Magnetic Vestibular Stimulation

Abstract

Strong static magnetic fields such as those in MRI machines can induce vertigo and nystagmus. The mechanism is a Lorentz force, generated in the inner ear fluids of the labyrinth by the interaction between normal ionic currents entering into labyrinthine hair cells and the strong static magnetic field of the MRI machine. The Lorentz force is constant and displaces the cupulae of the semicircular canals to a deviated position, simulating a response to a constant acceleration of the head with its consequent sustained nystagmus. The Lorentz effect scales with the strength of the magnetic field, but is not harmful, except for inducing transient dizziness and nausea. Magnetic vestibular stimulation (MVS) has implications for studies of vestibular physiology and adaptation, the interpretation of functional MRI studies, and human safety when undergoing diagnostic imaging studies.