*Acute neurocognitive and vestibular effects of Magnetic Resonance Imaging related magnetic fields*

Previous studies showed acute subtle detrimental neurocogntive effects of
movement in a static magnetic field of 1.5 T, 3 T and 7 T MRI scanners. In
addition, an acute effect on postural sway was observed in our previous
experiment, suggesting a change in vestibular function. These effects probably
arise due to induced electrical currents that are generated during movement in
the static magnetic fields in the vicinity of the scanners. However, it is not
clear to what extend these effects are related to the static magnetic field or
to time-varying magnetic field induced by movement in the static magnetic
field. Furthermore, effects on postural stability (vestibular functioning) have
not been shown before and should be replicated and further characterised.
Although the observed acute effects are subtle, they are relevant in clinical
practice, since for example surgeons and radiologists working close to MRI
systems need to maintain a high level of neurocognitive and postural
performance.

The main objective of this study is to gain more insight into the working
mechanism of static magnetic fields alone, as well as in combination with
movement-induced time-varying magnetic fields near MRI-scanners on
neurocognitive and vestibular performance. In addition, we will correlate
subjects* test results to the sensitivity of their vestibular system.

Double blind randomised crossover design

Subjects will be exposed to four experimental conditions; two exposure
conditions with a static magnetic field of 1.0 T at the near end of a MRI bore
(with and without additional head movements to induce time varying magnetic
fields) and two control conditions without static magnetic fields (with and
without additional head movements). The standardised short head movements will
induce time-varying fields of around 2400 mT/s in the exposure condition and 0
mT/s in the control condition. These head movements will precede each test of
the test battery.

Participants are requested to visit the UMCU on three occasions. During the
first visit there is a practice session and two test sessions where they are
subjected to test battery of 30 minutes (2 hours in total). In the second
visit, two test sessions of 30 minutes each are assessed (1.5 hours in total).
On the third day sensitivity of the vestibular system will be defined using
standard clinical tests (1 hour). Potential short-term effects of exposure such
as mild vertigo and nausea will probably last for a few minutes based on
previous experience. No long-term effects of exposure to magnetic fields and
vestibular sensitivity testing are known. A travelling allowance and a
financial gift voucher of seventy-five euros* for three completed visits will
be provided.