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MBME 5 Q


One week history of feeling dizzy, warm water instilled into left ear elicits nystagmus with a quick phase to the left. Warm water instilled in to the right ear elicits no eye movement. Where is the lesion?

A. Left frontal eye fields
B. Right frontal eye fields
C. Left pontine gaze center
D. Right pontine gaze center
E. Left vestibular apparatus
F. Right vestibular apparatus

FF

Thank you.

is it f?

right

Can you explain please ?
I'm thinking of (D), as I know that Caloric test use to test for Brain stem integrity.
Confused ?

caloric test: stimulate horizontal semicircular duct.
use to detect brain stem function usually in (unconscious pt ):
normally irrigation of ear with water cause nystagmus in which side?
warm: in same side
cold: in opposite side ,(kaplan mnemonic COWS Cold Opposite Warm Same)

thanks sarim

Good question. Good explanation.

See there is a neumonic
COWS
COLD WATER OPPSITE SIDE
WARM WATER SAME SIDE

Since it's warm water is used and only left ear shows nystagmus so
It will OPP to COWS NEUMONIC hence right ear is involved
So rt vestibular apparatus

Sorry instead of *opp I should have written *ACC TO COWS
NEUMONIC

I have a doubt in this question.. If warm water effects same side (fast component towards same side) acc to COWS neumonic then it should be left vestibular apparatus defect? plz someone explain?