Vestibular migraine (VM) differs from migraine without vestibular symptoms in regard to mild and low frequency roll tilt (of the head) perceptual thresholds, a study in Science Reports suggests.
The study enrolled patients with VM, measuring the frequency-dependence of self-motion perceptual thresholds during movements. These movements were designed to activate the canals and otolith organs both together and in isolation.
In patients with VM, the researchers observed abnormally low below-0.5-Hz roll tilt thresholds. Roll rotation and interaural translation thresholds in these patients were considered normal. Patients were divided into 2 clusters on the basis of analysis of the 2 limbs separately: VM1 and VM2 clusters.
In the first cluster, positive correlations were observed between thresholds and symptoms and the vestibulo-ocular reflex time constant. In the second cluster, thresholds were low and were independent of the time constant and symptoms. There was a demonstrated frequency-dependence of the VM threshold abnormality paralleling the brain stem velocity storage mechanism. The researchers also found that roll tilt perceptual thresholds in VM are not attributable to migraine and/or not primarily a result of vestibular symptoms. Overall, these thresholds “reflect abnormal integration of canal and otolith information in the brain.”
A total of 12 patients participated in this study, possibly limiting the generalizability of these findings across a wider patient population.
According to the investigators, the findings from this study “support a pathogenic model where vestibular symptoms emanate from the vestibular nuclei, which are sensitized by migraine-related brainstem regions and simultaneously suppressed by inhibitory feedback from the cerebellar nodulus and uvula, the site of canal-otolith integration.” The researchers also suggested that the findings from this study provide evidence for a likely VM perceptual biomarker.