Objective: To explore the modulation of transcutaneous auricular vagus nerve stimulation (taVNS) on default mode network (DMN) in patients with primary insomnia (PI).
Methods: A total of 22 PI patients (one patient dropped off and two patients were excluded) were included and treated with taVNS. The bilateral auricular points of Xin (CO15) and Shen (CO10) were selected and treated with disperse-dense wave at frequency of 4 Hz/20 Hz, the intensity was based on the patient's tolerance. taVNS was given once in the morning and once in the evening for 30 minutes each time. The treatment lasted for at least 5 days a week for 4 weeks. At the same time, 16 healthy subjects matched with gender and age were recruited. The Pittsburgh sleep quality index (PSQI) score was evaluated before and after treatment in PI patients. The resting-state functional magnetic resonance imaging (rs-fMRI) data of PI patients before and after treatment and healthy subjects at baseline period were collected to observe the effect of taVNS on the functional connection (FC) between posterior cingulate cortex (PCC) and whole brain.
Results: After treatment, the total score of PSQI in PI patients was lower than that before treatment (P<0.01). Compared with healthy subjects, the FC of the left PCC was increased either with the left orbital superior frontal gyrus or with left middle frontal gyrus (P<0.001), and the FC between right PCC and left middle frontal gyrus was increased in PI patients before treatment (P<0.001). Compared before treatment, the FC between left PCC and left middle frontal gyrus was decreased (P<0.05), and the FC of the right PCC was decreased either with the right medial prefrontal cortex or with the left middle frontal gyrus in PI patients after treatment (P<0.001, P<0.01).
Conclusion: taVNS can modulate the FC between anterior and posterior DMN, and between DMN and cognitive control network of PI patients, which may be one of the brain effect mechanisms of taVNS in the treatment of PI patients.
目的：探索经皮耳穴-迷走神经电刺激（taVNS）对原发性失眠（PI）患者默认网络（DMN）的调制作用。方法：对纳入的22例（脱落1例，剔除2例）PI患者给予taVNS治疗，取双侧耳穴心、肾，予疏密波，频率4 Hz/20 Hz，强度以患者耐受为度，早晚各1次，每次持续30 min，每周至少治疗5 d，共4周。同时招募性别、年龄相匹配的健康受试者16例。评估PI患者治疗前后匹兹堡睡眠质量指数（PSQI）评分，采集PI患者治疗前后及健康受试者基线期的静息态功能磁共振成像（rs-fMRI）数据，观察taVNS对PI患者后扣带回（PCC）与全脑功能连接（FC）的影响。结果：治疗后，PI患者的PSQI总分较治疗前降低（P<0.01）。与健康受试者比较，治疗前PI患者左侧PCC与左侧眶部额上回、左侧额中回的FC值升高（P<0.001），右侧PCC与左侧额中回的FC值升高（P<0.001）。与治疗前比较，PI患者治疗后左侧PCC与左侧额中回的FC值降低（P<0.05），右侧PCC与右内侧前额叶、左侧额中回的FC值降低(P<0.001，P<0.01)。结论：taVNS可调制PI患者前后默认网络间及DMN与认知控制网络之间的功能连接而抑制大脑过度兴奋，这可能是其治疗PI的脑效应机制之一。.
Keywords: cognitive control network; default mode network; posterior cingulate cortex; primary insomnia; reward network; transcutaneous auricular vagus nerve stimulation.