Vestibular Stimulation in Humans by Static Magnetic Fields of A 3T MRI Scanner – A Pilot Study

Background: The presence of vertigo and nystagmus in high magnetic field opens up the possibility of using such a stimulation for clinical purposes. OBJECTIVE: The aim of this study was to test the possibility of vestibular activation, expressed by nystagmus, using a custom clinical MRI scanner. Methods: Twelve volunteers were included. The right eye gaze location was recorded during introduction of the subject to the 3T MRI scanner's bore and during a similar movement outside the MRI suite. From the raw data from eyetracker Arrington, deviation angles of gaze and angular velocities and another parameters of nystagmus were calculated. Results: All subjects presented the changes in eye movements direction and strength during introduction to the scanner. In control conditions, obtained nystagmus was predominantly vertical- this domination disappeared in magnetic field. The results presented a significant inter-subject variability. Movement on the scanner's table resulted in a larger and faster change in the pupil's position in X and Y axes (P<0.02). Compared to standard conditions, magnetic field tended to stabilize the movement in Y axis (P<0.02). Statistical analysis showed that during 120 s of observation, the maximal nystagmus was noted in 52,2s; the minimal in 71,6s. Nystagmus did not disappear, its frequency was 0,45. The direction of nystagmus in MRI was predominantly horizontal. Conclusions: Introduction of healthy individuals into an MRI scanner during custom clinical conditions results in a vestibular activation that is different from the same movement outside artificial magnetic field. However, the reaction presents a significant inter-subject variability.