Postural Instability Induced by Visual Motion Stimuli in Patients With Vestibular Migraine

Abstract

Patients with vestibular migraine are susceptible to motion sickness. This study aimed to determine whether the severity of posture instability is related to the susceptibility to motion sickness. We used a visual motion paradigm with two conditions of the stimulated retinal field and the head posture to quantify postural stability while maintaining a static stance in 18 patients with vestibular migraine and in 13 age-matched healthy subjects. Three parameters of postural stability showed differences between VM patients and controls: RMS velocity (0.34 ± 0.02 cm/s vs. 0.28 ± 0.02 cm/s), RMS acceleration (8.94 ± 0.74 cm/s2 vs. 6.69 ± 0.87 cm/s2), and sway area (1.77 ± 0.22 cm2 vs. 1.04 ± 0.25 cm2). Patients with vestibular migraine showed marked postural instability of the head and neck when visual stimuli were presented in the retinal periphery. The pseudo-Coriolis effect induced by head roll tilt was not responsible for the main differences in postural instability between patients and controls. Patients with vestibular migraine showed a higher visual dependency and low stability of the postural control system when maintaining quiet standing, which may be related to susceptibility to motion sickness.

The neural basis of motion sickness

“…Similar findings were recently demonstrated by Lim et al (2018), in a combined postural and visual motion study. Vertical movement of horizontal lines in the peripheral visual field, but not the central visual field, caused significant motion sickness and imbalance.…”

“…At first inspection, these visually induced cases of motion sickness would appear to invalidate the Bles-Bos hypothesis, or to seriously weaken it. However, as recently demonstrated by Lim et al (2018) in a study of central and peripheral exposure to horizontal lines oscillating vertically, there may be other ways to interpret the Golding et al data. In the Lim et al study, presentation of vertically oscillating horizontal lines did not cause motion sickness when presented in frontal, foveal vision, but it did do so when presented to the visual periphery.…”

“…One possibility is that the vertical oscillation in the periphery was perceived internally as part of a larger oscillation in roll, centered about the naso-occipital axis. If this speculation is correct, the Golding et al (1995) and the Lim et al (2018) results support, not deny, that oscillation in roll is critical for generating motion sickness, although oscillation of the background in pitch can also produce the disorder.…”

“…If one takes Lim et al's results into account, they show that vertical oscillation of horizontal lines does not cause motion sickness when presented in the central visual field, but they have a potent effect on generating motion sickness when presented in the periphery (Lim et al 2018). If one asks what is the peripheral visual stimulus telling the brain?…”

Vestibular migraine — an underdiagnosed cause of vertigo. Diagnosis and treatment

“…Moreover, patients with VM have shown compromised body balance in static posturography tests, and higher visual dependency and low stability of the postural control system when maintaining quiet standing [67,76]. Brain MRI is unremarkable in VM sufferers, although some studies found that grey matter volume of some brain regions of patients with VM is significantly larger than in patients with migraine or healthy controls, mostly areas linked with assessment, integration and pain expectations as well as those associated with mood and anxiety [16,77].…”