Dynamic EEG network responses to acupuncture stimulation in patients with stroke: a neurophysiological study

Objective Acupuncture may modulate brain activity through effects on the central nervous system. This study aimed to investigate short-term changes in spontaneous EEG activity and functional connectivity during acupuncture in patients with stroke using multichannel electroencephalography (EEG). Methods Multichannel EEG recordings were collected at three stages: before acupuncture, during acupuncture, and after acupuncture. Acupuncture was applied at Jianyu, Quchi, and Waiguan. EEG activity was evaluated using power spectral density (PSD) analysis. Functional connectivity was assessed using the weighted phase lag index (wPLI). Functional brain networks were constructed for different frequency bands. Graph theory analysis was used to examine clustering coefficient and global efficiency across different network sparsities. Results Power spectral density analysis showed significant stage-related changes in delta, theta, and alpha relative power, but not in beta power. Delta relative power decreased during acupuncture and partially recovered after acupuncture, but remained comparable to the pre-acupuncture level. Theta relative power increased during acupuncture and then decreased after acupuncture, with the post-acupuncture level lower than the pre-acupuncture level. Alpha relative power increased during acupuncture and decreased after acupuncture, but remained higher than the pre-acupuncture level. Whole-brain average wPLI showed a decrease in the delta band and an increase in the alpha band during acupuncture. No significant stage-related changes were observed in the theta-band average wPLI after correction for multiple comparisons. Graph-theoretical measures, including clustering coefficient and global efficiency, did not show statistically significant stage-related changes at the selected sparsity. Conclusion Acupuncture was associated with short-term, frequency-dependent changes in spontaneous EEG activity and functional connectivity in patients with stroke. The observed changes were mainly reflected in spectral power and whole-brain average wPLI, while changes in overall network topology were not statistically supported. These findings provide preliminary neurophysiological evidence for the brain response to acupuncture stimulation.