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"As shown, only visual tracking performance … differed significantly (P <.01) between different levels of static magnetic field exposure, and the magnitude of the effect also depended on the magnitude of the exposure (P <.01). Performance of the Pursuit Aiming II-test (P =.09) and the time to complete the line bisection-test (P =.06) showed a trend towards dependence on the magnitude of exposure, with borderline statistical significance. There was also a trend for the average deviance in the line bisection-test to improve with increased exposure (P =.08)....Since this and previous studies suggest that cognitive effects occur particularly in the visual sensory domain, a possible mechanism might be that the widely recognized "vertigo’’ effect of moving in a magnetic field, might interfere with the vestibulo-ocular reflex."
"As shown, only visual tracking performance … differed significantly (P <.01) between different levels of static magnetic field exposure, and the magnitude of the effect also depended on the magnitude of the exposure (P <.01). Performance of the Pursuit Aiming II-test (P =.09) and the time to complete the line bisection-test (P =.06) showed a trend towards dependence on the magnitude of exposure, with borderline statistical significance. There was also a trend for the average deviance in the line bisection-test to improve with increased exposure (P =.08)....Since this and previous studies suggest that cognitive effects occur particularly in the visual sensory domain, a possible mechanism might be that the widely recognized "vertigo’’ effect of moving in a magnetic field, might interfere with the vestibulo-ocular reflex."
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'''Yang et al 2006''' PMID 16611792
Examined vital signs (e.g. heartrate, blood pressure, oxygen saturation) on subjects (18 normal, 72 with cerebral pathologies) undergoing MR imaging in an 8T magnet. Two subjects had nausea and vomiting.
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After imaging, however, some subjects still reported transient nausea vertigo, and unusual metallic taste in the mouth, especially upon the entering and/or exiting of the magnet. These phenomena have been reported since the introduction of first 4 T system, as well as previous normal subject studies on 8T, and have been found to disappear rapidly after subjects leave the magnet.The mechanisms of these phenomena are based on the influence of induced magnetohydrodynamic (MHD) forces on the inner ear and electric currents introduced on the surface of the tongue. In general, these phenomena should be regarded as unavoidable, though they can be minimized, and patients should be given detailed explanation before imaging to alleviate any anxiety associated with these sensations. Two subjects [out of 92 subjects] vomited immediately after scanning. Had vomiting occurred during scanning, aspiration would have occurred. If a subject is found to be experiencing significant nau-sea while in the scanner, the imaging procedure may need to be terminated immediately and the subject carefully removed from the magnet to avoid such a circumstance.
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'''Glover et al 2007''' PMID 17427890
Nice discussion of mechanisms and effect of magnetic fields on otoconia. Thorough psychophysics of both changing magnetic fields around a static subject, and of head movements inside a 7 T magnet.