Nausea, dizziness often neglected
Baseline prevalence of vestibular symptoms was 75% in the migraine group and 5% in the control group (P < .0001). These symptoms included dizziness (60% and 5%, respectively; P < .0001) and postural symptoms (40% and 0%, respectively; P = .003).
At baseline, vestibular symptoms were more frequent (P = .001), more intense (P < .0001), and were associated with greater disability (P = .001) in patients with migraine, compared with participants without migraine. The patients with migraine were also more susceptible to motion sickness (P = .02) and had higher depression scores (P = .001).
During the roller-coaster simulation, dizziness was more prevalent among patients with migraine than among those without migraine (65% vs. 30%; P = .03). Patients with migraine also reported more motion sickness (SSQ score, 47.3 vs. 24.3; P = .004), longer symptom duration (1:19 minutes vs. 00:27 minutes; P = .03), and symptoms of greater intensity (VAS, 22.0 vs. 9.9; P = .03).
Brain activity also differed between groups. Among patients with migraine, neuronal activity was greater in clusters within the right superior and left inferior occipital gyrus, the left pontine nuclei, and the left cerebellar lobules V and VI.
There was a moderately negative correlation of activation of the inferior occipital gyrus with migraine disability (r = –0.46; P = .04). Activation within the pontine nuclei correlated positively with motion sickness scores (r = 0.32; P = .04).
In addition, among patients with migraine, activity in the cerebellar lobule VIIb and in the left middle frontal gyrus was decreased in comparison with persons without migraine. Also among patients with migraine, there was enhanced connectivity between the pontine nuclei, cerebellar areas V and VI, and the interior and superior occipital gyrus and numerous cortical areas.
Clinicians often neglect to treat dizziness and nausea in patients with migraine, said Dr. May. However, these symptoms are part of migraine, even when attacks are not occurring.
“I have learned that if we can explain such symptoms, they are better accepted,” said Dr. May. “We need more and better basic research because we need to understand before we treat.”
Toward faster, more effective treatment
Commenting on the study, Erik Viirre, MD, PhD, professor in the department of neurosciences, University of California, San Diego, said, “we can be excited and celebrate that these researchers are using these news tools to investigate the operation of the migraine brain.
“That will combine with the new therapies and the genomics to give us a powerful approach to this particular condition,” said Dr. Viirre, who was not involved with the research.
The findings provide significant detail about the interconnections between the various brain regions affected by migraine, he noted. These regions include not just the sensory centers but also areas involved in higher executive function and emotional responses.
By identifying these regions, the findings show “some of the underlying mechanisms of these clinically relevant features,” said Dr. Viirre, who is also director of UCSD’s Arthur C. Clarke Center for Human Imagination.
The investigators set up the motion simulation well and used sound fMRI methodology, he added. However, imaging studies of the brain’s response to motion pose several challenges.
“The biggest challenge in any of these circumstances is that you can’t put an actual fMRI scanner on a roller-coaster,” said Dr. Viirre. “The actual acceleration and gravitational sensations delivered by a roller-coaster and gravity, of course, do not occur when you’re lying still in an MRI scanner.” Nevertheless, the pseudoacceleration produced by a visual stimulus is a reasonable proxy.
The findings also suggest that researchers in the future could examine whether any new therapeutic interventions for migraine modulate the brain functions differently for individuals with migraine than for those without migraine, he noted.
“That’s going to lead us to a faster, more effective, more reliable suite of migraine therapies,” said Dr. Viirre.
The study also reminds clinicians to take a broader approach to patients with migraine, and it underscores the value of strategies such as self-calming techniques, which can reduce the number and intensity of headaches, he said.
“Literally demonstrating these functional differences in the migraine brain is a hugely important message of advocacy for people with migraine,” Dr. Viirre concluded.
The study was funded by the German Research Foundation. Drs. May and Viirre have reported no relevant financial relationships.
A version of this article first appeared on Medscape.com.