The Massachusetts General Hospital Handbook of Neurology

2017-07-07 02:10:07

Authors: Flaherty, Alice W.; Rost, Natalia S.

Title: Massachusetts General Hospital Handbook of Neurology, The, 2nd Edition

> Table of Contents > Procedures > Caloric Testing

Caloric Testing

A. Check ears

TM perforation is contraindication. Wax can block test.

B. Tilt head

30 degrees backward in supine position. This makes horizontal canal perpendicular to floor.

P.223

C. Instill water

Use angiocath (with needle removed). Temperature should be 7 degrees above and below body temperature: wait 5 min after each. In comatose pt., use ice water.

D. Interpretation

Normal: Normally start seeing nystagmus at end of infusion or within 1 min. COWS (Cold Opposite, Warm Same) describes normal direction of the fast component of nystagmus.

Brainstem damage: Smaller or absent response on damaged side.

Inner ear dz: Smaller or absent response on damaged side.

Cerebellar dz: Fixation does not suppress nystagmus (normally does).

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