vestibulo-ocular reflex ) :
The textbooks says that we administer cold water into the right external ear ( for example ) ; the cold water exerts an inhibitory effect on the flow of the endolymph in this side, which, in turn, inhibits the Right Hair Cells (Vestibular Nerve Receptors), and in consequence, the Right Vestibular Nucleus, thus, the Left Vestibular Nucleus, now that is liberated from the (Inhibitory effect) of the Right VN, acts as if it is stimulated (And this stimulation implies that the head is turning to the Left ) and causes the eyes to move slowly (Slow phase of the Nystagmus) to the right, HOWEVER ( AND HERE IS WHY I AM CONFUSED ) the textbooks dictates that a Rapid CORRECTIVE movement of the eyes occurs to the LEFT ( because the head is not moving, and we only administered water ), which produces the Left Nystagmus (A nystagmus is named after the direction of its RAPID phase)
My question is the following :
If the first stimulator of this whole cascade (which is the INHIBITION the right hair cells, and thus the assumption that the right side is DAMAGED), how come a corrective action is taking place with no consideration to the previously mentioned assumption ?
I hope that you would help me figure this out guys, because I am really confused …
Thank you so much for your patience and help.
Kind regards,
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The Maestro says its Mozart...but it sounds like bubble gum
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| mildus
Forum Guru
Topics: 19
Posts: 614
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Sorry, I wouldn't go into physiological details since it is rather complicated and I can't keep it in my mind all the time, I only know as a mnemonic that eyes run away from the cold water and it is opposite for hot water.
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