Magnetic field changes associated with caloric stimulation of the human vestibular organ

Caloric stimulation of the ear produces a shift of the vestibular resting potential. The current produced by the change in this potential produces a corresponding change in the associated magnetic field. A sensitive magnetic detector (second-derivative gradiometer) was used to detect a large shift in the magnetic field close to the ears of two normal subjects who underwent cold thermic ear stimulation. The shift in the magnetic field tracked the reflex responses in both individuals. This technique could offer a noninvasive direct measure of end-organ function.