Effect of acupuncture on brain functional networks in patients with mild cognitive impairment: an activation likelihood estimation meta-analysis

Background: Prior research has shown that acupuncture, a traditional Chinese medical therapy, may have a certain therapeutic effect in patients with mild cognitive impairment (MCI). Furthermore, some studies have explored the effects of acupuncture on the brain functional networks of MCI patients to investigate the mechanism of action. Different studies have analysed the brain regions involved in acupuncture-induced changes, but (to our knowledge) these have not been summarized by a systematic review. Methods: We searched PubMed, EMBASE, Cochrane Library, SinoMed, CNKI and other databases in Chinese and English to identify neuroimaging studies of acupuncture interventions in MCI patients. After two stages of literature screening, bias risk assessment and data extraction, brain regions with significant differences were input into GingerALE software. Based on the activation likelihood estimation algorithm, coordinate-based meta-analyses were conducted. Results: The changes in functional activation of 95 different areas in 8 trials, including 212 MCI patients, were analysed. The three most commonly used traditional acupuncture point locations in acupuncture interventions for MCI were KI3 (Taixi), LR3 (Taichong) and LI4 (Hegu). The results of the ALE data analysis showed that, after acupuncture intervention, the degree of activation in the anterior cingulate, inferior frontal gyrus, medial frontal gyrus and cerebellar tonsil of MCI patients increased significantly. Conclusions: Acupuncture intervention for MCI appears to change the plasticity of brain function and improve the cognitive function of patients. Due to the small number and low quality of the included studies, the conclusion of this meta-analysis should be treated with caution.