Effect of head pitch and roll orientations on magnetically induced vertigo.

Omar S Mian,Paul M Glover,Andre Antunes,Yan Li,Brian L Day

doi:10.1113/jp271513

Omar S Mian, Paul M Glover + Show 3 more

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https://doi.org/10.1113/jp271513

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Abstract

Key points Lying supine in a strong magnetic field, such as in magnetic resonance imaging scanners, can induce a perception of whole‐body rotation.The leading hypothesis to explain this invokes a Lorentz force mechanism acting on vestibular endolymph that acts to stimulate semicircular canals.The hypothesis predicts that the perception of whole‐body rotation will depend on head orientation in the field.Results showed that the direction and magnitude of apparent whole‐body rotation while stationary in a 7 T magnetic field is influenced by head orientation.The data are compatible with the Lorentz force hypothesis of magnetic vestibular stimulation and furthermore demonstrate the operation of a spatial transformation process from head‐referenced vestibular signals to Earth‐referenced body motion.

Highlights

It is well established that vertigo is sometimes experienced inside magnetic resonance imaging (MRI) scanners (Schenck et al 1992; Glover et al 2007; Theysohn et al 2008; Versluis et al 2013)
We will refer to the conditions according to target head orientation for the remainder of the paper
This study has shown that static magnetic fields produce non-veridical perceptions of self-motion that are significantly affected by static head orientation

Summary

Introduction

It is well established that vertigo is sometimes experienced inside magnetic resonance imaging (MRI) scanners (Schenck et al 1992; Glover et al 2007; Theysohn et al 2008; Versluis et al 2013). A number of these depend on movement or varying components of the magnetic field, such as its rate of change with respect to time and space (Glover et al 2007) These states are experienced transiently when entering and exiting the magnet, but not whilst stationary at the centre of the magnet. Roberts et al (2011) proposed an alternative mechanism for magnetic vestibular stimulation that does not depend on movement or varying components of the magnetic field They suggested that the magnetic field interacts with permanent ionic currents, which occur spontaneously in the labyrinthine endolymph, to induce orthogonal Lorentz forces that can push on a semicircular canal cupula if it is orientated appropriately with respect to the magnetic field. Movement and varying components of the field do not appear to be critical factors for other manifestations of magnetic vestibular stimulation, such as nystagmus in humans (Roberts et al 2011) and locomotor circling in rodents (Houpt et al 2007, 2011)

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