Anatomic Variations in Temporal Bones Affect the Intensity of Nystagmus During Warm Caloric Irrigation.

Hypothesis: Anatomic variables within the mastoid will correlate with intensity of caloric responses.

Background: During caloric irrigation, heat is transferred from the external auditory canal to the lateral semicircular canal (LSCC) through aerated mastoid bone. Temporal bone airspace volume and bone volume vary widely but the effect of this variation on caloric irrigation testing is not well characterized.