Real acupuncture and simulated acupuncture relieve menstrual pain through distinct brain blood-flow responses, while baseline activity in memory-related regions may predict poorer improvement.
The study enrolled women with primary menstrual pain who received either real acupuncture or simulated acupuncture over eight weeks. Researchers assessed pain, brain blood flow using imaging, and reproductive hormone levels before and after treatment, then examined whether initial brain blood-flow patterns were associated with subsequent symptom improvement.
Both real and simulated acupuncture reduced menstrual pain, but they produced different changes in brain blood flow. Real acupuncture was associated with reduced blood flow in a region involved in pain processing and emotional regulation, whereas simulated acupuncture affected prefrontal, striatal, and insular regions. Higher pre-treatment blood flow in the precuneus and hippocampus was linked to less symptom improvement, suggesting that baseline brain activity may help identify individuals less likely to respond well.
