Effect of acupuncture at the acupoints for Yizhi Tiaoshen on the functional connectivity between the hippocampus and the brain in the patients with Alzheimer's disease

Objectives: To analyze the effect of acupuncture at the acupoints for Yizhi Tiaoshen (benefiting the intelligence and regulating the spirit) on the functional connectivity between the hippocampus and the whole brain in the patients with Alzheimer's disease (AD), and reveal the brain function mechanism of acupuncture in treatment of AD using resting state functional magnetic resonance imaging (rs-fMRI).

Methods: Sixty patients with mild to moderate AD were randomly divided into an acupuncture + medication group (30 cases, 3 cases dropped out) and a western medication group (30 cases, 2 cases dropped out). In the western medication group, the donepezil hydrochloride tablets were administered orally, 2.5 mg to 5 mg each time, once daily; and adjusted to be 10 mg each time after 4 weeks of medication. Besides the therapy as the western medication group, in the acupuncture + medication group, acupuncture was supplemented at the acupoints for Yizhi Tiaoshen, i.e. Baihui (GV 20), Sishencong (EX-HN 1), and bilateral Shenmen (HT 7), Neiguan (PC 6), Zusanli (ST 36), Sanyinjiao (SP 6) and Xuanzhong (GB 39). The needles were retained for 30 min in one treatment, once daily; and 6 treatments were required weekly. The duration of treatment was 6 weeks in each group. The general cognitive function was assessed by the mini-mental state examination (MMSE) and Alzheimer's disease assessment scale-cognitive part (ADAS-Cog) before and after treatment in the two groups. Using the rs-fMRI, the changes in the functional connectivity (FC) of the left hippocampus and the whole brain before and after treatment were analyzed in the patients of the two groups (11 cases in the acupuncture + medication group and 12 cases in the western medication group).

Results: After treatment, compared with those before treatment, MMSE scores increased and ADAS-Cog scores decreased in the two groups (P<0.05); MMSE score was higher, while the ADAS-Cog score was lower in the acupuncture + medication group when compared with those in the western medication group (P≤0.05). After treatment, in the western medication group, FC of the left hippocampus was enhanced with the left fusiform gyrus, the inferior frontal gyrus of the left triangular region, the bilateral superior temporal gyrus and the right superior parietal gyrus (P<0.05), while FC was weakened with the left inferior temporal gyrus, the left middle frontal gyrus and the right dorsolateral superior frontal gyrus when compared with that before treatment (P<0.05). After treatment, in the acupuncture + medication group, FC of the left hippocampus was increased with the right gyrus rectus, the left inferior occipital gyrus, the right superior temporal gyrus and the left middle occipital gyrus (P<0.05), and it was declined with the left thalamus (P<0.05) when compared with those before treatment. After treatment, in the acupuncture + medication group, FC of the left hippocampus was strengthened with the bilateral inferior temporal gyrus, the bilateral middle temporal gyrus, the right gyrus rectus, the bilateral superior occipital gyrus, the left lenticular nucleus putamen, the left calcarine fissure and surrounding cortex, the inferior frontal gyrus of the left insulae operculum, the left medial superior frontal gyrus and the right posterior central gyrus (P<0.05) compared with that of the western medication group.

Conclusions: Acupuncture at the acupoints for Yizhi Tiaoshen improves the cognitive function of AD patients, and its main brain functional mechanism is related to intensifying the functional connectivity of the left hippocampus with the default network (inferior temporal gyrus, middle temporal gyrus and superior frontal gyrus, gyrus rectus), as well as with the sensory (posterior central gyrus) and visual (calcarine fissure and surrounding cortex and superior occipital gyrus) brain regions.