Acupuncture Therapy for Insomnia: An Alternative Therapy for the Modulation of Brain Functions

Acupuncture can restore normal physiological function by regulating the viscera, improving blood circulation, harmonizing the Yin and Yang, regulating the qi, benefiting the brain, and calming the mind to aid sleep. Acupuncture, as either an alternative or complementary treatment, can improve primary insomnia (PI) and significantly improve sleep quality. Various acupuncture methods have been used, including filiform needling, electroacupuncture, auricular acupuncture, scalp acupuncture, and acupoint embedding. Acupuncture treatment for PI regulates central neurotransmitters, hypothalamus secretion, melatonin-mediated biological clock regulation, and insomnia-related hormones to improve sleep quality. The design models, intervention characteristics, and clinical outcomes of various acupuncture procedures were analyzed. The main mechanisms of effect were summarized from a neuroimaging perspective by analyzing the results of different imaging methods. Functional magnetic resonance imaging indicators of multiple brain areas responsible for psychological, cognitive, and executive control were correlated with improvements in thinking and sleep symptoms after treatment. These were associated with an increase in the low-frequency oscillation amplitude in specific brain regions, such as the superior frontal gyrus, right middle frontal gyrus, and right dorsal anterior cingulate, as well as an increase in the ratio of low-frequency amplitude in the inferior gyrus and double-border superior gyrus. In addition, the therapy has been observed to improve regional homogeneity and reduce Epworth Sleepiness Scale scores in the superior frontal gyrus, right auxiliary motor area, right dorsal anterior, and middle cingulate gyrus. Moreover, acupuncture may immediately modulate the default mode network, which could be the central mechanism underlying PI treatment. A single imaging index is insufficient to define the pathophysiological processes linking insomnia with cognitive impairment. Acupuncture is indicated for the treatment of PI.