The Spontaneous Activity Pattern of the Middle Occipital Gyrus Predicts the Clinical Efficacy of Acupuncture Treatment for Migraine Without Aura

This study represents an important milestone in personalized medicine for migraine, being the first to use functional neuroimaging markers to predict the efficacy of acupuncture in patients with migraine without aura. The researchers conducted three interconnected studies using advanced machine learning technologies and resting-state functional magnetic resonance imaging. The study enrolled 40 patients with migraine without aura diagnosed according to rigorous international criteria and 40 matched healthy controls. Participants underwent neuroimaging before and after a 4-week period of treatment with manual acupuncture, totaling 20 sessions.

The methodology employed multivariate pattern analysis (MVPA) based on Support Vector Classification to identify distinctive brain features between patients and controls. The researchers used the z-transformed amplitude of low-frequency fluctuations (zALFF) as an indicator of spontaneous brain activity. In the first study, five brain regions were identified as significant classification features: bilateral middle occipital gyrus, right fusiform gyrus, left insula, and left superior cerebellum, achieving classification accuracy greater than 70%. The overall classifier reached an impressive accuracy of 86.25% in distinguishing between patients and healthy controls.

In the second study, using Support Vector Regression, the researchers demonstrated that activity patterns in the bilateral middle occipital gyrus could effectively predict treatment response. Specifically, the right middle occipital gyrus predicted improvement in pain intensity with R² = 0.38, while the left middle occipital gyrus predicted reduction in attack frequency with R² = 0.28. The third study revealed that after acupuncture treatment, there was a significant reduction in spontaneous activity in these predictive regions, and these changes correlated positively with clinical improvement. Clinical results showed significant improvement in pain intensity measured by the Visual Analog Scale (from 5.49 to 3.80 points), although the reduction in monthly migraine frequency did not reach statistical significance after Bonferroni correction.

The middle occipital gyrus, a central region of visual processing, proved to be fundamental both in the pathophysiology of migraine and in predicting therapeutic response. This finding is particularly relevant considering that more than 75% of patients in the study presented photophobia, suggesting a connection between hyperexcitability of the occipital cortex and clinical symptoms. The clinical implications are substantial, offering a quantitative tool for selecting patients who will benefit from acupuncture, potentially optimizing medical resources and improving outcomes. The study has some important limitations, including the absence of a sham acupuncture control group, a single-center sample, relatively small sample size, and a focus only on short- to medium-term effects.

Future research should validate these findings in independent multicenter samples and explore the prediction of long-term effects.