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added Patel and Theysohn refs
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'''de Vochet et al 2007''' PMID 17290435
'''de Vocht et al 2007''' PMID 17290435
Subjects seated right outside a 7T MRI machine to assess effects of stray field on neurobehavioral tests; highest exposure was 1.6 - 2.0 T (but a very high gradient). Deficits in visual tracking were found after head movements in the stray field, which might be secondary to vestibular effects (although no vertigo is reported in this paper).
Subjects seated right outside a 7T MRI machine to assess effects of stray field on neurobehavioral tests; highest exposure was 1.6 - 2.0 T (but a very high gradient). Deficits in visual tracking were found after head movements in the stray field, which might be secondary to vestibular effects (although no vertigo is reported in this paper).
'''Glover et al 2007''' PMID 17427890
'''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.
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. Subjects moved at 0.1 m/s into 7T MRI machine. WHen at center, asked to slowly nod or rotate heads axially (30 s per movement, with 1 min rest period). Head movements while in the field induced mild to severe vertigo.
2 subjects reported subjective movement into magnet, so were inserted into magent from opposite direction -- apparent motion was reversed. (Consistent with reversal of current flow).
'''Patel et al 2008''' PMID 18469627
Evaluated nystagmus with EOG, postural testing, caloric function at 30 min or 3 month after working for 30 min in room with 9.4 T MRI machine (i.e., not clear if exposed to 9.4T for entire 30 minutes). Workers around 9.4 T MRI machine consistently reported "illusions of movement", but other vestibular tests were normal. No apparent correlation with time since last exposure to 9.4T, and no control group.
'''Theysohn et al. 2008''' PMID 18064501
Survey of 102 subjects 7T MRI of head, extremities or breast. In 43 of subjects, also compared to 1.5T scan. Subjects introduced to scanner either head-first or feet first. patient table was moved slowly by hand. Over 25 % reported vertigo while moving into the MRI machine, with very few sensations reported when motionless in the center of the scanner. Vertigo much more common when subjects were moved head-first into the MRI machine (the head only advances to 2-3T field). Also 48/100 subjectes experienced "vertigo, tottering, or sleepiness" when leaving the 7T scanner room.
[[Category:Magnetic Fields]]
[[Category:Magnetic Fields]]