Researchers recruited 20 migraine patients from a university hospital headache clinic and 20 healthy controls from the community. All participants completed an experiment that exposed them to a virtual roller coaster during functional MRI (fMRI). The virtual roller coaster rides had blocks of randomly generated sequences of motion stimulation as well as low speed upward motion.
Participants rated their perceived level of motion sickness and vestibular symptoms during exposure to the virtual roller coaster and again after the experiment ended.
None reported experiencing migraines during the experiment. However, more migraine patients than controls (65% vs 30%) reported dizziness, and migraine patients also had more motion sickness based on simulator sickness questionnaire (SSQ) scores (47.3) than controls (24.3).
"Indeed, migraine patients reported more dizziness and motion sickness as well as longer symptom duration and intensity in a virtual roller coaster ride and the brain of migraine patients reacted differently," said senior study author Dr. Arne May of University Medical Center Eppendorf in Hamburg, Germany.
"We found differences not just in behavioral results but also in specific activations of areas within the cerebellum and the frontal gyrus," Dr. May said by email. "Migraine patients process such visual input differently from controls and activate a specific brain network to do so."
Migraine patients also reported longer symptom duration (1.19 vs 0.27 minutes) than controls, as well as higher intensity symptoms, researchers report in Neurology.
The fMRI results also revealed changes in nerve cell activity based on blood flow to certain areas of the brain. People with migraine had increased activity in five areas of the brain, including two areas in the occipital gyrus, which is tied to visual processing, and two other areas including the middle frontal gyrus.
Participants who experienced these changes in the brain also had higher motion sickness and migraine disability. This suggests abnormal processing of visual motion stimuli in the brain was linked to migraine disability and more susceptibility to motion sickness, the researchers conclude.
One limitation of the study is that its small sample size made it impossible to identify significant differences between migraine patients with and without aura, the study team notes.
Even so, the findings build on previous studies that documented more issues with balance in patients with migraines, even when they are not actively experiencing a migraine, said Dr. Heidi Schwartz, a professor of clinical neurology at the University of Rochester Medical Center in New York. The results also aren't surprising given that migraine patients often experience car sickness during childhood, Dr. Schwartz, who wasn't involved in the study, said by email.
"In essence, a virtual roller coaster mimics car sickness in that the individual is stationary but the visual input is moving so there is a mismatch between visual cues and vestibular input," Dr. Schwartz said.
Beyond this, the fMRI data showing not only differential activation between migraineurs and controls in the occipital, pontine and some cerebellar regions but also the functional connectivity between these areas provides a scientific explanation for this enhanced response among migraine patients, Dr. Schwartz said.
"There is a tendency to dismiss symptoms that occur between attacks as something other than migraine," Dr. Schwartz said. "However, presence of these symptoms of motion sickness or dizziness between attacks might be better managed by migraine treatments, especially those aimed at migraine prevention rather than vestibular suppressants such as meclizine."
SOURCE: https://bit.ly/3x1kJXE Neurology, online July 21, 2021.
By Lisa Rapaport
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