Effects of long-term acupuncture treatment on resting-state brain activity in migraine patients: a randomized controlled trial on active acupoints and inactive acupoints

Abstract

Background: Acupuncture has been commonly used for preventing migraine attacks and relieving pain during a migraine, although there is limited knowledge on the physiological mechanism behind this method. The objectives of this study were to compare the differences in brain activities evoked by active acupoints and inactive acupoints and to investigate the possible correlation between clinical variables and brain responses.

Methods and results: A randomized controlled trial and resting-state functional magnetic resonance imaging (fMRI) were conducted. A total of eighty migraineurs without aura were enrolled to receive either active acupoint acupuncture or inactive acupoint acupuncture treatment for 8 weeks, and twenty patients in each group were randomly selected for the fMRI scan at the end of baseline and at the end of treatment. The neuroimaging data indicated that long-term active acupoint therapy elicited a more extensive and remarkable cerebral response compared with acupuncture at inactive acupoints. Most of the regions were involved in the pain matrix, lateral pain system, medial pain system, default mode network, and cognitive components of pain processing. Correlation analysis showed that the decrease in the visual analogue scale (VAS) was significantly related to the increased average Regional homogeneity (ReHo) values in the anterior cingulate cortex in the two groups. Moreover, the decrease in the VAS was associated with increased average ReHo values in the insula which could be detected in the active acupoint group.

Conclusions: Long-term active acupoint therapy and inactive acupoint therapy have different brain activities. We postulate that acupuncture at the active acupoint might have the potential effect of regulating some disease-affected key regions and the pain circuitry for migraine, and promote establishing psychophysical pain homeostasis.

Trial registration: Chinese Clinical Trial Registry ChiCTR-TRC-13003635.

Figure 1. Locations of active acupoints and inactive acupoints.

The active acupoints were located as follows: SJ5, on the dorsal aspect of the forearm on the line connecting SJ4 and the tip of the elbow, 2 cun above the transverse crease of the wrist between the ulna and radius; GB20, in a depression between the upper portion of the sternocleidomastoid muscle and the trapezius; GB34, on the lateral aspect of the lower leg in the depression anterior and inferior to the head of the fibula; GB40, anterior and inferior to the external malleolus in a depression on the lateral side of the tendon of the extensor digitorum longus. The inactive acupoints were located as follows: SJ22, on the side of the head on the posterior border of the hairline of the temple at the level with the root of the auricle, posterior to the superficial temporal artery; PC7, in the middle of the transverse crease of the wrist between the tendons of the palmaris longus and flexor carpi radialis; GB37, on the lateral aspect of the lower leg 5 cun above the tip of the external malleolus on the anterior border of the fibula; SP3, proximal and inferior to the head of the 1st metatarsal-phalangeal joint in a depression at the junction of the red and white skin.

Figure 2. The flow chart of study.

The flow chart of this study according to the CONSORT Statement.

Figure 3. Brain activity in migraineurs without aura after different acupuncture treatment.

Long-term active acupoint therapy elicited a more extensive and remarkable cerebral response compared with acupuncture at inactive acupoints.

Figure 4. Direct comparison of the ReHo changes between the active and inactive group.

The active acupoint group showed higher ReHo in the thalamus, ACC, superior temporal gyrus, SMA and lower ReHo in the hippocampus, middle frontal gyrus, and middle temporal cortex than the inactive group (P<0.001, uncorrected).

Figure 5. Correlation coefficients of brain response and VAS score.

A. Active acupoint group; B. Inactive acupoint group. The decrease in the VAS score was significantly related to the increased average ReHo values in the ACC in the two groups (P<0.05, Bonferroni corrected). Moreover, the decrease in the VAS score was associated with increased average ReHo values in the insula (P<0.05, Bonferroni corrected) which could be detected in the active acupoint group.